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Acute toxicity of sodium nitrate, potassium nitrate, and potassium chloride and their effects on the hemolymph composition and gill structure of early juvenile blue swimmer crabs ( Portunus pelagicus Linnaeus, 1758) (decapoda, brachyura, portunidae)
Author(s) -
Romano Nicholas,
Zeng Chaoshu
Publication year - 2007
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/07-144r.1
Subject(s) - portunus pelagicus , hemolymph , toxicity , potassium , decapoda , biology , sodium , gill , acute toxicity , zoology , crustacean , juvenile , nitrate , sodium nitrate , toxicology , chemistry , fishery , ecology , fish <actinopterygii> , organic chemistry
Various nutrients, including K + and NO − 3 , are increasingly being discharged into aquatic systems via anthropogenic sources, which may impact marine organisms. The present study was conducted on blue swimmer crab ( Portunus pelagicus ) early juveniles to determine the acute toxicity of NaNO 3 , KNO 3 , and KCl; if a toxicity interaction exists between K + and NO − 3 ; the hemolymph Na + , K + , and Ca 2+ changes; and the gill histopathological alterations following exposure to elevated NaNO 3 , KNO 3 , and KCl levels. A total of 20 replicate crabs were exposed to each of the five NaNO 3 , KNO 3 , and KCl concentrations for 96 h. After 96 h, the surviving crabs were sampled for hemolymph Na + , K + , and Ca 2+ levels and fixed for histological examination of the anterior gills. The 96‐h median lethal concentration of NaNO 3 ‐N, KNO 3 ‐N, KNO 3 ‐K, and KCl‐K was 3,452, 112, 312, and 356 mg/L, respectively, for early P. pelagicus juveniles. The toxicity of NaNO 3 ‐N was significantly less ( p < 0.01) than that of KNO 3 ‐N. Furthermore, at the same K + levels, KNO 3 ‐K was significantly ( p < 0.05) more toxic than KCl‐K, indicating a toxicity interaction between K + and NO − 3 . Following exposure to elevated KNO 3 and KCl levels, the crabs had significantly higher ( p < 0.01) hemolymph K + levels compared to the control. Conversely, following exposure to elevated NaNO 3 concentrations, the crabs had significantly higher ( p < 0.01) hemolymph Na + levels but significantly lower ( p < 0.01) hemolymph K + levels. Despite the markedly different hemolymph ionic changes following NaNO 3 and KNO 3 /KCl exposure, the histopathological changes to the anterior gill lamellae of the crabs appeared to be similar, including lamellae swelling, epithelial thickening, pillar cell disruption, necrosis, and distortion.