This study presents the occurrence and impact of 78 anticancer drugs compounds in Spanish river basins based on consumption data during the period 2010–2015 and calculation of the predicted environmental concentrations (PEC). The total consumption of anticancer drugs in Spanish pharmacies was of 23.4 tons in 2015, being mycophenolic acid and hydroxycarbamide the drugs with the highest prescription. Their PECs in river at national scale were up to 80 ng/L. However, the use of different dilution factors revealed major differences between hydrographic basins, and PECriver rose up to 68,014 ng/L in highly populated rivers with low flows. Concerning acute toxicity, there was no expected risk for the aquatic environment. However, chronic toxicity tests revealed possible long-term mutagenic effects for aquatic organisms. This study provides the tools for the estimation of PEC at river basin scale using time trend consumption data compilation. This information is very useful for prioritization of compounds of concern and permit to focus resources in environmental monitoring and risk evaluation.

Glaciers, particularly alpine glaciers, have been receding globally at an accelerated rate in recent decades. The glacial melt-induced release of pollutants (e.g., mercury) and its potential impact on the atmosphere and glacier-fed ecosystems has drawn increasing concerns. During 15th–20th August, 2011, an intensive sampling campaign was conducted in Qugaqie Basin (QB), a typical high mountain glacierized catchment in the inland Tibetan Plateau, to investigate the export and transport of mercury from glacier to runoff. The total mercury (THg) level in Zhadang (ZD) glacier ranged from <1 to 20.8 ng L−1, and was slightly higher than levels measured in glacier melt water and the glacier-fed river. Particulate Hg (PHg) was the predominant form of Hg in all sampled environmental matrices. Mercury concentration in Qugaqie River (QR) was characterized by a clear diurnal variation which is linked to glacier melt. The estimated annual Hg exports by ZD glacier, the upper river basin and the entire QB were 8.76, 7.3 and 157.85 g, respectively, with respective yields of 4.61, 0.99 and 2.74 μg m−2 yr−1. Unique landforms and significant gradients from the glacier terminus to QB estuary might promote weathering and erosion, thereby controlling the transport of total suspended particulates (TSP) and PHg. In comparison with other glacier-fed rivers, QB has a small Hg export yet remarkably high Hg yield, underlining the significant impact of melting alpine glaciers on regional Hg biogeochemical cycles. Such impacts are expected to be enhanced in high altitude regions under the changing climate.

Solomon Islands is rapidly developing its natural resource exploitation sector, but data needed to assess consequent environmental impacts are scarce. We assessed catchments surrounding the Gold Ridge gold mine (Guadalcanal, Solomon Islands) and found that extensive changes in river course, and water and sediment quality have occurred downstream of the gold mine since its development. Sediment run-off from exposed areas associated with the mine pit has increased, elevating turbidity (up to 2450 NTU) and metal and arsenic levels, with levels of the latter being up to 0.141 mg/L in surface waters and 265 mg/kg in sediments. An overfull, inoperative tailings storage facility associated with the currently inactive gold mine with fluctuating arsenic levels (up to 0.087 mg/L in the water; 377 mg/kg in the sediment) presents an ongoing threat to the environment. Arsenic, due to its toxicity, appears to be the greatest threat, with sediment and water guideline levels in rivers exceeded 10-fold and exceeded nearly 20-fold in the tailings dam sediments. Despite elevated metal and arsenic content in the area, no toxic inorganic arsenic was found to have bioaccumulated in locally harvested food. In summary, the natural environment surrounding the Gold Ridge mine has been modified substantially and requires an ongoing monitoring program to ensure the ecosystem services of food and water for the local communities continue to be safe. This study informs not only the local area but also provides a microcosm of the broader global challenges facing the regulation of extractive industries in proximity to subsistence communities.

Infections with antibiotic resistant bacteria are among the major threats for human health. Studies elucidating the role of the environment in their spread are still in their infancy, it, however, seems that different environments might function as a long-term reservoir of antibiotic resistance genes (ARGs) that reside within their microbial communities. An increasing number of studies target the presence and the persistence of ARGs in waters and soils that are exposed to human activities; they, however, rarely consider the spatial/temporal variability that predominate in these environments. Here we evaluated the effect of a moderate rain event (4 mm rain h−1) on the abundance and distribution of ARGs (tetA, ermB, blaCTXM, sulII, and qnrS), by comparing measurements of gene abundances during the rainfall to the yearly average, in the waters of a large subalpine river. ARG abundances, which all increased during the rain event, were then correlated to several microbiological, physical and chemical variables, in order to establish their potential origin. Increments in ARG abundances during rainfall (total ARGs: 24 fold) was concomitant to an increase in total phosphorous, N-NH4, and microbial aggregates. Our results show a strong influence of a moderate rainfall on the abundances of ARGs, and suggest the catchment as their source. The impact of moderate rainfalls in areas exposed to anthropic activities should then be considered in modelling and management of ARG dynamics.

Understanding the sources, occurrence and sinks of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in the urban water cycle is important to protect and utilize local water resources. Concentrations of 22 target PFASs and general water quality parameters were determined monthly for a year in filtered water samples from five tributaries and three sampling stations of an urban water body. Of the 22 target PFASs, 17 PFASs were detected with a frequency >93% including PFCAs: C4-C12 perfluoroalkyl carboxylates, C4, C6, C8, and C10 perfluoroalkane sulfonates, perfluorooctane sulfonamides and perfluorooctane sulfonamide substances (FOSAMs), C10 perfluoroalkyl phosphonic acid (C10 PFPA), 6:2 fluorotelomer sulfonic acid (6:2 FTSA) and C8/C8 perfluoroalkyl phosphinic acid (C8/C8-PFPIA). The most abundant PFASs in water were PFBS (1.4–55 ng/L), PFBA (1.0–23 ng/L), PFOS (1.5–24 ng/L) and PFOA (2.0–21 ng/L). In the tributaries, PFNA concentrations ranged from 1.2 to 87.1 ng/L except in the May 2013 samples of two tributaries, which reached 520 and 260 ng/L. Total PFAS concentrations in the sediment samples ranged from 1.6 to 15 ng/g d.w. with EtFOSAA, PFDoA, PFOS and PFDA being the dominant species. Based on water and sediment data, two types of sources were inferred: one-time or intermittent point sources and continuous non-point sources. FOSAMs and PFOS released continually from non-point sources, C8/C8 PFPIA, PFDoA and PFUnA was released from point sources. The highly water soluble short-chain PFASs including PFBA, PFPeA and PFBS remained predominantly in the water column. The factors governing solution phase concentrations appear to be compound hydrophobicity and sorption to suspended particles. Correlation of the dissolved phase concentrations with precipitation data suggested stormwater was a significant source of PFBA, PFBS, PFUnA and PFDoA. Negative correlations with precipitation indicated sources feeding FOSAA and FOSA directly into the tributaries.

Overburden and tailings materials from oil sands production were used as construction materials as part of a novel attempt to create a self-sustaining, peat accumulating fen-upland ecosystem. To evaluate the potential for elemental release from the construction materials, total elemental concentrations in the tailings sand, petroleum coke and peat used to construct a fen ecosystem were determined using microwave-assisted acid digestions and compared to a leaching experiment conducted under environmentally-relevant conditions. A comparison of solid phase to aqueous Na, Ca, S and Mg concentrations showed they were highly leachable in the materials. Given that the concentrations of these elements can affect plant community structure, it is important to understand their leachability and mobility as they migrate between materials used to construct the system. To that end, a mass balance of aqueous Na, Ca, S and Mg was conducted based on leaching experiments and materials analysis coupled with existing data from the constructed system. The data indicate that there is a large pool of leachable Na, Ca, S and Mg in the system, estimated at 27 t of Na, 14 t of Ca, 37.3 t of S and 8.8 t of Mg. Since recharge mainly drives the fen-upland system water regime, and discharge in the fen, evapo-accumulation of these solutes on the surface may occur.

Diluted bitumen (dilbit) from Alberta oil sands (Canada) is transported across major continental watersheds, yet little is known about its toxicity to fish if spilled into aquatic environments. The toxicity of Cold Lake (CLB) dilbit was assessed for medaka embryos (Oryzias latipes) exposed to water accommodated fractions (WAF) and chemically-enhanced WAF (CEWAF) using Corexit®EC9500A as dispersant. The effects of CLB toxicity were similar to conventional crude oils and Access Western Blend (AWB) dilbit. The prevalence of malformations and cyp1a mRNA synthesis in hatched fish increased monotonically with concentration during WAF and CEWAF treatments and provided a novel indicator of dilbit PAH toxicity. Apart from nfe2 (an antioxidant transcription factor), there were no statistically significant monotonic exposure-responses of ahr, arnt2, cat, sod, gpx, gst, gsr, g6pdh, p53, and hsp70 transcripts at total polycyclic aromatic hydrocarbons (TPAH) concentrations bracketing EC50s for embryotoxicity (WAF ≅ 3 μg/L; CEWAF ≅ 0.1 μg/L TPAH). Based on measured TPAH concentrations in exposure test solutions, CLB dilbit was 6–10 fold more toxic to medaka than AWB during chronic exposures. Lack of direct monotonic gene transcription responses to increasing oil concentrations during exposures that were embryotoxic suggests that the capacity of the oxidative stress response is limited in earlier lifestages or that differences exist among species in mechanisms of toxicity. This study provides a comparative framework for identifying suitable biomarkers and toxicity methods for those fish species in sensitive lifestages at highest risk of Canadian oil sands dilbit exposure following a spill in the freshwater environment.

A systematic grid sampling method and geostatistics were employed to investigate the spatial distribution, inventory, and potential ecological and human health risks of the residues of hexachlorobenzene (HCB) and chlorinated cyclodiene pesticides in soils of the Campanian Plain, Italy, and explore their relationship with the soils properties. The geometric mean (Gmean) concentrations of HCB and cyclodiene compounds followed the order CHLs (heptachlor, heptachlor epoxide, trans-chlordane, and cis-chlordane) > DRINs (aldrin, dieldrin, and endrin) > SULPHs (α-endosulfan, β-endosulfan, and endosulfan sulfate) > HCB. The residual levels of most cyclodienes in agricultural soils were generally higher than those of corresponding counterparts in the other land uses. Significant differences in the concentration of HCB and cyclodienes in the soils across the region are observed, and the Acerra-Marigliano conurbation (AMC) and Sarno River Basin (SRB) areas exhibit particularly high residual concentrations. Some legacy cyclodienes in the Campanian Plain may be attributed to a secondary distribution. The Gmean inventory of HCB, SULPHs, CHLs, and DRINs in the soil is estimated to be 0.081, 0.41, 0.36, and 0.41 metric tons, respectively. The non-cancer and cancer risks of HCB and cyclodienes for exposed populations are deemed essentially negligible, however, endosulfan poses significant ecological risks to some terrestrial species.

Oil extraction activities in the Northern Peruvian Amazon have generated a long-standing socio-environmental conflict between oil companies, governmental authorities and indigenous communities, partly derived from the discharge of produced waters containing high amounts of heavy metals and hydrocarbons. To assess the impact of produced waters discharges we conducted a meta-analysis of 2951 river water and 652 produced water chemical analyses from governmental institutions and oil companies reports, collected in four Amazonian river basins (Marañon, Tigre, Corrientes and Pastaza) and their tributaries. Produced water discharges had much higher concentrations of chloride, barium, cadmium and lead than are typically found in fresh waters, resulting in the widespread contamination of the natural water courses. A significant number of water samples had levels of cadmium, barium, hexavalent chromium and lead that did not meet Peruvian and international water standards. Our study shows that spillage of produced water in Peruvian Amazon rivers placed at risk indigenous population and wildlife during several decades. Furthermore, the impact of such activities in the headwaters of the Amazon extended well beyond the boundaries of oil concessions and national borders, which should be taken into consideration when evaluating large scale anthropogenic impacts in the Amazon.