Aluminum sodium oxide

Long-term toxicity to fish

Additional information

No reliable studies on the chronic toxicity of sodium aluminate to fish are available. Therefore, a weight of evidence is applied and data are read-across to various aluminium compounds based on an analogue approach. Five studies are available using aluminium chloride and aluminium sulphate as aluminium sources.

In a non-GLP non-guideline study Gundersen et al. (1994) exposed rainbow trout for 16 days to AlCl₃ at a water hardness of 10 and 100 mg/L as CaCO₃ and at pH 7.3 and 8.3. NOECs reported for nominal pH 8 were around 1.5 mg/L (total Al) and 0.15 mg/L (dissolved Al). Similar LOECs were 3.2 and 2.75 mg/L (total Al) and 0.27 mg/L (dissolved Al). There was no significant difference between effect values at different water hardness.

 

A GLP guideline study was conducted with Pimephales promelas for 7 days using aluminium chloride hexahydrate (Parametrix 2009). As in the acute toxicity study the test was conducted with filtered and unfiltered test media. Water hardness was 48 mg/l as CaCO₃ in the unfiltered test at pH 7.7 -8.1 and 52 mg/L as CaCO₃ in the filtered test with a pH of 7.8 -8.4. No deformities were noted in exposed organisms during this study. There was no significant effect on survival in any of the filtered concentrations, but a significant survival effect was observed in the unfiltered concentration at the two highest nominal concentrations tested (nominal 120 and 240 mg/L). Growth, as defined by mean dry weight (weight of surviving fish) and mean dry biomass (a dual endpoint of weight divided by the number of original fish) was significantly lower from the control in all of the unfiltered concentrations. In the filtered test, the mean dry biomass in the nominal concentration of 30000 µg/L Al was statistically different from the controls. This was most likely due to the fact that this concentration had the highest amount of measured total and dissolved Al in all of the unfiltered concentrations (total: 831.8 µg/L Al and dissolved: 1074.3 µg/L Al). Results suggest that toxicity was caused by high concentrations of total Al in the unfiltered test and filtering removed most toxicity of Al to the survival and growth of exposed organisms. NOECs and LOECs for total Al were derived based on mortality, mean dry weight and mean dry biomass. In the unfiltered tests NOECs and LOECs were in the range of < 14434.5 to 56476.6 µg/L and 14434.5 to 91421.8 µg/L, respectively. In the filtered tests NOECs and LOECs were in the range of 751.7 to 831.8 µg/L and ≥ 831.8 µg/L, respectively.

Clevelandet al. (1989) exposed Salvinelus fontinalis to aluminium sulphate for 60 days in their non-GLP non-guideline study. The hardness was reported as 246 µeq/L and pH was 6.5. NOEC and LOEC values were determined for mortality, length, weight, number hatched, and swimming behaviour, and ranged between 57 to >350 µg/L and 88 to 350 µg/L total Al, respectively. In a similar study (60 days, water hardness 254 µeq/L, pH 5.7) with aluminium sulphate and using Salmo salar. Buckler et al.(1995) derived NOEC and LOEC values of similar magnitude with 88 and 169 µg/L total Al, respectively, based on length and weight.

In a 28 day study with Pimephales promelas Kimball (1978) exposed fish to aluminium sulphate at a pH of around 7.3 and under hard water conditions. NOECs and LOECs were determined for mortalities of the fry, weight, length, and number hatched. Based on total Al NOECs were in the range of 4.7 to 23.1 mg/L and LOECs in the range of 7.1 to 53.8 mg/L.