Assimilation of Elements and Digestion in Grass Shrimp Pre-Exposed to Dietary Mercury

• Published in: Archives of environmental contamination and toxicology 2012-08, Vol.63 (2), p.230-240
• Main Authors: Seebaugh, David R., Wallace, William G., L’Amoreaux, William J., Stewart, Gillian M.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Animals; Applied ecology; Aquariums; Assimilation; Biological and medical sciences; Cadmium; Cadmium - analysis; Cadmium - pharmacokinetics; Carbon; Carbon - analysis; Carbon - pharmacokinetics; Crustacea; Digestion; Digestion - drug effects; Earth and Environmental Science; Ecotoxicology; Ecotoxicology, biological effects of pollution; Environment; Environmental Chemistry; Environmental Health; Feces; Food Contamination; Food contamination & poisoning; Fundamental and applied biological sciences. Psychology; General aspects; Grasses; Heavy metal content; Hydrogen ions; Indicator organisms; Ingestion; Invertebrates; Mercury; Mercury - analysis; Mercury - pharmacokinetics; Mercury - toxicity; Monitoring/Environmental Analysis; Oligochaeta; Oligochaeta - chemistry; Palaemonetes pugio; Palaemonidae - chemistry; Palaemonidae - drug effects; Palaemonidae - physiology; Physiology; Pollutants; Pollution; Seawater; Shrimps; Soil Science & Conservation; Spectrophotometry, Atomic; Studies; Toxicity; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - pharmacokinetics; Water Pollutants, Chemical - toxicity; Water pollution; Worms
• ISSN: 0090-4341; 1432-0703
• DOI: 10.1007/s00244-012-9760-9

Grass shrimp Palaemonetes pugio were fed mercury (Hg)-contaminated oligochaetes for 15 days and analyzed for Hg, cadmium (Cd), and carbon assimilation efficiencies (AE) as well as toxicological end points related to digestion. Disproportionate increases in stable Hg concentrations in shrimp did not appear to be related to partitioning to trophically available Hg in worms. Hg AE by pre-exposed shrimp reached a plateau (approximately 53 %), whereas Cd AE varied (approximately 40–60 %) in a manner that was not dose-dependent. Carbon AE did not differ among treatments (approximately 69 %). Gut residence time was not impacted significantly by Hg pre-exposure (grand median approximately 465 min), however, there was a trend between curves showing percentages of individuals with markers in feces over time versus treatment. Feces-elimination rate did not vary with dietary pre-exposure. Extracellular protease activity varied approximately1.9-fold but did not exhibit dose-dependency. pH increased over the range of Hg pre-exposures within the anterior (pH approximately 5.33–6.51) and posterior (pH approximately 5.29–6.25) regions of the cardiac proventriculus and Hg assimilation exhibited a negative relationship to hydrogen ion concentrations. The results of this study indicate that previous Hg ingestion can elicit post-assimilatory impacts on grass shrimp digestive physiology, which may, in turn, influence Hg assimilation during subsequent digestive cycles.