EVALUATION OF PEROXIDASE AS A BIOCHEMICAL INDICATOR OF TOXIC-CHEMICALEXPOSURE IN THE AQUATIC PLANT HYDRILLA-VERTICILLATA, ROYLE

Laboratory bioassays were conducted to determine the utility of peroxi dase (POD) activity as a biochemical indicator of contaminant exposure in the aquatic plant Hydrilla verticillata, Royle. The plants were ex posed to anthracene, sulfometuron methyl (OUSt(R)), Cd2+, Cr6+, Cu2+, Mn2+, and Se4+ in concentration factors of 10. POD was extracted and m easured by spectrophotometric assay. There was a significant increase in POD activity after a 5-d exposure to each of the chemicals at 1 mg/ L. The optimum pH for POD activity after exposure to the chemicals was 5.5 to 6.0. The increase in POD was found to be dose dependent for ea ch of the chemicals. The lowest concentration of chemical to induce a significant POD increase was 0.01 mg/L for anthracene, Oust, Cd, Cr, a nd Cu; 0.1 mg/L for Se; and 1.0 mg/L for Mn.