Abstract for RACB90029

Reproductive Toxicity of Iowa Pesticide/Fertilizer Mixture in CD-1 Swiss Mice

Report Date: August 1992


The following abstract presents results of a study conducted by a contract laboratory for the National Toxicology Program. The findings were not evaluated in accordance with the levels of evidence for reproductive or developmental criteria established by NTP in March 2009. The findings and conclusions for this study should not be construed to represent the views of NTP or the U.S. Government.

Pesticide/Fertilizer Mix - Iowa (PFM-I) contained alachlor, atrazine, cyanazine, metolachlor, metribuzin, and ammonium nitrate and is representative of samples taken in groundwater in Iowa. PFM-I was evaluated using the RACB protocol for reproductive toxicity in Swiss mice. The low dose was the median level found in samples of Iowa groundwater. This was termed "1X"; the middle dose was 10-times this, and the high dose was 100-times the low dose. Thus, the doses are termed 0, 1X 10X, and 100X in drinking water. These dose levels produced calculated consumptions of between 9 and 20 µg/kg body weight per day for the pesticides, nearly equal to 250 mg/kg/d for the ammonium nitrate, and nearly equal to 130 mg/kg/d for propylene glycol, a solubilizer and stabilizer. Water consumption was increased for the F0 females at the high dose at wk 16, when it was increased by nearly equal to 17%.

F0 body weights were unchanged by exposure to water containing these pesticides and nitrate. Functional indices of fertility (pup number, weight, etc) were also unchanged by exposure. After the end of the continuous cohabitation phase, when the second generation was weaned, the control and 100X F0 mice were killed and necropsied; no effects were found in terminal organ weights, sperm indices, or vaginal cyclicity.

Only the high dose F1 mice were reared to mating at pnd (post-natal day) 74; there were no effects of mixture exposure on body weight or survival of these animals. Similarly, there were no effects on the reproductive indices in the F1 mating trial. When the F1 mice were killed and necropsied, no differences were found between controls and 100X mice in organ weights, histopathology, or sperm or vaginal indices.

In summary, exposure of CD-1 mice to groundwater containing basal levels of pesticides and nitrate, or log-multiples thereof, had no detectable effect on any measure of reproductive or systemic toxicity in this study.

NTIS #PB93109270/AS