Tap water, lead

Pocock SJ, Shaper AG, Walker M, et al. 1983. Effects of tap water lead, water hardness, alcohol, and cigarettes on blood lead concentrations. J Epidemiol Community Health 37 1-7. 

Since 1989, as regulatory upper limits for lead in drinking water have fallen, e.g. to 50 pg (EC) and now to 10 pg (WHO), orthophosphate has been added to the water supply in Glasgow to precipitate insoluble lead compounds such as Pb3(P04)2 and Pb5(P04)30H. This has resulted in a fall in the proportion of households with water lead > 10 pg from 49% in 1981 to 17% in 1993. Despite this improvement, an estimated 13% of infants were still exposed via bottle feeds to tap water lead concentrations in excess of 10 pg and it seems very unlikely that further treatment of the water supply will be able to guarantee water lead concentrations <10 pg L . ... 

Lead (tap water, leaded paint chips, herbal remedies, gas-sniffing, glazed kitchenware, etc.) Acute N and V, GI distress and pain, malaise, tremor, tinnitus, paresthesias, encephalopathy (red or black feces) Chronic multisystem effects—anemia (X heme synthesis), neuronathv (wrist dronL nephropathy (proteinuria, failure), hepatitis, mental retardation (from pica), >1 fertility and 1 stillbirths Decontamination—gastric lavage + dimercaprol (severe) or EDTA or succimer (penicillamine if unable to use dimercaprol or succimer) Children succimer PO... 

Lead enters surface water or eventually groundwater from ambient air or from soil via runoff, and eventually provides tap water lead exposures either directly through drinking water or through use of lead-contaminated water for cooking. 

Lead in tap water can occur in either fully soluble form or a mixture of soluble and particle-bound, suspended lead. If filtered samples are used, the lead in the insoluble fraction is not accounted for although it can contribute to lead exposures. The latter is of relatively more significance for individual or community wells than for water being distributed from public treatment plants in relatively high-population communities. However, fine particles of lead soldering in household plumbing in suburban and urban areas can contribute to water lead intakes and need attention. In regulatory assessments, such as Superfund risk assessment, total tap water lead, i.e., use of unfiltered samples, is recommended (U.S. EPA, 1989). 

Recent studies of environmental Pb impacts on children s blood Pb levels have included the relationship of potential changes in tap water lead with changes in community water treatments. Miranda et al. (2007) examined 7,270 PbB screening records in a North Carolina county and linked these to drinking water sources, age of residences, and other variables such as season of screening. Statistically significant associations with PbB included use of chloramines as disinfectants in water treatment... 

U.S. studies of plumbosolvency in the 1970s and 1980s clearly indicated that there was a high correlation between soft, acidic water and associated lead surface corrosivity and that the overall U.S. picture for contamination frequencies of water by Pb was a variable one. U.S. national household tap water lead surveys (Patterson and O Brien, 1979 U.S. EPA/Levin, 1986 McCabe et al., 1970 Craun and McCabe, 1975) showed (1) one-sixth (16%) of U.S. tap water lead levels were >20 pg/1 (2) 100% of residences with new plumbing with recently soldered connections in copper systems showed Pb s20 pg/1 and that (3) for the sampling year 1988, a total of 42 million U.S. residents had some exposure to water Pb >20pg/l, about 34 million from older housing exposures and 8 million from newly constructed residences (U.S. ATSDR, 1988). 

Lead and copper are regulated by a Treatment Technique that requires systems to control the corrosiveness of their water. If more than 10% of tap water samples exceed the action level, water systems must take additional steps. For copper, the action level is 1.3 mg/L, and for lead is 0.015 mg/L. 

The unequal attack which occurs in tap water, condensate and other mild electrolytes may lead to perforations of thin-gauge sheet and even to deep pitting of castings. In stronger electrolytes the effect is variable. In chloride solutions such as sea-water, attack on the metal usually results in the pitting of some areas only, but where the metal surface has been rendered reactive, as by shot blasting, attack may be so rapid that uniform dissolution over the whole surface may occur. In either case magnesium-base alloys are not usually suitable for use in aqueous liquids since they are not intrinsically resistant to these electrolytes. 

Voltaic cells 64. 504 Voltammetry 7, 591 anodic stripping, 621 concentration step, 621 mercury drop electrode, 623 mercury film electrode, 623 peak breadth, 622 peak current, 622 peak potential, 622 purity of reagents, 624 voltammogram, 622 D. of lead in tap water, 625 Volume distribution coefficient 196 Volume of 1 g of water at various temperatures, (T) 87... 

Quantitative data on the nationwide range of lead levels in drinking water drawn from the tap (which would include lead corrosion by-product) were insufficient to assign a national value at the time of the 1991 EPA publication. One set of data comprised of 782 samples taken in 58 cities in 47 states shows that the average lead level in tap water was 13 pg/L with 90% of the values below 33 pg/L (EPA 199 Id). 

According to EPA s National Compliance Report for calendar year 1996 (EPA 1998g), the vast majority of people in the nation received water from systems that had no reported violations of the maximum contaminant level and treatment technique requirements or significant monitoring and reporting requirements. Lead has a maximum permissible level of 15 pg/L delivered to any user of a public water system. Lead and copper are regulated in a treatment technique that requires systems to take tap water samples at sites with lead pipes or copper pipes that have lead solder and/or are served by lead service lines. The water system is required to take treatment steps if the action level (15 pg/L for lead) is exceeded in more than 10% of tap water samples. For calendar year 1996, nearly 6 million people in the United States were served by community water systems that reported maximum contaminant level and treatment technique violations of the Lead and Copper Rule (EPA 1998g). 

De Mora SJ, Harrison RM, Wilson SJ (1984/1987) The effect of water treatment on the speciation and concentration of lead in domestic tap water derived from a soft upland source. Water Res 21(l) 83-94... 

Coupling Medium. Distilled water has proven to be more effective than tap water as the conducting liquid as evidenced by greater cavitation in the reaction flasks (and faster reaction rates). Moreover, distilled water leads to significantly less corrosion of the bath walls. Other low vapor pressure liquids such as ethylene glycol can be used. 

Lead poisoning can also occur from drinking tap water contained in pipes that have been soldered with lead-alloy solder. This risk can be reduced by running the tap water until it is cold, which assures a fresher supply of water. 

An anion exchange resin (e.g. Amberlite R-120) was treated with protonated dithiooxamine, H2NC(S)C(S)NH2 Using the supported ligand, quantitative removal of copper, cadmium, and lead ion solutions at neutral or slightly alkaline solutions of deionized or tap water, but poor results were obtained with sea water [22]. 

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