Toxicology of oil field pollutants in cattle: a review.

Cattle are poisoned by petroleum and substances used in drilling and operating oil and gas wells. The most common reported route of exposure for non-gaseous material is oral. Exposures occur when the petroleum or chemicals used in oil and gas field activities are available to cattle and when water and feed-stuffs are contaminated. Cattle, as a leisure activity, explore and ingest crude oil. Based on morbidity patterns in cattle herds, the amount of toxic substance ingested is variable. When water and feedstuffs are contaminated, a larger number in a herd generally are affected. Cattle have been poisoned by a wide variety of chemical mixtures. For substances high in volatile hydrocarbons, the lung is a target organ. Hydrocarbons also target the kidney, liver and brain. Exposure-linked abortions have been reported in cattle. Diethylene glycol targets the brain, liver and kidney. The reported threshold dose of unweathered oil for cattle ranges from 2.5 to 5.0 ml/kg bw, and the reported threshold dose for weathered oil is 8.0 ml/kg.