Summary

Description

Chemicals at oil production sites can be hazardous to migratory birds and other wildlife. Oil, grease, and other chemical wastes related to well drilling are commonly stored in pits at oil production sites. Oil lost at valves is frequently caught in open containers. Oil production sites are located in arid regions of South Dakota where wildlife mistake open pits for wetlands and are often attracted to them. The Service studied the chemical composition and toxicity of oil pit liquids and searched oil production sites for dead wildlife. Liquids andor sediments from 31 pits located in Fall River and Harding Counties were evaluated for oil and grease in 1992. Oil and grease concentrations were at levels known to reduce benthic invertebrate numbers in all liquid samples analyzed. Due to a decline in the number of pits, only 15 Harding County pits were evaluated in 1993. Oil and grease concentrations were at levels similar to those found in 1992 in only 2 of 15 samples analyzed. Forty pits were searched for dead wildlife in 1992 and 15 were searched in 1993. Dead wildlife, especially small mammals and birds were found around oil production sites. Salvaged carcasses were partially or totally covered with oil. Studies of scats indicated that predators consumed birds that died from oil exposure. Electrical conductivity of 17,000 umhoscm has been shown to significantly reduce duckling growth. In 1992 and 1993, electrical conductivity in 4 pits equaled or exceeded 17,000 umhoscm. Electrical conductivity of pit liquids also could impact the diversity and abundance of aquatic invertebrate and plant species in and around pits. The best method for preventing impacts to wildlife from chemical wastes at oil production sites is to totally eliminate wildlife contact with the waste liquids. Colored flags on guy wires had been installed at some pits to scare birds and other pits had been covered with nets. Flagging is ineffective at deterring birds Esmoil, 1991. Properly maintained netting can be an effective deterrent for larger birds. However, the best way to prevent wildlife mortality is to store waste liquids in closed tanks until they can be reinjected back into the ground. Many oil companies have begun extensive liquid reinjection efforts, thus making pits unnecessary. The conclusions of this study are that pit liquids and sediments contained high concentrations of oil, grease, and other unidentified toxic chemicals that through contact or ingestion, could immobilize or cause mortality to birds and other wildlife. Several oil companies have initiated management strategies which minimize hazards to wildlife.