Aluminium chloride

Short-term toxicity to fish

Description of key information

All available studies data were used in a weight of evidence approach to cover this endpoint. Literary studies investigating the effects of aluminum in the aquatic environment have extensively used test solutions with aluminum concentrations above that of its solubility limit. Results of these studies are therefore limited for the investigation of intrinsic toxicity.

Additional information

Many “acute” toxicity studies (i.e. <12 days) have been conducted with fish in acidic soft waters due to concern about aluminium leaching in environments sensitive to acid rain. Many of these experiments were conducted in flow-through systems to mimic the effects of mixing zones where some type of substance (i.e. lime) is added to increase the system pH. In the cases where effects due to transient forms of aluminium were investigated (i.e. Teien et al. 2004, 2006), fish were maintained in certain sections of a raceway, with a specified time of equilibration, or time after mixing. Most of the existing literature for fish focused on effects to Salmo salarsince it is among the most sensitive fish species. Roy and Campbell (1997) showed that DOM had a protective effect against aluminium toxicity to S. salar. Gundersen et al. 1994 suggested just a minor effect of HA on aluminium toxicity with Oncorhynchus mykiss. It is possible that in some of the flow-through studies, aluminium toxicity is due to transient forms of aluminium, because transient forms may be present for the first several minutes after mixing in the flow-through diluter mixing chambers.

 

While there are many studies that have investigated the toxicity of aluminium to fish, relatively few evaluated aluminium toxicity over a range of pH values. Roy and Campbell (1995) demonstrated that aluminium toxicity, on the basis of monomeric aluminium, decreased (less toxic) as pH decreased from 5.3 to 4.4. At weakly alkaline pH (i.e. pH 7.58 to 8.14), Gundersen et al. (1994) demonstrated very little effect of pH or hardness on aluminium toxicity to O. mykissover higher pH ranges. Studies conducted at Norwegian Institute for Water Research (

NIVA) (Figure 7.1.1.1.1-1) show the effect of pH and other characteristics on survival at 190 hours; the results also demonstrate the effect of mixing time on mortality. From the literature, there were minimal studies that investigated the effect of water hardness on aluminium toxicity to fish. 

All the studies are for informational purposes with a total of seven fish species, and are presented for demonstrating the completeness of the literature review. The available 96-h LC50s varied from 0.078 to > 218.6 mg Al/L, and 16-d LC50s ranged from 0.43 to 3.91 mg Al/L. The NOECs (96 h) varied from > 0.07 to > 50 mg Al/.