CRIs, Chemicals and SIC
The types of evaluations performed of the CRIs involved specific chemical reports, summarizations of reports of similar or identical chemicals on a per site basis, summarizations of reports of chemicals regrouped or reclassed into specific chemical categories (two systems were developed for these reclasses), and summarization of site history for sites reclassed or regrouped based on an analysis of their Standard Industrial Classification (SIC) codes in relation to chemical spill classes and release history.
These detailed analyses of the sites data allow for GIS maps to be produced depicting exposure risks and release histories in numerous ways. We can essentially map out exposure based on an individual type of chemicals released locally or statewide (i.e. a statewide map depicting benzene release and theoretical exposure), the types of chemicals released based on how they are reclassed by chemical groups (i.e. aromatic versus non-aromatic halogenic compounds), the types of industries based on their SIC identity known to release chemicals related to that SIC (for example the release of polycyclic aromatics by various types of lumber industries).
It ends up that the use of SIC alone to identify an industry-related chemcal release history is very poor at actually telling us much about the site’s actual release history. It is also true that many sites are tested for specific chemicals regardless of whether or not they actually spilled or released these chemicals. It ends up, that many times concentrations are provided for the chemicals tested for as part of the site EPA-required testing procedures (i.e. a water or soil sampling procedure). In cases where concentrations are documented as being above the EPA standards, these sites can be mapped and risks assigned to the area impacted by these spills. Other studies can be done by interpreting the test for possible presence of a given chemical as an indicator that the possibility for exposure may have existed for this area as well, regardless of whether high or low levels are found as a result of field tests performed at these sites.
The following is an example of the results of our initial review of state chemical spill data, in which the chemicals were reclassified into types of chemicals and then maps depicting risk on a per county basis were generated for these various groups.
Four Chemical Classes and Spills or Releases, by County
We can also use bar charts in ArcView to demonstrate the chemical history of a place. In the following display of county-wide release site totals, the differences between the most urban setting of the state and the non urban regions make it difficult to interpret the meanings of chemical exposure the more rural counties. Nevertheless these are valuable ways of demonstrating the data, even if this information does not represent the data on a point by point basis. In general, this information displays averages for a county, which in this case do not take into account the surface area of the county. So a concentration of releases is not what is being displayed, only the numbers of reports filed, per county, regardless of their findings.
Two groups of potentially carcinogenic chemicals, using a barchart display
Another topic popular to Oregon, especially close to it major urban center Portland, is the possible contamination of groundwater. Spill/release site data provides us with insights into how this issue is also dealt with as part of the Superfunds project devoted to this particular spill site. In the following maps, the state map displays groundwater contamination as a statewide problem, with a focus of the urban-trimetropolitan setting serving as the focus in the second map. Each map depicts this issue in distinctly different manners based on data extracted from the state database.
State and Local Groundwater Assessment according to the State Database
Brian Altonen, MPH, MS 