COMPARISON OF ACUTE TOXICITY OF PROCESS CHEMICALS USED IN THE OIL REFINERY INDUSTRY, TESTED WITH THE DIATOM CHAETOCEROS-GRACILIS, THE FLAGELLATE ISOCHRYSIS-GALBANA, AND THE ZEBRA FISH, BRACHYDANIO-RERIO

Chemicals under the trade names Nalco 537-DA, Nalco 625, Nalco 7607, N alco 5165, Ivamin, and technical monoethanolamine are used extensively in the oil refinery industry. Aquatic toxicity tests were conducted u sing zebra fish fry (Brachydanio rerio) and the unicellular algae Isoc hrysis galbana (a flagellate) and Chaetoceros gracilis (a diatom). Inh ibition of cell division, chlorophyll content, and (CO2)-C-14 uptake i n the algae were sensitive end points. The effective concentrations (E C50s) of growth inhibition were 0.1 mg/L (Ivamin; I. galbana), 0.8 mg/ L (Nalco 7607; I. galbana), 6 mg/L (Nalco 625; I. galbana), 10 mg/L (N alco 5165; C. gracilis), and 15 mg/L (Nalco 537-DA; C. gracilis). The lethal concentrations (LC50s) (96 h) toward zebra fish fry was 1 mg/L for Nalco 7607, 6.5 mg/L for Nalco 537-DA, 7.1 mg/L for Nalco 625, and 20 mg/L for Ivamin 803. Monoethanolamine had an LC50 higher than 5,00 0 mg/L. Nalco 5165 was not tested on fish fry. The heartbeat frequency of fish embryos was reduced by 2.5 mg/L Nalco 537-DA, but this was an insensitive end point for the other chemicals.