Calcium dihydroxide precipitated with carbon dioxide during sugar juice purification

Endpoint summary

Additional information

The genotoxic potential of SFL has been determined by direct testing in an bacterial mutagenicity test and by read across from studies performed using calcium carbonate, which is the main constituent of SFL(61.8 - 95.6 %w/w). The other components of SFL (silicon dioxide, sugar beet fragments and a small amount of other inorganic salts) are not classified for genotoxicity and hence the read across is considered to be justified.

In vitro gene mutation study in bacteria:

In a reliable GLP OECD guideline 471 study [Thompson (2013)], SFL (Sugar Factory Lime (Wet)) was tested in a bacterial reverse mutation assay in Salmonella typhimurium (strains TA 98, TA 100, TA 1535 and TA 1537) and Escherichia coli WP2 uvrA with and without metabolic activation (S9). The concentrations tested were 50, 150, 500, 1,500 and 5,000 μg/plate. No increase in mutation frequency occurred.

In a reliable GLP OECD guideline 471 study [Thompson (2010)], calcium carbonate (nano) was tested in a bacterial reverse mutation assay in Salmonella typhimurium (strains TA 98, TA 100, TA 1535 and TA 1537) and Escherichia coli WP2 uvrA with and without metabolic activation (S9). The concentrations tested were 50, 150, 500, 1,500 and 5,000 μg/plate. No increase in mutation frequency occurred. Since this study can be read across to SFL, this supports the result (non-mutagenic) of the study on SFL and also supports the read-across strategy.

In vitro chromosome aberration study in mammalian cells:

In a reliable GLP OECD guideline 473 study [Lacey and Durwood (2010)], calcium carbonate (nano) was tested for its ability to induce structural chromosomal aberrations in cultured mammalian cells (human lymphocytes) in the presence and absence of metabolic activation. Calcium carbonate (nano) did not induce any statistically significant increases in the frequency of cells with aberrations or in the numbers of polyploid cells, in either the absence or presence of metabolic activation and was therefore considered to be non mutagenic under the conditions of the test. Since this study can be read across to SFL, it is expected that SFL would also be non-mutagenic.

In vitro gene mutation study in mammalian cells:

In a reliable GLP OECD guideline 476 study [Flanders (2010)], calcium carbonate (nano) was tested for its ability to induce mutations in mouse lymphoma L5178Y cells in the presence and absence of metabolic activation. Calcium carbonate (nano) did not induce any toxicologically significant increases in the mutant frequency at the TK +/- locus in L5178Y cells and was therefore considered to be non mutagenic under the conditions of the test. Since this study can be read across to SFL, it is expected that SFL would also be non-mutagenic.

Short description of key information:
SFL is not genotoxic.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

The results of an in vitro gene mutation study in bacteria, an in vitro chromosome aberration study in mammalian cells and an in vitro gene mutation study in mammalian cells were all negative with the test material calcium carbonate (nano). It is therefore concluded that calcium carbonate is not genotoxic. These studies can be read across to SFL and hence SFL does not warrant classification for mutagenicity under either the DSD or CLP.