The toxicity of Prudhoe Bay crude oil in erythrocytes and chick embryos

Abstract

When it was incubated with herring gull or human erythrocytes Prudhoe Bay crude oil (PBCO) was found to induce methemoglobin formation, hemolysis and glutathione depletions in the-presence of a metaboluractivation system such as rat liver microsomes plus NADPH, these effect's were greatly enhanced. -- Components of crude oil such as naphthalene and methylated naphthalenes induced methemoglobin formation in vitro in erythrocytes only when liver microsomes and NADPH were present in the incubation medium. However, naphthalene metabolites such as 1, 2 and 1 , 4-naphthoquinone, 1,2- and 1,4- dihydrbxynaphthalene and 1-naphthol required no metabolic activation to produce toxic effects. In these studies naphthalene was used as a model to investigate the mechanism of PBCO toxicity in erythrocytes. -- The aliphatic, aromatic and heterocyclic fractions of Prudhoe Bay crude oil were tested on the developing chick embryo for toxicity (in terms of mortality) and Influence oncytochrome P-4,50 and aryl hydrocarbon hydroxylase induction. Induction of these enzymes by the fractions of crude oil was studied in the liver, kidney and lung. The aromatic fraction was found to be responsible for most of the embryo toxicity and enzyme inducing ability, based on its concentration in PBCO. -- Although the heterocyclic fraction was less than 7% (w/v) of PBC0 on a weight equivalent basis, it was approximately as potent as the aromatic fraction in causing embryo toxicity and inducing increases in levels of cytochrome P-450 and aryl hydrocarbon hydroxylase. The aliphatic fraction had no toxic or inductive effects. These, results suggest that embryo toxicity may be due to the metabolism of aromatic compounds to more toxic derivatives by aryl hydrocarbon hydroxylase.