The different fate of antibiotics in the Thames River, UK, and the Katsura River, Japan

Little is known about the mechanisms influencing the differences in attenuation of antibiotics between rivers. In this study, the natural attenuation of four antibiotics (azithromycin, clarithromycin, sulfapyridine, and sulfamethoxazole) during transport along the Thames River, UK, over a distance of 8.3 km, and the Katsura River, Japan, over a distance of 7.6 km was compared. To assist interpretation of the field data, the individual degradation and sorption characteristics of the antibiotics were estimated by laboratory experiments using surface water or sediment taken from the same rivers. Azithromycin, clarithromycin, and sulfapyridine were attenuated by 92, 48, and 11% in the Thames River stretch. The first-order decay constants of azithromycin and sulfapyridine were similar to those in the Katsura River, while that of clarithromycin was 4.4 times higher. For sulfamethoxazole, the attenuation was limited in both rivers. Loss of sulfapyridine was attributed to both direct and indirect photolysis in the Thames River, but to only direct photolysis in the Katsura River. Loss of azithromycin and clarithromycin was attributed to sorption to sediment in both rivers. The probable explanation behind the difference in loss rates of clarithromycin between the two rivers was considered to be sediment sorption capacity

Linking changes in antibiotic effluent concentrations to flow, removal and consumption in four different UK sewage treatment plants over four years

The arrival and discharge of seven antibiotics were monitored at two trickling filter sewage treatment plants of 6,000 and 11,000 population equivalents (PE) and two activated sludge plants of 33,000 and 162,000 PE in Southern England. The investigation consisted of 24 h composite samples taken on two separate days every summer from 2012 to 2015 and in the winter of 2015 (January) from influent and effluent. The average influent concentrations generally matched predictions based on England-wide prescription data for trimethoprim, sulfamethoxazole, azithromycin, oxytetracycline and levofloxacin (within 3-fold), but were 3-10 times less for clarithromycin, whilst tetracycline influent concentrations were 5-17 times greater than expected. Over the four years, effluent concentrations at a single sewage plant varied by up to 16-fold for clarithromycin, 10-fold for levofloxacin and sulfamethoxazole, 7-fold for oxytetracycline, 6-fold for tetracycline, 4-fold for azithromycin and 3-fold for trimethoprim. The study attempted to identify the principal reasons for this variation in effluent concentration. By measuring carbamazepine and using it as a conservative indicator of transport through the treatment process, it was found that flow and hence concentration could alter by up to 5-fold. Measuring influent and effluent concentrations allowed assessments to be made of removal efficiency. In the two activated sludge plants, antibiotic removal rates were similar for the tested antibiotics but could vary by several-fold at the trickling filter plants. However, for clarithromycin and levofloxacin the variations in effluent concentration were above that which could be explained by either flow and/or removal alone so here year on year changes in consumption are likely to have played a role

Assessing the population equivalent and performance of wastewater treatment through the ratios of pharmaceuticals and personal care products present in a river basin: application to the River Thames basin, UK

The quality of surface waters in lowland rivers is largely dependent on the efficiency of wastewater treatment. Even in the developed countries, there have been difficulties in evaluating the effectiveness of wastewater management and the proportion of wastewater content (WWC) in the river, as well as in estimating the contributing human population. This study aimed to develop a wastewater quality and quantity assessment based on the occurrence of pharmaceuticals in the receiving waters. A survey of 53 pharmaceuticals in 324 samples (river water and influent and effluent of sewage (wastewater) treatment plants) was carried out in southern England in the River Thames catchment over four years. Carbamazepine was selected as stable marker and from its concentration WWC in the rivers and cumulative human populations along the catchment were estimated. The estimated population had a strong relationship (R2=0.94) with that reported by the local water company. The concentration ratio of the labile marker caffeine to carbamazepine indicated the efficiency of wastewater treatment in the different treatment systems (i.e. trickling filter or activated sludge) and in the receiving waters. The ratio in some river samples revealed unexpected discharges of untreated or poorly treated wastewater, with a total concentration of the analytes (up to 20mug/L) five times higher than that in treated wastewater. Such information could be valuable to estimate the discharge or occurrence of not only non-targeted chemicals, but also pathogens within the basin

Quantification of pharmaceutical related biological activity in effluents from wastewater treatment plants in UK and Japan

While pharmaceuticals are now routinely detected in aquatic environments, we know little of the biological activity their presence might provoke. It is estimated that nearly 40% of all marketed pharmaceuticals are G protein-coupled receptors (GPCRs) acting pharmaceuticals. Here, we applied an in-vitro assay, called the TGFα shedding assay, to measure the biological activities of GPCRs-acting pharmaceuticals present in effluents from municipal wastewater treatment plants in the United Kingdom (UK) and Japan from 2014 to 2016. The results indicated that compounds were present in the wastewater with antagonistic activities against angiotensin (AT1), dopamine (D2), adrenergic (β1), acetylcholine (M1), and histamine (H1) receptors in both countries. The most consistent and powerful antagonistic activity was against the H1, D2, and AT1 receptors at up to microgram-antagonist-equivalent quantity/L. Chemical analysis of the same UK samples was also conducted in parallel. Comparing the results of the bioassay with the chemical analysis indicated (1) the existence of other D2 or M1 receptor antagonists besides sulpiride (D2 antagonist) or pirenzepine (M1 antagonist) in wastewater and (2) that there might be a mixture effect between agonist and antagonistic activities against β1 receptor. GPCR-acting pharmaceuticals should be paid more attention in the environmental monitoring and toxicity testing in future studies

畜産地域における動物用医薬品の排出・流出モデルの構築

金沢大学環境保全センター医薬品の使用量・代謝率や、流域の家畜頭数・家畜糞尿排水処理率等を用いて、畜産排水処理施設のみを排出源とした動物用医薬品の水圏排出モデルを構築した。国内有数の畜産地域である大淀川流域において動物用医薬品3物質の河川調査を月1-2回の頻度で1年間実施したところ、モデル推定値は実測値の1/2～2倍の範囲内に含まれており、対象河川・物質については、本モデルにより水圏排出量が高い精度で予測可能であった。We developed a model for predicting annual loads of veterinary antibiotics discharged into surface waters as effluent from livestock farms, sewage treatment plants, and households. To verify the model, we monitored three antibiotics which are much used for livestock in Japan and are stable during river transport, i.e., sulfamonomethoxine (SMM), sulfamethoxazole (SMX), and lincomycin (LCM), over one year in the Oyodo River, which has the most active swine farming area in Japan in its catchment. Concentrations and mass flows of SMM and SMX showed a sharp peak in winter, and those of LCM were also higher in winter than in summer in the river. Annual mass flows observed in the river were within a range of 1/2 to 2 times the model estimates.研究課題/領域番号:19K20470, 研究期間(年度):2019-04-01 - 2021-03-31出典：「畜産地域における動物用医薬品の排出・流出モデルの構築」研究成果報告書　課題番号19K20470（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/report/KAKENHI-PROJECT-19K20470/19K20470seika/）を加工して作

Evaluation of the photolysis of pharmaceuticals within a river by 2 year field observations and toxicity changes by sunlight.

Accepted 27 Oct 2014.To improve the risk assessment of pharmaceuticals, it is helpful to know how rapidly they are removed from river water. Direct photolysis by sunlight could be an important process, but so far few studies have attempted to compare modeled with actual losses in a river. Therefore, we quantified natural attenuation by monitoring 56 pharmaceuticals and personal care products over 2 full years in a 2.6 km stretch of an urban river. In addition, to screen photoproducts, we used the Microtox test with Vibrio fischeri to evaluate changes in the toxicity of two photolabile pharmaceuticals, ketoprofen and diclofenac, under sunlight. During transport along the river stretch, ketoprofen and the photolabile pharmaceutical furosemide were attenuated by median values of 77% and 39%. The observed attenuation showed good agreement with photochemical attenuation estimated by an existing method at each sampling, suggesting that the method appeared to be effective for estimating the direct photolysis of the pharmaceuticals during river transport. The toxicity of diclofenac decreased under sunlight, while that of ketoprofen increased immediately after exposure (around 12 times in EC20) and remained high, indicating the existence of toxic and photostable photoproducts of ketoprofen. Therefore, ecological risks of photolabile pharmaceuticals may increase during river transport in some cases, indicating the necessity to incorporate their photoproducts into the estimation method

水環境中における医薬品類の光分解生成物の濃度予測手法の構築とリスク評価

金沢大学環境保全センター / 京都大学太陽光照射実験により医薬品類の光分解産物について、量子収率や親物質からの生成率が定量され、解熱鎮痛剤のketoprofen（KTP）について主要な光分解産物が明らかとなった。また、生成したKTPの光分解産物は太陽光に対して比較的安定であることが明らかとなった。現地調査により、日中は河川流下過程においてKTPが減衰し光分解産物が生成していること、また、光分解産物は下水処理場内でも太陽光により生成していることが示された。また、一部の光分解産物に対しては構築したモデルによる予測値と実測値とが概ね一致していたが、両者が解離しており新たなパラメータの組み込みが必要な物質の存在も明らかとなった。We conducted this study to evaluate the occurrence and fate of photoproducts of PPCPs, using photoproducts of ketoprofen (KTP). Photolysis experiments determined the fraction of KTP transformed into photoproducts, and their photodegradability. Field studies in urban rivers revealed that photoproducts were produced substantially during the river transports, while they were also produced in sewage treatment plants. We developed a model to predict concentrations of PPCPs photoproducts in rivers. The model was effective at predicting concentrations in rivers for a photoproduct. However, some predicted concentration was much higher than measured concentration for the others, indicating further study should be conducted to increase the model accuracy for them.研究課題/領域番号:15K16142, 研究期間(年度):2015-04-01 - 2017-03-3

Modeling the Photochemical Attenuation of Down-the-Drain Chemicals during River Transport by Stochastic Methods and Field Measurements of Pharmaceuticals and Personal Care Products

Existing stochastic models for predicting concentrations of down-the-drain chemicals in aquatic environments do not account for the diurnal variation of direct photolysis by sunlight, despite its being an important factor in natural attenuation. To overcome this limitation, we developed a stochastic model incorporating temporal variations in direct photolysis. To verify the model, we measured 57 pharmaceuticals and personal care products (PPCPs) in a 7.6-km stretch of an urban river, and determined their physical and biological properties in laboratory experiments. During transport along the river, 8 PPCPs, including ketoprofen and azithromycin, were attenuated by >20%, mainly owing to direct photolysis and adsorption to sediments. The photolabile PPCPs attenuated significantly in the daytime but persisted in the nighttime. The observations were similar to the values predicted by the photolysis model for the photolabile PPCPs (i.e., ketoprofen, diclofenac and furosemide) but not by the existing model. The stochastic model developed in this study was suggested to be a novel and useful stochastic model for evaluating direct photolysis of down-the-drain chemicals, which occurs during the river transport