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Figure 1. Site Vicinity Map

Figure 2. Concentration of Chromium in Soil

Figure 3. Concentration of Arsenic in Soil

Figure 4. Monitoring Well Locations


The following section was not available in electronic format for conversion to HTML at the time of preparation of this document. To obtain a hard copy of the document, please contact:

Agency for Toxic Substances and Disease Registry
Division of Health Assessment and Consultation
Attn: Chief, Program Evaluation, Records, and Information Services Branch
1600 Clifton Road NE, Atlanta, Georgia 30333


1. Technically, the site is located in the city of Hanover, MD which is adjacent to Harmans. However, the Remedial Investigation and Feasibility Study documents locate the site in Harmans, a practice which will be continued in this public health assessment.

2. This assumption was appropriately justified and used in the risk assessments presented in the RI.

3. The TRI was developed by USEPA from the chemical release information provided by certain industries in compliance with Section 313 of the Superfund Amendments and Reauthorization Act (SARA).

4. The Target Compound List (TCL) is a list of organic and inorganic chemicals for which every collected Superfund sample must be analyzed. The Target Analyte List (TAL) is a list of inorganic compounds for which every collected Superfund sample must be tested.

5. The inability to judge water safety using a CREG is not unique to the MAWP site, but is a technology-based problem that applies to any site which has contaminants whose comparison values are lower than the detection limits of the analytical chemistry methods employed.

6. However, high levels of Chromium III (14 mg/kg/day) administered orally were found to reduce sperm counts in mice but not rats (ATSDR, 1991b). The doses required to produce this effect were much higher than those associated with the MAWP site.

7. The wood preserving solution used at MAWP contains chromium in a soluble hexavalent form, but the chromium detected in shallow soil was mostly in the trivalent form. The CCA solution was the source of observed excess chromium in soil, as natural processes are capable of converting hexavalent into trivalent chromium. Some of the contaminated soil is thought to become airborne as dust. However, because no air measurements were actually taken at the MAWP, the levels of chromium in air presented in this public health assessment are estimates, based on models, and should be interpreted with caution. Like the soil from which it comes, chromium in air would be expected to be predominantly in the trivalent form.

8. The majority of the chromium that leached into groundwater after the 1978 spill was in the hexavalent form. However, the high concentrations observed in the year after the spill have appeared to have attenuated; by the mid-1980's, total chromium levels -- of which hexavalent chromium is a component -- in off-site groundwater had fallen to levels which were not detectable (see Table 7). Human exposure to site-related chromium in drinking water could have potentially occurred only off-site and in the past, since no on-site groundwater wells were ever used for drinking water and the off-site wells were not used for drinking water after the initial groundwater contamination was discovered.

9. Total chromium is used to calculate doses rather than the component hexavalent and trivalent forms because the latter were not routinely measured, whereas the former was.

10. Pica behavior consists of eating small quantities of non-food substances, such as dirt or clay, and is exhibited by a small proportion of young children. Pica children are assumed to consume on average 5000 mg soil per day.

11. This dose corresponds to environmental concentrations of 2 X 10-5 mg arsenic/L of water or 0.40 mg arsenic/kg soil for adults; and 5.7 X 10-6 arsenic/L of water and 0.001 mg arsenic/kg soil for pica children.

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