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On May 4, 1998, J.E.Godfrey, staff hydrogeologist; Alice Hoffman, and Robert Stroman of PADOH visited the site and surrounding area in preparation for this HC. Mr. Godfrey surveyed the area's geological formations during the site visit. The group noted a corn field south of the site across Route 562 and a residential development southwest of the site across Route 562. The groundwater beneath the residential development was apparently contaminated by the Cryochem site one half mile to the west, a National Priority List site [2]. Since the development is cross-gradient to the local groundwater flow direction from the Boyertown Scrap site, the groundwater contamination in the development is not related to the site.

PADOH believes that wells within a 4 mile radius of the site are not at risk because the geological formations underlying the site will not allow the formation of large plumes of contamination. PADOH bases this conclusion upon a review of available information and our site visit. Information and observations indicate that the site is underlain by carbonate rocks of the Leithsville formation. Although rocks of the Leithsville formation may be subject to dissolution (cave formation, etc.), that formation at the site is only about three-quarters of a mile wide north to south, and narrows sharply east-west (Figure 3). It is bounded on the north (upgradient) by quartzite and granitic gneiss, both hard crystalline rocks not subject to dissolution. To the south is a Triassic border fault and Triassic sedimentary rocks intruded by diabase dikes. Given the geological setting as described above, the carbonate zone is of limited areal extent and a large plume (miles long) in virtually any direction is not possible.

DOH reviewed historic private well water (HW-2, HW-3, HW-4) [Figure 4] sampling results to determine if site contaminants had affected water quality beneath and near the site and to evaluate the public health significance of our findings. With the exception of lead in HW-2, site contaminants were not present in samples collected from the three on-site or near-site wells at levels that would threaten public health [1] (Figure 4). In 1983 and 1993, 15 micrograms per liter (g/L) and 6 g/L of lead were detected in HW-2, respectively. The EPA Office of Drinking Water has established 15g/L as an action level for lead in drinking water. We do not know if the lead detected in HW-2 is from the Boyertown site or the shop's plumbing.

The concentration of lead in whole blood is the most widely used index of total lead exposure. Lead exposure across a broad range of blood lead levels has been associated with a wide range of health effects and biologic changes. In addition to renal disease, cardiovascular effects, and reproductive toxicity, lead may cause irreversible neurologic damage (impaired cognitive function) [4,5].

Research has shown that blood lead concentrations in adults increase by about 0.06g/dL of blood for every 1g of lead per liter of water [6]. At this conversion rate we would expect the added blood lead burden from drinking HW-2 to be between approximately 0.7-1.8g/dL of blood for the adult male based on the detected lead levels of 6-15g/L in the well water [6]. The Third National health and Nutrition Examination Survey (NHANES III) 1998-91 estimated that the geometric blood lead levels for U.S. adults aged 20-74 was 3.0g/dL [7]. Therefore, in the absence of blood lead data for the adult male using the welding shop, the estimated total blood lead with added lead from HW-2 will be up to 4.8g/dL. We base our health evaluation on the estimated level of blood lead. Based on the limited data, this estimated level is not likely to pose a significant health threat to the adult using this facility. However, welding represents a potential occupational source of exposure to lead. If welding is presently occurring in the building served by HW-2, then the small amount of lead from the contaminated well water represents an additional burden to the lead the occupant may be exposed to occupationally. The Occupational Safety and Health Administration (OSHA) limits the concentration of lead in workroom air to 50 g/m3 for an 8-hour workday. If a worker has a blood lead level of 40 g/dL, OSHA requires that worker to be removed from the workroom. Therefore, it will be prudent for the individual working in the welding shop to monitor the air quality in the work area. In addition, in order to know the amount of lead exposure, a blood test can be obtained to measure the amount of lead in blood.

Lead exposure in young children is a particular hazard because they absorb lead more readily than adults do and because their developing nervous systems are more susceptible to the harmful effects of lead [7]. However, we do not believe that young children are present in the welding shop and routinely drink water from HW-2. The low levels of lead are not expected to cause adverse health effects among children if they only drink the water occasionally. Since lead serves no beneficial purpose in the human body, it is best if drinking water contains no lead. Limited data for HW-3 and HW-4 indicate that lead is not present in these wells.

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