Review of:

Screening Level Ecological Risk Assessment (SLERA); Elizabeth Mine South Strafford, Vermont 4/15/2003

SUMMARY OF DOCUMENT:

This is the first step that needs to be completed prior to another study called a “Baseline Ecological Risk Assessment” (BERA). This step is conducted according to EPA protocols for ecological risk assessments at superfund sites and is part of the superfund process. The study lists areas of interest (AOI). These are areas that are potentially affected by the contaminants from the mine drainage and include both terrestrial and aquatic habitat.

The impact to humans is not assessed in this report. This will be done in other reports. This report examines the impact to: aquatic vegetation, aquatic bugs, amphibians and reptiles, birds, fish and mammals that eat bugs and fish. On the land it looks at plants, bugs and micro-organisms in the soil, birds and mammals (but not humans) that eat plants, other animals or everything.

The study summarizes the results of existing data collection from multiple areas of interest (AOI) from the watersheds of the tributaries and mainstem of the W. Branch of the Ompompanoosuc River that are impacted by the acid mine drainage. These AOI’s may change on the basis of a more comprehensive habitat assessment that will occur (or has occurred) in the spring of 2003.

The maximum level of each chemical detected in the AOI’s are compared to established guidelines on the impact of those chemicals. These guidelines are based on ecological risk and come from a number of sources include national and state standards and standards developed in Canada. These standards are summarized in Tables 2-1 to 2-3.

Page iii of the executive summary lists the overall conclusions, and the areas that need further study. Most of the areas that need further study are adjacent to the areas that are directly impacted. Further analysis will tell how much the impact has ‘spread’ to adjoining areas.

The mine area itself (around TP 1 –3 ) will not be assessed for ecological impact because it is “unlikely that there is habitat to support ecologically significant populations of ecological receptors”.

On the basis of this initial summary, the report recommends that the next step the “Baseline Ecological Risk Assessment” be taken.

Completion of this study seems to be a pre-requisite to take the next steps. This allows (I believe) the site to move forward in the process.

SUMMARY OF RESULTS

Tables 3.1 – 3.18 give good summaries of the minimum and maximum concentrations found of different metals/compounds, the percent of samples that had the chemical and the average concentration in the samples. There are 2 –3 tables for each site: 1) surface water, 2) sediment and 3) surficial soils. Most of the sites have had sediment and surface water tested. Very few have had the surficial soils tested. A hazard quotient (HQ) is assigned to each compound. This is the ‘ratio of measured contaminant concentration to the applicable screening criteria.” If the number is greater than 1 then the criteria are exceeded. Every compound that had an HQ greater than 1 is a compound of potential concern (COPC). A statistical analysis was also conducted.

Table 3-19 lists the areas and the chemicals that exceeded the established standards (had HQ’s >1). The compounds that were found in every surface water location that exceeded guidelines were aluminum, barium, chromium, copper, iron, lead and silver; manganese, cyanide were found in some locations; and Selenium, thallium and vanadium were limited to Copperas Brook and the air vent. Other compounds were found to exceed standards at limited locations.

In general, surface soils around Sargeant Brook had the highest exceedances of standards of a number of compounds include copper (4633 x higher), lead (670 x higher), and cadmium (500 x higher). Since other areas have not had surficial soils tested, it may be found that there are other areas (apart from the source area) which may have high exceedances in soils.

Other ‘high’ points include - cyanide concentrations in sediment around the air vent (337 x higher than standard) and the WBOM (237 x higher than standard).

The laboratory analysis was very thorough and included testing for synthetic organic compounds (SOC) like pesticides. Several pesticides were detected at the air vent and the WBOM and they will be looking into those further.

Appendix B contains the original data for the analysis. This is great, but it is in pdf format which would make it difficult for anyone who wanted to do any analysis of the data. It would be great if it came in read-only files as text or spreadsheets.

MISSING INFORMATION

The tables in the appendix use abbreviations without explanations of what the abbreviations mean.

The report contains several errors listed below.

ERRORS:

2.1.1.2 Physiography

Copperas Brook watershed is larger than 300 acres, has a larger flow range than 50 – 2000 gpm at the confluence with the WBOR and has a change in elevation that is greater than 750’. Correct information should be supplied. This information had been copied from a report by ADL.

2.1.1.5 Past sampling of environmental media

ANR completed an initial study in April 1969 titled ‘Mine Pollution In The Ompompanoosuc River Basin. The predecessor of ANR, Water Resources Department did the first sampling in 1954 and printed the first study of the Elizabeth Mine in 1969 on the basis of data collected in 1967. ANR’s study is referenced as 1977. No reference is given for the 1977 study.

EMSG sampled 5 locations (not 3) and sampled all locations in 1998 and none in 1994. this is clear in text and appendix of study, but USGS file used 94 date on some samples.

MISSING INFORMATION:

EPA has specific protocols that need to be followed, samples need to be taken in a certain way, chain’s of custody established etc. The report mentions some previous work conducted by different agencies in Section 2.1.1.5 and says that data for surface water, sediment and soil will be included in this SLERA. However, Appendix B does not contain information prior to 2000. This is an inconsistency in the report. Missing analyses includes USGS groundwater, surface water and sediment data and a bat study completed in 1999. The report should be consistent and if data is to be included, than it should be, if it is not included, then it is best to say that it is not included. This is a minor detail.