Biodegradation and aquatic toxicity of β-alaninediacetic acid (β-ADA)

The aquatic toxicity and biodegradability of the new chelating agent β-alaninediacetic acid (β-ADA) were investigated. There is no inhibition effect of β-ADA in the daphnia magna 24h test up to a concentration of 1000 mg/L. The algal growth inhibition test resulted in an EC 50 of 19.7 mg/L. An EC 20 of 740 mg/L was determined in the luminescent bacteria test. An EC 50 was not obtained in this test up to a concentration of 2000 mg/L β-ADA. The degree of biodegradation of β-ADA was determined in a static and a continuous test. The β-ADA removal reached 98 % at the end of the test after eight weeks in the continuous test which was carried out with laboratory activated sludge units simulating a waste water treatment plant. Further, biodegradation and toxicity tests were coupled, i.e. the effluents of the laboratory activated sludge units were applied in the toxicity tests. A higher toxicity of the effluents of the test units in comparison with the control unit was not observed.