| The toxicity data of 15 representative aquatic organisms was obtained through the toxicity tests. The aquatic organism criteria of trifluralin derived by assessment factor, species sensitivity distributions and toxicity percentile rank were 0.007 5 mg·L-1, 0.075 mg·L-1 and 0.071 mg·L-1 respectively. The criterion derived by assessment factor was lower, because it mainly based on toxicity data of the most sensitive species, which might result in over protection for aquatic organism. The criteria derived by species sensitivity distributions and toxicity percentile rank were close to each other, both of them were greater than the criterion derived by assessment factor. The latter two methodologies required more toxicity data to derive the criteria, which could protect majority of aquatic organisms. The results of this study will provide scientific basis for pesticide water quality standard development and aquatic ecological risk assessment. |
