Water lead concentrations

Pbs=soil lead concentration PbD=dust lead concentration Pbw=water lead concentration PbA0=outside air lead concentration PbAI = inside air concentration PbF=food lead concentration T=relative time spent... 

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 . ... 

Raab, G. M., et al. 1993. The influence of pH and household plumbing on water lead concentration. Envir. Geochem. Health 15(4) 191-200. 

Results from 12 treatment plants. Most plants showed a minimal removal of lead. Average raw water lead concentration 0.012 mg dm . ... 

Beattie et al. (1972) earlier associated blood lead concentrations of 30.9 12.0 pg/dl with water lead concentrations greater than 300 pg/1 and associated a blood lead concentration of 19.7 pg/dl with a water lead concentration of 50 pg/1. 

Quinn and Sherlock (1990) also drew attention to health studies in Ayr and Glasgow (Scotland) which found a curvi-linear relationship between water lead and blood lead, with an average water lead concentration of 20 pg/1 correlating with a blood lead concentration of 10 pg/dl (albeit with much scatter around the best fit lines). 

The chapters that follow present evidence that water-lead levels during the nineteenth and early twentieth centuries in various parts of the world contained large amoimts of lead by both historical and modern standards. This evidence is not useful unless we know the extent to which water lead was absorbed by the human system. It is certainly possible that other environmental exposures, such as industrial emissions and paint chips, were the main source of lead exposure. In light of this, a key question becomes Is there any modem, scientific evidence showing a correlation between water-lead concentrations and blood-lead levels If so, can one use this research to draw inferences about the contribution of water lead to body-lead burdens historically ... 

Letting L equal the water-lead concentration expressed in terms of parts per 100,000, the abortifacient equivalent can be expressed as... 

The association between lead concentrations in teeth and domestic water lead concentrations. Clin. Chim. Acta, 87, 77-S3... 

Beattie et al, 1972 Goldberg and Beattie, 1972 Moore, 1973 Addis and Moore, 1974 Moore et al, 1977). We (Moore et al, 1977) were also able to demonstrate that such a relationship between blood and water lead concentrations was nonlinear, following a cube root equation of the type ... 

Moore, M. R., Meredith, P. A., Campbell, B. C., Goldberg, A. and Pocock, S. J. (1977) Contribution of lead in drinking water to blood lead. Lancet, 2, 661-662 Moore, M. R, Campbell, B. C., Meredith, P. A., Beattie, A. D., Goldberg, A. and Campbell, D. (1978) The association between lead concentrations in teeth and domestic water lead concentrations. Clin. Chim. Acta, 87, 77-83... 

Surfactants have also been of interest for their ability to support reactions in normally inhospitable environments. Reactions such as hydrolysis, aminolysis, solvolysis, and, in inorganic chemistry, of aquation of complex ions, may be retarded, accelerated, or differently sensitive to catalysts relative to the behavior in ordinary solutions (see Refs. 205 and 206 for reviews). The acid-base chemistry in micellar solutions has been investigated by Drummond and co-workers [207]. A useful model has been the pseudophase model [206-209] in which reactants are either in solution or solubilized in micelles and partition between the two as though two distinct phases were involved. In inverse micelles in nonpolar media, water is concentrated in the micellar core and reactions in the micelle may be greatly accelerated [206, 210]. The confining environment of a solubilized reactant may lead to stereochemical consequences as in photodimerization reactions in micelles [211] or vesicles [212] or in the generation of radical pairs [213]. 

Sodium hydroxide, 10% in water. Dissolve 10 g of NaOH in 100 mL of distilled water Lead acetate, 30% in water. Dissolve 30 g of acetate in 100 mL of distilled water Stannous chloride solution. Dissolve 40 g of reagent in 100 mL of concentrated hydrochloric acid... 

Lead may also interact detrimentally with aquatic life. Once lead deposits in soil, it sticks to soil particles and is only displaced by rain water, ending up in water sources where it affects the aquatic life. Some plants accumulate Pb from both contaminated soils and water sources or more specifically water in the rhizosphere. Besides, contaminated soils are liable to remain polluted with lead this will affect soil fertility.3,4 The fact that large changes in the lead content of soil are required to produce changes in the aerial parts of the plants as compared to changes in aerial lead concentration is closely reflected in the leaf lead concentration. Accumulation of Pb in grasses remains a potential hazard to livestock.3... 

Renal Effects. Ingestion of drinking water containing lead was found to be associated with evidence of renal insufficiency in humans (Campbell et al. 1977). Lead concentrations in drinking water were compared to PbB concentrations in 283 residents who ingested this water for a mean of 21.5 years. A highly significant correlation was found for these two parameters. In addition, elevated PbB concentrations were associated with renal insufficiency, reflected as raised serum urea concentrations and hyperuricemia. No renal biopsies were performed. 

Other investigators have been unable to demonstrate lead-induced effects on various components of the immune system in laboratory animals. The effects of lead exposure of varying duration on natural killer cell and T-lymphocytc function were investigated in rats. Male Alderly Park rats received lead as lead acetate in the drinking water at lead concentrations equivalent to 14.3 and 143 mg lead/kg/day for... 

Lead levels ranging between 10 and 30 pg/L can be found in drinking water from households, schools, and office buildings as a result of plumbing corrosion and subsequent leaching of lead. The combination of corrosive water and lead pipes or lead-soldered joints in either the distribution system or individual houses can create localized zones of high lead concentrations that exceed 500 pg/L (EPA 1989f). 

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