Some effects of copper, zinc and boron on the spiny scallop, Chlamys hastata hericia
Date
1977
Authors
Cox, Robert K.
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Abstract
Some effects of CuS0₄, ZnSO₄ and NaB0₄ were observed on the Pacific coast scallop, Chlamys hastata hericia.
LC50-96hr static bioassy tests produced values of 200 and 1500 micrograms per litre for Cu and Zn. No LC50-96hr value could be found for NaB0₄ up to 14,000 µg/1. Animals exposed to high levels of Cu and Zn displayed abnormal behaviour including swimming "escape" movements and excessive mucus secretion.
To test for the pathological effects of chronic low dosage exposure, scallops were exposed for 61 days to 1/10, 3/10 and 9/10 (10, 30, 90 µg/1 Cu and 75, 225, and 675 µg/1 Zn) of the LC50-96hr values, while boron levels were tested at 3500, 7000, and 14,000 µg/1. Tissue samples were fixed after 5, 19, 33, 47 and 61 days.
Tissue damage appeared to be directly related to type of toxicant and concentration, with 90 µg/1 Copper being most toxic, and Zinc more toxic than Boron. Histopathological analysis showed lesions in epithelium of mantle edge, kidney and gill. Sub-epithelial damage was also present, but was more restricted and less severe. All stressed tissues displayed amoebocytic infiltration. Limited areas of epithelial regeneration occurred on the mantle edge.
Ultrastructural analysis of gill tissue showed an increase in lysosomal activity and morphological aberrations of most major cell organelles. Severe damage resulted from cell lysis and total breakdown of the gill filament structure. Degenerative and necrotic effects generally become more severe and widespread with exposure time.
Sublethal concentrations of the three toxicants cause damage sufficient to reduce the animals capability of surviving in the natural environment. Even at these low levels, damage may occur within a short period of time (i.e. < 61 days).