Environmental issues in Syria Attacks on oil refineries can cause oil fires which release harmful chemicals into the air, such as sulfur dioxide, nitrogen dioxide, carbon monoxide and polycyclic aromatic hydrocarbons (PAHs). The sulphur and nitrogen compounds are linked to acid rain which can have dire impacts on vegetation as well as cause soil acidification. PAHs persist in the environment for long periods of time and are known carcinogens. Syria also extracts heavy crude oil, which generally has a higher proportion of noxious substances, including heavy metals, making it especially dangerous when these substances seep into the soil. Syria has two oil refineries. The
Bioindicator organisms comprising both fungi and algae. They are found on rocks and tree trunks, and they respond to environmental changes in forests, including changes in forest structure – conservation biology, air quality, and climate. The disappearance of lichens in a forest may indicate environmental stresses, such as high levels of sulfur dioxide, sulfur-based pollutants, and nitrogen oxides. The composition and total biomass of algal species in aquatic systems serve as an important metric for organic water pollution and nutrient loading such as nitrogen and phosphorus. There are genetically engineered organisms that can respond to toxicity levels in the environment; "e.g.",