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 be determined. In initial versions of the SEM-AVS approach, six metals were measured: nickel, zinc, cadmium, copper, lead, and mercury. More current methods call for the measurement of silver in addition to these metals. In applying the SEM-AVS approach, two concentrations are determined: the total concentrations of all toxic heavy metals of interest, represented as [SEM], and the acid-volatile sulfide concentration, represented as [AVS]. From these concentrations, the [SEM]/[AVS] ratio can be obtained, summarizing the results in a single value. Based on the extremely low K values for heavy metal sulfides, if [SEM]/[AVS] is less than 1 ([SEM < [AVS]),