Effects of low-level arsenic exposure on the developmental toxicity of anilofos in rats

In view of the increased use of anilofos for crop protection and ever increasing arsenic levels in drinking water in many countries, the coexistence of arsenic and anilofos in the environment is a reality and simultaneous exposure of humans and animals to these contaminants could be potentially hazardous. The aim of the present study was to examine whether coexposure to arsenic at the groundwater contamination level could alter the embryofetal toxicity of anilofos in rat model. Anilofos (100 mg kg(-1) day(-1)) and sodium arsenite (1 mg arsenic kg(-1) day(-1)) were administered by gavage either individually or in combination to the pregnant rats from day 6 to day 15 of gestation. Arsenic did not produce any significant effects either on maternal or fetal parameters at the given dose. Anilofos alone significantly decreased maternal weight gain, feed and water intakes, gravid uterine weights, number of live fetuses and fetal body weights and increased resorptions. There were increased incidences of gross, skeletal and visceral anomalies in the fetuses of anilofos-treated group. The main skeletal abnormality was increased intercostal space, while the visceral anomaly was an interventricular septal defect. Treatment with the combination of arsenic and anilofos significantly enhanced the fetal changes with much greater magnitude compared with the effects produced by anilofos alone. Anomalies such as midfacial cleft, exencephaly and anophthalmia were seen only in the fetuses of the combination group. The results show that anilofos interferes with embryofetal development and coexposure with arsenic at environmentally realistic concentrations produces additive or synergistic effects on the developmental toxicity of anilofos in rats. Copyright (c) 2007 John Wiley & Sons, Ltd.