Chemical Release Analysis and Cancer
Chemical Release Sites can be broken down numerous ways into categories, which in turn are used to define the degree of sophistication researchers wish to engage in with their GIS research project on chemical releases. The most common methods of identifying sites for research typically involved reported case data, eitehr through local hearsay or by way of county-related research projects involving particular chemical cases. When a series of cases are reported or publicized, thereby creating or increasing the suspicion for one or more local release sites as a possible cause, the type of research these claims can often lead to are rightfully considered highly biased in many cases–in crude terms, the researchers (and public sponsoring such research) are really just looking at some industry or place to point the finger at, a relic of the old Love Canal history of environmental pollution research and studies.
Fortunately, most research employed by epidemiologists pretty much prevent these prejudgments from happening. However, the problem with epidemiological research is it is typically hindered by the limits of the data that are provided. We most often rely upon block or areal data in order to improve the chances for anonymity on behalf of the victims whose changes in health led to this research in the first place. This use of areal data does hinder the mathematical power of such studies due in part to the error introduced by these methods. In GIS, there are some methods proposed that reduce the high value placed on demographic data utilization to study areas. We can use census data, and apply it using a house-by-house or building-by-building, relying upon some rather sophisticated calculations designed to produce such outcomes using aerial photography and remote sensing data.
The studies I tend to engage in pay heed to census data, and use it whenever necessary, but also rely more upon the site data instead of people data in order to draw my conclusions. As you will see by reviewing these methods, some of the methods tested here have considerable power when evaluated in combination with other spatial population data forms, including the use of the Gini Coefficient used to measure local poverty, or the use of any opf several aerial economic calculations methods is use by demographers and economists. For now, I will stick to the sites and their chemistry to make most of my spatial analyses points with regard to chemical release sites mapping.
Chemical release is very much the focus of most of my studies in cancer epidemiology GIS. This is due in part to my twenty years of experience as a lecturer/adjunct professor in chemistry, toxicology, phytoecology and phytochemistry, environmental chemistry, disease ecology, and GIS-Remote Sensing.
Since 1987, Oregon has had more than 25,000 sites either reported and reviewed, or considered for review for their potential toxicity following the reported release. Many of these reports filed were immediately removed from the list of toxic sites due to the type of report filed, the inability to locate the site or find the spill that was reported, and the inability to confirm that a spill or release happened due to lack of environmental chemical evidence following field visits. Many sites remain on any of several lists due to the need for clean-up. Less than 5% of those sites are under current or consideration for superfund site clean-up, and/or are included in the pending lists of sites due for environmental clean-up.
In addition, since 1987, Oregon has had many of its sites removed from toxic site listings, and many others reviewed in any of several ways. During the first phase of this release site research project in fact (the first 2 years), first the superfund sites were mapped, followed by the mapping of 82 other sites considered for superfund funding but not yet included on the superfund list. In addition, of the thousands of chemical release sites with suspected exposure risks to the public, approximately 450 were classified as “Confirmed Release Inventory Sites” (CRIs), meaning a certain amount of confirmation was made regarding the reported chemical spill and land use history. Each of these 450 sites was then evaluated independently and their chemical spills reports data pulled from the Oregon State University database on these sites, which was then analyzed in numerous ways and finally these results mapped. During the subsequent phases of this development of the database on all of the remaining Oregon ECSI or TRI sites, site information was gathered a small percentage at a time, and databases developed and then used to produce the first maps on this information. Anywhere from two to three thousand sites, most recently reported or very small in size or amounts of chemicals released, still have to be mapped.
In a recent review, database update, and mapping of 670 of the first 1000 sites placed in the ECSI/TRI report during the first two years approximately, most these sites contained chemical data but were not in the CRI listing in spite of their considerable age on the list. Reasons for their exclusion were interesting (politically that is). Two counties had little chemical data filed at all for many of their sites This may have been due to the fairly rural nature of these counties, since due to their location and limited revenues it was presumed that both were simultaneously by the same environmental recovery program or agency, with actions that may have not been initated at the time of this research. Other times, the causes for exclusion from sueprfund review were obvious. Some sites lacked chemical information and/or filed the required papers for superfund review fairly late. This was the case for at least one of the most toxic sites in the state, in need of but not eligible for superfund funding needed to clean-up its suburban setting. By missing such deadlines for superfund clean-up consideration, these outcome delayed the cleanup process for several more years.
As time passed over the years while carrying out this project, I noted that with time, the percentage of CRIs in the remaining site lists decreased as the number of new TRI sites increased. In general, the overall severity of all sites combined has decreased with time, making the seriousness of these sites less a public health concern, at least at the sueprfund level. For now, the CRIs and portions of the ECSIs/TRIs documents in the state and federal databases remain the focus of this study.
The sites described at the Oregon data storage facility provide the best details for reviewing these sites, although not in any easily downloadable form. The fairly complete reports filed for most of these sites contrats greatly with similar datasets received from otehr region warehouses in the midwest. The Oregon reports provide the best information related to TRIs, on a per site, per chemical report basis. This method of guessing a site’s chemical release history I have termed “chemical fingerprinting.” The data used to develop this work has therefore enabled me to develop a way of catagorizing these sites based on their chemical profiles. This fingerprinting of a site is covered extensively later in this work, and is based primarily on my review of approximately 450 to 550 sites (depending on sites being referred to). As some of my much later research shows, this method is fairly reliable for use in identifying chemical indicators that are strongly related to just certain site types or classes (these are also reviewed separately due to the methods used to reclass chemical release sites for such a review). And I am not the first person to try and document the chemical characteristics of sites based on their landuse and industrial and manufacturing history. My method does differ though from earlier attempts in that I used a reclassification method previously not considered, in which both chemical groups and toxicity/carcinogenicity were taken into consideration along with a site’s SIC data and the need for reclassifying that SIC to more appropriately group chemically-related sites together for more extensive reviews.
To date, more than 45,000 chemical spill reports have been reviewed and added to the database, and are used to produce many of the isoline maps you will see.
ECSI/TRI reports data
Several times, fairly large datasets were obtained from federal sources on the web other than those made available through the state of Oregon. This data was mapped and reviewed to determine its validity and reliability and to see how this data mapped out in relation to the maps produced using Oregon data. This data lacked detailed chemical report information, in which the outcomes of each site inspection are provided, but this information still provides insight into Oregon’s industrial history.
These first figures depict the summaries of numbers of toxins evaluated at the sites. This provides us with information on the frequencies that different types of toxins are inspected for at these sites. Due to greater public and public health concerns, the most frequently chemicals tested for such include lead and benzene.
These lists of ECSI or TRI (Toxic Release Inventory) sites were not purged of any Confirmed Release Inventory data use in the next study of Oregon sites. The resulting maps therefore depict chemical release history based on the more important sites at the time this dataset was collected (ca. 1998). The following are examples of the outcomes of this work.