Aluminum chloride, basic

Long-term toxicity to fish

Additional information

Long Term Fish Toxicity Literature Review: Three long-term reliable chronic toxicity studies on two aluminium salts, aluminium sulphate and aluminium nitrate performed on three species of fish (Pimephales promelas, Danio rerio and Salvelinus fontinalis) were identified as acceptable from the published literature. NOECs and EC10s ranged from 0.088 to 2.3 mg Al/L and 0.078 to 5.19 mg Al/L, respectively. 

13 further sub-chronic studies were performed on fathead minnow (P. promelas) exposed to aluminium nitrate under various conditions of DOC, hardness and pH in order to obtain information on the relative importance and influence of these parameters and to calibrate the Biotic Ligand Model.

One further 7 day study was performed on aluminium chloride.

The following information is taken into account for long-term fish toxicity for the derivation of PNEC:

The Al BLM developed using gill accumulation data from S. salar was applied to the chronic Pimephales promelas data (Oregon State University Aquatic Toxicology Laboratory 2010; Figure 7.1.1.1.2.-1). Application of the model to new data requires development of a critical accumulation value appropriate for the exposure duration and toxicity endpoint. In addition, calibration of the model to these data benefited from two other changes in parameter values. First, since the chronic endpoints for this species and in these test conditions were at much higher aluminium concentrations and saturation of NOM binding sites included in the model was beginning to occur, resulting in a somewhat reduced predicted effect of NOM compared with the observed effect. The binding site density for NOM was increased by two fold to provide adequate binding sites at these high Al concentrations. In addition, although the effect of hardness on observed aluminium toxicity was consistent in acute and chronic exposures, the predicted effect of hardness could be improved by a small change in the binding strength of Ca (i.e. the log K for binding at the biotic ligand was increased from 4.2 to 4.8. 

After application of the Al BLM, the variability in the response curve between effects of aluminium on the biotic ligand was reduced compared with response curve based on total aluminium (Figure 7.1.1.1.2.-2). Values for critical accumulation were estimated directly from the predicted response curve on the biotic ligand to establish the CA10, or the critical accumulation level that results in a chronic effect of 10% (in this case a reduction in growth). 

Figure 7.1.1.1.2.-3 provides an evaluation of the ability of the long-term fish BLM to predict EC10 values. In this case, most of the EC10 values are predicted within 2-fold of the reported EC10 values, and all of the predicted EC10 values are within 4-fold of the reported values.