Toxicity testing with embryos of marine mussels: protocol standardization for Perna perna (Linnaeus, 1758).

摘要

The objective of this study was to adapt the marine bivalve embryo standard toxicity testing methods (ASTM 1992) developed for temperate species for use with the tropical mytilid P. perna and to provide preliminary data of the test performance using selected contaminants. 100 mussels were collected from Sao Paulo, Brazil, and were stimulated to collect gametes. Assays were conducted in test tubes containing the embryos with 10 ml test water or contaminant solution. There were 5 replicates per treatment. The experiments lasted for 48 h. The larvae from the assays were classified as having normal or abnormal development. Sperm densities at 102, 103 and 105 spermatozoa/ova were established. An experiment was also conducted with 10, 20, 30, 40, 50 and 60 eggs/ml sea water to determine the most adequate density for normal development greater than 70%. The effect of different combinations of salinity (15, 20, 25, 30, 35 and 40%) and temperature (15, 20, 25 and 30 degrees C) on embryonic development was also determined. Different concentrations of sodium dodecyl sulfonate (SDS) detergent and potassium dichromate were used as toxicants. It was shown that all sperm densities resulted in 100% fertilization of the ova. There were no significant differences in larval development among the different ova densities. Normal larval development rate greater than 70% only occurred at 35% salinity and at 20-25 degrees C. There was no development at 30 degrees C. at 15-20% salinities. Larval development at 15-20 degrees C was significantly lower than at 25 degrees C. Embryos were more sensitive to SDS compared to potassium dichromate, with 48-h EC50 values of 1.72+or-1.07 and 16.45+or-3.24 mg/litre, respectively. In conclusion, the ASTM 1992 method for toxicity testing in bivalve embryos is considered adequate for use with P. perna. Some recommended modifications to this method are proposed.