| In the process of human production and life copper is not absent, and its presence in the environment will causes a widespread pollution. Copper toxicity prediction model using biotic ligand model (BLM) is been widely used for fishes and fleas in surface water. This model has been applied for toxicity prediction and the establishment of ecological water quality standards by US EPA and other government departments. The extension of specie library of BLM is fundamental for the broader applications of BLM. Typical fishes of cyprinidae (Cyprinus carpio, Hypophthalmichthys molitrix, Ctenopharyngodon idellus) are widely distributed in Chinese surface water and captured as consumption of residents. It is thus important to build BLM of these species. Chlorella(chlorella vulgaris’) is a micro-single-celled plant as one of common primary producer, and a source of green food. So there is some scientific significance to investigate the applicability of BLM. So the establishment of copper BLM about three kinds of fishes and chlorella vulgaris is necessary not only more accurately to predict the toxicity of copper in the environment, but also to provide strong support for ecological water quality benchmark.In this study, based on the current version of BLM, in the absence of (or less) DOC copper acute toxicity for Cyprinus carpio, Hypophthalmichthys molitrix and Ctenopharyngodon idellus were conducted to correct their LA50. Then, a test of copper complexation with DOC was done to get the complexation constants. Finally, by LC50 values under different water chemical characteristics these LA50 values were verified. The prediction of toxicity data in literature by their BLM also has verified the accuracy of these models. On the other hand, at the conditions of varied Ca, Mg, Na, K, pH, DOC, acute inhibition tests of chlorella vulgaris were implemented. Then we explored the mechanism of influence of different factors and suitability of BLM in the chlorella. Based on above, the main conclusions as follow:(1) Compared to the inherent value pKCuHA_A=1.5 in BLM, the value pKCuHA-A=1.84 in this study is larger. But about the largest amount of complexing it is just the opposite ([CA] (mol-g-1)=3.29E-3 in BLM< 4.68E-3 in this study). DOC from different sources has different chemical properties and complexing constants with copper.(2) For Cyprinus carpio, Hypophthalmichthys molitrix and Ctenopharyngodon idellus, DOC has a greater impact on LC50. For chlorella vulgaris, it is not significant about the influence of Ca, Mg, Na, K. But it is great influence about pH and DOC.(3) LA50 of Cyprinus carpio, Hypophthalmichthys molitrix and Ctenopharyngodon idellus are 9.00,5.16,11.60 nmol·g-1. The results showed that the rank of sensitivity to copper is:Hypophthalmichthys molitrix> Cyprinus carpio> Ctenopharyngodon idellus. Based on this, the prediction results of LC50 values from the study and literature are more accurate.(4) In BLM a series of parameters:log KCaBL=-5, log KMgBL=-5, log KNaBL=-5, log KKBL=-5, log CuOHBL=-5, log KHBL=7.71, log KCuBL=8.6, LA50=10.1 nmol-g’1 are obtained for chlorella vulgaris. Based on these parameters above, the BLM of chlorella vulgaris is built. By the prediction of this BLM the predicted IC50 values about DOC-sets are too larger than observed IC50 values. The toxicity caused by Cu-HA complexes in the cell surface should be considered. |
PDF Full Text Request