Peter V. Hodson

Qsar Studies On Chlorophenols, Chlorobenzenes and Para-Substituted Phenols

The acute toxicities of chlorophenols (CP’s) chlorobenzenes (CB’s) and para-substituted phenols (PP’s) to rainbow trout (Salmo gairdneri) as intraperitoneal injection lethality, serum sorbitol dehydrogenase activity, and 96-hr lethal concentration are investigated in terms of quantitative structure-activity correlations (QSARs). The effects of CP’s and CB’s are primarily related to the chemicals’ octanol/water partition coefficients (log P). The slopes of the QSARs of CP’s for rainbow trout are nearly parallel to those of acute and semichronic CP toxicities to bluegill (Lepomis macrochirus), guppy (Poecilia reticulata), waterflea (Daphnia magna), and the marine organismPhotobacterium phosphoreum, indicating similar mechanisms of toxic effects. The toxicites of PP’s are dependent on both log P and other molecular descriptors, such as molar refractivity and field and resonance constants of the para-substituents.

Lethal Dose Versus Lethal Concentration as Indicator of Contaminant Toxicity to Fish

Median lethal dose determinations by intraperitoneal injection (IPLD50) provide a rapid and reliable indication of the lethal effects of chemicals on fish. The IPLD50s are correlated with oral lethal dose (OILD50) as well as aqueous lethal concentration (LC50), the traditional measure of toxicity. The speed and efficiency of toxicity testing by IPLD50 makes it a valuable tool for structure-activity studies of toxic substances.

The use of Rapid Biochemical Indicators of Toxicant Stress to Generate Biological Data Bases for QSAR

The assay of serum sorbitol dehydrogenase and plasma leucine aminonaphthylamidase activities to indicate liver damage of toxicant to rainbow trout (Salmo gairdneri) was asssessed using paramethylphenol (para-cresol) as a model toxicant. Both tests appear to be useful indicators for the rapid assessment of toxicant effects on fish.