Much attention is currently focused on how to permanently remediate the San Jacinto waste pits off Interstate 10 in eastern Harris County. Now is a critical time to be sure that the very real and measurable risks associated with one of the options — full excavation of the site — are clearly understood by those who live either nearby or downstream from this area.
Fortunately, people in the community anxious about what decision is made don’t have to take the word only of advocates — either those who call for uncovering the contaminated material through dredging or those who prefer the site remain fully capped, upgraded and then sealed permanently.
Recently, the U.S. Environmental Protection Agency turned to the U.S. Army Corps of Engineers to independently assess and model the effects of each of the proposed permanent remedies: capping vs. removal. For the first time, the Corps studies even included analysis of a newer alternative not previously studied. That option is to deploy what’s known as enhanced “Best Management Practices” (BMPs), which involves constructing barriers that seek to enable excavation to take place “in the dry.”
Unfortunately, these removal solutions were found by Army Corps’ experts to be far from risk-free. According to the full report, just released to the public in August, “… full removal … would be expected to significantly increase short-term exposures to contaminants.”
Even more concerning, if flooding occurs during remedial construction — even with enhanced BMPs deployed — the report says “releases may be up to five times greater” if these barrier structures were overtopped. Worse, if a storm were to occur “during the actual removal/dredging operation, the likelihood of extremely significant releases of contaminated sediment occurring is very high,” the report states.
In addition, the Army Corps’ report explains that for several years after removal, fish tissue contamination in the river will be dozens of times greater than under current conditions with removal using enhanced BMPs. The report even acknowledges that after removal of the existing cap and underlying material, dioxin-impacted material would still remain in place at the site. It concluded “… short-term releases [of residuals] … would subsequently be available for redistribution during erosion events from high flows or storm events.”
Natural environmental recovery of the area from these contaminants, now occurring, would also be delayed by 10 to 20 years, the report says.
In contrast, the Army Corps report concludes that enhancing the current armored cap would be highly effective in permanently preventing releases of contaminants to the environment. It notes that, when compared to capping, “ … short-term releases for the new full removal [alternative] is about 400,000 times greater than the releases from the intact cap.”
A new set of sampling results just released reinforces that the current cap is working. These results — validated and submitted to the EPA — measured samples taken from sediment surrounding the cap, groundwater underneath the capped site, surface water above and around the site, and porewater in the crevices of the rocks that comprise the cap. Dioxin concentrations from within the waste pits were not detected in either the groundwater or porewater samples. In short, the existing cap is preventing release of dioxin into the environment. Fish tissue samples from around the site also show that dioxins in these fish are at levels similar to other fish found both upstream and downstream from the waste pits. And we all know the San Jacinto River contains various other dioxins not related to the waste pits.
Before settling on a final decision about the best remedy for the site, EPA will follow Superfund protocol and take into account all verifiable data — not solely public opinion and the assortment of points of views expressed by observers. (The latter are only one of nine Superfund criteria evaluated.) The independent expert analysis of alternatives by the Army Corps, together with the new results from recent sampling of the site mandated by EPA, point to what is scientifically required to remediate the pits.