Disinfection by-Products and Ecotoxic Risk Associated with Hypochlorite Treatment of Tramadol

Abstract

In recent years, many studies have highlighted the consistent finding of tramadol (TRA) in the effluents from wastewater treatment plants (WTPs) and also in some rivers and lakes in both Europe and North America, suggesting that TRA is removed by no more than 36% by specific disinfection treatments. The extensive use of this drug has led to environmental pollution of both water and soil, up to its detection in growing plants. In order to expand the knowledge about TRA toxicity as well as the nature of its disinfection by-products (DBPs), a simulation of the waste treatment chlorination step has been reported herein. In particular, we found seven new by-products, that together with TRA, have been assayed on different living organisms (Aliivibrio fischeri, Raphidocelis subcapitata and Daphnia magna), to test their acute and chronic toxicity. The results reported that TRA may be classified as a harmful compound to some aquatic organisms whereas its chlorinated product mixture showed no effects on any of the organisms tested. All data suggest however that TRA chlorination treatment produces a variety of DBPs which can be more harmful than TRA and a risk for the aquatic environment and human health.

Ecotoxicity screening evaluation of selected pharmaceuticals and their transformation products towards various organisms

“…The available ecotoxicological data for this compound is very limited. However, our observation is consistent with the data recently published by the group of Romanucci et al (2019), who also did not observed any toxic effect of TRA towards V. fischeri at the concentration of 100 mg L −1 and documented the toxicity of TRA towards D. magna (EC 50, 24h = 88.5 mg L −1 ) and R. subcapitata (EC 50 = 87.1 mg L −1 ). Very low toxicity of TRA was also observed in the other studies (Αntonopoulou and Konstantinou 2016;Αntonopoulou et al, 2020).…”

LC and NMR Studies for Identification and Characterization of Degradation Byproducts of Olmesartan Acid, Elucidation of Their Degradation Pathway and Ecotoxicity Assessment

“…The OLM chlorination experiments were performed by mimicking the conditions of a typical WWTP, in which a 10 −5 M solution of the drug was treated for 10 min with 10% hypochlorite (OLM:hypochlorite molar ratio of 1:1; concn.) at room temperature [ 38 , 39 ]. Then, the tests are repeated at much higher concentrations of the contaminant (>10 −3 M), with a much lower ratio of OLM:oxidizing agent (1:5 or 1:6), so as to ensure the degradation of the studied contaminant and the possibility of isolating sufficient quantities of degradation byproducts for the subsequent structural identification.…”

Amoxicillin in Water: Insights into Relative Reactivity, Byproduct Formation, and Toxicological Interactions during Chlorination

“…The AMO chlorination experiments were performed by mimicking the conditions of a typical WWTP, in which a 10 −5 M solution of the drug was treated for 10 min with 10% hypochlorite (AMO/hypochlorite molar ratio of 1:1; concn.) at room temperature [45][46][47] for different pH values (Figures 1 and 2). The measurements of the AMO concentration as a function of time at the two different buffered pH values show how degradation was greater at pH = 7, with a percentage of about 80% after just 20-25 min of treatment.…”

“…The data reported in the literature for other emerging micropollutants generally observed longer reaction times, even in the order of hours. Oxidant concentrations even doubled that of the pollutant to ensure the complete mineralization of the latter, which was not infrequently after a double or triple treatment [44][45][46][47].…”