Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/20/2007
Publication Date: 10/10/2007
Citation: Koskinen, W.C., Devault, D.S. 2007. Adverse impacts of waste water treatment a case study [abstract]. In: Book of abstracts of the 14th International Symposium on Environmental Pollution and its impact on life in the Mediterranean Region with Focus on Environmental Health, October 10-14, 2007, Sevilla, Spain. p. 316.
Technical Abstract: Industrial metal plating processes coat materials with metals, such as chromium, copper and nickel. After the plating process, excess metals are rinsed off and the rinse water is collected and then treated to remove metals prior to discharge of the rinse water into rivers. This waste water is typically treated with sodium dimethyldithiocarbamate, which will precipitate the metals in the water resulting in aqueous metal concentrations low enough that the treated water can be released into rivers. However, misuse of this treatment can result in adverse environmental impacts. During a period from June through October, there were three fish kills in the Ohio River, downstream from an industrial plating plant. By October, the invasive Zebra mussels in a portion of the river near the plant were gone, there was 100% native mussel mortality in beds nearest the plant, and mussels 8 km downstream from the plant were dead or dying. The net result was that 9,000 fish (primarily fresh water Drum), 10,000,000 gastropods, 1,000,000 freshwater mussels (>20 species, including 2 Federally-listed endangered species, some of which were >30 yrs old), and all benthic organisms within 80 m of the shore near the plant were killed. The water quality parameters during that time were: dissolved oxygen 6-8 mg/L, water temperature 20-25 C, pH 7.0, no microcystin or other algal toxins detected, and no PCBs or other pesticides detected. In the fish, there were no viral or bacterial diseases or unusual parasites. Other factors were investigated as possible causes of the fish and mussel kill. In the area of the kill, just downstream from the plating plant, chromium concentrations were many times greater in sediments, mussels and fish as compared to levels just upstream from the plating plant. However, it is questionable whether the chromium levels were acutely toxic. Although sodium dimethyldithiocarbamate is typically used to remove metals from waste water, there are reports that it under certain circumstances it can react to form 1-(dimethylthiocarbamoyldisulfanyl)-N,N-dimethyl-methanethioamide, or thiram, a fungicide that is highly toxic to fish and mussels. Analysis of sediment, mussel, and fish samples by lc-ms resulted in positive detects for thiram in sediment and mussel samples. It appears that the plating plant misused the sodium dimethyldithiocarbamate during the treatment of the metals resulting in thiram formation, which in turn caused the fish and mussel kill. Although sodium dimethyldithiocarbamate is very effective in precipitating metals from waste water, its use has become controversial, other fish kills attributed to the misuse of this chemical have been reported since this incident.