HEALTH CONSULTATION
Evaluation of Health Risks from Consuming Vegetation Foraged
in Kelly Brook Wetlands in the Vicinity of the Beede Waste Oil NPL Site
BEEDE WASTE OIL SITE
PLAISTOW, ROCKINGHAM COUNTY, NEW HAMPSHIRE
The New Hampshire Office of Health Management (OHM), Bureau of Health Risk Assessment
received an inquiry from a resident who lives near the Beede Waste Oil NPL site who was
concerned about health risks from consuming vegetation foraged in the wetlands along Kelley Brook
near the Beede site. The resident collects a plant called a Marsh Marigold (Caltha Palustris) that
grows in the sediments near Kelley Brook. This plant is harvested for consumption in late March
through April before it blooms. The harvest period is approximately six weeks. After that time the
plant tissue becomes bitter and inedible. The leaves are collected,cooked, and eaten similar to
spinach. The leaves are not eaten raw because the plant produces a natural toxin called helleborin
which is removed by boiling. The total amount harvested is estimated to be enough for about six
meals1
, with each meal estimated on the average to be 86 grams, similar to the average quantity of
spinach consumed per meal2. According to this resident, no other wild plants are harvested from
Kelley Brook wetlands.
Sediment samples were taken from Kelley Brook in October 1997 by The New Hampshire Department of Environmental Services and Sanborn, Head and Associates as part of the remedial investigation process at the Beede Waste Oil Site. Sampling showed elevated concentrations of metals and organic compounds. Plants can accumulate metals from soil and sediment, and when eaten can result in a completed human exposure pathway to these contaminants. Analytical results for sediment metal contaminant levels are presented in Table 1.
Table 1. Metal concentrations detected in sediments in Kelly Brook
| Metal | Range of concentration (mg/kg) | Mean concentration (mg/kg) |
| Arsenic | 4.80 - 35.30 | 11.29 |
| Cadmium | 0.96 - 2.10 | 1.48 |
| Mercury | 0.06 - 0.17 | 0.11 |
| Nickel | 13.20 - 42.3 | 21.88 |
| Selenium | 0.81 - 3.10 | 1.55 |
| Zinc | 28.70 - 159 | 93.10 |
The metals concentrations in sediments were compared to soil screening levels (SSL) specifically developed for the soil-plant-human pathway by EPA3. These screening levels define the concentration of metals in soils that are below levels of concern for cancer and non-cancer human health effects from ingesting plants grown in metal contaminated soils. Arsenic was the only metal that was above its soil screening level (see Table 2) at both mean and maximum concentrations.
No screening levels are currently available for plant uptake of organic contaminants from contaminated sediments and soils. It is assumed that uptake of organic contaminants in soil into the leaf tissues is negligible4. It is further assumed that exposure to organic contaminants deposited on the leaf surface is minimal because the contaminant is removed during washing and cooking.
No ATSDR comparison values are available for the soil-plant-human exposure pathway, though the sediment arsenic concentrations exceeded the cancer risk evaluation guideline (CREG) and child environmental media evaluation guideline (EMEG) for direct soil ingestion. CREG and EMEGs are media specific concentrations of chemicals that do not pose a risk for adverse human health effects, and are similar to SSLs. The screening levels and comparison values for arsenic are presented in Table 2.
Table 2. Screening levels and comparison values for arsenic (mg arsenic/kg soil or ppm)
| SSL | Child EMEG | Adult EMEG | CREG |
| 0.4 | 20 | 200 | 0.5 |
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