The acute and chronic toxic effects of triphenyltin (TPT) and acute toxic effects of tributyltin (TBT) on Daphnia magna were studied. The influence of environmental factors (hardness, hu-mic acid, acid) on 24h-EC50 was also discussed. The results showed that 24h-EC50 of TPT and TBT on D. magna were 13.33μg·l-1 and 3.91μg·l-1 respectively. Furthermore the acid, hardness , humic acid all had influence on the 24h-EC50. The results of chronic test disclosed that TPT inha-bited the growth and reproduction of D. ...