Toxicity testing mercury

McCrary JE, Heagler MG. 1997. The use of a simultaneous multiple species acute toxicity test to compare the relative sensitivities of aquatic organisms to mercury. J Environ Sci Health Part A Environ Sci Eng Toxic Hazardous Substance Control 32 73-81. 

A waste is toxic under 40 CFR Part 261 if the extract from a sample of the waste exceeds specified limits for any one of eight elements and five pesticides (arsenic, barium, cadmium, chromium, lead, mercury, selenium, silver, endrin, methoxychlor, toxaphene, 2,4-D and 2,4,5-TP Silvex using extraction procedure (EP) toxicity test methods. Note that this narrow definition of toxicity relates to whether a waste is defined as hazardous for regulatory purposes in the context of this chapter, toxicity has a broader meaning because most deep-well-injected wastes have properties that can be toxic to living organisms. 

By a strict definition, these electrical and electronic wastes are hazardous. Fluorescent lamps contain mercury, and almost all fluorescents fail the U.S. Environmental Protection Agency (U.S. EPA) toxicity test for hazardous wastes. Fluorescent lamp ballasts manufactured in the mid-1980s contain polychorinated biphenyls (PCBs), a carcinogen most of these ballasts are still in service. Batteries can contain any of a number of hazardous materials, including cadmium (nickel-cadmium... 

If a medical office has photoprocessing waste, typically from x-ray processes, which leaches silver in a concentration of 5 mg/L or more, or has a dental waste which leaches mercury in a concentration of 0.2 mg/L or more, this medical office is a generator of hazardous waste, of which concentrations are determined by an extraction procedure toxicity test. 

See also Copper Mercury Silver Toxicity Testing, Dermal Toxicity Testing, Inhalation. 

Because the Mad Hatter in Alice in Wonderland exhibited some of the symptoms of erethism, he is sometimes held to be a model for the afflictions suffered by workers in the hat industry whether Lewis Carrol intended such a parallel is still disputed, but the resemblances are uncanny. Even in the absence of identifiable symptoms, psychological testing has revealed what could be called nascent erethism in workers exposed to mercury vapor but showing no overt signs of toxicity. Tests of coordination and reaction time reveal differences between exposed and unexposed workers. Performance on elements of adult intelligence tests, such as the ability to repeat strings of digits, also shows differences. 

Thus the toxicity of mercury as determined by the solution tests reveals the wrong picture if extended to its effect in soils. The important point is that this technique indicates the impact of a pollutant in soil and not only its concentration. 

Toxicological studies on direct food additives have revealed toxic and harmful actions. Food dyes and preservatives have been used since ancient Roman times to improve the color of wine or to disinfect wine containers. The development of chemistry led to many unwise experiments, such as the dying of food with copper, chrome, lead, mercury, arsenic, and cadmium salts. In the U.S. in 1906, over 300 food dyes were officially tested, of which only seven passed and were allowed to be used in food. Only two of them - erythrosine and idigotine - are permitted now. The lists of preservatives are also constantly modified in different countries. Quite recently, formic acid, which is used to preserve semi-products, was banned in Poland due to its deleterious effects. 

The biological half-life in humans for methyl mercury is about 70 days because elimination is slow, irregular, and individualized, there is a considerable risk of an accumulation of mercury to toxic levels. A precise relationship between atmospheric levels of alkyl mercury and concentrations of mercury in blood or urine has not been shown. Clinical observations indicate that concentrations of 50-100pg mercury/lOOml of whole blood may be associated with symptoms of intoxication concentrations around 10-20pg mercury/ 100 ml are not associated with symptoms. In a study of 20 workers engaged in the manufacture of organic mercurials and exposed for 6 years to mercury concentrations in air between 0.01 and O.lmg/m, there was no evidence of physical impairment or clinical laboratory abnormalities. Low levels of methyl mercury in the blood do not seem to affect the results of behavioral performance tests. ... 

NFS claims that DeHg technology offers a low-temperature alternative to other mercury recovery processes. They claim that the final waste form generated by processing passes Toxicity Characteristic Leaching Procedure (TCLP) criteria for disposal, and that centrifuge testing has proven that no free liquid mercury remains in the treated product. 

---