| Popis: |
Publisher Summary This chapter reviews the current use and hazard and exposure profiles for aldicarb and outlines their integration into a quantitative risk assessment. Aldicarb chemistry, biological characteristics, mammalian toxicity data, pharmacokinetics, and the determination of the point of departure (POD) for risk assessment are described. Aldicarb is a carbamate insecticide with activity on a broad range of pests (insects, mites, nematodes). Technical aldicarb belongs to the N-methyl carbamate chemical family. The pure (technical) material is a white crystalline solid with a water solubility of approximately 6000 ppm at 25 °C and is stable at room temperature. It is a soil-incorporated, systemic insecticide that is absorbed by the root system with subsequent translocation throughout the plant for control of chewing and sucking pests. It has a very robust toxicity database including acute, chronic, developmental, reproductive, and neurotoxicity studies. Aldicarb has high acute toxicity, causing cholinergic symptoms due to the inhibition of acetylcholinesterase (AChE). These symptoms are dose-dependent, are rapidly reversible, and do not occur at expected human exposure levels. Aldicarb is neither genotoxic nor carcinogenic. It does not cause developmental or reproductive effects in the absence of maternal toxicity. Dose levels of 0.1 and 0.26 mg/kg are considered to be high doses, and clinical signs, typical of anticholinesterase agents, were observed at these doses within 1 h of aldicarb administration. ChEI at these very high dose levels was observed in all volunteers within 1–2 h after treatment. Recovery was evident within the first 6 h after treatment. No evidence of toxicity was observed at 0.05 mg/kg. Urine analysis showed that approximately 10% of the administered dose was excreted as carbamates within the first 8-h interval. This chapter also discusses advances in the methodology for incorporating the rapid reversibility kinetics of cholinesterase inhibition (ChEI) by aldicarb into a quantitative dietary risk assessment. |
