MARINE POLLUTION BIOASSAY BY SEA URCHIN EGGS, AN ATTEMPT TO ENHANCE ACCURACY

Abstract

1. To improve the previous method (1971) especially in sensitivity, some experiments were made upon the aged sea urchin eggs. 2. The eggs were left in respective test water for some hours before they were inseminated. And then rates of fertilization, first cleavage, gastrulation and some anomalies in the test water were observed. 3. Various abnormalities, i. e. the retarded formation of the fertilization membrane or its lacking, polyspermy, irregular cleavage and development, etc., occurred more sensitively on aged eggs, and this seems to be available to bioassay of marine pollution. 4. Hours to insemination should be limited within the range in which the eggs follow the normal development in the ordinary (unpolluted) sea water, but the abnormalities occur more pronouncedly in the polluted water. They were 9 hours in Pseudocentrotus, 6 hours (warmed) in Hemicentrotus and 3 hours in Anthocidaris. 5. The effects of heavy metals and other chemicals upon the aging of the eggs are not so significant. 6. A new ranking of the sea water pollution (Ranking II) is proposed here tentatively as seen in Table 8. The Ranking II is more exact than the Ranking I; the former is available to see the effects of pollution more precisely, especially in the cases of organic pollution.