Aluminum sodium oxide

Long-term toxicity to aquatic invertebrates

Additional information

A study on the chronic toxicity of sodium aluminate to invertebrates is available (CIMM 2010). However, as results of this study refer to the toxicity of aluminium as studies with other compounds do, a weight of evidence is applied and data are read-across to various aluminium compounds based on an analogue approach.

In three studies the toxicity of aluminium to Ceriodaphnia dubia and Daphnia magna was tested using sodium aluminate and aluminium nitrate as sources for aluminium (CIMM 2010). Studies were conducted according to method 1002.0, USEPA 2002 and OECD 211. In the study using sodium aluminate, tests were conducted at a single pH of 8 and a water hardness of 10.6 mg/L as CaCO3. pH was adjusted using HEPES 5mM buffer. Endpoints were based on adverse effects on adult survival and number of neonates produced per female. The following effect values for reproduction were determined: EC50: 782.3 and 550 µg/L for total and dissolved Al, respectively; NOEC and LOEC for total Al of 250 and 500 µg/L, respectively.

The first study using aluminium nitrate was conducted at a single pH of 6.3 and additional test series were run with different water hardness (25, 60, 120 mg/L as CaCO3) and different concentrations of DOC (0, 2, 4 mg/L). pH was stabilised using MES 5mM buffer. Same endpoints were addressed. EC50s determined for total Al were: 286 - 1042.3 µg/L at hardness of 25 and DOC 0 to 4, 382.1 - 1117.6 µg/L at hardness 60 and DOC 0 to 4, 582 - 1619.1 µg/L at hardness 120 and DOC 0 to 4. For dissolved Al EC50s were: 7.6 - 170.4 mg/L at hardness of 25 and DOC 0 to 4, 14.4 - 151.5 µg/L at hardness of 60 and DOC 0 to 4, 7.7 - 59.5 µg/L at hardness of 120 and DOC 0 to 4. For both total and dissolved aluminium these results clearly demonstrate and decreasing toxicity of aluminium with both increasing water hardness and increasing DOC. NOECs and LOECs were reported for nominal concentrations. At a hardness of 25 and DOC 0, 2, 4 NOECs and LOECs were 62.5, 500, 500 and 125, 1000, 1000, respectively. At hardness of 60 and DOC 0, 2, 4 NOECs and LOECs were 125, 500, 500 and 250, 1000, 1000, respectively. At hardness of 120 and DOC 0, 2, 4 NOECs and LOECs were 100, 500, 1000 and 200, 1000, 2000, respectively.

The second sudy using aluminium nitrate was again conducted with a single pH of 6.3 and at a water hardness of 140 mg/L. pH was adjusted using MES 5 mM buffer. In contrast to both of the above studies this test was run for 21 days rather than only 7 days. The following endpoints were determined: EC50s for total and dissolved Al were 986.5 and 27.1 µg/L, respectively. NOEC and LOEC were 600 and 1200 µg/L, respectively, for total Al.

A further study was conducted by CIMM (2009) according to method 1002.0, USEPA 2002 in which Ceiodaphnia dubia were exposed to aluminium nitrate for 7 days at pHs 7 and 8 and a water hardness of 10.6 mg/L as CaCO3. At both pHs test were conducted filtered and unfiltered. pH was adjusted by aid of 5 mM MOPS and HEPES buffers. IC50s, NOECs, and LOECs were determined for reproduction. At pH 7 no difference was to observe between NOECs and LOECs of non-filtered and filtered tests with NOECs of 100 µg/L and LOECs of 1000 µg/L. At pH 8 non-filtered values were lower than filtered ones with NOECs of 10 and 500 µg/L and LOECs of 100 and 1000 µg/L.

The studies by CIMM (2009, 2010) are the most thorough and elaborate ones. Further chronic data are available from Call et al. (1984), McCauley et al. (1986), Kimball (1978), and Biesinger & Christensen (1972). Besides Kimball (1978) who used aluminium sulphate all studies were conducted using aluminium chloride as aluminium source. Test organisms were Daphnia magna and Ceriodaphnia dubia. All studies were non-GLP non-guideline studies. NOEC and LOEC values reported by these authors for reproduction based on total Al were in the range of 1.1 - 4.9 mg/L and 2.4 - 12.1 mg/L, respectively.