Comparative marine toxicity testing: A cold-water species and standard warm-water test species exposed to crude oil and dispersant

Abstract

There are many methods in current use for testing the toxicity of discharges to marine waters. For practical purposes, standard tests and species are commonly used. None of these standard test procedures or species are done with the cold seawater and species typical of northern latitudes. This paper reports the toxicity testing of oil and dispersed oil to a cold-water species, the Tanner crab ( Chionocetes bairdi) larvae, and compares the result to two standard warm-water test species, the saltwater mysid ( Mysidopsis bahia) and fish ( Menidia beryllina) larvae. The method of reporting the exposure dose: loading rate, volatile organic analytes (VOA, C6–C9), total petroleum hydrocarbons (TPH C10–C36), or their summation, total hydrocarbon concentrations (THC C6–C36) would result in different conclusions. These differences are especially important with the water-accommodated fraction (WAF) in cold water, but may as well be significant when reporting the chemically enhanced-water accommodated fraction (CE-WAF), i.e., dispersed oil. The differences are chiefly due to the greater accommodation of VOA in the colder water.