Toxicity of arsenic and PCB to a green alga (Chlamydomonas).

Abstract

High arsenic and PCB concentrations have recently been reported for Green Bay, Lake Michigan. The source of arsenic has been localized to a chemical company producing arsenic herbicides in Marinette, Wisconsin. While the production ceased several years ago, the arsenic pollution persists because of ground water infiltration of leachates from storage piles of arsenic-containing wastes. The sources of PCBs are less well known. The sources are probably non-point in nature, and originate in part from local dumpings of PCBs previously used as dielectrics and hydraulic fluids. The levels of these contaminants, e.g., up to 10 ..mu..g As/L and 0.45 ..mu..g PCB/L could present a hazard to the biota. The effect of arsenic and PCB on algae have been studied for each of these toxicants acting separately, but not in combination. PCB at 10 to 100 ..mu..g/L inhibit chlorophyll production and RNA synthesis. On the other hand, arsenate at 1 ..mu..M behaves as an antimetabolite occupying sites for phosphate. Based on the different toxic mechanisms for the two compounds, it is hypothesized that they will show independent joint action, i.e., that they will not form a particular toxic combination. The purpose of this study was to establish toxic thresholds and possiblemore » interactive effects of arsenic and a PCB (Aroclor 1248) for the green alga Chlamydomonas isolated from Lake Michigan.« less