Use of a Field Portable X-Ray Fluorescence Analyzer for Environmental Exposure Assessment of a Neighborhood in Cairo, Egypt Adjacent to the Site of a Former Secondary Lead Smelter.

The objectives of this study are to demonstrate for the first time the use of a field portable X-Ray Fluorescence Analyzer (XRF) in a multi-media environmental survey and to use the survey results to determine if residual lead from a once-active secondary lead smelter in Cairo, Egypt, still posed a health risk to the residents when comparing results with US EPA standards. Results were analyzed to determine if relationships among the variables indicated that there were residual impacts of the former smelter. Samples collected inside and near a total of 194 dwellings were analyzed. The mean floor dust lead loading was 7.48 µg lead/ft(2). Almost 10% of the dwellings had at least one floor dust wipe sample that exceeded the United States Environmental Protection Agency's (USEPA) interior settled dust lead level of 40 µg lead/ft(2). The median paint lead level was 0.04 mg lead/cm(2). 17% of the dwellings had at least one interior paint sample that exceeded the USEPA standard of 1.0 mg lead/cm(2). Mean soil lead concentration in the study area was 458 ppm and 91 ppm outside the study area. Four of nine composite soil samples exceeded the US EPA limit for bare soil in play areas. Lead concentrations in samples collected in locations outside the study area did not exceed the limit. The highest concentration was in the plot closest to the smelter and may represent residual impact from the former smelter. Statistically significant relationships were not detected between interior floor dust lead loading and either interior paint lead loading or exterior dust lead concentration. Thus, no significant exposure from the former smelter was indicated by these analyses. This may have resulted from the time elapsed since the closing of the smelter and/or the relatively low paint lead levels. Further study is needed in other areas of Egypt near former and active lead smelters. Elevated levels of mercury and arsenic detected in soil samples do not appear to be related to the smelter but warrant further study.

Lead levels in new residential enamel paints in Taipei, Taiwan and comparison with those in mainland China.

Five brands of new enamel household paints from Taiwan were analyzed: two multi-nationals and three local. The median lead concentration of 2574 parts per million (ppm) dry weight was more than 30 times the current US standard of 90ppm for new paints and was more than 4 times the former standard of 600ppm. Lead levels ranged from below detection (4.5ppm) to 158,000ppm. Lead concentrations varied significantly by color of paint and paint brand but not by price per liter. Fifty-six percent of Taiwan paints had lead levels above the 90ppm US limit. One of the multi-national brands and two of the local brands had high levels of lead with the averages ranging from 12,890 to 53,640ppm. Concentrations were less than 90ppm in each of the samples from the other two brands. One of the two multi-national paint brands was imported as the house brand for its big box store in Taipei and had lead levels above 600ppm in four of five samples. Comparison of the lead concentrations of paints from Taiwan with those that we previously analyzed from mainland China revealed higher levels in Taiwan where the median level was 2574ppm compared to 46ppm in mainland China.

Longevity of the effectiveness of interim soil lead hazard control measures and influencing factors.

A 7-year follow-up was conducted to determine factors associated with the longevity of interim soil lead hazard control measures that had been applied to housing in the Cleveland OH area. The approach involved (1) visual determination of the treatment integrity, (2) collection of information regarding 14 factors that may contribute to longevity of treatment integrity and (3) collection of one composite soil sample from treated areas with visual failure at each house and another composite sample from areas without visual failure. For the 200 houses studied, an average of 4 different soil areas were treated. For 96% of these areas, the treatments used were: (1) re-seeding, (2) mulch/wood chips and (3) gravel. Of a total of 191,034 ft(2) of treated soil areas observed, less than one-third, i.e. 59,900 ft(2) (31.3%) exhibited visual failure at the time of follow-up. Hazard control method and the presence/absence of shade were the only factors found to significantly affect visual failure rates. Of the three most commonly used control measures, the lowest visual failure rate was for re-seeding, 29.1% after a mean of 7.3 years; for non-shaded areas, which had been re-seeded, the failure rate was 22.2% compared to 35.7% for shaded areas. At 116 of the 193 houses (60%) that had both visually failed and visually non-failed treated soil areas, the geometric mean soil lead concentration was higher in the failed areas (p=0.003). The actual difference was only 13% with most levels equal to or exceeding 400 ppm. However, when compared to the US EPA limit for bare soil in other residential areas (1200 ppm) the percent equal to or exceeding the limit was much higher in the visually failed areas, 33.1%, than in areas where such failure was not observed, 22.0%.

Lead levels in new enamel household paints from Asia, Africa and South America.

In 2006 a report on the analysis for lead in 80 new residential paints from four countries in Asia revealed high levels in three of the countries (China, India and Malaysia) and low levels in a fourth country (Singapore) where a lead in paint regulation was enforced. The authors warned of the possible export of lead-painted consumer products to the United States and other countries and the dangers the lead paint represented to children in the countries where it was available for purchase. The need for a worldwide ban on the use of lead in paints was emphasized to prevent an increase in exposure and disease from this very preventable environmental source. Since the earlier paper almost 300 additional new paint samples have been collected from the four initial countries plus 8 additional countries, three from Asia, three from Africa and two from South America. During the intervening time period two million toys and other items imported into the United States were recalled because the lead content exceeded the United States standard. High lead paints were detected in all 12 countries. The average lead concentration by country ranged from 6988 (Singapore) to 31,960ppm (Ecuador). One multinational company sold high lead paint in one country through January 2007 but sold low lead paint later in 2007 indicating that a major change to cease adding lead to their paints had occurred. However, the finding that almost one-third of the samples would meet the new United States standard for new paint of 90ppm, suggests that the technology is already available in at least 11 of the 12 countries to produce low lead enamel paints for domestic use. The need remains urgent to establish effective worldwide controls to prevent the needless poisoning of millions of children from this preventable exposure.

Manganese accumulation in the mouse ear following systemic exposure.

There is evidence in human populations that exposure to manganese (Mn), or Mn in combination with excessive noise exposure, results in hearing loss. Quantitative reverse-transcriptase polymerase chain reaction revealed expression of the metal transporters DMT1, ZIP8, and ZIP14 in control mouse ears. ZIP8 is known to have a high affinity (K(m) = 2.2 microM) for Mn transport, and ZIP8 protein was localized to the blood vessels of the ear by immunohistochemistry. We treated mice (strains C57BL/6J and DBA/2J) with Mn (100 mg/kg MnCl(2), by subcutaneous injection, on three alternating days), and Mn was significantly elevated in the ears of the treated mice. Mn concentrations remained elevated over controls for at least 2 weeks after treatment. These studies demonstrate that metal transporters are present in the mouse ear and that Mn can accumulate in the ear following systemic exposure. Future studies should focus on whether Mn exposure is associated with hearing deficits.