Abstract  Acute toxicity of four relatively new chelating agents and their equimolar manganese and cadmium complexes was studied. The chelating agents studied were gluconic acid (GA), beta-alaninediacetic acid (ADA), diethylenetriaminepentakismethylenephosphonic acid (DTPMP), and nitrilotriacetic acid (NTA). Three common bioassays, namely Daphnia magna, Raphidocelis subcapitata, and Photobacterium phosphoreum (Microtox bioassay) were applied. R. subcapitata proved the most sensitive to these compounds. With D. magna bioassay the LC(50) values were 600-900 mg/L with all other studied chelates and their Mn complexes, except Mn-GA, which yielded LC(50) value of 240 mg/L. The Cd-chelate complexes proved highly more toxic compared to Mn-chelate complexes or uncomplexed chelates exhibiting LC(50) values of 130-200 microg/L. However, Cd-DTPMP was an exception exhibiting LC(50) value of 2170 microg/L. That is to say, DTPMP proved the strongest chelating agent to reduce the Cd toxicity in the present study. The results from these bioassays were well in agreement to each other as well as with the results published elsewhere.

Abstract  Gluconate derivatives are presented as a category. Gluconic acid and its mineral salts freely dissociate to the gluconate anion and the respective cations. Glucono-delta-lactone (GDL), the 1,5-inner ester of gluconic acid, is formed from the free acid by the removal of water. On the basis of these spontaneous chemical rearrangements, glucono-delta-lactone, gluconic acid and its sodium, calcium and potassium salts can be considered as a category, with all members sharing the same representative moiety, the gluconate anion. Manufacturing and uses of the category members are also interlinked. The data summarized in this report are focused on the environmental and health effects from the gluconate anion and read-across to the lactone but do not deal with specific effects of the cations. Thus toxicological effects related to the cationic components are not part of the present report.