Assessment of methods for estimating ecological risk in the terrestrial component: A case study at the baird & mcguire superfund site in holbrook, massachusetts

Abstract

Predictive, bioassay, and field methods were compared with regard to assessing conditions and risks to terrestrial biota at a Superfund site contaminated with pesticides. Research indicated that predictive methods could result in large uncertainties, especially when attempting to estimate food chain transfer from soil to higher trophic levels (birds and mammals). Of the examined predictive methods, the soil‐to‐earthworm model yielded results that agreed best with field observations and literature values. Laboratory and in‐field bioassays on soils provided good information on the potential toxicity of soils and the potential for bioaccumulation. In‐field bioassay tests with earthworms were useful for defining the spatial distribution of toxic soils at the site as well as for indicating potential bioaccumulation in invertebrates. An attractive feature of in‐field bioassays is that samples do not have to be removed from the field and assessments can begin to be made in the field. The importance of performing reality checks by conducting field studies was clearly demonstrated in our study with regard to the soil invertebrate community as well as birds and mammals. The main advantage of the field studies is that they provide direct information on conditions and thus aid in the interpretation or application of laboratory data. Difficulties were encountered in the conduct of population studies of the birds and mammals. Therefore, although site surveys of birds and mammals provide gross indications as to the presence and diversity of animals, it is probably more useful to rely on measures of residues and biomarkers to assess potential exposures and the possibility of subtle effects. Overall, it appears that ecological risk assessments at Superfund sites are best conducted by using a mix of predictive, laboratory, and field methods.

A critical assessment of the ecological risk assessment process: A review of misapplied concepts

“…There is no shortage of references in the open literature that also acknowledge this point (Kolluru 1996; Tannenbaum et al 2003b). Nevertheless, the HQ is routinely computed today with its values of varying magnitude said to correspond to different levels of ecological risk (Menzie et al 1992). Aside from the mystery of why the U.S. EPA's acknowledgement of this critical HQ limitation goes unheeded by professionals in the ERA field (including those within the U.S. EPA), there are dramatic consequences for the ERA process (more so than for the HHRA process) (Tannenbaum et al 2003b).…”

Toxicological benchmarks for wildlife: 1994 Revision

“…In most screening assessments, because they rely on existing data, available data are likely to be restricted to contaminant concentration in abiotic media (e.g., soil and water). Contaminant concentrations in wildlife foods may need to be estimated using contaminant uptake models such as those described in Baes et al (1984), Travis and Arms (1988), or Menzies et al (1992). Table 13 provides a simplified example of the use of benchmarks in a screening assessment.…”

Estimating Exposure of Terrestrial Wildlife to Contaminants

“…Travis and Arms (1988) report that uptake factors for organic chemicals in vegetation are inversely proportional to the square-root of the octanol-water partitioning coefficient (K ). Uptake of organics by earthworms ow may be estimated according to the method of Menzie et al (1992) where:…”