| 1. |
- Liu, Zhikun, et al.
(författare)
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A review of spatiotemporal patterns of neonicotinoid insecticides in water, sediment, and soil across China
- 2022
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Ingår i: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 29:37, s. 55336-55347
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Forskningsöversikt (refereegranskat)abstract
- Neonicotinoid insecticides (NNIs) have been widely used to control insect pests, while their environmental residues and associated hazardous impacts on human and ecosystem health have attracted increasing attention worldwide. In this study, we examined the current levels and associated spatial and temporal patterns of NNIs in multiple environmental media across China. Concentrations of NNIs in surface water, sediment, and soil were in the range of 9.94-755 ng.L-1, 0.07-8.30 ng.g(-1) DW, and 0.009-356 ng.g(-1) DW, respectively. The high levels of NNIs in surface water, such as in Yangtze River (755 ng.L-1), North River (539 ng.L-1), Nandu River (519 ng.L-1), and Minjiang River (514 ng.L-1), were dominated by imidacloprid, thiamethoxam, and acetamiprid due to their extensive use. The levels of NNIs in sediments were relatively low, and the highest concentration (8.30 ng.g(-1) DW) was observed in Dongguan ditch. Sediment-water exchange calculated from fugacity fraction indicated that NNIs in sediment can be released back into the water due to their high solubility and low KOW. Soils from agricultural zones contained the largest residual NNIs, with imidacloprid concentrations in cultivated soil reaching 119 ng.g(-1) DW. The calculated leaching potential showed that clothianidin has the highest migration potential to deep soil or groundwater. The monitored data of NNIs presented a decreasing trend from 2016 to 2018, which might be caused by the implementation of relevant control policies for NNI applications. The high levels of NNIs mainly occurred in southern China due to frequent agricultural activities and warm and humid meteorological conditions. The results from this study improve our understanding of the pollution levels and environmental behavior of NNIs in different environmental media across China and provide new knowledge that is needed for making future control policies for NNIs production and application.
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| 2. |
- Chen, Deliang, 1961, et al.
(författare)
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Summary of a workshop on extreme weather events in a warming world organized by the Royal Swedish Academy of Sciences
- 2020
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Ingår i: Tellus Series B-Chemical and Physical Meteorology. - : Stockholm University Press. - 1600-0889 .- 0280-6509. ; 72:1
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Tidskriftsartikel (refereegranskat)abstract
- Climate change is not only about changes in means of climatic variables such as temperature, precipitation and wind, but also their extreme values which are of critical importance to human society and ecosystems. To inspire the Swedish climate research community and to promote assessments of international research on past and future changes in extreme weather events against the global climate change background, the Earth Science Class of the Royal Swedish Academy of Sciences organized a workshop entitled 'Extreme weather events in a warming world' in 2019. This article summarizes and synthesizes the key points from the presentations and discussions of the workshop on changes in floods, droughts, heat waves, as well as on tropical cyclones and extratropical storms. In addition to reviewing past achievements in these research fields and identifying research gaps with a focus on Sweden, future challenges and opportunities for the Swedish climate research community are highlighted.
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| 3. |
- Cui, Song, et al.
(författare)
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Heavy Metals in Sediment from the Urban and Rural Rivers in Harbin City, Northeast China
- 2019
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 16:22
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Tidskriftsartikel (refereegranskat)abstract
- The concentrations and ecological risk of six widespread heavy metals (Cu, Cr, Ni, Zn, Cd and Pb) were investigated and evaluated in sediments from both urban and rural rivers in a northeast city of China. The decreasing trend of the average concentration of heavy metals was Zn > Cr > Cu > Pb > Ni > Cd in Majiagou River (urban) and was Zn > Cr > Pb > Cu > Ni > Cd in Yunliang River (rural). The results showed that the concentrations of Cd and Zn were significantly elevated compared to the environmental background value (p < 0.05). Half of all sampling locations were deemed 'contaminated' as defined by the improved Nemerow pollution index (P-N' > 1.0). Applying the potential ecological risk index (RI) indicated a 'high ecological risk' for both rivers, with Cd accounting for more than 80% in both cases. Source apportionment indicated a significant correlation between Cd and Zn in sediments (R = 0.997, p < 0.01) in Yunliang River, suggesting that agricultural activities could be the major sources. Conversely, industrial production, coal burning, natural sources and traffic emissions are likely to be the main pollution sources for heavy metals in Majiagou River. This study has improved our understanding of how human activities, industrial production, and agricultural production influence heavy metal pollution in urban and rural rivers, and it provides a further weight of evidence for the linkages between different pollutants and resulting levels of heavy metals in riverine sediments.
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| 4. |
- Cui, Song, et al.
(författare)
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Understanding the risks from diffuse pollution on wetland eco-systems : The effectiveness of water quality classification schemes
- 2020
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Ingår i: Ecological Engineering. - : Elsevier. - 0925-8574 .- 1872-6992. ; 155
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Tidskriftsartikel (refereegranskat)abstract
- Eco-environmental safety and health is an important concept for the protection of flora and fauna in the wetland eco-system. Identifying impacts of human activities on wetland ecology and risk factors of environmental decline have become significant components of habitat protection. In this study, the Qixing River wetland, one of the Ramsar Sites, was taken as the research area. Seven water quality indices, including dissolved oxygen (DO), chemical oxygen demand (COD), ammonia nitrogen (NH3 - N), total phosphorus (TP), total nitrogen (TN), nitrates and nitrites were monitored at fifteen sampling locations. Entropy weight-set pair analysis, combined with discriminant analysis, was used to identify the most sensitive indicators for changes in water quality. Average concentrations for the indicators measured were: DO 7.24 (4.64-9.98) mg/L; COD 21.67 (5-50) mg/L; NH3-N 1.09 (0.41-2.15) mg/L; TP 0.18 (0.10-0.73) mg/L; TN 1.38 (0.76-2.17) mg/L, nitrite 0.016 (ND - 0.030) mg/L and nitrate concentration was 0.420 (0.315-0.613) mg/L. Water quality was found to be poorest at locations closer to sources of diffuse pollution such as agricultural land. In contrast, the more remote buffer zone and core zone of the wetland was characterized by improved indicators of water quality. The results of entropy weight-set pair analysis showed that the overall water quality grade of Qixing River wetland conforms to Class III of the "Environmental Quality Standards for Surface Water" of China (GB3838-2002). Discriminant analysis indicated that TP was the main contributory factor to reduced water quality classification while COD, ammonia nitrogen and total nitrogen were the key drivers of improving water quality grade and responsible for the Class III award. The prominence of these indicators is indicative of long-term use of fertilizers and pesticides in agricultural production. The more remote core area of the wetland was less affected by human activities, reflected in improved water quality results. The results showed that entropy weight-set pair analysis coupled with discriminant analysis adds value to widely used water environment quality indices and helps identify the main environmental factors driving water quality classification. In the case of the Qixing River wetland, there is clear potential to protect wetland eco-system safety by improving the water quality classification and reforming agronomic and land management practices.
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| 5. |
- Zhang, Fuxiang, et al.
(författare)
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Heavy metals exposure risk to Eurasian Spoonbill (Platalea leucorodia) in wetland ecosystem, Northeast China
- 2020
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Ingår i: Ecological Engineering. - : Elsevier. - 0925-8574 .- 1872-6992. ; 157
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Tidskriftsartikel (refereegranskat)abstract
- Qixing River wetland is very representative of the marsh environment of Sanjiang Plain, northeast China. The wetland plays an important role in maintaining ecological service functions especially for protecting migratory birds. Despite Qixing River wetland being impacted by a number of diffuse and point sources of pollution (primarily from agricultural activities), a comprehensive survey of heavy metal exposure risk to migratory birds has never been undertaken. Identifying heavy metals exposure risk is significant for further improving the protection scheme of migratory birds. In the present study, the comprehensive water pollution index (WPI) and geo-accumulation index (I-geo) were calculated to assess the degree of contamination of water and sediments, respectively. Single-pollutant exposure metrics (HQ) were applied to measured concentrations in order to estimate the heavy metal exposure risk to migratory birds. In addition, an integrated hazard index (HI) was derived to assess the comprehensive risk of exposure to multiple heavy metals and associated risk threshold values calculated. The decreasing trends of average concentration of heavy metals were Zn > Cr > Ni > Cu > Pb > Cd in sediments and Zn > Cr > Pb > Ni > Cu > Cd in water. Concentrations of Cr were significantly elevated compared to the threshold of Aquatic Life Water Permissible Limits (AWPL) and Sediment Quality Guidelines (SGQ) (p < 0.01), thus may pose negative impacts to the aquatic ecological system. Values of WPI indicated 'Clean' status for more than 85% sampling sites with Zn accounting for 58% of the value of the WPI. Most of the sediment sampling locations were deemed to be 'Clean' or 'Low' status as defined by I-geo with Zn and Cd (mainly derived from agricultural sources) identified as the dominant indicators of pollution. Comprehensive exposure risk assessment indicated 'Moderate' risk (HI > 1) status for local populations of Eurasian Spoonbill. Despite the majority of heavy metals (except for Zn) being assigned 'Clean' or 'Low' pollution status, the elevated hazard quotient (HQ > 3) associated with Cr enhanced overall values of HI, especially for nestlings, indicating that current pollution control measures are insufficient for the protection of migratory birds. This study has supplemented current knowledge of the impacts of agriculture on wetland ecosystems and provides evidence that exposures of migratory birds to some heavy metals may exceed 'safe' levels. This study thus provides a scientific rationale for determining the safe feeding water depth for migratory birds.
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| 6. |
- Zhang, Fuxiang, et al.
(författare)
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Levels, Inventory, and Risk Assessment of Heavy Metals in Wetland Ecosystem, Northeast China : Implications for Snow Cover Monitoring
- 2021
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Ingår i: Water. - : MDPI. - 2073-4441. ; 13:16
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Tidskriftsartikel (refereegranskat)abstract
- Snow cover is a unique environmental medium in cold regions that can cause potential risks to the ecological environment, due to the release of pollutants that are stored in it. In this study, the Qixing River wetland, located in the Sanjiang Plain of China, was taken as the target research area. Heavy metals in snow cover, including Cu, Ni, Cr, Cd, Pb, and Zn were measured at 19 sampling sites. The results showed that the average concentrations of heavy metals were: Zn (103.46 +/- 39.16) > Pb (13.08 +/- 4.99) > Cr (11.97 +/- 2.82) > Ni (9.55 +/- 4.96) > Cu (6.19 +/- 1.79) > Cd (0.55 +/- 0.25) mu g center dot L-1. Cr and Zn were between Class I and Class II in the "Environmental Quality Standards for Surface Water" of China (GB3838-2002). Pb in snow exceeded the upper limit of Class II, and was significantly higher than concentrations measured in water samples from the Qixing River wetland (p < 0.05), indicating that atmospheric deposition during winter was the major source of Pb. The water pollution index (WPI) indicated that 61.0% of samples could be considered of "clean" status, while the contribution of Zn, Pb, and Cr to WPI were 33.3%, 21.0%, and 19.3%, respectively. A preliminary evaluation of heavy metal inventory in snow cover showed that the residue level of Zn was the highest (2313.57 +/- 1194.67 mu g center dot m(-2)), while Cd was the lowest (13.91 +/- 10.45 mu g center dot m(-2)). The areas with high residues of heavy metals were all located near the buffer zone of the wetland (except for Zn), where snow depth tended to be greatest. Exposure analysis indicated that the risks to winter resident birds from snow ingestion was minimal, but it should be noted that the exposure risk was higher in birds with lower bodyweights. This study provides important information and scientific knowledge on the pollution characteristics and residue inventory of heavy metals in wetland ecosystems, while the results can also provide a monitoring method, reflecting atmospheric environmental quality at a local or regional scale.
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| 7. |
- Cui, Liang, et al.
(författare)
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Four additional natural 7-deazaguanine derivatives in phages and how to make them
- 2023
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Ingår i: Nucleic Acids Research. - : Oxford University Press. - 0305-1048 .- 1362-4962. ; 51:17, s. 9214-9226
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Tidskriftsartikel (refereegranskat)abstract
- Bacteriophages and bacteria are engaged in a constant arms race, continually evolving new molecular tools to survive one another. To protect their genomic DNA from restriction enzymes, the most common bacterial defence systems, double-stranded DNA phages have evolved complex modifications that affect all four bases. This study focuses on modifications at position 7 of guanines. Eight derivatives of 7-deazaguanines were identified, including four previously unknown ones: 2 & PRIME;-deoxy-7-(methylamino)methyl-7-deazaguanine (mdPreQ(1)), 2 & PRIME;-deoxy-7-(formylamino)methyl-7-deazaguanine (fdPreQ(1)), 2 & PRIME;-deoxy-7-deazaguanine (dDG) and 2 & PRIME;-deoxy-7-carboxy-7-deazaguanine (dCDG). These modifications are inserted in DNA by a guanine transglycosylase named DpdA. Three subfamilies of DpdA had been previously characterized: bDpdA, DpdA1, and DpdA2. Two additional subfamilies were identified in this work: DpdA3, which allows for complete replacement of the guanines, and DpdA4, which is specific to archaeal viruses. Transglycosylases have now been identified in all phages and viruses carrying 7-deazaguanine modifications, indicating that the insertion of these modifications is a post-replication event. Three enzymes were predicted to be involved in the biosynthesis of these newly identified DNA modifications: 7-carboxy-7-deazaguanine decarboxylase (DpdL), dPreQ(1) formyltransferase (DpdN) and dPreQ(1) methyltransferase (DpdM), which was experimentally validated and harbors a unique fold not previously observed for nucleic acid methylases.
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| 8. |
- Snyder, Gretchen L., et al.
(författare)
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Preclinical profile of ITI-214, an inhibitor of phosphodiesterase 1, for enhancement of memory performance in rats
- 2016
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Ingår i: Psychopharmacology. - : Springer Science and Business Media LLC. - 0033-3158 .- 1432-2072. ; 233:17, s. 3113-3124
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Tidskriftsartikel (refereegranskat)abstract
- Rationale: Therapeutic agents for memory enhancement in psychiatric disorders, such as schizophrenia, are urgently needed.Objective: The aim of this study is to characterize the preclinical profile of ITI-214, a potent inhibitor of phosphodiesterase 1 (PDE1).Methods: ITI-214 was assayed for inhibition of PDE1 versus other PDE enzyme families using recombinant human PDE enzymes and for off-target binding to 70 substrates (General SEP II diversity panel; Caliper Life Sciences). Effects of ITI-214 (0.1–10 mg/kg, po) on memory performance were assayed in rats using the novel object recognition (NOR) paradigm, with drug given at specified time points prior to or following exposure to objects in an open field. ITI-214 was evaluated for potential drug-drug interaction with risperidone in rats using conditioned avoidance response (CAR) and pharmacokinetic assessments.Results: ITI-214 inhibited PDE1A (Ki = 33 pmol) with >1000-fold selectivity for the nearest other PDE family (PDE4D) and displayed minimal off-target binding interactions in a 70-substrate selectivity profile. By using specific timing of oral ITI-214 administration, it was demonstrated in the NOR that ITI-214 is able to enhance acquisition, consolidation, and retrieval memory processes. All memory effects were in the absence of effects on exploratory behavior. ITI-214 did not disrupt the risperidone pharmacokinetic profile or effects in CAR.Conclusions: ITI-214 improved the memory processes of acquisition, consolidation, and retrieval across a broad dose range (0.1–10 mg/kg, po) without disrupting the antipsychotic-like activity of a clinical antipsychotic medication, specifically risperidone. Clinical development of ITI-214 is currently in progress.
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| 9. |
- Xie, S., et al.
(författare)
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A re-assessment of metal pollution in the Dexing mining area in Jiangxi province, China : current status, hydro-geochemical controls, and effectiveness of remediation practices
- 2022
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Ingår i: International Journal of Environmental Science and Technology. - : Springer Nature. - 1735-1472 .- 1735-2630. ; 19, s. 10707-10722
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Tidskriftsartikel (refereegranskat)abstract
- This study re-assess the environmental impacts of the Dexing copper mine (the largest open-pit copper mine in Asia) on the Lean river and its two tributaries (the Dawu river and Jishui river) in the Jiangxi province, China, with particular focus on metal pollution as well as the effectiveness and side-effects of remediation activities. Results show that the Dawu river and its mixing zone with the Lean river were still heavily influenced by acid mine drainage (AMD) and loaded with elevated levels of metals, in particular Mn, Ni, and Al whose concentrations were frequently above the health-based guideline values. Manganese and Ni in the AMD-impacted waters were predicted to occur as free ions or sulfate and carbonate complexes, and thus highly-toxic to living organisms. Although Al in the AMD-impacted waters was predicted to exist largely as colloidal hydroxides with low bioavailability, abundant formation of such nano-sized particles could impair the respiratory and circulatory systems of aquatic macro-invertebrates. The integration and comparison of the results from the current and previous studies show that the concentrations of several metals (Cu, Zn, and Cd) in the Dawu river decreased significantly after 2011-2012, during which several remediation practices were implemented (e.g., AMD neutralization, excavation of contaminated sediments in impounded rivers, and rehabilitation of mine tailings and open-pit slopes). This provides evidence that these remediation practices have effectively limited the dispersion of metals from the mining area. However, AMD neutralization greatly enhanced the release of sulfate, making the mining area an even more important sulfate source.
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