This study aimed to provide the first and comprehensive data on the occurrence of 17 target pharmaceuticals and personal care products (PPCPs) in urban water environment in Singapore. Meanwhile, this study also verified the suitability of these PPCPs as specific markers of raw wastewater contamination in receiving water bodies in highly urbanized areas where both surface water and groundwater are not impacted by the discharge of treated wastewater effluents. Analytical results of wastewater showed that among 17 target PPCPs examined, only 5 PPCPs were detected in 100 % of raw wastewater samples, including acetaminophen (ACT), carbamazepine (CBZ), caffeine (CF), diethyltoluamide (DEET), and salicylic acid (SA). Similarly, these PPCPs were found in most surface water and groundwater. Interestingly, the three PPCPs (ACT, CBZ, and SA) were only detected in surface water and groundwater in the sampling sites close to relatively older sewer systems, while they were absent in background samples that were collected from the catchment with no known wastewater sources. This suggests that ACT, CBZ, and SA can be used as specific molecular markers of raw wastewater in surface water and groundwater. This study also confirmed that CF and DEET were not really associated with wastewater sources, thus cannot serve well as specific molecular markers of wastewater contamination in receiving water bodies. To the best knowledge of the authors, the use of ACT and SA as specific molecular markers of raw wastewater contamination in urban surface waters and groundwater was first reported. Further studies on the use of ACT, CBZ, and SA along with other chemical/microbial markers are recommended to identify and differentiate contamination sources of surface waters/groundwater.

Recent technical guidance has been published by the European Commission that outlines methodologies for the derivation of Environmental Quality Standards (EQS) in European surface waters under the Water Framework Directive (WFD). The guidance allows the derivation of a long-term EQS from a small dataset. Specifically an EQS can be derived from just three acute data points, although the safety factors built into such an EQS are large (e.g. up to a factor of 1,000). Large safety factors make such EQS uncertain, and often difficult to achieve in practice. We examine dataset requirements for the derivation of EQS and specifically the minimum number of tests needed for setting EQS for long-term chemical exposures that result in reduced relative uncertainty, as assessed simply through the reduction in standard deviation of the means of the values derived. Using ecotoxicity datasets for four example chemicals, for which EQS have been derived in many jurisdictions, we show that variation in the EQS is greatest when using the minimum dataset allowable under the WFD guidance, but decreases rapidly when seven or more datapoints are available. Increasing the minimum number of ecotoxicity data in deriving an EQS results in a greater understanding of ecotoxicological effects. With this knowledge, the mitigating effects of water chemistry can be accounted for in deriving an EQS, even with relatively limited datasets. The new guidance suggests “simplistic” approaches to account for chemical availability, but does not detail how this might be undertaken. We provide examples of ways by which water chemistry effects can be included in deriving implementable EQS for metals with relatively few reliable and relevant data.

Quinestrol has shown potential for use in the fertility control of the plateau pika population of the Qinghai–Tibet Plateau. However, the environmental safety and fate of this compound are still obscure. Our study investigated degradation of quinestrol in a local soil and aquatic system for the first time. The results indicate that the degradation of quinestrol follows first-order kinetics in both soil and water, with a dissipation half-life of approximately 16.0 days in local soil. Microbial activity heavily influenced the degradation of quinestrol, with 41.2 % removal in non-sterile soil comparing to 4.8 % removal in sterile soil after incubation of 10 days. The half-lives in neutral water (pH 7.4) were 0.75 h when exposed to UV light (λ = 365 nm) whereas they became 2.63 h when exposed to visible light (λ > 400 nm). Acidic conditions facilitated quinestrol degradation in water with shorter half-lives of 1.04 and 1.47 h in pH 4.0 and pH 5.0 solutions, respectively. Moreover, both the soil and water treatment systems efficiently eliminated the estrogenic activity of quinestrol. Results presented herein clarify the complete degradation of quinestrol in a relatively short time. The ecological and environmental safety of this compound needs further investigation.

In the actual environment, temperatures fluctuate drastically through season or global warming and are thought to affects risk of pollutants for aquatic biota; however, there is no report about the effect of water temperature on toxicity of widely used herbicide diuron to fresh water microalgae. The present research investigated inhibitory effect of diuron on growth and photosynthetic activity of a green alga Pseudokirchneriella subcapitata at five different temperatures (10, 15, 20, 25, and 30 °C) for 144 h of exposure. As a result, effective diuron concentrations at which a 50 % decrease in algal growth occurred was increased with increasing water temperature ranging from 9.2 to 20.1 μg L–¹for 72 h and 9.4–28.5 μg L–¹for 144 h. The photochemical efficiency of photosystem II (Fᵥ/Fₘratio) was significantly reduced at all temperatures by diuron exposure at 32 μg L–¹after 72 h. Inhibition rates was significantly increased with decreased water temperature (P < 0.01). Intracellular H₂O₂levels as an indicator of oxidative stress were also decreased with increasing temperature in both control and diuron treatment groups and were about 2.5 times higher in diuron treatment groups than that of controls (P < 0.01). Our results suggest water temperatures may affect the toxicokinetics of diuron in freshwater and should therefore be considered in environmental risk assessment.

Overlying water, pore water, and sediment samples were collected from the Dahuofang reservoir in November 2011 and April 2012, respectively. Total arsenic and arsenic species including arsenite, arsenate, monomethylarsonic, and dimethylarsinic were analyzed by ICP-MS and HPLC–ICP-MS. The results indicated that the environments of the Dahuofang reservoir were in reduced conditions, arsenite was the predominant species in pore water and sediments in the reservoir. Arsenic concentrations in overlying water were very low in all the samples but showed different trend during the different time. In November, arsenic concentrations in the reservoir inlet were higher than that in the other sites, whereas arsenic showed accumulation from the upstream to downstream of the reservoir in samples collected in April. In pore water, arsenic concentrations were about 23 and 37 times higher than those in overlying water in November and April, respectively, and relatively high levels of arsenite were also detected in the pore water. In surface sediments, total arsenic and arsenic species content in the reservoir inlet showed the following decreasing order: R1 > R10 > R4. The results also showed that moderate ecological risks exist in pore water and sediments in the Dahuofang reservoir.

Triclosan (TCS) is a broad-spectrum bactericide, highly toxic to algae, which is released into the environment via wastewater effluents. Predicted no-effect concentrations (PNECs) for aquatic biota have been proposed in the literature, varying from 1.4 to 1,550 ng/L, reflecting contradicting protection goals. In this work, six rivers in the state of São Paulo were monitored for TCS and caffeine, a tracer for untreated sewage disposal, over a period of more than 1 year. From 71 samples analyzed, 32 contained TCS at concentrations above the limit of quantification, ranging from 2.2 to 66 ng/L, corresponding to a frequency of exceedance of the lowest PNEC of 86 % (six out of seven sites). No correlation between TCS and caffeine was observed, and one of the reasons for that could be the different use patterns in the local populations. Given the high values found in the investigated rivers, TCS seems to be a strong candidate in the priority list of compounds that should be regulated in Brazil to preserve the aquatic environment.

The occurrence of pharmaceuticals in the aquatic environment has become a matter of concern in the last decade due to potential risks posed to non-target organisms and the potential for unintended human exposure via food chain. This concern has been driven by a high detection frequency for drugs in environmental samples; these substances are produced in large quantities and are used in both veterinary and human medicine, leading to deposition and potential effects in the environment. However, few studies have focused on the presence of pharmaceuticals in rural areas associated with farming activities in comparison to urban areas. The aim of this study is to investigate the occurrence of pharmaceutically active compounds in surface waters collected from urban and rural areas in northwestern Spain. A monitoring study was conducted with 312 river water samples analysed by high-performance liquid chromatography coupled to tandem mass spectrometry. Positive detection of pharmaceuticals was made for 51 % of the samples. Decoquinate, sulfamethazine, sulfamethoxypyridazine and trimethoprim were the drugs most frequently detected, being present in more than 10 % of the samples. The sampling sites located downstream of the discharge points for wastewater treatment plants yielded the highest number of positive samples, 13 % of the positive samples were detected in these sites and 38 % of the samples collected near the collection point of a drinking water treatment plant were positive.

Overgrowth of water chestnut (Trapa spp.) is a regional problem throughout Asia and North America because of waterway blockage and water fouling upon decomposition. In the present study, we investigated the potential of water chestnut to control cyanobacterial blooms, via a high content of phenolic compounds. In addition, we assessed the impact of biomass harvesting and crude extract application on nutrient balance. We showed that the floating parts of water chestnut contained high concentrations of total phenolics (89.2 mg g⁻¹dry weight) and exhibited strong antioxidant activity (1.31 mmol g⁻¹dry weight). Methanol-extracted phenolics inhibited growth of Microcystis aeruginosa; the half maximal effective concentration (EC₅₀) of the extracted phenolics was 5.8 mg L⁻¹, which was obtained from only 103 mg L⁻¹of dry biomass (the floating and submerged parts). However, the crude extracts also added important quantities of nitrogen, phosphorus, and potassium (1.49, 1.05, and 16.3 mg g⁻¹, respectively; extracted dry biomass weight basis); therefore, in practice, nutrient removal before and/or after the extraction is essential. On the other hand, biomass harvesting enables recovery of nitrogen, phosphorus, and potassium from the water environment (23.1, 2.9, and 18.7 mg g⁻¹, respectively; dry biomass weight basis). Our findings indicate that water chestnut contains high concentrations of phenolics and exhibits strong antioxidant activity. Utilization of these resources, including nutrients, will contribute to reclamation of the water environment, and also to disposal of wet biomass.

To document the toxicity of copper and nickel in binary mixtures, freshwater amphipods Gammarus pulex were exposed to the metals given independently or as mixtures. Toxicity to Cu alone was relatively high: 96-h LC₁₀and LC₅₀were found at 91 and 196 μg L⁻¹, respectively. Toxicity to Ni alone was very low, with 96-h LC₁₀and LC₅₀of 44,900 and 79,200 μg L⁻¹, respectively. Mixture toxicities were calculated from single toxicity data using conventional models. Modeled toxicity was then compared with the measured toxicity of the binary mixture. Two kinds of mixtures were tested. Type I mixtures were designed as combinations of Cu and Ni given at the same effect concentrations, when taken independently, to identify possible interactions between copper and nickel. In type II mixtures, Cu concentrations varied from 0 to 600 μg L⁻¹while the nickel concentration was kept constant at 500 μg L⁻¹to mimic conditions of industrial wastewater discharges. Ni and Cu showed synergic effects in type I mixtures while type II mixtures revealed antagonistic effects. Low doses of Ni reduced Cu toxicity towards G. pulex. These results show that even for simple binary mixtures of contaminants with known chemistry and toxicity, unexpected interactions between the contaminants may occur. This reduces the reliability of conventional additivity models.

Industrially contaminated sites with hazardous materials are a priority and urgent problem all over the world. Appropriate risk assessment is required to determine health risks associated with contaminated sites. The present study was conducted to investigate distribution of potentially hazardous, heavy metal (As, Cd, Cr, Cu, Ni, Pb and Zn) concentrations in surface and groundwater samples collected during summer (pre-monsoon) and winter (post-monsoon) seasons from an industrially contaminated site, Hyderabad, India, with potential source of metal contamination because of industrial effluents and usage of pesticides in agriculture. Heavy metal (HM) concentrations were analysed by using inductively coupled plasma-mass spectrometer and were compared with permissible limits set by the World Health Organisation. Data obtained was treated using multivariate statistical approaches like R-mode factor analysis (FA), principal component analysis, cluster analysis, geoaccumulation index, enrichment factor, contamination factor and the degree of contamination. Health risk assessment like chronic daily intake (CDI) and hazard quotient (HQ) were also calculated. Relatively high levels were noted in surface water with average concentrations during summer and winter seasons showing 16.13 and 11.83 for As, 7.91 and 1.64 for Cd, 88.33 and 32.90 for Cr, 58.11 and 28.26 for Cu, 53.62 and 69.96 for Ni, 173.8 and 118.6 for Pb, and 2,943 and 1,889 μg/L for Zn. While in groundwater, the mean metal levels during two seasons were 18.18 and 3.76 for As, 1.67 and 0.40 for Cd, 29.40 and 5.15 for Cr, 17.03 and 4.19 for Cu, 25.4 and 6.09 for Ni, 81.7 and 2.87 for Pb and 953 and 989 μg/L for Zn, respectively. FA identified two factors with cumulative loadings of F1—60.82 % and F2—76.55 % for pre-monsoon surface water and F1—48.75 % and F2—67.55 % for groundwater. Whereas, three factors with cumulative loadings of F1—39.13 %, F2—66.60 % and F3—81.01 % for post-monsoon surface water and F1—50.31 %, F2—66.18 % and F3—81.54 % for groundwater. The health risk assessment like CDI and HQ indices with increased levels of hazardous elements in the surface and groundwater were safe for drinking purposes provided some water treatment methodologies are adopted.