Developing a protocol whole sediment toxicity testing with the polychaete Armandia agilis

Abstract

Sediments constitute a key compartment of coastal and marine ecosystems. They also constitute the ultimate sink for most of the chemical substances and a source of contamination to the benthic fauna. In this study, we aimed to develop a protocol for acute toxicity tests using the polychaete Armandia agilis as a model species. To achieve that, we evaluated the species tolerance to the salinity of overlying water (in the presence and absence of sediment), the tolerance to sediments with different particle sizes, the sensitivity to reference substances (potassium dichromate – K2Cr2O7, zinc sulfate – ZnSO4; and Sodium Dodecyl Sulfate - SDS), and the responses to clean and contaminated sediments. The species survives in several latitudes on the American coast (North Carolina, Gulf of Mexico, and South-Southeast of Brazil) in different haline conditions (above 20) in typically sandy textures. In Ilhabela (SE Brazil), the species was available throughout the year. The LC50-48h values calculated to the K2Cr2O7, ZnSO4, and SDS, were 20.94 (33.38-14.04); 4.25 (7.66-2.98); 4.90 (6.59-3.84) mg L-1 respectively; thus A. agilis can be considered as sensitive as other benthic organisms. The responses of A. agilis to environmental sediments were similar to those exhibited by the amphipod Tiburonella viscana, showing that this polychaete is responsive to contaminated sediments. Armandia agilis can be considered a promising organism to be used in sediment toxicity tests.