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Recently two high quality terrestrial tests have been performed with EDTA-ZnK2 which resulted in a NOEC for earthworm (OECD 207) of 316 mg/kg dw and an EC50 of 491 mg/kg dw as observed for the most sensitive species: Rape (OECD 208) and endpoint: shoot freshweight. For EDTA-Zn(NH4)2 these results need to be corrected (for justification see Chapter 13) for the difference in MW (389.7/431.8). The results in a NOEC for earthworm of 285 mg EDTA-Zn(NH4)2/kg dw and EC50 for rape of 443 mg EDTA-Zn(NH4)2/kg dw.

Additional information

An acute earthworm test according to OECD 207 was performed with EDTA-ZnK2 which resulted in a NOEC of 316 mg/lg dw. Corrected for the MW difference this results in a NOEC of 285 mg EDTA-Zn(NH4)2/kg dw.

In addition one acute toxicity study with earthworms is available for EDTA-H4 (Edwards, 2009). The EC50 was determined at 156 mg/kg soil dry weight. This corresponds to 213 mg/kg soil dw EDTA-ZnNa2.

Three studies with EDTA salts or complexes have been performed, examining different end-points (vegetative vigour and seedling emergence) in different plant species. In the 21d veg vigour study (Evangelou et al., 2006) a true NOEC could be established, while in the 14d seedling emergence test (Geebelen et al., 2002) no effect was observed at the highest tested dose. Recalculation of the NOEC from EDTA-Na2H2 to EDTA-ZnNa2 will give a NOEC of 100 mg/kg soil dw.

The recent study from Klix (2019) which was performed with EDTA-ZnK2 resulted in an EC50 of 491 mg/kg dw. Corrected for the MW difference (389.7/431.8) this results in an EC50 of 443 mg EDTA-ZnNa2 for rape shoot freshweight.

Finally two studies with birds are available; an acute oral dose as well as an acute dietary study with bobwhite quail, both tested with FeNaEDTA. The LD50was determined to be > 5000 mg/kg b.w., equivalent to > 5443 mg/kg b.w. ZnNa2EDTA (399.6/367.1, MW ratio). The LC50was > 5000 ppm equivalent to > 5443 ppm ZnNa2EDTA (399.6/367.1, MW ratio), and this corresponds to a LD50> 965 mg ZnNa2EDTA/kg bw/d.

The hazard assessment of EDTA-ZnNa2 reveals neither a need to classify the substance as dangerous to the environment, nor is it a PBT or vPvB substance. The substance is expected to have a low potential for adsorption based on its ionic structure under environmental relevant pH conditions and its low log Kow , the low log Kow also indicates that the substance will not be bioaccumulative. There are no further indications that the substance may be hazardous to the environment.

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