Water lead levels

Adult males N=7,735 0.06 24 British towns sampled water lead levels <100 pg/L Pocock et al. 1983... 

Bailey, R. J. and P. F. Russel (1981), Predicting drinking water lead levels. Environmental Technology Letters 2, 57-66. 

To DEVELOP CORRECTIVE MEASURES RELATED TO USE PATTERNS AND LIVING CHARACTERISTICS (e.G., flushing THE WATER LINE IF WATER LEAD LEVELS ARE HIGH, MOVING THE pet s sleeping area IF IT APPEARS THE PET IS TRACKING IN LEADED DUST, AND SO FORTH). 

Do YOU USE THE WATER IMMEDIATELY OR DO YOU LET THE WATER RUN FOR AWHILE FIRST (If water lead levels are elevated in the FIRST FLUSH, BUT LOW IN THE FLUSHED SAMPLE, RECOMMEND FLUSHING THE WATER AFTER EACH PERIOD THE WATER HAS REMAINED STANDING IN THE PIPE FOR MORE THAN 6 HOURS.)... 

As with dry precipitation, a number of factors govern the rate of wet deposition lead removal rates. These include particle size, seasonality, altitude, amount of precipitation, and thermal inversion (Conko et al., 2004 Davidson and Rabinowitz, 1992 Miller and Friedland, 1994). Input rates of lead to the atmosphere affect rainwater lead content. Table 5.4 presents water lead levels for various areas over a broad time frame. There is a clear trend to lower levels with lower anthropogenic impact, and a clear trend with time. Compared to the 1960s and 1970s when leaded gasoline consumption was at a maximum in the United States, later years showed dramatic drops in lead content. 

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). 

The 1974 Act also mandated that there be testing and monitoring of system-treated water lead levels at the point of distribution. 

Watt, G.C.M., Britton, A., Gilmour, H.G., Moore, M.R., Murray, G.D. and Robertson, S.J. (2000). Pubhc health implications of new guidehnes for lead in drinking water a case study in an area with historically high water lead levels. Food and Chemical Toxicology, 38, S73-S79. 

Town (see chapters 8 and 9). Is it possible that in some cities, water-lead levels were even higher than in Cape Town Conversely, what explains the contrast between Cape Town and cities like Chicago, London, and Paris where the historical record suggests that lead pipes were used safely Engineers have long emphasized the importance of various chemical processes in determining the propensity of any given water source to dissolve lead (see chapter 6). 

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 ... 

Beyond concerns about the functional specification, there are other factors that make it difficult to correlate blood-lead levels with water-lead levels. Studies that measure the role of competing sources of lead exposure (e.g., airborne lead particles versus the amount of lead in tap water) sometimes find that non-waterborne exposure vectors explain the variation in blood-lead levels better than water-lead levels do. " It is easy to infer too much from such findings because exposure to water lead is... 

Figure 3.1 illustrates the relationship between the abortifacient equivalent and the modern EPA standard regarding water lead. The y-axis is scaled logarithmically and the function approaches both axes asymptotically. The figure shows that when water-lead levels exceed the modern EPA standard by more than a factor of 300, consuming less than 2 ounces of water per day would allow one to reach the abortifacient equivalent. In contrast, when water-lead levels are only 2-4 times greater than the modern EPA standard, one need consume between 150 and 300 ounces of water per day to reach the abortifacient equivalent. 

Charles River. Water from the river was more polluted than that from the wells, and therefore had to be filtered. The company installed a slow-sand filtration system, which not only eliminated bacterial contaminants, it also reduced the lead solvency of the river water." The introduction of these measures in 1902 and 1903 reduced the average water-lead levels in area homes from 1.39 ppm (627 times the modern EPA standard) to 0.27 ppm (175 times the modern EPA standard). Although 0.27 ppm is a high lead level by modern standards, it was well below the 0.5-ppm threshold then considered safe by the Massachusetts Board of Health." ... 

The introduction of lime dosing in 1914 had an immediate and beneficial effect on water-lead levels in the area. In particular, the average water-lead level in Milford and Hopedale fell from 0.27 to 0.1 ppm. Although the 0.1 level exceeds the modern EPA standard by a factor between 6 and 7, it was well below the threshold considered safe around 1910 and 1920." ... 

Figure 6.1 plots the relationship between water lead and water hardness. The hardness measure is an indicator of the amount of calcium and magnesium in a water supply. The figures show that water-lead levels decrease as water hardness rises. The relationship is logarithmic so that, at low levels of hardness, water-lead levels decline rapidly with small increases in hardness. However, there is a threshold effect so that after the hardness measure reaches 20, water-lead levels never rise above 0 and are unaffected by variations in hardness. Furthermore, there is evidence that even at fairly high levels of hardness, water can still dissolve sizeable amounts of lead. For example, one water sample with a hardness measure of 17 dissolved a sufficient amount of lead to place it in... 

---