Page 84 - Environmental Control in Petroleum Engineering

CHAPTER 3

The Impact of Drilling

and Production

Operations

Many of the materials and wastes associated with drilling and
production activities have the potential to impact the environment. The
potential impact depends primarily on the material, its concentration
after release, and the biotic community that is exposed. Some environ-
mental risks may be significant, while others are very low.
The most common measure of the potential environmental impact
of a material is its toxicity. Toxicity occurs when a material causes a
deleterious effect on an organism, population, or community. These
effects can range from temporary disorientation to lethality. This
chapter reviews how toxicity is measured and then summarizes many
of the toxicities measured for materials associated with drilling and
production activities.

3.1 MEASURING TOXICITY

The toxicity of a substance is a measure of how it impairs the life
and health of living organisms following exposure to the substance.
In most cases, the effects of the substance on human life and health
is of primary importance. Toxicity is determined through bioassays by
exposing laboratory animals to different amounts of the substance
in question. The resulting effects on the health of the animals are
observed. For petroleum industry wastes, common test species used
for marine waters are the mysid shrimp (Mysidopsis bahia) and
sheepshead minnow (Cyrinidon variegatus}, while fathead minnow

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