Diclofenac and its transformation products: Environmental occurrence and toxicity - A review

Abstract

Diclofenac (DCF) is a prevalent anti-inflammatory drug used throughout the world. Intensive researches carried out in the past few decades have confirmed the global ubiquity of DCF in various environmental compartments. Its frequent occurrence in freshwater environments and its potential toxicity towards several organisms such as fish and mussels makes DCF an emerging environmental contaminant. At typical detected environmental concentrations, the drug does not exhibit toxic effects towards living organisms, albeit chronic exposure may lead to severe effects. For DCF, about 30-70% removal has been obtained through the conventional treatment system in wastewater treatment plant being the major primary sink. Thus, the untreated DCF will pass to surface water. DCF can interact with other inorganic contaminants in the environment particularly in wastewater treatment plant, such as metals, organic contaminants and even with DCF metabolites. This process may lead to the creation of another possible emerging contaminant. In the present context, environmental fate of DCF in different compartments such as soil and water has been addressed with an overview of current treatment methods. In addition, the toxicity concerns regarding DCF in aquatic as well as terrestrial environment along with an introduction to the metabolites of DCF through consumption as well as abiotic degradation routes are also discussed. Further studies are required to better assess the fate and toxicological effects of DCF and its metabolites and must consider the possible interaction of DCF with other contaminants to develop an effective treatment method for DCF and its traces.

Recovery from reproductive and morphological abnormalities in medaka (Oryzias latipes) following a 14‐day exposure to diclofenac

“…Monitoring studies using native fish also indicated that measured concentrations of diclofenac in fish were less than or equal to those in the river water, suggesting low bioconcentration potential in fish ; therefore, we do not expect diclofenac to cause persistent effects with regard to reproductive endpoints. In addition, concentrations of diclofenac in aquatic environments are generally very low (<1 µg/L) . The lowest effective concentration of diclofenac obtained in the present study (37 µg/L) was at least 1 order of magnitude greater than the ambient levels of diclofenac present in rivers.…”

An insight into the adsorption of diclofenac on different biochars: Mechanisms, surface chemistry, and thermodynamics

“…The incomplete degradation of DCF in wastewater treatment plants leads to its presence in surface water and even in drinking water (Vieno & Sillanpää, 2014). This presence in water resources causes toxic concerns towards several aquatic and terrestrial organisms (Lonappan et al, 2016a). It has been reported that even at 250 ng L − 1 , DCF can induce tissue damages in several mussel species and at 1 μg L − 1 , cytological alterations in rainbow trout (Ericson et al, 2010).Thus, even very small concentrations of DCF can lead to a considerable effect on the aquatic ecosystems.…”

Advancement in treatment of wastewater: Fate of emerging contaminants

“…Furthermore, Fatta‐Kassinos et al reported that diclofenac is not completely removed by WWTPs due to its poor degradation and higher consumption rates. The toxicity of diclofenac and its transformation products in the aqueous environment was reviewed by Lonappan et al They reported that the available ecotoxicology data of diclofenac showed acute toxic effects on many aquatic organisms including mussels. They stated that more studies are required in order to determine the possible interaction of diclofenac with other contaminants present in the WWTPs to determine the toxicological effects of diclofenac and its metabolites during different treatment processes.…”

“…This study, using the LDTD‐MS/MS quantification method, reported varying concentrations of CTC (8–61 μg/L) in WW. Lonappan et al compared the LDTD‐APCI‐MS/MS approach with an established LC‐ESI‐MS/MS method for the quantification of diclofenac in WW. They reported that the newly developed LDTD‐APCI‐MS/MS method reduced the analysis time to 12 s compared to 12 min for LC‐ESI‐MS/MS method and further suggested that the LDTD‐APCI‐MS/MS method can be effectively used for the detection and quantification of diclofenac in WW samples instead of the traditional slow, matrix sensitive LCESI‐MS/MS method.…”