Aquatic ecosystems are confronted with multiple stress factors. Current approaches to assess the risk of anthropogenic stressors to aquatic ecosystems are developed for single stressors and determine ...stressor effects primarily as a function of stressor properties. The cumulative impact of several stressors, however, may differ markedly from the impact of the single stressors and can result in nonlinear effects and ecological surprises. To meet the challenge of diagnosing and predicting multiple stressor impacts, assessment strategies should focus on properties of the biological receptors rather than on stressor properties. This change of paradigm is required because (i) multiple stressors affect multiple biological targets at multiple organizational levels, (ii) biological receptors differ in their sensitivities, vulnerabilities, and response dynamics to the individual stressors, and (iii) biological receptors function as networks, so that actions of stressors at disparate sites within the network can lead via indirect or cascading effects, to unexpected outcomes.
Pharmaceuticals are designed to improve human and animal health, but even the most beneficial pharmaceuticals might raise some questions concerning the consequences of exposure to non-target ...organisms. To illustrate this situation and using diclofenac as a case-study, we analyze global consumption and occurrence data to identify hot spots of consumption without occurrence data, review the scientific literature on the harmful environmental effects to determine whether the observed concentrations in freshwater are of environmental concern, summarize the current pharmaceutical and environmental policies to highlight policy gaps, and suggest a series of research and policy recommendations, which can be summarized as follows: we need to improve the current knowledge on occurrence in freshwaters to properly implement environmental policies (i), diclofenac might pose a risk to non-target organisms in freshwater (ii); the harmful effects that some pharmaceuticals may have on the environment are not always addressed by environmental policies (iii).
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•Global analysis reveals hotspots of Diclofenac consumption with no occurrence data.•Diclofenac occurs in freshwaters at ecotoxicological relevant concentrations.•Research on occurrence and ecotoxicology is needed to properly assess risks posed by pharmaceuticals.
Why Should We Care About Temporary Waterways? Acuña, V.; Datry, T.; Marshall, J. ...
Science (American Association for the Advancement of Science),
03/2014, Letnik:
343, Številka:
6175
Journal Article
Recenzirano
Intermittently flowing streams and rivers should be recognized, afforded protection, and better managed.
A proposed ruling by the U.S. Environmental Protection Agency (EPA), aimed at clarifying which ...bodies of water that flow intermittently are protected under law (
1
), has provoked conflict between developers and environmental advocates. Some argue that temporary streams and rivers, defined as waterways that cease to flow at some points in space and time along their course (see the figure, left) ( Fig. 1) (
2
), are essential to the integrity of entire river networks. Others argue that full protection will be too costly. Similar concerns extend far beyond the United States. Debate over how to treat temporary waterways in water-policy frameworks is ongoing (
3
), particularly because some large permanent rivers are shifting to temporary because of climate change and extraction of water (
4
). Even without human-induced changes, flow intermittency is part of the natural hydrology for streams and rivers globally.
Wastewater treatment plants (WWTPs) are one of the main sources of pharmaceuticals and endocrine disrupting compounds in freshwater ecosystems, and several studies have reported bioaccumulation of ...these compounds in different organisms in those ecosystems. River biofilms are exceptional indicators of pollution, but very few studies have focused on the accumulation of these emerging contaminants. The objectives of this study were first to develop an efficient analytical methodology for the simultaneous analysis of 44 pharmaceuticals and 13 endocrine disrupting compounds in biofilm, and second, to assess persistence, distribution, and bioaccumulation of these contaminants in natural biofilms inhabiting a WWTP-impacted river. The method is based on pressurized liquid extraction, purification by solid-phase extraction, and analysis by ultra performance liquid chromatography coupled to a mass spectrometer (UPLC–MS/MS) in tandem. Recoveries for pharmaceuticals were 31–137%, and for endocrine disruptors 32–93%. Method detection limits for endocrine disruptors were in the range of 0.2–2.4ngg−1, and for pharmaceuticals, 0.07–6.7ngg−1. A total of five endocrine disruptors and seven pharmaceuticals were detected in field samples at concentrations up to 100ngg−1.
•Method for analysis of pharmaceuticals & endocrine disruptors in river biofilm•Bioaccumulation in biofilm of a WWTP-impacted river evaluated•Seven PhACs and five EDCs detected in biofilm downstream of the WWTP
Targeting cell cycle has become one of the major challenges in cancer therapy, being Palbociclib, a CDK4/6 inhibitor, an excellent example. Recently, it has been reported that Palbociclib could be a ...novel radiosensitizer agent. In an attempt to clarify the molecular basis of this effect we have used cell lines from colorectal (HT29, HCT116) lung (A549, H1299) and breast cancer (MCF-7). Our results indicate that the presence of a p53 wild type is strictly required for Palbociclib to exert its radiosensitizing effect, independently of the inhibitory effect exerted on CDK4/6. In fact, abrogation of p53 in cells with functional p53 blocks the radiosensitizing effect of Palbociclib. Moreover, no radiosensitizing effect is observed in cells with non-functional p53, but restoration of p53 function promotes radiosensitivity associated to Palbociclib. Furthermore, the presence of Palbociclib blocks the transcriptional activity of p53 in an ATM-dependent-fashion after ionizing radiation exposure, as the blockage of p21/WAF1 expression demonstrates. These observations are a proof of concept for a more selective therapy, based on the combination of CDK4/6 inhibition and radiotherapy, which would only benefit to those patients with a functional p53 pathway.
•Palbociclib promotes radiosensitivity in lung and colon cancer derived cell lines.•Palbociclib promotes radiosensitivity independently of CDk4/6 chemical inhibition.•Palbociclib associated radiosensitivity requires a functional p53 signalling.•P53 could be a novel biomarker for the combination of Palbociclib and radiotherapy.
This paper assesses annual and seasonal trends in runoff and sediment load resulting from climate variability and afforestation in an upland Mediterranean basin, the Ribera Salada (NE Iberian ...Peninsula). We implemented a hydrological and sediment transport distributed model (TETIS) with a daily time-step, using continuous discharge and sediment transport data collected at a monitoring station during the period 2009–2013. Once calibrated and validated, the model was used to simulate the hydrosedimentary response of the basin for the period 1971–2014 using historical climate and land use data. Simulated series were further used to (i) detect sediment transport and hydrologic trends at different temporal scales (annual, seasonal); (ii) assess changes in the contribution of extreme events (i.e. low and high flows) and (ii) assess the relative effect of forest expansion and climate variability on trends observed by applying a scenario of constant land use. The non-parametric Mann–Kendall test indicated upward trends for temperature and decreasing trends (although non-significant) for precipitation. Downward trends occurred for annual runoff, and less significantly for sediment yield. Reductions in runoff were less intense when afforestation was not considered in the model, while trends in sediment yield were reversed. Results also indicated that an increase in the river's torrential behaviour may have occurred throughout the studied period, with low and high flow events gaining importance with respect to the annual contribution, although its magnitude was reduced over time.
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•We applied a distributed hydrological model to reconstruct runoff and sediment yield.•Decreasing trends were detected for both variables at the annual and seasonal time scales.•Afforestation seemed to be the main factor driving the trends observed.•An increase in the torrential behaviour and reduction of peak flows was detected.
We analyzed the diatom assemblages inhabiting the epipelic biofilm of a Pampean stream, characterized by their high basal nutrient levels, when exposed to a continuous surplus of inorganic nutrients. ...An in situ experience was conducted, increasing concentrations of N and P in water 3-fold from the basal concentration. Nutrient enrichment was achieved by the use of fertilizer bags distributed along the reach. The period of exposure was of 14 months. The effects of nutrient enrichment were analyzed following a BACIPS ANOVA design. The changes in nutrient concentration were associated with a significant increase in diatom density and a decrease in species richness and diversity. The additional nutrient load also caused the change in the diatom taxa proportion, favoring motile forms, Nitzschia species mainly. The fertilization in La Choza, caused a mild to moderate effect, indeed not immediate, on the diatom assemblage. These delayed responses of moderate intensity could be related with intrinsic characteristics of diatom assemblages pre-adapted to nutrient-rich environments. The rising urbanization and agricultural activity in the Pampean plain, may seriously impair the biodiversity of its rivers if the entrance of nutrients to these ecosystems is not mitigated.
•Chemical pharmaceuticals fate model was calibrated for diclofenac at the Global scale.•2.7% of the global river network has concentrations exceeding the EU limit of 100 ng DCL L-1.•Under ...business-as-usual scenarios, Global change will increase the DCL concentration.•Sanitation improvements won’t suffice to mitigate impact on pharmaceuticals occurrence.•Source control mitigation actions need to be considered.
Human consumption of pharmaceuticals leads to high concentrations of pharmaceuticals in wastewater, which is usually not or insufficiently collected and treated before release into freshwater ecosystems. There, pharmaceuticals may pose a threat to aquatic biota. Unfortunately, occurrence data of pharmaceuticals in freshwaters at the global scale is scarce and unevenly distributed, thus preventing the identification of hotspots, the prediction of the impact of Global Change (particularly streamflow and population changes) on their occurrence, and the design of appropriate mitigation actions. Here, we use diclofenac (DCL) as a typical pharmaceutical contaminant, and a global model of DCL chemical fate based on wastewater sanitation, population density and hydrology to estimate current concentrations in the river network, the impact of future changes in runoff and population, and potential mitigation actions in line with the Sustainable Development Goals. Our model is calibrated against measurements available in the literature. We estimate that 2.74 ± 0.63% of global river network length has DCL concentrations exceeding the proposed EU Watch list limit (100 ng L-1). Furthermore, many rivers downstream from highly populated areas show values beyond 1000 ng L-1, particularly those associated to megacities in Asia lacking sufficient wastewater treatment. This situation will worsen with Global Change, as streamflow changes and human population growth will increase the proportion of the river network above 100 ng L-1 up to 3.10 ± 0.72%. Given this background, we assessed feasible source and end-of-pipe mitigation actions, including per capita consumption reduction through eco-directed sustainable prescribing (EDSP), the implementation of the United Nations Sustainable Development Goal (SDG) 6 of halving the proportion of population without access to safely managed sanitation services, and improvement of wastewater treatment plants up to the Swiss standards. Among the considered end-of-pipe mitigation actions, implementation of SDG 6 was the most effective, reducing the proportion of the river network above 100 ng L-1 down to 2.95 ± 0.68%. However, EDSP brought this proportion down to 2.80 ± 0.64%. Overall, our findings indicate that the sole implementation of technological improvements will be insufficient to prevent the expected increase in pharmaceuticals concentration, and that technological solution need to be combined with source mitigation actions.
We evaluated the distribution of eleven groups of pharmaceutically active compounds (PhACs) in surface waters and biota of different trophic levels, in five sites of two lowland urban rivers in ...Argentine. Twenty-nine out of 39 PhACs and two metabolites were detected in at least one water sample (2–9622 ng/L), eleven detected in biofilms (1–179 ng/g d.w.) and eight in the macrophyte Lemna gibba (4–112 ng/g d.w). The two more polluted sites had a similar distribution of the main groups of compounds. In surface waters, the largest concentrations were for the analgesic acetaminophen (9622 ng/L), the antibiotic sulfamethoxazole (326 ng/L), the antihypertensive valsartan (963 ng/L), the β-blocking agent atenolol (427 ng/L), the diuretic hydrochlorothiazide (445 ng/L) and the psychiatric drug carbamazepine (99 ng/L). The antibiotic ciprofloxacin exhibited the highest concentration in the biofilm (179 ng/g d.w.) and in the macrophyte L. gibba (112 ng/g d.w.) Several compounds were detected in the water but not in the biota (e.g., codeine and bezafibrate), and others (e.g., azithromycin and citalopram) were found in the biota but not in the surface water. Significant bioaccumulation factors (>1000 L/kg d.w.) were obtained for venlafaxine and ciprofloxacin in biofilm. Our results show that PhACs may accumulate in several biological compartments. Within an environmental compartment, similar PhACs profile and concentrations were found in different sites receiving urban pollution. Among different compartments, biofilms may be the most suitable biota matrix to monitor the immediate reception of PhACs in the biota. Our results indicate that the presence of PhACs in urban rivers and their accumulation in the biota could be incorporated as symptoms of the urban stream syndrome.
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•Pharmaceutical active compounds and metabolites detected in surface water and biota•Similar PhACs water profiles between two urban lowland rivers•Biofilm is biota matrix most suitable for monitoring PhACs in aquatic ecosystems.•PhACs in surface water and biota are symptoms of the urban stream syndrome.
The number of studies assessing soil erosion and sediment transport has increased with the aim of achieving sustainable land and water management. Mediterranean rivers have been the object of many of ...these studies due to their naturally high values of sediment fluxes and a higher vulnerability under future climate scenarios. In this context, we attempt to use empirical relationships to (i) further assess the relation between sediment yield and basin scale and (ii) provide an update on the main drivers controlling sediment yield in these particular river systems. For this purpose, sediment yield data (from reservoir sedimentation surveys and sediment transport records) was collected from >100 locations distributed across the western Mediterranean area, with basin areas ranging from 1 to 100,000km2. Quantile Regression analysis was used to assess the correlation between basin area and sediment yield, while additional basin-scale descriptors were related to sediment yield by means of multiple regression analysis. Results showed the complexity in the relationship between basin scale and sediment yield, with changes in supply conditions with increasing area introducing uncertainties in the correlation. Despite the large scatter, analysis pointed towards the same direction and area appeared to be the main constrain for the maximum value of sediment yield that can be found at a specific basin scale. Results from the multiple regression indicated that variables representing basin's physiography, climate and land use were highly correlated with the basins' sediment yield. Also, a better model performance was obtained when using total sediment yield instead of specific values (per unit area). Validation showed model instability, potentially due to data limitations and the use of catchments with varying characteristics. Overall, despite providing some insights on the correlation between sediment yield and basin-scale characteristics, validation prevented direct extrapolation of the model to other catchments.
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•We used data on sediment yield and basin characteristics on the western Mediterranean.•Area proved to be a limiting factor in the upper range of sediment yield values.•Multiple regression using basin-scale variables analysis indicated model instability.•Uncertainties prevent the use of the model in other regions.
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