Acid throwing and readily available in many instances. For example, often acid throwers can purchase a liter of concentrated sulfuric acid at motorbike mechanic shops for about 40 U.S. cents. Nitric acid costs around $1.50 per liter and is available for purchase at gold or jewelry shops, as polishers generally use it to purify gold and metals. Hydrochloric acid is also used for polishing jewelry, as well as for making soy sauce, cosmetics, and traditional medicine/amphetamine drugs. Due to such ease of access, many organizations call for a stricter regulation on the acid economy. Specific actions include required licenses for all acid
Simultaneously extracted metals and Acid-volatile sulfide initially unbound to AVS (due to insufficient AVS in the sediment to "mop up" all the metal ions). The concentrations of metals in the acid solution can be measured by a number of analytical chemistry methods, including atomic emission spectrometry, atomic absorption spectrometry (AAS), or mass spectrometry. These are known as "simultaneously extracted metals" because they are the metals liberated from the sediment "while the volatilization of sulfide is occurring". Metals extracted from sediment by digestion, or with a different acid than HCl are "not" simultaneously extracted metals. By correcting appropriately for dilution, the SEM concentration in the sediment can