ABSTRACT
Biomarkers can be defined as biochemical, physiological, or pathological responses measured in individual organisms, which provide information concerning exposures to environmental contaminants and/or sublethal effects arising from such exposures. This chapter describes selected biomarkers that may be of particular potential utility in hazard assessments of contaminated sediments. It also provides an overview of considerations required in the actual application of biomarkers. The chapter describes a number of organismal-level responses that appear to have significant potential as biomarkers. Biochemical responses to contaminants have received the greatest amount of attention as potential biomarkers for environmental quality. A complex array of enzyme systems functions in many organisms to transform lipophilic organic compounds to more hydrophilic products. Metallothioneins comprise the major metal-binding proteins in animals and occur in plants and prokaryotes as well. Stress proteins include a diverse array of proteins that are inducible by a variety of stressors. Oxidative stress, or oxygen toxicity, refers to injurious cellular effects due to activated oxygen species.
