The versatile, changing, and advancing roles of fish in sediment toxicity assessment—a review

Abstract

Sediments serve as integral and dynamic parts of our aquatic systems. Within the last 15 to 20 years, however, the scientific community has begun noticing deterioration of sediment quality at an alarming rate worldwide. Sediments are now harboring hazardous pollutants that can directly influence water quality, thereby creating very stressful conditions for aquatic life. As a consequence, global efforts were initiated in the early 1970s, to find ways to assess sediment quality. Because of their obvious ecological and economic significance, fish have remained a major taxonomic group for appraising the general quality of aquatic systems. However, for sediment risk assessment, fish have lagged behind invertebrates due to their mobility and generally, pelagic lifestyle. To our knowledge, this is the first paper that comprehensively presents and reviews the versatile role of fish in assessing the state of health of aquatic sediments. Through a literature search of the more relevant and/or more recent studies, this review attempted to trace the development of the various approaches as well as to describe the future prospects of using fish as sentinels for sediment quality assessment. Initially, the use of whole fish (juveniles or adults) bioassays contributed immensely to our understanding of sediment contamination and ecotoxicology. But due to economic as well as ethical issues linked to the use of live vertebrates for toxicity testing, the approach has shifted to using fish cell cultures and fish embryos. Much newer approaches involving receptors and gene arrays in fish cells to elucidate the mode of action of sediment-borne contaminants are very promising. The review paper also lists and explores some of the issues associated with the use of juvenile or adult fish, fish cell cultures, fish embryos, and fish gene expression profiles in sediment toxicity evaluations to stimulate further discussions, and hopefully, to serve as benchmark for future handling of similar or related aspects of fish utilization in sediment risk assessment. Overall, the present review has comprehensively explored the changing and progressing roles of fish in sediment toxicity evaluation. Indeed the usefulness of this taxon as test organisms has provided a significant contribution to the advancement of sediment toxicology. However, despite the quite optimistic and bright future for these current procedures, a number of issues and problems remain. Therefore, efforts to develop new technologies and to refine current methods and approaches continue to challenge many laboratories worldwide.