PARENT SESSION
MP7 Bioassays for specific hazards
3:00 PM to 6:30 PM, Monday, 07 May 2001
Session Chair: H.T. Ratte
Room 7

(126) Toxicity Testing and Hormonal Activity of Landfill Leachates.

WARD, Marnie¹, BITTON, Gabriel¹, DENSLOW, Nancy¹, Townsend, Timothy¹, ¹

ABSTRACT- Acute and chronic toxicity as well as hormonal activity of leachates from six Florida solid wastes landfills were followed for a six-month period, using Ceriodaphnia dubia, Selenastrum capricornutum, Microtox, MetPLATE, and a recombinant yeast estrogen assay. Both the Ceriodaphnia dubia and the Selenastrum capricornutum toxicity tests displayed similar sensitivity and showed that the landfill leachates were highly toxic with EC50s < 10% in most of the samples. The 15-min Microtox test was the least sensitive to leachate toxicity. MetPLATE, a toxicity test specific for heavy metal toxicity, showed no metal toxicity in most of the samples, except for a steady small toxicity in the Orlando landfill leachates. Subsequent testing with MetPLATE showed that landfill leachates displayed a high metal binding capacity (i.e., high water effect ratios). A recombinant yeast, Saccharomyces cerevisiae, containing the human estrogen receptor (hER) was utilized to assay for hormonal activity in the landfill leachates. It was found that the assay has a detection limit of 4.2 ng/L for 17b-estradiol which was used as the positive control. Our study shows a relatively high degree of hormonal activity in the landfill leachates, ranging from 5 to 75 times greater than that induced by the positive control. The sampling site, month, and strength of landfill leachates influenced the degree of hormonal activity. This work was supported by the National Science Foundation, Grant # BES-9906060

Key words: Hormonally Active Agents, YES assay, Solid wastes leachates, Toxicity