For twenty-five world lakes and three engineered nanoparticles (ENP), lake retention was calculated using a uniformly mixed lake mass balance model. This follows similar approaches traditionally used in water quality management. Lakes were selected such that lake residence times, depths and areal hydraulic loadings covered the widest possible range among existing lakes. Sedimentation accounted for natural colloid as well as suspended solid settling regimes. An ENP-specific mixed sedimentation regime is proposed. This regime combines ENP sedimentation through slow settling with natural colloids from the water column, with faster settling with suspended solids from a selected part of the water column. Although sedimentation data and hydrodynamic concepts as such were not new, their first time combination for application to ENPs shows in which cases lake retention is important for these particles. In combination with ENP emission data, lake retention translates directly into potential risks of ENPs for lake benthic communities.

Ecosystems modified by human activities are generally predicted to be biologically impoverished. However, much pollution impact theory stems from laboratory or small-scale field studies, and few studies replicate at the level of estuary. Furthermore, assessments are often based on sediment contamination and infauna, and impacts to epibiota (sessile invertebrates and algae) are seldom considered. We surveyed epibiota in six estuaries in south-east Australia. Half the estuaries were relatively pristine, and half were subject to internationally high levels of contamination, urbanisation, and industrialisation. Contrary to predictions, epibiota in modified estuaries had greater coverage and were similarly diverse as those in unmodified estuaries. Change in epibiota community structure was linearly correlated with sediment-bound copper, and the tubeworm Hydroides elegans showed a strong positive correlation with sediment metals. Stressors such as metal contamination can reduce biodiversity and productivity, but others such as nutrient enrichment and resource provision may obscure signals of impact.

Fate and occurrence of 4 selective serotonin reuptake inhibitors, one serotonin-noradrenergic reuptake inhibitor and one noradrenergic-dopamineric reuptake inhibitor and their human metabolites were determined in a German municipal wastewater treatment plant as well as in the Rhine River and selected tributaries. The enantiomeric fractions of venlafaxine and its metabolites were not altered during wastewater treatment and were similar in all river samples underlining that no appreciable biodegradation occurs. In the Rhine catchment area highest concentrations were detected for venlafaxine, citalopram and their human metabolites. Projected future climate change would lead to an increased portion of treated wastewater in rivers due to reduced discharges during low flow situations by the end of the 21st century. However, the effect of climate change on the pattern and concentrations of antidepressants is predicted to be of minor importance in comparison to altered consumption quantities caused by demographic developments and changes in life styles.

In England and Wales, steroid estrogens: estrone, estradiol and ethinylestradiol have previously been identified as the main chemicals causing endocrine disruption in male fish. A national risk assessment is already available for intersex in fish arising from estrogens under current flow conditions. This study presents, to our knowledge, the first set of national catchment-based risk assessments for steroid estrogen under future scenarios. The river flows and temperatures were perturbed using three climate change scenarios (ranging from relatively dry to wet). The effects of demographic changes on estrogen consumption and human population served by sewage treatment works were also included. Compared to the current situation, the results indicated increased future risk:the percentage of high risk category sites, where endocrine disruption is more likely to occur, increased. These increases were mainly caused by changes in human population. This study provides regulators with valuable information to prepare for this potential increased risk.

We evaluated the occurrence of 12 veterinary antibiotics and a beta agonist over spatial and temporal scales in Shell Creek, an intensively agricultural watershed in Nebraska, using Polar Organic Chemical Integrative Samplers (POCIS). Twelve pharmaceuticals were detected with concentrations ranging from 0.0003 ng/L to 68 ng/L. The antibiotics measured at the highest time-weighted average concentrations were lincomycin (68 ng/L) and monensin (49 ng/L), and both compounds were detected at increased concentrations in summer months. Analysis of variance indicates that mean concentrations of detected pharmaceuticals have no significant (p > 0.01) spatial variation. However, significant temporal differences (p < 0.01) were observed. This study demonstrates the utility of passive samplers such as POCIS for monitoring ambient levels of pharmaceuticals in surface waters.

The present study investigated temporal influences on metal distribution in gudgeon (Gobio gobio) and roach (Rutilus rutilus), and its relation to condition metrics and fish community structure. Fish communities were sampled in two seasons (autumn and spring) during two successive years and the Index of Biotic Integrity (IBI) was calculated. Cadmium, Cu, Pb, Zn and As concentrations were measured in gill, liver, kidney and muscle, and condition factor (CF) and hepatosomatic index (HSI) were measured. Cadmium (max. 39.0 μg g−1 dw) and Zn (max 2502 μg g−1 dw) were most strongly stored in kidney and liver and periodical influences on metal accumulation were observed. CF appeared to be a stable metric related to accumulated metal-mixtures and was best related to hepatic levels, while the HSI was less useful. Relations between single metal accumulation and IBI were influenced by sample period, however, when taking into account multiple metals periodical influences disappeared.

In reverse osmosis, a frequently used technology in water desalination processes, wastewater (RO concentrate) is generated containing the retained solutes as well as so-called antiscalants (AS), i.e. chemical substances that are commonly applied to prevent membrane-blocking. In this study, a risk assessment of a possible discharge of concentrate into a small stream was conducted. The acute toxicity of two concentrates containing two different ASs and of concentrate without AS to the amphipods Gammarus pulex and Gammarus roeseli was studied. Mortality of gammarids exposed to the concentrate without AS was not different to the control, whereas concentrates including ASs caused mortality rates up to 100% at the highest test concentrations after 168 h. Resulting EC50-values were 36.2–39.4% (v/v) after 96 h and 26.6–58.0% (v/v) after 168 h. These results suggest that the ecotoxicological relevance of antiscalants is greater than currently assumed.

We examined 10 wood frog populations distributed along an agricultural gradient for their tolerance to six pesticides (carbaryl, malathion, cypermethrin, permethrin, imidacloprid, and thiamethoxam) that differed in date of first registration (pesticide novelty) and mode-of-action (MOA). Our goals were to assess whether: 1) tolerance was correlated with distance to agriculture for each pesticide, 2) pesticide novelty predicted the likelihood of evolved tolerance, and 3) populations display cross-tolerance between pesticides that share and differ in MOA. Wood frog populations located close to agriculture were more tolerant to carbaryl and malathion than populations far from agriculture. Moreover, the strength of the relationship between distance to agriculture and tolerance was stronger for older pesticides compared to newer pesticides. Finally, we found evidence for cross-tolerance between carbaryl and malathion (two pesticides that share MOA). This study provides one of the most comprehensive approaches for understanding patterns of evolved tolerance in non-pest species.

Four genotypes of snap bean (Phaseolus vulgaris L.) were selected to study the effects of ambient ozone concentration at a cropland area around Beijing by using 450 ppm of ethylenediurea (EDU) as a chemical protectant. During the growing season, the 8h (9:00–17:00) average ozone concentration was very high, approximately 71.3 ppb, and AOT40 was 29.0 ppm.h. All genotypes showed foliar injury, but ozone-sensitive genotypes exhibited much more injury than ozone-tolerant ones. Compared with control, EDU significantly alleviated foliar injury, increased photosynthesis rate and chlorophyll a fluorescence, Vcmax and Jmax, and seed and pod weights in ozone-sensitive genotypes but not in ozone-tolerant genotypes. EDU did not significantly affect antioxidant contents in any of the genotypes. Therefore, EDU effectively protected sensitive genotypes from ambient ozone damage, while protection on ozone-tolerant genotypes was limited. EDU can be regarded as a useful tool in risk assessment of ambient ozone on food security.

The reuse of treated wastewater for agricultural irrigation in arid and hot climates where plant transpiration is high may affect plant accumulation of pharmaceutical and personal care products (PPCPs) and endocrine disrupting chemicals (EDCs). In this study, carrot, lettuce, and tomato plants were grown in solution containing 16 PPCP/EDCs in either a cool-humid or a warm-dry environment. Leaf bioconcentration factors (BCF) were positively correlated with transpiration for chemical groups of different ionized states (p < 0.05). However, root BCFs were correlated with transpiration only for neutral PPCP/EDCs (p < 0.05). Neutral and cationic PPCP/EDCs showed similar accumulation, while anionic PPCP/EDCs had significantly higher accumulation in roots and significantly lower accumulation in leaves (p < 0.05). Results show that plant transpiration may play a significant role in the uptake and translocation of PPCP/EDCs, which may have a pronounced effect in arid and hot climates where irrigation with treated wastewater is common.