The Morses Pond Culvert Site is located in Wellesley, Massachusetts. As shown in Figure 1, the site includes a residential property and portions of properties owned by the Town of Wellesley and the Massachusetts Bay Transportation Authority. Morses Pond drains into a 200-ft long culvert which discharges under the railroad tracks into a pond (Paintshop Pond) downstream of the site. The southern portion of the site includes a steeply sloped, 35- foot high, earthen embankment that is divided by the culvert into eastern and western embankments. The northern portion of the site includes a 0.2 acre cove area. The site is adjacent to a town beach and additional residential properties.
In 1994, in response to the presence of stained soils around the culvert at the site, the Massachusetts Department of Environmental Protection (MADEP) collected one surface water and six surface soil samples. Results from the analyses of these samples showed soils containing chromium at levels as high as 10,000 mg/kg, and surface water containing hexavalent chromium at a concentration of 210 ug/L and zinc at concentrations above ambient water quality criteria. A 1998 Phase 1 investigation identified elevated levels of total chromium, hexavalent chromium, and lead in the soil at the site. In December 1998, MADEP covered the portions of the site nearest the culvert with geotextile fabric and polyethylene tarps and installed fencing to minimize erosion and human exposure to the soil, in response to evidence that portions of the site were being used by the public for recreation. Results of additional site investigations conducted in 1999 identified levels of total chromium as high as 129,000 mg/kg and hexavalent chromium as high as 31,000 mg/kg in surface soils located on the residential property, the embankment, and areas adjacent to the pond, and levels of total chromium as high as 10,800 mg/kg in soils and sediments in the culvert and cove areas.