The assessment of peak flow rate, total runoff volume, and pollutant loads during rainfall process are very important for the watershed management and the ecological restoration of aquatic environment. Real-time measurements of rainfall-runoff and pollutant loads are always the most reliable approach but are difficult to carry out at all desired location in the watersheds considering the large consumption of material and financial resources. An integrated environmental modeling approach for the estimation of flash streamflow that combines the various hydrological and quality processes during rainstorms within the agricultural watersheds is essential to develop targeted management strategies for the endangered drinking water. This study applied the Hydrological Simulation Program—Fortran (HSPF) to simulate the spatial and temporal variation in hydrological processes and pollutant transport processes during rainstorm events in the Miyun Reservoir watershed, a drinking water resource area in Beijing. The model performance indicators ensured the acceptable applicability of the HSPF model to simulate flow and pollutant loads in the studied watershed and to establish a relationship between land use and the parameter values. The proportion of soil and land use was then identified as the influencing factors of the pollution intensities. The results indicated that the flush concentrations were much higher than those observed during normal flow periods and considerably exceeded the limits of Class III Environmental Quality Standards for Surface Water (GB3838-2002) for the secondary protection zones of the drinking water resource in China. Agricultural land and leached cinnamon soils were identified as the key sources of sediment, nutrients, and fecal coliforms. Precipitation volume was identified as a driving factor that determined the amount of runoff and pollutant loads during rainfall processes. These results are useful to improve the streamflow predictions, provide useful information for the identification of highly polluted areas, and aid the development of integrated watershed management system in the drinking water resource area.

Coal rock would emit the electromagnetic radiation (EMR) while deformation and fracture, and there exists structural body in the coal rock because of mining and geological structure. In this paper, we conducted an experimental test the EMR characteristics of cracked rock under loading. Results show that crack appears firstly in the prefabricated crack tip then grows stably parallel to the maximum principal stress, and the coal rock buckling failure is caused by the wing crack tension. Besides, the compressive strength significantly decreases because of the precrack, and the compressive strength increases with the crack angle. Intact rock EMR increases with the loading, and the cracked rock EMR shows stage and fluctuant characteristics. The bigger the angle, the more obvious the stage and fluctuant characteristics, that is EMR becomes richer. While the cracked angle is little, EMR is mainly caused by the electric charge rapid separates because of friction sliding. While the cracked angle is big, there is another significant contribution to EMR, which is caused by the electric dipole transient of crack expansion. Through this, we can know more clear about the crack extends route and the corresponding influence on the EMR characteristic and mechanism, which has important theoretical and practical significance to monitor the coal rock dynamical disasters.

Conventional wastewater treatment plants (WWTPs) have a limited capacity to eliminate micropollutants. One option to improve this is tertiary treatment. Accordingly, the WWTP Eriskirch at the German river Schussen has been upgraded with different combinations of ozonation, sand, and granulated activated carbon filtration. In this study, the removal of endocrine and genotoxic effects in vitro and reproductive toxicity in vivo was assessed in a 2-year long-term monitoring. All experiments were performed with aqueous and solid-phase extracted water samples. Untreated wastewater affected several endocrine endpoints in reporter gene assays. The conventional treatment removed the estrogenic and androgenic activity by 77 and 95 %, respectively. Nevertheless, high anti-estrogenic activities and reproductive toxicity persisted. All advanced treatment technologies further reduced the estrogenic activities by additional 69–86 % compared to conventional treatment, resulting in a complete removal of up to 97 %. In the Ames assay, we detected an ozone-induced mutagenicity, which was removed by subsequent filtration. This demonstrates that a post treatment to ozonation is needed to minimize toxic oxidative transformation products. In the reproduction test with the mudsnail Potamopyrgus antipodarum, a decreased number of embryos was observed for all wastewater samples. This indicates that reproductive toxicants were eliminated by neither the conventional nor the advanced treatment. Furthermore, aqueous samples showed higher anti-estrogenic and reproductive toxicity than extracted samples, indicating that the causative compounds are not extractable or were lost during extraction. This underlines the importance of the adequate handling of wastewater samples. Taken together, this study demonstrates that combinations of multiple advanced technologies reduce endocrine effects in vitro. However, they did not remove in vitro anti-estrogenicity and in vivo reproductive toxicity. This implies that a further optimization of advanced wastewater treatment is needed that goes beyond combining available technologies.

Mercury (Hg) is a heavy metal known as one of the most toxic elements on the planet. The importance of Hg on living organisms resides on its biomagnification ability. Artisanal gold extraction activities release substantial amounts of this metal, polluting the ecosystems. To assess the impact of gold mining in Las Orquideas National Natural Park (Colombia), total Hg (T-Hg) levels were evaluated from 37 bird and 8 small rodent species collected at two sites within the boundaries of the Natural Park (Abriaqui and Frontino municipalities) that have experienced some gold-extraction history. The mean concentration of T-Hg in bird feathers from both sites was 0.84 ± 0.05 μg/g fw. Differences between species were found according to diet. Total Hg levels were greater on insectivorous (1.00 ± 0.08 μg/g fw), followed by nectarivorous (0.73 ± 0.07 μg/g fw) and frugivorus (0.57 ± 0.09 μg/g fw) species. These Hg levels were greater than those found in feathers from a control sample belonging to the species Penelope perspicax (0.53 ± 0.03 μg/g fw), a frugivorous species living at the Otun Quimbaya Fauna and Flora Sanctuary, a forest without known gold mining. Mercury concentrations in the livers of small rodents were greater in specimens from Frontino (0.15 ± 0.01 μg/g fw) than those from Abriaqui (0.11 ± 0.01 μg/g fw), but levels were not different between species. These results indicate that Hg in birds depends mainly on their diet, but geographical location may affect Hg concentration in rodents. Moreover, Hg sources in natural parks of Colombia may not rely solely on gold mining, atmospheric deposition, among others factors, could be influencing its accumulation in biota.

The development of neuroprotective drugs through eco-friendly production routes is a major challenge for current pharmacology. The present study was carried out to synthesize gold nanoparticles (AuNPs) through biogenic route using ethanolic bark extract of Terminalia arjuna, a plant of high interest in Asian traditional medicine, and to evaluate its neuroprotective effects. The synthesized AuNPs were characterized by UV-Vis spectroscopy, FTIR spectroscopy, XRD, FESEM, EDX, HRTEM, DLS, and zeta potential analyses. UV-Vis spectroscopy showed a characteristics SPR absorption band at 536 nm specific for AuNPs. XRD, TEM, and FESEM analyses revealed the formation of face-centered cubic crystalline, spherical and triangular shaped AuNPs, with size ranging between 20 and 50 nm. DLS and ZP analysis illustrated that the average size of AuNPs was 30 nm, which was found to be stable at 45 mv. The neuroprotective potential of AuNPs was evaluated by assessing its antioxidant, cholinesterase inhibitory, and antiamyloidogenic activities. AuNPs showed dose-dependant inhibition of acetylcholinesterase and butyrylcholinesterase with IC₅₀ value of 4.25 ± 0.02 and 5.05 ± 0.02 μg/ml, respectively. In vitro antioxidant assays illustrated that AuNPs exhibited the highest reducing power and DPPH radical scavenging activity. In addition, AuNPs also efficiently suppressed the fibrillation of Aβ and destabilized the preformed mature fibrils. Results of toxicity studies in PBMC and adult zebra fish illustrated that AuNPs are non-toxic and biocompatible. Overall, our results highlighted the AuNPs promising potential in terms of antioxidant, anticholinesterase, antiamyloidogenic effects, and non-lethality allowing us to propose these nanomaterials as a suitable candidate for the development of drugs helpful in the treatment of neurodegenerative disorders like Alzheimer’s disease. Graphical abstract ᅟ

The aim of this study was to jointly show the results of three independent ecotoxicological studies performed to investigate pollutants in three Brazilian tropical reservoirs undergoing accelerated eutrophication. In order to accomplish this goal, the full toxicity identification and evaluation procedure (TIE approach) was performed, at Pampulha (Minas Gerais State) and Salto Grande and Barra Bonita reservoirs (São Paulo State). Acute and chronic toxicity tests were performed using the cladocerans Daphnia similis and Ceriodaphnia dubia (exotic) and Daphnia laevis and Ceriodaphnia silvestrii (native) as test organisms. Results from TIE procedure stage I indicated the existence of nonpolar organic and filterable compounds in the water from Pampulha, probably cyanotoxins, and oxidants as part of the toxic agents. TIE results for sediments identified ammonia (Pampulha and Salto Grande), organic compounds (Pampulha), metals (Pampulha, Barra Bonita, and Salto Grande), and acidity (Salto Grande) as responsible for toxicity. Whole-sediment remediation experiments for Pampulha reservoir confirmed, through reproduction decrease, ammonia and organic compounds as contaminants. Such pollutants represent threats to aquatic biota and must be prevented. Higher temperatures as predicted from global climate change will severely affect tropical shallow reservoirs, accelerating eutrophication, the release of contaminants from sediments, and increasing toxicity.

The estrogen agonistic/antagonistic activity of 16 brominated by-products of parabens was assessed by using a yeast two-hybrid assay transfected with the human estrogen receptor α. Characterization of synthetic compounds including novel brominated parabens was performed using ¹H-NMR spectroscopy and high-resolution mass spectrometry. For the agonist assay, five C₃–C₄ alkylparabens exhibited significant activity (P < 0.05) relative to that of 17β-estradiol, ranging from 3.7 × 10⁻⁵ to 7.1 × 10⁻⁴. In contrast, none of the brominated alkyl parabens exhibited agonistic activity. In the antagonist assay, 12 brominated alkylparabens and butylparaben exhibited significant antagonistic activity (P < 0.05). Their antagonistic activity relative to 4-hydroxytamoxifen ranged from 0.11 to 2.5. The antagonist activity of C₁–C₄ alkylparabens increased with the number of bromine substitutions. Benzylparaben exhibited both agonistic and antagonistic activity, and these activities dissipated or were weakened with increased bromination. Thus, increased bromination appeared to attenuate the estrogen agonistic activity of most parabens such that it resulted in increased antagonistic activity, a feature of parabens that had not been previously described.

Although nickel (Ni) frequently enters into water, documents on speciation of the metal and its toxicity to freshwater organisms are scanty. Laboratory experiments, made in this study, with 1.0–5.0 mg/L of Ni revealed that Ni was not quickly removed from water. Application of cubic regression followed by classical optimization technique showed that maximum reduction time (T) of Ni in water ranged between 60 to 65 h. Ninety-six hours of LC₅₀ value of Ni to crustacean Diaptomus forbesi, fish Cyprinus carpio, and worm Branchiura sowerbyi was respectively 5.43, 14.70, and 19.73 mg/L. Normalizing the lethal values and plotting them against time, it was observed that C. carpio was more sensitive than D. forbesi, which was not reflected in the 96-h LC₅₀ values. However, sensitivity of these organisms to Ni was better explained by power regression equation (M = aNiᵇ), which exhibited that mortality (M) of D. forbesi and B. sowerbyi increased slowly between 24 to 72 h, increasing sharply at 96 h, while mortality of C. carpio increased steadily every 24 till 96 h. Experiment with 1.0 mg/L of Ni in outdoor vats showed that crustacean zooplankton and worms accumulated high concentration of Ni, while only gut and liver tissues of fish C. carpio accumulated trace and moderately high concentration of Ni, respectively. It is assumed that toxicity of Ni to fish is mediated primarily through gill.

One of the most important sources of pollution caused by metals, if not the most important, is mining. Metal pollution is covert, persistent and irreversible. For this reason, soil metal pollution has become a severe problem in many parts of the world. The aim of this study was to observe which combination of amendments (compost + biochar or technosol + biochar) combined with Brassica juncea L. was best at reducing the assimilable contents of Cu, and which also increased to a lesser extent the contents of other metals (Ni, Pb, Zn) found in these amendments. We also studied the phytoremediation capacity of brassicas in these amendments. The experiment was carried out using 45-cm-deep cylinders over and 11-month period, with soil from the settling pond in the depleted copper mine located in Touro (Galicia, north-west Spain). At depth 0–15 cm, the settling pond soil (S) had a higher CaCl₂-extractable Cu, Pb, and Ni concentration, at the three time periods measured (time 1 = 3 months, time 2 = 7 months, time 3 = 11 months). The settling pond soil + technosol + biochar and vegetated with Brassica juncea L. (STBP) had the highest CaCl₂-extractable concentrations of Zn over time. In general terms, the most effective treatment for reducing the phytoavailable contents of Cu, Pb, Ni and Zn was the treatment using compost +b iochar + Brassica juncea L. In the two treatments applied, Brassica juncea L. had a good phytostabilisation capacity.

A sensitive and selective method was developed and validated for the determination of pyrethrin residues in turnips (turnip leaves, turnip tubers, and the whole of plant) and cultivated soil using gas chromatography coupled with mass spectrometry (GC-MS). Six major components of pyrethrins (pyrethrin I and II, cinerin I and II, and jasmolin I and II) were separated and identified. The method involving solid-phase extraction (SPE) cleanup led to satisfactory average recoveries (88.1–104%) with limits of quantification (LOQs) of 0.05 mg/kg. The dissipation and final residue of pyrethrins in six provinces (among these places, two experiments were conducted in greenhouse and other four experiments in open filed) in China were studied. The trial results suggested that the half-lives of pyrethrins in the whole of turnips and soil were 0.5–1.6 and 1.0–1.3 days, respectively, and the degradation of pyrethrins in the greenhouse was quicker than that in open fields. The final residues of pyrethrins in turnip leaves and tubers were all below the maximum residue limit (MRL) established by the EU (1.0 mg/kg). A pre-harvest interval of 2 days and MRL of 1.0 mg/kg are recommended to ensure food safety standards for pyrethrins in turnips. Long-term risk assessment and short-term risk assessment of turnip tubers were evaluated. Hazard quotient (HQ) and acute hazard index (aHI) were significantly less than 100%, indicating negligible risk for consumption of turnip tubers.