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Additional information

EDTA-FeNa was negative in the Ames test, in the WP2 Mutoxitest and in the in vitro micronucleus test using a treatment period of 4 h (with and without S9 -mix). In a mouse lymphoma assay with EDTA-FeNa, increases in mutants were observed but only at high cytotoxic concentrations. Not taking the cytotoxic concentrations into account, no increase in mutant incidences above control values were seen. The absence of mutagenicity in the Ames test for the same compound suggests that mouse lymphoma cells may be particularly sensitive to incorporation of excessive quantities of iron salts in the tissue culture growth medium. In the in vitro micronucleus test using a treatment period of 20 h (continuous treatment without S9 -mix), EDTA-FeNa was positive at levels >= 500 µg/mL, inducing aneugenic but no clastogenic effects. This long treatment period together with the high concentrations of chelant may have resulted in exchange and substantial binding of essential elements such as zinc. Heimbach et al (2000; see robust summary) concluded that the lack of effects by the Zn-EDTA salt in contrast to effects induced by Ca-, Na- and Mn-salts of EDTA, provided evidence that zinc is required for the initiation or continuation of DNA synthesis and maintaining cell function. As such, the significance of mutations produced by EDTA-FeNa at non-physiological concentrations in an in vitro screening system is difficult to extrapolate for relevance to intact organisms. The two Chinese in vivo genotoxicity studies, although with major flaws such as lack of details, no GLP, and no official translation, however, did not show genotoxicity in vivo.

Therefore, the overall findings indicate that EDTA-FeNa lacks significant genotoxic potential under conditions that do not deplete essential trace elements required for normal cell function.

Short description of key information:
EDTA-FeNa tested up to 10,000 µg/plate Fe in the plate incorporation and pre-incubation Ames test dit not result in an increased number of revertant colonies in strains S. typhimurium strains TA 98, 97a., 100, 102, 1537, 1538. Another test showed absence of genotoxicity using E coli strains (WP2 Mutoxitest). The mutagenic activity of EDTA-FeNa and EDTA-Na2 was tested in a mammalian gene mutation assay with L5178Y mouse lymphoma cells. The authors of this study concluded that EDTA-FeNa is positive in the mouse lymphoma mutagenicity study. However, doubling of the number of mutants was only observed at test concentrations that cause significant cytotoxicity. Not taking into account the cytotoxic concentrations does not give a dose related increase in the mutant frequency. EDTA-Na2 is much less cytotoxic and is negative in this assay. An in vitro micronucleus test in human lympocytes did not result in an increased number of micronuclei following exposure for 4 h (with and without S9 mix), but it did following exposure for 20 h (without S9 mix).

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

The test substance gave negative results in three in vitro mutagenicity studies, viz. the Ames test, the WP2 Mutoxitest, and the micronuclueus test following exposure for 4 h (with and without S9 mix) but gave positive results (aneugenicity) following exposure for 20 h (without S9 -mix). The latter was most probably explained by induction of Zn deficiency. The ambiguous results in the mouse lymphoma test were ascribed to cytotoxicity. Overall, it was concluded that classification for genotoxicity is not warranted.

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