Development of a Chronic Sublethal Sediment Bioassay Using the Estuarine Amphipod Leptocheirus Plumulosus (Shoemaker)

Abstract

Abstract-Based on the need for a test to evaluate chronic sublethal toxicity in estuarine sediments, a 28-d sediment bioassay with the estuarine amphipod Leptocheirus plumulosus (Shoemaker) was developed. The test was initiated with animals less than 2 weeks old (i.e., 425-600 m sieved size class). Test endpoints included survival, growth (g dry weight/d), and reproduction (number of neonates/surviving female). Factors with the potential to influence test animal performance (i.e., nontreatment factors) such as artificial sea salts, salinity, food ration, size at test initiation, intraspecific density, sediment grain size, and diet were evaluated. For example, intraspecific densities between 10 and 60 animals/beaker (i.e., 0.18-1.4 animals/cm 2 ) did not affect survival, growth, or reproduction. Similarly, L. plumulosus were tolerant of a wide range of sediment grain sizes with only extremely fine grained (e.g., Ͼ75% clay) or coarse grained (e.g., Ͼ75% sand) material significantly affecting survival, growth, and reproduction. Test performance criteria included control survival (Ͼ80%) and reproduction (production of offspring in all control replicates), and response to a reference toxicant test with cadmium chloride in a control chart format.

Multi-level assessment of chronic toxicity of estuarine sediments with the amphipod Gammarus locusta: II. Organism and population-level endpoints

“…Compared to acute tests using amphipods, very few chronic tests have been developed, standardized and widely applied. An exception is the North American amphipod Leptocheirus plumulosus, and to a certain extent Ampelisca abdita, for which chronic toxicity protocols have been developed (Emery et al, 1997;Redmond, Scott, Swartz, & Jones, 1994;USEPA-USACE, 2001;Weston, 1996), and which have been used in various studies of chronic sediment toxicity. To the best of our knowledge, no such chronic test with European amphipod species has been fully developed and/or protocol has been described (cf.…”

“…Chronic toxicity tests are an exceptionally valuable environmental assessment tool, since they consider various relevant environmental circumstances that are not addressed in acute sediment tests: (1) chronic exposure to contaminants is much more common in natural environments than acute exposure, (2) moderately contaminated sediments are more common than highly contaminated ones and (3) biological effects of contamination other than survival may be of greater ecological relevance for understanding the impact of contaminants on organisms and ecosystems (Emery et al, 1997;Ingersoll, Brunson, Dwyer, Hardesty, & Kemble, 1998;USEPA-USACE, 2001).…”

“…Few test organisms have appropriate characteristics, and not all species that are adequate for acute toxicity tests can be used in chronic testing. For chronic tests, preference is given to organisms with a relatively short life cycle, enabling assessment of biological effects at endpoints such as growth and reproductive features within a few weeks period (e.g., Emery et al, 1997;Ingersoll et al, 1998). Also the ecology of the test species, particularly demographic and reproductive features, must be given careful consideration.…”

An integrated assessment of pollution and biological effects in flounder, mussels and sediment in the southern Baltic Sea coastal area

“…According to Kennedy et al (2009), the amphipod mortality can be also elicited by energetic or physical stress due to some intrinsic natural factors, such as the sediment grain-size distribution. Although the tested sediments differed to some extent with regard to the content of the fine fraction (<63 μm) and organic matter (LOI, %), it can be assumed that these factors were well within the amphipods tolerance range (Emery et al 1997;Strom et al 2011) and unlikely to cause confounding mortality.…”

Chronic exposure of Leptocheirus plumulosus to Baltimore Harbor sediment: Bioenergetic and population-level effects

“…Food consisted of finely ground Wardley Goldfish Flakes (Seacaucus, New Jersey), with rations increasing throughout the experiment: 100 mg/beaker three times per week for day 0-13, 200 mg for day 14-27, and 300 mg for day 28-42. Food rations were twice the recommended amount per individual suggested by Emery et al (1997), to ensure that food would not be a limiting resource. Dissolved oxygen, salinity, and water temperature were measured every seven days.…”