A rational approach to selecting and ranking some pharmaceuticals of concern for the aquatic environment and their relative importance compared with other chemicals

Abstract

Aquatic organisms can be exposed to thousands of chemicals discharged by the human population. Many of these chemicals are considered disruptive to aquatic wildlife, and the literature on the impacts of these chemicals grows daily. However, because time and resources are not infinite, research must focus on the chemicals that represent the greatest threat. One group of chemicals of increasing concern is pharmaceuticals, for which the primary challenge is to identify which represent the greatest threat. In the present study, a list of 12 pharmaceuticals was compiled based on scoring the prevalence of different compounds from previous prioritization reviews. These included rankings based on prescription data, environmental concentrations, predicted environmental concentration/predicted no-effect concentration (PEC/PNEC) ratios, persistency/bioaccumulation/(eco)toxicity (PBT), and fish plasma model approaches. The most frequently cited were diclofenac, paracetamol, ibuprofen, carbamazepine, naproxen, atenolol, ethinyl estradiol, aspirin, fluoxetine, propranolol, metoprolol, and sulfamethoxazole. For each pharmaceutical, literature on effect concentrations was compiled and compared with river concentrations in the United Kingdom. The pharmaceuticals were ranked by degree of difference between the median effect and median river concentrations. Ethinyl estradiol was ranked as the highest concern, followed by fluoxetine, propranolol, and paracetamol. The relative risk of these pharmaceuticals was compared with those of metals and some persistent organic pollutants. Pharmaceuticals appear to be less of a threat to aquatic organisms than some metals (Cu, Al, Zn) and triclosan, using this ranking approach.

Which commonly monitored chemical contaminant in the Bohai region and the Yangtze and Pearl Rivers of China poses the greatest threat to aquatic wildlife?

“…To assist the collection of aquatic ecotoxicity data for an individual chemical, it was found that the US Environmental Protection Agency's ECOTOX database was a good starting point, and this was supplemented by searching the Web of Science database using a series of keywords (Donnachie et al 2014(Donnachie et al , 2016. Ecotoxicity data for Chinese local freshwater species and standard test species were selected for each chemical (see Supplemental Data, Table S5 for the species included).…”

“…China has also considered a "black list" of high PBT chemicals, being the ones deserving the most attention (Jin et al 2014). To avoid these potential errors, a different risk-ranking method has been proposed where a median or percentile of the ecotoxicity data set is compared against the median or a percentile of the MEC, and this has been recently applied to a range of chemicals in the United Kingdom (Donnachie et al 2014(Donnachie et al , 2016Johnson et al 2017) and in China . Typically, this is linked to the toxicity of the chemical and is based on a predicted-no-effect concentration (PNEC).…”

“…Together, both could distort the risk assessment by overlooking the chemical causing the most frequent damage to wildlife. To avoid these potential errors, a different risk-ranking method has been proposed where a median or percentile of the ecotoxicity data set is compared against the median or a percentile of the MEC, and this has been recently applied to a range of chemicals in the United Kingdom (Donnachie et al 2014(Donnachie et al , 2016Johnson et al 2017) and in China . Thus, the ecotoxicity value used in the present study is bounded firmly within the data set and is not a prediction beyond what has been recorded in ecotoxicity testing such as is used to generate a PNEC.…”

Pharmaceuticals in the environment: An introduction to the ET&C special issue

“…Prioritization strategies is one area that has received considerable attention in the present special issue and elsewhere in the literature, with a number of articles proposing risk‐based approaches, taking into account not only anticipated exposure levels but also the relative potency of the compounds . Despite some differences in the composition of prioritization lists, the represented pharmaceutical classes overlap and include antibiotics, selective serotonin reuptake inhibitors (SSRIs), antidepressants, endocrine active pharmaceuticals, and nonsteroidal anti‐inflammatory drugs.…”

Which metal represents the greatest risk to freshwater ecosystem in bohai region of china?

“…However, a recent approach has been proposed which argues that only two factors are critical—the proximity of the median exposure and toxicity concentrations, when evaluating relative risk (Donnachie et al. , ). There is no perfect system of course, but the focus on only these two factors has the merit of simplicity and transparency.…”