**5. Effect of thermal annealing on metamict zircon and titanite**

Zircon has a high melting temperature (above 2700–2800 K), and crystalline ZrO2

~2670 K [66]. It is difficult to quench zircon melts without decomposition into ZrO2

treated zircon in a study with laser melting, near the boundaries between the unmolten and molten regions (where a relatively large temperature gradient could exist) [67]. The large tem‐ perature gradient is expected to increase the quench rate and facilitate a "freeze" of the local

region of 600 and 1100 cm–1 [Ref, [40], modified). This indicates the spectral dispersion related to Si‐O and Ti‐O vibrations in the two types of disordered materials. However, the two materials exhibit some local maximums with similar or close

glasses produced by quenching titanite melts (thermal glass‐1 and thermal glass‐2 are prepared by

melts) show overall spectra patterns different from those of metamict titanite, especially in the

results indicate that the metamict state is different from the glassy state obtained by quench‐ ing melts. Apparently, the processes and structural states associated with metamictization and irradiation amorphization are more complex than those in common thermal glasses. The formation of the metamict state involves not only amorphization, but also defect accumula‐ tion caused by alpha‐particle damage and further radiation or irradiation may lead to damage

So far, although the issue remains under debates, there have been substantial evidences indicating characteristic discrepancies between two types of amorphous states (metamict and glass states) [68], for example: (i) the two types of materials commonly have spectral and structural discrepancies [40, 43, 69, 70]; (ii) high‐energy heavy ion irradiation may lead to significant modifications in local structures of glasses [71–74]; (iii) upon heating, radiation‐damaged minerals tend to recrystallize epitaxially and recover to their original

may coexist for a composition of ZrSiO4

peak positions (indicated by dash lines) in the far infrared region (100 and 500 cm–1).

uid of SiO2

**Figure 4.** CaTiSiO5

quenching CaTiSiO5

112 Raman Spectroscopy and Applications

however, glass‐like zircon (ZrSiO4

configuration of the ZrSiO4

as well as recrystallization.

and a liq‐

and SiO2

;

at a temperature region of ~1960 K and

) has been recorded with Raman spectroscopy in laser‐

melts before the decomposition takes place. These experimental

Thermal annealing of metamict minerals at high temperatures is commonly used in studies of radiation‐damaged minerals [30]. Its aims are to restore the original crystal structure for the purpose of studying recrystallization temperature, activation energy, types of radiation‐ induced local defects and phase identification, and to obtain a good comprehension of the recrystallization process and mechanism. Extensive studies were carried out to investigate changes at the atomic level in metamict materials during high‐temperature annealing [10, 15, 36, 40, 44, 47, 48, 50, 52, 54, 55, 65, 75, 78–81]. However, controversies remain regarding the recrystallization path and activation energy.

Thermal annealing results in recrystallization of metamict zircon (**Figure 5**). The effect of annealing temperature on the structural recovery of damaged zircon can be clearly seen in the frequency and FWHM of the ν3 Si**‐**O stretching (B1g) as a function of temperature (**Figure 6**). With increasing annealing temperature, the frequency of this mode shows, systematically, a large increase in the region between 800 and 1050 K and a weaker increase with temperature above 1050 K. This is due to the healing of the defective lattice and the recrystallization of remaining crystalline domains. Highly damaged zircon tends to decompose into tetragonal ZrO2 and SiO2 near 1100 K, and the transformation of tetragonal ZrO2 into monoclinic ZrO2 is reported at higher temperatures [47]. The findings may explain the cause of some previously reported ZrO2 and SiO2 in natural zircon, which likely experienced natural heating processes.

Spectroscopic data [47, 48, 61] revealed different recrystallization processes between partially and heavily damaged zircons, that is, the recrystallization process depends on the cumula‐ tive radiation dose (**Figure 5**, **6a** and **6b**). Being similar to metamict zircon [47], the thermal response of the damaged titanite (CaTiSiO5 ) is affected by their initial degrees of damage, that is, at the same treatment conditions, weakly or partially damaged samples are more likely to recover to crystalline titanite as compared with highly metamict samples [40]. Intermediately and heavily damaged titanite samples show a recovery of Ti‐O and Si‐O bands after annealing at 1300–1400 K, and these recovered crystals are consistent with the *P*21 */a* symmetry, although in terms of band widths, they are far from a fully recovering [40]. Similar results were reported by the work of another group [44] who thermally treated a metamict titanite sample, which has an accumulated radiation dose of 1.2 × 1018 alpha‐event/g by multistep annealing up to 1173 K, and found it was insufficient to recover the crystalline structure of the studied sample.

**Figure 5.** Raman spectra recorded from weakly metamict (dose = 1.8 × 1018 alpha‐events g−1 ), intermediately metamict (dose = 3.5) and highly metamict zircon (dose = 13.1) thermally treated in N2 up to 1700 K and then punched (Ref. [47], modified).

The failure of a full recovery from the damage in thermally treated metamict titanite is also revealed by infrared spectroscopy [43]; however, the physics behind this remain unclear.

The thermally induced structural recovery and recrystallization of metamict zircon and titanite is also characterized a recovery of the anisotropy of the sample, which is restored Raman Study of the Crystalline-to-Amorphous State in Alpha-Decay–Damaged Materials http://dx.doi.org/10.5772/65910 115

**Figure 6.** Phonon frequency and FWHM of the Raman ν3 Si‐O stretching (B1g) in zircon (ZrSiO4 ) with different degrees of damage as a function of annealing temperature (Ref. [47], modified with unpublished data).

during annealing, as evidenced by the recovery of orientational dependence of IR (as well as Raman) spectra along with the original crystallographic orientations as shown in **Figure 7**, which indicates an epitaxial recrystallization. This behavior indicates that in highly metamict zircon and titanite, crystalline nanodomains with original crystallographic orientations might still exist.

In conclusion, Raman spectroscopy, as shown above, is a very powerful tool for study of radia‐ tion damage in actinide‐bearing phases and for estimation of their long‐term durability of their physical properties and chemical stability. This type of Raman applications can provide a better understanding of the mechanism of radiation damage and thermal recrystallization processes. It has a wide usage in condensed mater physics, material science, nuclear material sciences, mineralogist, and geochemistry. It has also been used analysis other radiation‐damaged min‐ erals, such as fergusonite [82, 83], actinide‐bearing monazite [32], titanoaeschynite (Nd) and

The failure of a full recovery from the damage in thermally treated metamict titanite is also revealed by infrared spectroscopy [43]; however, the physics behind this remain unclear.

), intermediately metamict

up to 1700 K and then punched (Ref. [47],

**Figure 5.** Raman spectra recorded from weakly metamict (dose = 1.8 × 1018 alpha‐events g−1

(dose = 3.5) and highly metamict zircon (dose = 13.1) thermally treated in N2

modified).

114 Raman Spectroscopy and Applications

The thermally induced structural recovery and recrystallization of metamict zircon and titanite is also characterized a recovery of the anisotropy of the sample, which is restored nioboaeschynite (Ce) [84], uranyl titanate mineral davidite‐(La) [85], aeschynite‐(Y) and poly‐ crase‐(Y) [86], and steenstrupine [87], and pyrochlore (Zietlow et al., personal communication).

**Figure 7.** Orientational dependence of polarized infrared spectra of radiation‐damaged zircon crystal (dose = 3.8 × 1018 alpha‐events g−1) annealed between 292 and 1700 K (Ref. [48], modified). The interval of the angle between the c‐axis and the incident radiation E is 10°. The arrows indicate the appearance of an extra signal near 790 cm−1, suggesting a possible intermediate phase. Thermal annealing results in a recovery of the anisotropy of the damage zircon crystal to its original crystallographic orientations.


**6. Others**

#### **6.1. Glucose transporters**

Glucose transporters (GLUT) are integral membrane proteins that mediate the transport of glucose and structurally-related substances across the cellular membranes [67].

Sugar transport catalyzed by 11 out of 14 members of the human GLUT family. There are specific characteristics of each isotypes. They are different in expression profile, substrate specificity and kinetic characteristics. Therefore, the tissue adaptation of the glucose uptake will be determined and regulated by specific tissue gene expression. GLUT4 malfunction in expression or regulation contributes to IR while GLU2 plays a role in hormonal and neuronal control by acting a glucose sensor in β-cells of the pancreas and neuronal cells [68]. GLUT1 is ubiquitously expressed with particularly high levels in human erythrocytes and in the endothelial cells lining the blood vessels of the brain. GLUT3 is expressed primarily in neurons and, together, GLUT1 and GLUT3 allow glucose to cross the blood-brain barrier and enter neurons [69].

The GLUTI, GLUT2, and GLUU3 are the major glucose transporters isoforms present in these cells and they are constitutively localized to the plasma membrane. The glucose flux across the membrane is largely dependent upon the circulating blood glucose level or concentration. In acute state, the glucose regulated the transport system in the muscles and fat cells responded within minutes to insulin [70].

GLUT4 is the primary hormonally-responsive transporter and it is the major insulin-respon‐ sive transporter [69]. GLUT4 expression is also reduced by low insulin states, such as in muscle during fasting, and in IR adipose tissue [71]. The malfunction of glucose transporter expression or regulation (GLUT4) appears to contribute to the IR syndrome [68].


**6. Two-dimensional difference gel electrophoresis: 2-D DIGE**

A promising alternative for circumventing possible variations in the technique already de‐ scribed (2-D PAGE) is the two-dimensional difference gel electrophoresis (2-D DIGE). This technique, which is based on fluorescent cyanine dyes, allows comparisons between two ex‐ act quantitative proteomic samples, which are resolved on the same gel, minimizing the problems previously mentioned [82]. Moreover, there is the advantage of the high sensitivi‐ ty of these dyes (*ca*. 1 fmol of protein), which enables the detection of low abundance pro‐ teins when compared to other dyes used in the detection of protein spots, such as Coomassie Brilliant Blue (CBB) and silver staining [82]. Frequently, three samples are la‐ beled in 2-D DIGE: two of them are experimental samples whereas the third one is com‐ posed of a mixture of equal amounts of all experimental samples (*i.e*., a pooled internal

standard). This creates a standard for each protein during analysis. After 2D separation, dif‐ ferent protein samples labeled can be visualized separately by exciting the different dyes at their specific excitation wavelengths. Therefore, from the images generated for each dye, the signals from labeled protein spots are determined and the normalized intensities or spot volumes for each spot from different dyes (Cy2, Cy3, Cy5) are compared in order to identify differentially expressed proteins between the samples [82-83].

Once this technique is finely developed for finding possible biomarkers, reference [79] applied the 2-D DIGE technique and mass spectrometry (ESI-QTOF MS/MS) to assess differences in proteomic profiles of transgenic and non-transgenic soybean seeds. Three biological replicates were analyzed. A regulation factor of 1.5 (50% variation) was chosen as determined by the image analysis program and statistically significant differences in expression were determined (p≤0.05, according to the Student *t* test). The program of im‐ age analysis uses the automatic detection of the spots, and does not require any manual editing, either in adding or in altering the area defining the spots, in contrast to other programs for 2-D PAGE image.

As a result, a total of four proteins were differentially expressed between transgenic and non-transgenic soybean seeds, where two were overexpressed, being more highly ex‐ pressed in transgenic soybean, and two were underexpressed, being less expressed in transgenic soybean. Thus, these four spots were selected for identification by mass spec‐ trometry. As results, the spots were identified as: Actin (fragment) (*Glycine max*), in‐ volved in various types of cell motility, widely expressed in all eukaryotic cells and binds to ATP and other proteins [84]; cytosolic glutamine synthetase (*Cucumis melo*) (Fig‐ ure 1a), considered as a ligand enzyme, being highly expressed in many types of roots, binds ATP molecules and is responsible for the primary assimilation of ammonia in all living organisms, participates in nitrogen fixation [84]; Glycinin subunit G1 (*Glycine max*), responsible for the nutritional, physicochemical, and physiological characteristics of soy‐ bean seeds [85] and Glycine-rich RNA-binding protein (*Glycine max*) (Figure 1b), in‐ volved in cellular response to environmental and developmental conditions [84]. It is noteworthy that the actin protein was also detected by Brandão et al. [66] working with 2-D PAGE and image analysis, and with the same sample.

The results obtained in reference [79], comments about some differential proteins found, es‐ tablishing a relationship between oxidative stress (ROS production) and genetic modifica‐ tion. In this way, spectrophotometric enzymatic assays demonstrate that soybean transgenic seeds (for glyphosate resistance) exhibited higher activities for APX, CAT and GR enzymes compared to non-transgenic. Considering these results, the authors concluded that the oxi‐ dative stressful condition in transgenic seeds resulted in an increase of H2O2, which is proba‐ bly controlled by the action of APX and CAT and even GR. Related to SOD, reference [79] showed the results for SOD activity in nondenaturing polyacrylamide gel electrophoresis, and it was possible to observe eight SOD isoenzymes detected in both transgenic and nontransgenic soybean seeds, one as Mn-SOD, two as Fe-SOD and five as Cu/Zn-SOD. The au‐ thors commented that the reduction in SOD activity in transgenic seeds was much more a result of a reduction in the Fe-SOD isoenzymes activities. Finally, and as a conclusion, the genetic modification itself might have induced extra ROS generation.

standard). This creates a standard for each protein during analysis. After 2D separation, dif‐ ferent protein samples labeled can be visualized separately by exciting the different dyes at their specific excitation wavelengths. Therefore, from the images generated for each dye, the signals from labeled protein spots are determined and the normalized intensities or spot volumes for each spot from different dyes (Cy2, Cy3, Cy5) are compared in order to identify

A Comprehensive Survey of International Soybean Research - Genetics, Physiology, Agronomy and Nitrogen

Once this technique is finely developed for finding possible biomarkers, reference [79] applied the 2-D DIGE technique and mass spectrometry (ESI-QTOF MS/MS) to assess differences in proteomic profiles of transgenic and non-transgenic soybean seeds. Three biological replicates were analyzed. A regulation factor of 1.5 (50% variation) was chosen as determined by the image analysis program and statistically significant differences in expression were determined (p≤0.05, according to the Student *t* test). The program of im‐ age analysis uses the automatic detection of the spots, and does not require any manual editing, either in adding or in altering the area defining the spots, in contrast to other

As a result, a total of four proteins were differentially expressed between transgenic and non-transgenic soybean seeds, where two were overexpressed, being more highly ex‐ pressed in transgenic soybean, and two were underexpressed, being less expressed in transgenic soybean. Thus, these four spots were selected for identification by mass spec‐ trometry. As results, the spots were identified as: Actin (fragment) (*Glycine max*), in‐ volved in various types of cell motility, widely expressed in all eukaryotic cells and binds to ATP and other proteins [84]; cytosolic glutamine synthetase (*Cucumis melo*) (Fig‐ ure 1a), considered as a ligand enzyme, being highly expressed in many types of roots, binds ATP molecules and is responsible for the primary assimilation of ammonia in all living organisms, participates in nitrogen fixation [84]; Glycinin subunit G1 (*Glycine max*), responsible for the nutritional, physicochemical, and physiological characteristics of soy‐ bean seeds [85] and Glycine-rich RNA-binding protein (*Glycine max*) (Figure 1b), in‐ volved in cellular response to environmental and developmental conditions [84]. It is noteworthy that the actin protein was also detected by Brandão et al. [66] working with

The results obtained in reference [79], comments about some differential proteins found, es‐ tablishing a relationship between oxidative stress (ROS production) and genetic modifica‐ tion. In this way, spectrophotometric enzymatic assays demonstrate that soybean transgenic seeds (for glyphosate resistance) exhibited higher activities for APX, CAT and GR enzymes compared to non-transgenic. Considering these results, the authors concluded that the oxi‐ dative stressful condition in transgenic seeds resulted in an increase of H2O2, which is proba‐ bly controlled by the action of APX and CAT and even GR. Related to SOD, reference [79] showed the results for SOD activity in nondenaturing polyacrylamide gel electrophoresis, and it was possible to observe eight SOD isoenzymes detected in both transgenic and nontransgenic soybean seeds, one as Mn-SOD, two as Fe-SOD and five as Cu/Zn-SOD. The au‐ thors commented that the reduction in SOD activity in transgenic seeds was much more a

differentially expressed proteins between the samples [82-83].

2-D PAGE and image analysis, and with the same sample.

programs for 2-D PAGE image.

Relationships

594

Proteins involved in the RNA processing and alternative splicing, RNA transport, messen‐ ger RNA (mRNA) translation, mRNA stability, and mRNA silencing mechanisms have been shown to be required for normal plant development and the responses of plants to altered environments [86-87]. In our case, just the glycine-rich RNA-binding protein was differen‐ tially found after DIGE analysis, and this protein correlated to ROS production according to different articles [88, 89]. As already mentioned, the cytosolic glutamine synthetase is in‐ volved in nitrogen fixation. Oxidative stress can also control the expression of nitrogen-me‐ tabolism genes as recently demonstrated [90], demonstrating that cytosolic glutamine synthetase can be altered because of the oxidative stress observed in the transgenic soybean line [90].

**Figure 1.** Examples of spots with expression variation among samples of transgenic (T) and non-transgenic (NT) soy‐ bean seeds: a - cytosolic glutamine synthetase (*Cucumis melo*) and b - Glycine-rich RNA-binding protein (*Glycine max*) [modified from reference 79].


**Abstract**

Neuromorphic computing, a bio-inspired computing architecture that transfers neuroscience to silicon chip, has potential to achieve the same level of computation and energy efficiency as mammalian brains. Meanwhile, threedimensional (3D) integrated circuit (IC) design with non-volatile memory crossbar array uniquely unveils its intrinsic vector-matrix computation with parallel computing capability in neuromorphic computing designs. In this chapter, the state-of-the-art research trend on electronic circuit designs of neuromorphic computing will be introduced. Furthermore, a practical bio-inspired spiking neural network with delay-feedback topology will be discussed. In the endeavor to imitate how human beings process information, our fabricated spiking neural network chip has capability to process analog signal directly, resulting in high energy efficiency with small hardware implementation cost. Mimicking the neurological structure of mammalian brains, the potential of 3D-IC implementation technique with memristive synapses is investigated. Finally, applications on the chaotic time series prediction and the video frame recognition will be demonstrated.

**Keywords:** analog signal processors, lab on a chip, neuromorphic computing, reservoir computing, analog/mixed-signal circuit design, three-dimensional integrated circuit, image classification


**2. Materials and Methods**

In this section, the various materials and methods used for the conduction of this work will be presented, starting with the presentation of the machining tools and workpiece material. The adopted methods regarding sample preparation and analyses will also be presented.


**2. Biomass characteristics and general conversion**

is stored in the organic form in the chemical state and supports human beings' daily life since our ancestor apes knew how to use fire to cook. In these millions of years, bioenergy was mostly used in small scale like household cooking. Now, people have realized that efficient exploitation of biomass resource can actually reduce their dependency over fossil fuel. Biomass gasification has been regarded as an effective pathway to utilization of bioresource. It takes biomass as raw materials and employs pyrolysis or thermal cracking under anoxic conditions. This is an energy conversion process including a group of complex chemical reactions that large organic molecules degrade into carbon monoxide, methane and hydrogen and other flammable gases in accordance with chemical bonding theory. Biomass feedstock with the gasification agent is heated inside an integrated gasifier. With temperature increase, biomass goes through dehydration, volatilization and decomposition. Eventually, the produced gases are used for central gas supply and power generation. This technology has already been developed over several decades and progressively achieved commercialization all over the world, especially in Sweden, Germany, Canada, the United States, India and China. In the early stage, downdraft gasifier had been implemented at a large scale in China and India due to its relatively low tar production. Recently, the development of circulating fluidized bed (CFB) gasifier makes it adaptable for both biomass quality and the raw particle size. Besides,

China, as a large agricultural country, produces a large number of crop straw, poultry manure, agricultural by-products and other plant biomass every year. Thus, research and development on key technologies and integrated peripherals of biomass gasification become very necessary. China has already developed various gasifiers, the size of which range from 400 KW to 10 MW. However, compared with fossil fuel, biomass has lower bulk density and energy density, which make it uneconomic for collection and transportation. Therefore, biomass gasification coupled with distributed power generation in small communities with abundant biomass

In recent years in China, the yield of domestic waste has increased every year and exceeds 400 million tonnes per year. Chinese government's 13th five-year plan proposed that the proportion of waste harmless treatment should be no less than 70% by 2020. But waste landfill is still the primary method used to deal with waste in rural areas. Compared with landfill, gasification has advantages of lower environmental impacts and does not consume land resource. When contrasting gasification with incineration, the gasification technology has better quality of gaseous emissions with much lower capital input, which makes gasification more suitable for distributed deployment in rural area. Therefore, there will be a great demand for deployment of waste gasification treatment plants in Chinese rural areas, and more and more people are now focusing on the development of more efficient small-scale gasifiers with capacity under 300 tonne/day. The relevant equipment has also been deployed in Iran, Thailand, Burma and Laos. However, several technical barriers are still there such as effective removal of tar with low cost, environmental influence, accuracy control of gasifier

Therefore, this chapter introduces both technological and logistics challenges of biomass gasification via introducing biomass characters and gasifier technologies. The details of tar minimization and socio-environmental impacts of biomass gasification are also presented as main contents to help understand the primary barriers for the deployment of biomass gasification.

CFB is also easy for scale-up and ash cleaning.

4 Gasification for Low-grade Feedstock

resource would be the way out in future [1].

inner temperature, solidification of fly ash and so on.

#### **2.1. Composition of biomass and its common characteristics**

Biomass includes all the living or recently living organisms, like land plants, grasses, waterbased vegetation and manures [2], and these organisms consist of a number of major elements such as C, H, O, N, P and S. The classification of biomass into different categories is based on their properties. One feasible way is based on the appearances and the growth environment of biomass: woody plants, herbaceous plants/grasses, aquatic plants, manures and wastes [2]. Biomass could also be divided into two types: low moisture content and high moisture content. The low moisture content biomass can be used in thermo-chemical processes (i.e., gasification, combustion and pyrolysis), while the high moisture content plants are more suitable to be used in some wet processing technologies (i.e., fermentation and anaerobic digestion) [3]. Such high moisture contents would consume a large amount of energy for the drying process if employed as resources for thermo-chemical processing.

Biomass is derived from solar energy via photosynthesis. Under a good illumination condition, carbon dioxide in the atmosphere can be converted into organic materials or, in another way, the solar energy is stored as chemical energy, which existed as chemical bonds in the organisms [4]. The said chemical energy is released when these bonds are broken either via thermo-chemical or wet processing. This is an ongoing energy transfer from the sun and hence the sustainability of biomass resource could be ensured. As we have known, the total energy captured annually in biomass is more than that of the annual energy consumption globally [5]. On the other hand, biomass is clean as it is carbon neutral. On the view of carbon network, the net emission of carbon dioxide into the environment during the harvesting of energy from biomass is zero. The final products of conversion of biomass (CO2 and H2 O) are originally absorbed into the plants from the atmosphere during photosynthesis. The conversion of biomass also has less harmful releases such as NOx and SOx compared with fossil fuels [6].

However, the characters of biomass also create many barriers during its actual application. On the aspect of species diversity, biomass usually does not behave as steady as fossil fuels, which causes a lot of difficulty during project planning stage including gasifier type, plant size and the way of energy output. On the other hand, the varieties of biomass resource also lead to different heating values and moisture contents. Compared with other energy carriers, biomass has much lower heating values. Taking wood and wheat straw as examples, their lower heating values are only 18.6 and 17.3 MJ/kg, respectively, while the lower heating value of coal is as high as 23–28 MJ/kg [2, 7]. The reason for this disparity is that the oxygen content of biomass carbohydrates is very high while the combustible elements such as C and H are low. In addition, the intrinsic moisture content in biomass is also very high, which requires more energy for drying before further processes take place [3]. Hence, use of biomass requires the complexity in material handling, pre-treatment and the design of processing facilities [3]. For the purpose of transportation and collection, biomass is unlike any other renewable resources (solar, wind, hydropower) where it is able to be stored directly and transported somewhere else. However, biomass is highly dispersed in regional distribution and the low volumetric of biomass makes it a bit more difficult for the collection and transportation. Therefore, smallscale gasification unit operated in small communities with abundant biomass resource or domestic waste would be the way out in future.

#### **2.2. General conversion technologies of biomass except gasification**

For the utilization purpose, the conversion technologies of biomass could be classified in three categories: mechanical extraction; thermo-chemical conversion; and biological conversion, as illustrated in **Figure 1** [3, 8]. Among them, direct combustion, gasification and pyrolysis are considered as the thermo-chemical processes; fermentation and anaerobic digestion are regarded as biological conversion.

(up to 35 wt% yield), while high temperatures (700–1100° C) and short reaction time favor the production of gases (up to 80 wt% yield) [11]. Bio-oil production is normally favored at 500° C,

Biomass Gasification: An Overview of Technological Barriers and Socio-Environmental Impact

http://dx.doi.org/10.5772/intechopen.74191

7

Fermentation is a bio-chemical process which is used for the production of about 80% of the world's ethanol [13]. The main process of fermentation involves using microorganisms to convert sugars into ethanol under a warm and wet environment. The sugar is typically obtained from the mechanical handling (crushing and mixing with water) of sugar-rich crops, such as sugar cane and sugar beet. However, the high cost of sugar-rich crops has diminished its proportion of utilization in fermentation. The starch-based biomass is also commonly used for ethanol production. However, it requires an extra step to convert starch

Anaerobic digestion involves using anaerobic microorganisms to convert biomass into bio-

anaerobic environment, the organic material in biomass is decomposed into usable-sized molecules, such as sugar, as the first step. The sugar molecules is then converted into organic

Gasification process converts biomass, a low-energy density material, into a gaseous product

tial oxidation process and it is commonly operated at 800–900° C for biomass gasification [2]. In some cases, steam is also used as the gasification agents. The gaseous products from the gasifier can be utilized in gas engines or gas turbines for the generation of electricity. In terms of economics, it has also been proven that the performance of a biomass gasification plant with a combined cycle gas turbine (CCGT) is comparable to that of a conventional coal power

The gasifier, as the principle component of a gasification plant, actually provides a space for biomass and gasification agent being mixed to a certain extent, in some cases with catalysts or additives [14]. The different selection of gasifiers is actually responsible for keeping steady the production of syngas regarding the variations of biomass. Literature shows that gasifiers could be categorized into three main types: fixed bed gasifiers, fluidized gasifiers and the

feasible technology and is widely applied in the rural areas of China.

), which is a mixture of CO, H2

as the main gaseous products) by means of decomposition. Under the

, CH4

and CO2

[10]. Gasification is a par-

gas. This process has been proven as a commercially

with very short retention time (<1 s) [12].

into sugar by enzymatic reactions.

acids and further decomposed to CH4

**3. Technologies of biomass gasification**

*2.2.4. Anaerobic digestion*

(LHV at 4–11 MJ/N/m3

plant [7], if not better.

**3.1. Types of gasifiers**

entrained flow gasifiers [15].

and CO2

gas (CH4

*2.2.3. Fermentation*

#### *2.2.1. Direct combustion*

The direct combustion of biomass is widely applied in small-scale cooking and domestic heating by converting chemical energy stored in biomass into heat [9]. In modern industrial technology, combustion is also employed in large-scale applications to produce mechanical power and electricity with the aid of boilers, steam turbines and turbo-generators. The temperature range of biomass combustion is within 800–1000 ° C. Materials with the moisture content higher than 50 wt% are not suitable for combustion processes [3]. The net efficiency of electricity generation from biomass combustion varies between 20 and 40% [8]. The efficiency could be improved either by scaling up the system to over 100 MWe or co-firing with coal (<10 wt% by weight) [10].

#### *2.2.2. Pyrolysis*

Pyrolysis is a thermo-chemical process, in which biomass decomposes into fuel gas, bio-oil and solid char in the absence of oxygen. The selectivity leading to different types of products could be controlled by manipulating the operating conditions (temperature and residence time). Low temperatures (<500° C) and long residence time favor the production of solid char

**Figure 1.** The main processes for the biomass conversion technologies [3].

(up to 35 wt% yield), while high temperatures (700–1100° C) and short reaction time favor the production of gases (up to 80 wt% yield) [11]. Bio-oil production is normally favored at 500° C, with very short retention time (<1 s) [12].

#### *2.2.3. Fermentation*

**2.2. General conversion technologies of biomass except gasification**

regarded as biological conversion.

*2.2.1. Direct combustion*

6 Gasification for Low-grade Feedstock

(<10 wt% by weight) [10].

*2.2.2. Pyrolysis*

For the utilization purpose, the conversion technologies of biomass could be classified in three categories: mechanical extraction; thermo-chemical conversion; and biological conversion, as illustrated in **Figure 1** [3, 8]. Among them, direct combustion, gasification and pyrolysis are considered as the thermo-chemical processes; fermentation and anaerobic digestion are

The direct combustion of biomass is widely applied in small-scale cooking and domestic heating by converting chemical energy stored in biomass into heat [9]. In modern industrial technology, combustion is also employed in large-scale applications to produce mechanical power and electricity with the aid of boilers, steam turbines and turbo-generators. The temperature range of biomass combustion is within 800–1000 ° C. Materials with the moisture content higher than 50 wt% are not suitable for combustion processes [3]. The net efficiency of electricity generation from biomass combustion varies between 20 and 40% [8]. The efficiency could be improved either by scaling up the system to over 100 MWe or co-firing with coal

Pyrolysis is a thermo-chemical process, in which biomass decomposes into fuel gas, bio-oil and solid char in the absence of oxygen. The selectivity leading to different types of products could be controlled by manipulating the operating conditions (temperature and residence time). Low temperatures (<500° C) and long residence time favor the production of solid char

**Figure 1.** The main processes for the biomass conversion technologies [3].

Fermentation is a bio-chemical process which is used for the production of about 80% of the world's ethanol [13]. The main process of fermentation involves using microorganisms to convert sugars into ethanol under a warm and wet environment. The sugar is typically obtained from the mechanical handling (crushing and mixing with water) of sugar-rich crops, such as sugar cane and sugar beet. However, the high cost of sugar-rich crops has diminished its proportion of utilization in fermentation. The starch-based biomass is also commonly used for ethanol production. However, it requires an extra step to convert starch into sugar by enzymatic reactions.

#### *2.2.4. Anaerobic digestion*

Anaerobic digestion involves using anaerobic microorganisms to convert biomass into biogas (CH4 and CO2 as the main gaseous products) by means of decomposition. Under the anaerobic environment, the organic material in biomass is decomposed into usable-sized molecules, such as sugar, as the first step. The sugar molecules is then converted into organic acids and further decomposed to CH4 gas. This process has been proven as a commercially feasible technology and is widely applied in the rural areas of China.


**A Nation-Wide Framework for Evaluating Freshwater Health in China: Background, Administration, and Indicators**

#### **Chen Xie 1 , Yifan Yang 2, \* , Yang Liu 1 , Guoqing Liu 1 , Ziwu Fan 1 and Yun Li 1**

Received: 31 August 2020; Accepted: 15 September 2020; Published: 17 September 2020

**Abstract:** This study reviewed the existing experience of implementing the nation-wide freshwater health evaluation in China and around the world and proposes a new framework that works in collaboration with the River Chief System (RCS). The institutional context of China with intertwined political and scientific considerations makes it essential to establish a concise and quantitative approach to assess the effectiveness of the RCS as well as local freshwater health conditions that can be easily understood by non-experts for decision-making. To fulfil this objective, we reconstructed the indicator categories based on the best practices in major western countries and the existing regional standards in China. The new indicator framework includes two main aspects: Ecosystem integrity (physical habitat, water quantity, water quality, and aquatic life) and non-ecological performance (social services and water governance). Specifically, the non-ecological attributes of freshwaters are in accordance with the purposes of the RCS and are usually ignored in many countries. The final health grade for a specific water body is determined by a weighted averaging method; this grade is the core element of an evaluation protocol designed to produce reliable data for adaptable water resources governance in China. The research findings in this study will also be integrated into the new national standard to be issued by the Ministry of Water Resources of China in late 2020.

**Keywords:** freshwater health; river chief system; ecological integrity; social services; water governance; national standard

#### **1. Introduction**

There has been a longstanding recognition of the need for maintaining and improving the status of freshwater ecosystems across the world. Freshwater resources, mainly consisting of rivers and lakes, are closely related to not only the natural environment but also the human society as well as how human beings are engaged with the environment. The United Nations' Sustainable Development Goal 6 (SDG6), 'Clean Water and Sanitation' [1] sets goals of ensuring global water access and safety by 2030 by investing in adequate infrastructure and protecting and restoring water-related ecosystems. SDG 6 recognizes that water has multiple values and that they are all related, i.e., the success in one may depend on another. For example, a healthy freshwater ecosystem entails not only good water quality (less pollution) and low water stress (reasonable consumption), but also the improved water governance. This worldwide consensus was reached after decades of exploration and efforts made by many countries to find a well-balanced combination of 'led-by-science' and 'led-by-administration', while this exploration still continues.

The well-known Clean Water Act of 1977 was enacted in response to the dramatic pollution in the 1970s in the USA and is the world's first comprehensive and systematic environmental law for managing freshwater health [2]. Since the 1990s, researchers have contributed to developing advanced freshwater health frameworks beyond the original non-modern working modes; and the governments of many countries are working with scientists and the public to explore innovative approaches. For example, the European Water Framework Directive 2000 (WFD) was a valuable attempt to establishing a large transboundary cooperation framework, although the outcomes are not satisfactory in some aspects due to the unrealistic timeframe and the lack of functional indicators [3,4]. The flawed performance of the WFD also highlights the importance of a system with consistent administrative supervisions and enforcements; for example, the United Kingdom, even Scotland itself, have their own detailed assessment approaches [5–7]. In New Zealand and Australia, officials and scientists have also been aware of the urgency and made remedial efforts to upgrade the existing protocols [8,9].

Understanding the meaning of river (lake) health is another obstacle for countries with goals of sustainable development. Many researchers have been describing and debating the concept of river (lake) health since the 1990s [10–14]. As usefully defined by Meyer [15], a healthy water body can keep its ecological functions while maintaining the needs of the society. The models proposed by Boulton and Lackey [12,16] provided an important point of view that the human use of rivers does not automatically mean that the ecosystem health is being degraded. A healthy river (or lake) should contain both ecological values (ecological integrity and resilience to stress) and human values (social services and benefits). Therefore, ecological integrity is one part of a healthy ecosystem but not the only part; the lack of human values might also be detrimental. Usually, ecological integrity includes the physical, chemical, and biological components [17] and has long been treated as the major (sometimes the only) aspect of freshwater assessments. Obviously, incorporating social indicators is of significance, as detailed by Hanna et al. [18].

In the past decades, the health status of rivers and lakes in China has undergone significant deteriorations due to urban development and theincreasingwater use. Severe outcomes, e.g.,water pollution, hydrologic mutation, the damaged physical structures, and the degenerated ecological diversity and functions, have attracted wide attention from governments and researchers. For example, in the 2000s, the water pollution in Guangdong Province, one of the most prosperous region in China, significantly affected the sustainability of the regional social economy while was rarely contained by local officials [19]. The outbreak of blue-green algae in Wuxi, Jiangsu Province, in 2007 eventually pushed the central government of China to establish a nation-wide system to contain pollution with a consistent protocol [20]. This is the origin of the River Chief System (RCS) known by the public nowadays. Since 2016, China has been fully implementing the RCS to build an efficient and productive framework that involves not only administrative innovations but also refined scientific guidelines to ensure the adequacy of specific evaluations. The principle of the RCS is using a hierarchical administrative structure with well-defined responsibilities and accountabilities to avoid the inaction of officials at different levels. Therefore, evaluating and improving freshwater health in China has become an issue with intertwined political and scientific drivers that make the original working models much less effective than expected. At the moment, China is still lacking a comprehensive evaluation framework due to the vast regional differences and the insufficient administrative experience of managing the massive RCS system. This study is conducted based on the request of the Department of River and Lake Management of the Ministry of Water Resources of China in 2019. As stated, it is essential to clarify the meaning and criteria of river/lake health and propose a systematic approach that fits for the characteristics of the RCS to improve the freshwater health in China.

The objectives of this paper include: (1) Reviewing the relevant research on the RCS comprehensively and providing a clear picture of its working mechanism; (2) comparing the best practices in China and the rest of the world to highlight the key aspects that are ignored and the lessons learnt; (3) analyzing the existing freshwater health indicators adopted by researchers and practitioners to help understand their strengths and weaknesses; and (4) proposing a new evaluation framework for the future implementation

within the framework of the RCS in China. The achievement made in this study will be integrated into the new national standard to be issued by the Ministry of Water Resources of China. The specific methods for field sampling and data collection, aggregation, harmonization, and integration are beyond the scope of this paper.

#### **2. Methodology**

The literature review in this study is mainly focused on two aspects: The research on the RCS in China, and the research and application of freshwater health indicators both in China and around the world. Regarding the RCS, only published materials in English are reviewed in this paper to reach a wider audience. Nevertheless, a large number of scholars in China have made significant contributions by publishing articles in Chinese, which are recommended to be read extensively, if possible, for a better understanding of the development of the RCS. Regarding freshwater health indicators, the authors have collected most of the systematic and well-structured regional standards/guidelines in China, which are either formal documents or unpublished drafts, by extensive data search and enquiry. Data sources without a clearly defined indicator framework are not included. International frameworks reviewed in this paper are restricted to those that have significant influence across the world and have been well studied and improved. Therefore, the selected frameworks include the European WFD and those applied in major English speaking countries, including the USA, the UK, Australia, New Zealand, and Canada. The practices of other countries or regions are also reviewed but not included. The indicators used by the reviewed materials are further summarized and analyzed later in this paper to produce a new evaluation framework. In regard to data integration, similar categories, sub-categories, or individual indicators that have different names are compared carefully in terms of their definitions, and only the most widely adopted names are kept to avoid confusing readers. For example, the term 'physical habitats' is used to replace all the similar terms like 'forms' or 'physical environments'; nitrogen-related indicators, e.g., total nitrogen and dissolved nitrogen, are all replaced by the generic term 'nitrogen'.

The methodology of this paper is also subjected to limitations. The detailed approaches to determine the characteristic value of each indicator are not addressed so that this paper intends to provide an overview of freshwater health evaluation instead of technical instructions. Furthermore, the practical experience gained in the developed world, as well as the working model of the RCS, might not be suitable for less developed countries or regions, as the tradition and awareness of preserving water resources differ, and their needs for boosting economy are much more urgent. We argue that protecting water resources and ecosystems does not automatically entail the sacrifice of economic development, and it is also inequal to enforce the same level of restrictions to countries of different levels of prosperity. More efforts should be made to facilitate the coordination of global sustainable development under the framework of the UN's SDG6.

#### **3. River Chief System (RCS) in China**

#### *3.1. Recent Literature in English*

The implementation of River Chief System has facilitated the effective integrated freshwater management and water protection campaigns in China in the last decade and also attracted extensive research interests both domestically and internationally. Dai [21] introduced the history of the River Chief System and provided a perspective to the water governance in China as well as what role formal laws have played during the transition to the RCS. Huang and Xu [22] argued that the public participation of RCS mainly depends on local government, which, although ensures effective integration of resources, might impede the real public participation and supervision due to the political complexity of water governance in China. Wang et al. [23] stated that, although RCS can improve the work efficiency of water governance in the short-term, more efforts are still needed to the problems of organizational logic and the responsibility dilemma that remain due to the persistence of vertical coordination of the

hierarchical system. Liu and Richards [20] summarized the structure of the RCS and the progress of implementation and identified future challenges. Similar to Wang et al. [23], Liu and Richards [20] also pointed out the flaw of the existing RCS regarding trans-regional collaboration and accountability. Liu et al. [24] presented a case study of Foshan in Fujian Province and showed that the RCS could establish a considerably sophisticated and effective management structure. More recently, Wang and Chen [25] argued that the institutional context and motivations are the external conditions influencing the collaborative governance regime and thus the outcomes of the RCS. In general, numerous studies in recent years have noticed and identified the internal flaws of the existing RCS that may influence its sustainability and efficacy in the long-term. Compared with the water governance policies in many other western countries (e.g., USA, UK, Australia, and New Zealand), the political and administrative complexity of China makes it necessary to come up with a more structured and practical approach to management the River/Lake Chiefs at different levels and assess their performances.

#### *3.2. Policy*

As summarized by Wang and Chen [25] the institutional context of China contains three major elements: The centralized political authority [26], the party-state hierarchy [27,28], and the cadre responsibility system [29]. This context enables the central government of China to play the role of 'policy issuer' while maintaining sufficient authority of enforcement at different administrative levels through a top-down performance assessment structure. Since the full implementation of the RCS in 2016, the central government (mainly the Ministry of Water Resources) has issued multiple instructive documents in regard of the responsibility, accountability, major problems to be addressed, and the principle of assessing the performance of Chiefs [30–32]. Meanwhile, the local governments (mainly in provincial level) are responsible for making their own regulations under the prescribed framework due to the absence of national legislation for the RCS. In contrast, many western countries tend to leave water resources management relying on a relatively flat structure by establishing managerial agencies at the level of individual river basins, which is partly due to the lack of central authority. For example, the European WFD provides motivations to initiate waterways monitoring programs as well as directions for its EU member states on data processing and reporting so that their results will be comparable. However, the duties of managing specific river basins, e.g., Rhine River Basin, still belongs to relatively independent organizations like The International Commission for the Protection of the Rhine against Pollution (ICPR), which is co-chaired by ministers from stakeholder countries. This working model is more about cross-border collaboration and coordination and is obviously not suitable for China that needs a well-defined procedure for top-down supervision.

#### *3.3. Assessing the Performance of Chiefs*

By the end of 2018, RCS had been established and fully implemented in all the 31 provinces and regions in China with over 300,000 River (Lake) Chiefs being appointed at provincial, municipal, county, and township levels. Thus, as mentioned above, it is necessary to build a comprehensive and effective approach to assess the performance of those River (Lake) Chiefs, and this approach is much different to the assessment of freshwater health itself that is mainly determined by scientific criteria. More considerations are raised due to the political and administrative complexity of the RCS. The transition from 'rule by men' to 'rule by law' [25] entails not only assessing to what extent the RCS has been established and supervised by the heads in different administrative levels, but also how intertwined scientific and political requirements are satisfied during this implementation process. Therefore, a practical and straightforward assessment approach was urgently needed and have been proposed accordingly based on the existing outlines [33], as summarized in Table 1. This approach was officially released in 2019, and, together with the freshwater health scoring approach to be discussed later in this paper, comply well with the principle of using quantifiable measures for assessments. We also believe this approach can be well applied in other countries after adaption.

**Table 1.**The approach to assessing the implementation of the River Chief System (RCS) with detailed scoring criteria.

(32 points)

> 16.

> 17.

Integrated

Public satisfaction

 management

 of ecosystem (5/32)

 (5/32)

•

•

• Integrated

Public satisfaction >90% (5/5); >80% (4/5); >70% (3/5); >60% (2/5); >50% (1/5); <50% (0/5).

Contamination

 ecosystem remediation

> management

 works are implemented

> rural waterway and waste, and livestock breeding. (3/5)

 of aquaculture,  at the provincial level. (2/5)

**Table 1.** *Cont.*

#### **4. Integrated Indicator Framework**

Evaluating the health status of freshwater also heavily relies on the establishment of a practical and comprehensive scientific framework based on the best practices around the world. In this study, we aim to investigate how ecological and non-ecological indicators are adopted and incorporated in different regions of China and other major western countries with substantial experience. A comprehensive data and literature research are therefore conducted and will be presented in detail in this section.

#### *4.1. Data Sources*

Although the River Chief System has already been established across the country, the lack of a nation-wide operational standard forced the local government to resort to their existing experience or routines for implementing assessments; those routines usually show enormous inconsistency and even contradiction sometimes. Currently, only a few standards have been issued officially in provincial or municipal levels, while some other regions still rely on "drafts", "trial documents", or informal manuals that are subjected to many limitations. Table 2 summarized the existing regional standards, guidelines, and specifications being used in China [34–48]. Furthermore, we also reviewed the frameworks implemented in some major western countries for comparative analysis, such frameworks including the United States (National Aquatic Resources Surveys (NARS)) [49–51], New Zealand (Cawthron's Freshwater biophysical ecosystem Health Framework) [9], Australia (Integrated Ecosystem Condition Assessment) [8], and the United Kingdom (Common Standards Monitoring Guidance for Rivers/Lakes) [5,6]. Some other national or regional frameworks known by the public (e.g., Canadian Aquatic Biomonitoring Network (CABIN), the Murray-Darling Basin Sustainable Rivers Audit of Australia, and the National Environmental Monitoring and Reporting of New Zealand) are also reviewed but are not included in this section as they only focus on limited aspects of freshwater health or are relatively outdated and have been superseded in their own countries. More details can be found in [52–55] regarding those frameworks. It should also be noted that although the European Water Framework Directive (WFD) streamlines the legislation across Europe and provides guidance to member states on what component indicators are necessary (i.e., biological quality, hydro-morphology, and physicochemical attributes), the implementation is still inconsistent and varies widely from country to country. Therefore, in this study, we only selected the UK guidelines as representatives as they have been widely accepted and well examined. The overseas frameworks included in Table 2 are the best practices in the corresponding countries and have been well revised and modified for better effectiveness.

#### **Table 2.** *Cont.*

#### *4.2. Key Components of an Evaluation Framework*

After reviewing the documents listed in Table 2, we summarized the core components of a freshwater health framework, as shown in Table 3. The definition of a healthy freshwater ecosystem in New Zealand is stated by the National Policy Statement for Freshwater Management (NPS-FM) [56] as that reflects the importance of physical and chemical as well as biological elements of ecosystems. In the United States, NARS divides the basic indicators into four categories: Biological, physical, chemical, and recreational; the last category is a measurement of the pathogen and pollutant substances that can threaten people's wellbeing during recreational activities. The UK and Australian guidelines [5–8] further introduced more indicators in regard to social services; the former concerns more about the direct disturbance to human beings while the latter about the social functions and values provided. In general, biophysical ecosystem health can be represented by a measure of 'ecological integrity' [9], but it is only one part of an assessment of the ability of a freshwater ecosystem to support multiple freshwaters values. Even for ecological integrity itself, a well-balanced assessment cannot be achieved by a single biophysical measure because an ecosystem is a complex network of interacting biological communities and their physical environment. Therefore, the core components of a freshwater health framework should include the following sectors: Aquatic life (fauna, flora and microbes), water quality (physio-chemical features and pathogens), water quantity (hydrology), physical habitat (forms), ecological processes, and, as mentioned above, social services and values. Specifically, "ecological processes" are the interactions among aquatic lives and their environment and can be represented by a series of individual indicators in other categories to suggest the status of dynamic biochemical processes [57,58]. The assessment of ecological processes entails advanced knowledge and experience and may be relatively more difficult than other categories.

It should also be noted that, as discussed previously, the unique administrative hierarchy in China make freshwater health a political mission that is directly related to the performance of local officials. Therefore, water governance indicators should also be included in this framework with quantifiable items and practical calculation methods.

**Table 3.** Indicator categories of a freshwater evaluation framework and definitions.

#### *4.3. Comparison*

Table 4 shows the detailed comparison of indicators used by the standards and guidelines summarized in Table 2. The following issues should be noted:

By comparison, we find that 11 indicators are mentioned over 10 times, including riparian vegetation coverage, dissolved oxygen, eco-water (environmental flow), water mobility and connectivity, riparian naturalness, macroinvertebrate, phosphorous, ammonia or nitrate, heavy metals, flood protection, and zoning indicators. The most significant distinction between Chinese standards and overseas frameworks will be further discussed in the following section.

#### *4.4. Indicators Highlighted*

Based on the comparison of detailed indicators shown in Table 4, the major difference between those widely usedin China andinmajor western countries aremainly non-ecologicalindicators, e.g., social services and water governance indicators. This difference is attributed to the different social cultures and administrative structures between China and western countries. The adoptions of ecosystem-related indicators are generally similar and consistent, as mentioned in the last section. This section discusses the details of those discrepancies as well as how those indicators are adapted in China.

#### 4.4.1. Indicators of Social Services and Values

Current frameworks used by major countries across the world have paid much attention to ecological values when evaluating the health status of rivers, lakes, and wetlands. In contrast, very few countries have made attempts to include human values. The Australian Integrated Ecosystem Condition Assessment (IECA) [8] recommends to include cultural, regulating, and provisioning services in the evaluation process but does not provide detailed indicator sets. The National Aquatic Resource Survey (NARS) of the United States [49–51] uses four indicators (Algal toxins, Cyanobacteria, Enterococci, and fish tissue contaminants) to assess the status of recreational functions, but does not pay much attention to the broader concepts of human values. In general, although a few studies have emphasized the importance of social services, more works are still needed to convert the existing research accomplishments of scientists to guide the actions of governments and authorities.

The first systematic attempt to define human services was made by the Millennium Ecosystem Assessment [59]. In this report, ecosystem services are divided into four categories, including cultural ecosystem services, provisioning ecosystem services, regulating ecosystem services, and supporting ecosystem services; the first three categories resemble those prescribed by the Australian IECA guideline. Specifically, cultural ecosystem services include non-material benefits such as recreational activities (e.g., swimming), the aesthetic beauty of rivers, and their spiritual significance among many communities. Provisioning ecosystem services include the products obtained, e.g., drinking water supply, fish, etc. Regulating ecosystem services include the benefits obtained from the regulation such as erosion prevention, pollution reduction, and flood protection. Furthermore, supporting ecosystem services include processes that help the production of other services, such as nutrient cycling and habitat provision, which are closely related to specific water quality indicators. As a recent and representative study, Hanna et al. [18] systematically reviewed 89 relevant studies and summarized the human services provided by rivers. It is found that the most studied and discussed social services are recreation and tourism and water supply that can provide visible monetary benefit. Regarding the categories, provisioning and regulating indicators have been much more studied than the other two categories (cultural and supporting). However, in China, more attention has been paid to flood protection engineering and public satisfaction as those measures can be more easily quantified and related to the performance of officials. Therefore, it is essential to combine the most emphasized indicators both in China and overseas to build a refined social services indicator set.

#### 4.4.2. Indicators of Water Governance

As mentioned previously, one distinct feature of evaluating freshwater health in China is the close connection between science and politics. The establishment of the River Chief System facilitates the clarification of the responsibility and accountability of local government officials, who, however, lack the necessary scientific background and expertise to actively engage with and manage the specialist teams and track their performances. The political structure and hierarchy in China could not grant sufficient authority to any stand-alone managerial committee that supervises the condition of specific water bodies. Therefore, introducing a set of water governance indicators is obviously necessary and may assist the local RCS heads (i.e., Chiefs) to involve with the detailed scientific programs in a practical and concise way.

One of the most typical water governance indicators is the water condition in different water function zones, which enable the RCS heads to gain a general understanding of the spatial-temporal distribution of health status without going through too many details. The definition of water function zones in China is prescribed by the Ministry of Water Resources [60] according to the purpose of water usage, as shown in Table 5. Many existing standards in China (see Table 4) only implicitly prescribed that "water quality status should meet the criteria in different water function zones". The criteria in Table 5 should be widely used for the classification of main water areas in China and clearly suggest the suitable working objectives of Chiefs in different regions.

Other water governance indicators in Table 4 are also closely related to the operation of the RCS and are rarely used by common guidelines oversea.

#### 4.4.3. Indicators of Ecosystem Resilience

The definition of resilience shows significant ambiguity regarding the restoring capability of an ecosystem and usually to some extent overlaps with some other individual indicators that can be more explicitly measured or quantified. Resilience is a measure of persistence; ecological resilience measures the magnitude of disturbance that a system can absorb before it undergoes changes in structure and function [61]. As stated by Davies et al. [54], ecosystems incorporate the properties of the living and non-living components with "emergent properties", e.g., diversity and resilience. Those properties are more like attributes of the system rather than its components and cannot be directly observed or measured intuitively. A typical ecosystem health monitoring may examine components and processes that are sensitive to disturbances over a range of spatial-temporal scales [13]. Those disturbances might include losses of native flora and fauna, and the invasion of alien species may further complicate the conditions. For example, Scotland's Environment Protection Agency (EPA) uses the condition of peatland and the number of a few alien species (e.g., grey squirrel and American mink) to determine the recovery capacity of an ecosystem. Another approach is to monitor the products of ecological processes operating over a range of scales [62], e.g., dissolved oxygen and chemical oxygen demand (COD), which are also key components of water quality monitoring. Although being of scientific significance, using resilience indicators needs balanced scientific judgement and may unnecessarily complicate the evaluating process. The tradeoff between science and administration is one of the core components of the RCS, and thus the formal application of resilience indicators might not be suitable but can provide supplementary information for experts.

#### 4.4.4. Eco-Water (Environmental Flow)

Eco-water, or environmental flow, is another key indicator to measure the level of satisfaction of water quantity needed for maintaining the basic ecosystem functions and processes. A large number of studies has been published in recent two decades regarding this topic. Tharme [63] provided a comprehensive review of the concept of environmental flow as well as the existing environmental flow methodologies around the world. The methodologies can usually be divided into four categories: Hydrological, hydraulic rating, habitat simulation, and holistic methodologies. Specifically, hydrological methodologies that rely on arbitrary low flow indices are the most widely applied and easy-to-use category. Kuriqi et al. [64,65] provided new insights into the interaction between hydropower energy yields and environmental flow, as well as the needs for maintaining the balance of the ecosystem. Although the European WFD does not use the term "environmental flow" explicitly, the required biological status can only be achieved when the necessary hydrological regimes are maintained [66]. The UK also has set environmental standards for water abstraction limits and appropriate water release from reservoirs. Poff and Zimerman [67] reviewed the relevant publications in the last decades and emphasized that the risk of ecological deterioration may increase with increasing magnitude of flow alteration. Many studies [68–70] have also paid attention to the significance of environmental flow for water governance.

**Tier-1 Category Tier-2 Category Description** Protection zone A protection zone is a water area of significance for the protection of water sources, drinking water, nature reserves, scenic locations, and the protection of rare and endangered species. It is prohibited to build, rebuild, expand, or engage in water-related activities that are not related to protection within the core areas of nature reserves and tier-1 water source areas. Reservation zone A reservation zone is a water area reserved and protected for future development and water resources utilization. Activities that may have a significant impact on water quantity, water quality, and water ecology should be strictly limited and managed. Buffer zone A buffer zone is a water area designated for the following purposes: (1) coordinating water-use relations among provinces and areas with prominent conflicts of benefit; (2) connecting inland/marine zones and protection/development zones that are designated for different purposes. In a buffer zone, all types of water-related activities should be strictly managed to prevent adverse effects on adjacent water function zones. All water-related activities that may be detrimental to the protection of water functional areas in the buffer zone at the provincial boundary shall be notified to the basin management agency in advance. Development zone Drinking water zone A drinking water zone is a water area delimited or reserved for providing drinking water for urban and rural areas. In the areas that have been supplying water, further protection areas should be delimited for subsided water sources to preserved the water quality and volume. It is prohibited to build, rebuild or expand any types of sewage outfalls. In the areas reserved for future water use, the discharge of pollutants should be strictly controlled, and no new discharge into the river is allowed. Industrial water zone An industrial water zone is an area designated to meet industrial water demand. Priority should be given to the specified water usage, and any type of water intake should be strictly managed. Any installation of sewage outfall should not influence the water quality required for the specified zonal functions. Agricultural water zone An agriculture water zone is an area designated to meet the water demand for irrigation. Priority should be given to the specified water usage, and any type of water intake should be strictly managed. Any installation of sewage outfall should not influence the water quality required for the specified zonal functions. Fishery zone A fishery zone is an area designated for protecting aquatic life (e.g., fish). The basic water demand for fishery should be maintained, and important physical environments (e.g., habitats for natural species, spawning beds, wintering beds, feeding grounds and migration passages) should be protected. Water pollution should be strictly controlled by the units and individuals engaged in aquaculture. Scenic and recreation zone A scenic and recreation zone is the area designated to meet the needs of landscape, entertainment, and various leisure activities. Any activity shall not influence the water quality status in the area. Transitional zone A transition zone is an area designated to connect adjacent function zones with different water quality requirements. Transition zone should be managed to guarantee the water quality in the downstream function zone. Any water-related activity that may damage the self-purification capacity of the water body should be strictly controlled. Sewage control zone A sewage control zone is the area designated to receive intensive domestic and industrial wastewater while restraining the adverse impacts on the functions of downstream zones.

**Table 5.**The definition and classification of water function zones under the framework of the RCS in China.

In China, most of the regional standards and guidelines reviewed in this study adopt eco-water/environmental flow methods to evaluate the health status of local rivers and lakes (see Table 4). Considering the difficulty of introducing complex methodologies within the framework of the RCS, a certain level of simplification is required. Currently, the standard issued by the Ministry of Water Resources of China [71] provides a simplified scoring method, based on the ratio of the minimum daily averaged discharge to the multi-year average discharge in the corresponding period. The final score is determined by calculating the lowest score in the periods of October to March and April to September, respectively. This approach, with the further involvement of aquatic life indicators, may reflect the local ecosystem-related hydrological conditions and is thus recommended to be carried on to the new framework.

#### **5. Discussion**

#### *5.1. Lessons Learnt*

#### 5.1.1. Well-Defined Objectives and Motivations

A strong policy driver from authorities may provide the purpose for, and clear direction on, setting well-defined and descriptive objectives for regional water governance and specific monitoring and reporting activities. This driver is essential for maintaining the long-term sustainability and consistency of the existing framework. For example, the European Union's WFD has stated that the objectives are protecting and enhancing the health of aquatic ecosystems while successfully maintaining social and economic systems [72]. As requested, all European Union member states should achieve at least 'good ecological status' for all 'natural' water bodies by 2015 and at the latest by 2027. Although being too strict regarding the timeframe, the WFD's objectives have facilitated the comprehensive implementation of freshwater surveys and thus successfully obtained a large dataset for scientific judgement and further policy adjustment. In the USA, the objective of the Clean Water Act is restoring and maintaining the chemical, physical, and biological integrity of the waters, and thus the aims of the National Aquatic Resource Survey (NARS) is to provide robust data to help the corresponding assessments. In China, as defined by the central government, the main objectives of water governance at the current phase include mitigating human disturbance to water bodies (e.g., illegal mining, occupation, disposing, and constriction), enhancing local and regional regulations, and improving the public satisfaction and people's living quality. Therefore, the RCS was established accordingly to build a hierarchical administrative structure with clear responsibility and accountability. In general, the detailed approach for implementation should fit for the high-level goals set by authorities.

#### 5.1.2. Comprehensive and Practical Indicator Metrics

Using a wide range of indicator metrics ensures that all essential aspects of ecosystem health are addressed. For those well-accepted frameworks outside China, biological (aquatic life) indicators are the core components that also reflect the need to measure the combined response to multiple pressures in a catchment. Those indicators are usually assessed in addition to water quality and habitat indicators and sometimes water quantity and ecosystem processes. As a result, the status of ecological integrity can be accurately assessed, but social values are rarely mentioned. In contrast, the previous practices in China overemphasized the importance of administration and management while not treating different aspects of an ecosystem as a dynamic entity.

Furthermore, during the establishment and implementation of the RCS in China in recent years, we found that the most complained part of the initial RCS framework is that the poorly trained local RCS heads had to be held accountable for what they did not fully understand. Overstretching the scientific aspect does not automatically lead to a better outcome.

### 5.1.3. A Standard Data Acquisition and Analysis Protocol

A standardized data approach ensures the consistency of evaluation results, which is crucial to the nation-wide implementation of the RCS. Some overseas frameworks (e.g., NARS and CABIN) are based on standardized approaches including field survey design, data collection and processing, and reporting. Some other frameworks (e.g., European WFD and the UN's SDG 6) integrate data from different methods and make comparisons by data harmonization. In New Zealand and Australia, scientists have also been making efforts to establish standardized measurement protocols, but more works are still required on determining how to incorporate different components of river health into assessment programs in terms of network design and reporting [9]. Therefore, we intend to propose a functional and standardized protocol that is suitable for the RCS in China, which will be discussed in detail in the next section.

#### 5.1.4. Adaptability

An adaptable framework is capable of adjusting or "upgrading" itself through a structured and iterative process that supports robust decision-making in the face of uncertainty. This feature is especially crucial for a country with typical hierarchical administrative structures that might cause unintended delay during decision-making. As a national standard, the indicator framework proposed in this study (see following sections) that is about to be officially issued this year will be reviewed and revised as a routine of two years.

#### *5.2. A New Evaluation Protocol*

As mentioned previously, a new protocol is proposed in this study to fit for the nation-wide implementation of RCS in China, which is displayed in Figure 1. This protocol is now going through the consultation process and will be officially issued by the end of 2020. Figure 1 shows the three core components of the protocol, including technical preparation, survey and monitoring, and report preparation. Specifically, "technical preparation" provides detailed instruction for preparing for field operation and data acquisition, and this sector is beyond the scope of this study. The following section will present and discuss the newly proposed indicator framework used as the core component of "survey and monitoring". In addition, the results in the complied final report will be concise and understandable to non-experts and can be used to support the assessment of Chiefs.

**Figure 1.** The new evaluation protocol proposed for nation-wide implementation in China.

#### *5.3. Modified Indicator Framework*

Table 6 summarizes the refined indicator framework to be adopted in China as well as the details of data sources and collection method. More specific sampling and testing methods are not discussed in this paper as they are beyond the scope of this study. It can be found that the indicators are classified into three main categories: ecological integrity, social service and water governance. Specifically, ecological integrity can further be classified into four sub-categories (physical habitat, water quantity, water quality and aquatic life) based on the existing experience and best practices around the world.

We recommend that the assessment of water quality follows the existing national standard implemented in China (GB3838-2002 and SL395-2007) [46,47] instead of building another new protocol, as the existing practices have been proved efficient with the reliable outcome. Specifically, GB3838-2002 [46] provides an extensive list of the substances (and threshold values) to be examined for general surface waters and, more importantly, centralized drinking water sources. The included items are more comprehensive than most of the overseas guidelines, and the testing can be conducted by the existing specialized agencies to produce concise reference reports for decision-making officials or Chiefs. SL395-2007 [47] provides an extra composite measure for lakes to determine the degree of eutrophication based on s series of individual water quality indicators (e.g., total nitrogen, total phosphorous, chlorophyll a, permanganate, clarity, etc). Those two standards have also been adopted by some pioneering provinces in China, e.g., Jiangsu, Shandong, and Fujian Provinces (see Table 4). Therefore, a seamless transition to the new nation-wide framework can be accomplished and save administrative resources significantly. Furthermore, the calculation of eco-water (environmental flow) demands can be made based on the existing standard [71]. The daily averaged discharge for rivers or daily averaged water level for lakes are compared with the calculated minimum demands to evaluate to what extent the necessary environmental flows are satisfied.

As shown in Table 6, weights (in parentheses) are assigned to each category and sub-category. A general health score will firstly be given to each selected river (lake) section. The determination of the score is based on weighted averaging approach. The equation can be expressed as:

$$RHI\_l = \sum\_{m=1}^{m} \left\{ \text{WC}\_m \times \sum\_{n=1}^{n} \left[ WS\_n \times \sum\_{k=1}^{k} (WI\_k \times G\_k) \right] \right\} \tag{1}$$

where *RHIi* = the general health score of the *i*th river (lake) section, *Wk* = the weight of the *k*th indicator, *Gk* = the score of the *k*th indicator, *WSn* = the weight of the *n*th sub-category, and *WCm* = the score of the *m*th category.

For the entire river or lake, the final score is averaged based on the score at each section, whose weights are determined by the corresponding ratio of length (for rivers) or area (for lakes). The equation for the final score can be expressed as:

$$RHI = \frac{\sum\_{i=1}^{R\_s} (RHI\_i \times A\_i)}{\sum\_{i=1}^{R\_s} A\_i} \tag{2}$$

where *RHI* = the final score of a river (lake), *Ai* = the length (area) of the *i*th river (lake) section, and *Rs* = the amount of the total sections. Based on the final score, a certain river or lake can be categorized as "very healthy" (*RHI*′′ 90), "healthy" (75 ≤ *RHI* < 90), "subhealthy" (60 ≤ *RHI* < 75), "unhealthy" (40 ≤ *RHI* < 60), or "hazardous" (*RHI* < 40).

#### *5.4. Limitation and Future Development*

It should be mentioned that the main limitation of the new framework is the over-simplification of some indicators (e.g., eco-water/environmental flow) for the convenience of implementing the RCS by non-experts. Furthermore, those more sophisticated indicators (e.g., ecological processes and ecosystem resilience) excluded from the framework should not be ignored by researchers, as they can better reflect the freshwater health as a dynamic status with multiple interrelated constituents. Adopting a simplified framework does not imply that the scientific principles are compromised; on the contrary, ongoing research should be carried out to monitor the efficacy of the framework and make adjustments accordingly.

Although the RCS has been proved as an effective system to manage freshwater resources and improve the health status, challenges still exist due to the fast urbanization in China and the increasing pollutant emission and water consumption, which may significantly influence people's lives. The future development of the RCS should be based on the essential goal that freshwater health status meets people's expectation for an enjoyable living environment, which is obviously more fundamental than any "index" or "grade" that describe the condition of water bodies in an unintuitive way. Some pilot works [73] have been done to explore a method to quantify the sensory aspect of rivers and lakes. In 2019, the Ministry of Water Resources in China had also set the objective of the RCS as "unblocked rivers, clear waters, green banks, beautiful scenery, people in harmony". Priority will be given to a few cities, regions, and catchments of significance to build healthy freshwater ecosystems that meet ecological, sensory, and safety demands under the framework of the RCS; those examples can further be the role models for the rest of China.

**Table 6.**The proposed new indicator framework. The weights for categories and sub-categories are shown in parentheses.

R Applicable to rivers; L Applicable to lakes;. \* Macroinvertebrate status is assessed using the B-IBI method proposed by [74,75]. \*\* The concept of water functions zones is simplified to focus on drinking water zones and avoid ambiguity.

#### **6. Summary and Conclusions**

In this paper, we analyze the administrative and scientific aspects of evaluating freshwater health in China under the framework of the River Chief System (RCS) and compare those features with the best practices around the world. The most significant distinctions between the principles in China and those overseas are discussed particularly. A new indicator framework is proposed together with a well-structured protocol for implementation. The research findings in the present study will be integrated into China's new national freshwater evaluation standard to be issued this year.

Regarding the administrative aspect, the unique institutional context in China (centralized authority, party-state hierarchy, and cadre responsibility system) make it is essential to adopt the top-down mechanism of accountability to avoid the inaction of local officials in different levels. Thus, the performance of the RCS should be graded in a concise and quantitative way to simplify the workload of local Chiefs who are usually non-experts. Regarding the scientific aspect, social services and water governance indicators should be appropriately integrated into the new framework, as those indicators emphasize some attributes that are particularly valued in China and also sometimes ignored in western counties. Those attributes, for example, include the effectiveness of water resources management by using a centralized model and the harmony between individuals, the society and the environment.

From this study, we argue that a series of issues should be paid attention to when establishing a widely implemented freshwater health evaluation framework, including well-defined objectives and motivations, comprehensive and practical indicators metrics, standardized data acquisition and analysis protocols, and the adaptability for future development. Regarding the last issue, the new framework proposed in this study is expected to be revised for every two years to ensure its appropriateness.

**Author Contributions:** Conceptualization, C.X., Y.Y., and Y.L. (Yun Li); formal analysis, C.X. and Y.Y.; funding acquisition, Y.L. (Yun Li); methodology, C.X. and Y.Y.; project administration, C.X. and Y.L. (Yun Li); resources, Y.L. (Yang Liu), G.L., and Z.F.; writing—original draft, C.X. and Y.Y.; writing—review and editing, Y.Y., Y.L. (Yang Liu), G.L., and Z.F.. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by National Key R&D Program of China (2018YFC0407205); Shanghai Chengtou Science and Technology Innovation Program (CTKY-ZDXM-2020-003) and the Special Research Fund of the Nanjing Hydraulic Research Institute (Y119016).

**Acknowledgments:** The authors would like to thank the research group from The University of Auckland, including Bruce Melville, Asaad Shamseldin, Naresh Singhal, and Graham Macky, for their contributions to the completion of this project.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

#### **References**

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

*Article*


**Author details**

Vidya Nimbalkar1 \*, Harish Kumar Verma2 and Jaswinder Singh3

1 KNP College of Veterinary Science, Satara, Maharashtra, India

2 Extension Education, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab, India

3 Department of Veterinary and Animal Husbandry Extension Education, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab, India

\*Address all correspondence to<EMAIL_ADDRESS>
© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


**4.6 Retinoic acid**

Topical tretinoin, although currently recommended for the treatment of acne, has also been reported to be of benefit in plane warts. A study of 25 children with plane warts treated with 0.05% topical tretinoin cream (applied once daily for 6 weeks) was compared with a control group of 25 untreated children. After 12 weeks, clearance of warts was observed in 84.6% of the treated group as compared with 32% of the control group. It was well tolerated with some redness and peeling in 42.3% of the treated group [19].