Heavy metals in drinking water

Heavy Metals - Heavy metals represent problems in terms of groundwater pollution. The best way to identify their presence is by a lab test of the water or by contacting county health departments. There are concerns of chronic exposure to low levels of heavy metals in drinking water. 

Discuss the toxicity of heavy metals in drinking water use additional materials from Chapter 12 for the answer. 

Figure 39. Flow diagram of the procedure for the polaro-graphic/voltammetric determination of heavy metals in drinking water, groundwater, and surface water according to DIN 38406 Part 16...

Issues of Water Quahty Heavy Metals in Drinking Water, http I www.everpure.coml issues/iowq003.html, 1998. 

It has been largely recognized that heavy metal concentrations are much higher in urban or industrial areas than in wild ones [1-3]. Consequently the possibility of incorporation of heavy metals into drinking water or trophic webs exits, and so the potentially generation of deleterious effects on human populations [4-6]. 

Atomic absorption spectrometry is one of the most widely used techniques for the determination of metals at trace levels in solution. Its popularity as compared with that of flame emission is due to its relative freedom from interferences by inter-element effects and its relative insensitivity to variations in flame temperature. Only for the routine determination of alkali and alkaline earth metals, is flame photometry usually preferred. Over sixty elements can be determined in almost any matrix by atomic absorption. Examples include heavy metals in body fluids, polluted waters, foodstuffs, soft drinks and beer, the analysis of metallurgical and geochemical samples and the determination of many metals in soils, crude oils, petroleum products and plastics. Detection limits generally lie in the range 100-0.1 ppb (Table 8.4) but these can be improved by chemical pre-concentration procedures involving solvent extraction or ion exchange. 

The Critical concentrations with respect to the soil organisms should be related to a low effect level on the most sensitive species. The effects on the process of metabolism and other processes within the organisms should be considered and also the diversity of the species, which is most sensitive to the heavy metals, has to be accounted. Critical limits must refer to the chronic or accumulated effects. For assessment of the critical concentrations in crops and in drinking water, human-toxicological information is required. In general, for establishing critical loads we should also account the additive effects of the different metals and combination effect between the acidification and biogeochemical mobilization of the heavy metals in soils and bottom sediments. 

Many countries have also established specific regulations to protect children from exposure to certain environmental hazards, including toxic chemicals. Examples include banning of heavy metals in toys, strict limit setting for persistent toxic substances in baby foods, and the setting of environmental limit values derived on the basis of infants sensitivities (e.g. nitrates in drinking-water). In the United States, concerns about children s special vulnerabilities... 

T. Roychowdhury, H. Tokunaga, M. Ando, Survey of arsenic and other heavy metals in food composites and drinking water and estimation of dietary intake by the villagers from an arsenic affected area of West Bengal, India, Sci. Total Environ., 308 (2003), 15-35. 

The cattle grazing in the river flood plains is exposed to three sources of heavy metals in the diet the drinking (river) water, the herbage and the ingested soil particles. Contribution of drinking water is less than 1% of the total heavy metal intake. The contribution of the contaminated grass and soil particles, however, is quite significant for the daily intake of As, Cd,... 

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