Zinc glycinate sulfate

Endpoint summary

Description of key information

- Short-term toxicity to aquatic invertebrates: The 48 h LC50 of zinc (Zn²⁺) in Daphnia magna was 0.799 mg/L in a flow-through experiment. This corresponds to a 48-h LC50 of 3.11 mg zinc monoglycinate sulfate monohydrate/L in Daphnia magna.

 - Toxicity to aquatic algae and cyanobacteria: The average 72-h EC50 of zinc was 0.133 mg Zn²⁺/L in Pseudokirchneriella subcapitata. This corresponds to a 72-h EC50 of 0.52 mg zinc monoglycinate sulfate monohydrate/L in Pseudokirchneriella subcapitata.

Additional information

 The zinc 48-h EC50 or LC50 for aquatic invertebrates (Daphnia magna) was determined in various studies. The LC50 value chosen in this approach is 0.799 mg Zn²⁺/L according to Attar and Maly (1982), for the following reasons: the reported 48-h EC50 values in the most reliable studies (RL2) range from 0.799 to 6.03 mg Zn²⁺/L. The well documented studies by Attar and Maly (1982) and Heijerick et al. (2002) report 48-h values of 0.799 (LC50) and 0.93 mg Zn²⁺/L (EC50), respectively, which are in a very close range. For precautionary reasons, the more conservative value was chosen.
 Apart from effect concentrations, Park et al. (2019) as well as Ergönül et al. (2012) report adverse effects of Zn²⁺ on Daphnia magna like internal injuries, lethargy, corrosion in the carapax and partial ruptures.  The 48 -h LC50 value chosen in this approach is 0.799 mg Zn²⁺/L.  This corresponds to a 48-h LC50 of 3.11 mg zinc monoglycinate sulfate monohydrate/L in Daphnia magna.

 

The zinc EC50 for aquatic algae were determined in various studies. The reported 72- or 96-h EC50 values in reliable studies range from 0.08 to 2.432 mg Zn²⁺/L. The zinc toxicity in green algae was shown to be strongly dependent on the examined species. The most sensitive species was Pseudokirchneriella subcapitata (72-h EC50: 0.133 mg Zn²⁺/L), while Ankistrodesmus falcatus (96-h EC50: 2.432 mg Zn²⁺/L), Chlorella vulgaris (96-h EC50: 2.4 mg Zn²⁺/L) and Desmodesmus subspicatus (96-h EC50: 2.258 mg Zn²⁺/L) were less sensitive. 
 The EC50 value chosen in this approach is 0.133 mg Zn²⁺/L according to De Schamphelaere et al. (2004) for the following reasons: the study reported by De Schamphelaere et al. (2004) was conducted according to OECD guideline 201 (RL1) using the sensitive species Pseudokirchneriella subcapitata, for regular 72 hours. In the other studies using Pseudokirchneriella subcapitata by Al-Hasawi et al.(2020)  and Rojíčková-Padrtová and Maršálek (1999), no guideline was followed and the study duration was 96 h. 
The 72-h EC50 value chosen in this approach is 0.133 mg Zn²⁺/L. This corresponds to a 72-h EC50 of 0.52 mg zinc monoglycinate sulfate monohydrate/L in Pseudokirchneriella subcapitata.