中国的酸化问题——一项基于重庆—广州森林监测点研究结果的评估

中国经济的快速增长一直伴随着污染的加剧。本文在现场观测和文献研究的基础上讨论了酸性降水及其先兆的范围和影响。目前酸性降水的主要原因是二氧化硫的排放,但氮氧化物的排放也在增加。中国污染最严重地区的硫化合物沉降比东欧和中欧经受严重污染的地区要高。中国南部很多地区的土壤和土壤水看来已经被酸化。这些地区的污染已经影响了森林和其他植物的生命力,特别是在位于和靠近城市地区的地方。地表水的酸化似乎在近期不会成为主要的区域性问题,但一些地区的河流,目前虽仅接受少量的酸沉降,却对酸化显得较敏感。

Multi-omics in nanoplastic research:a spotlight on aquatic life

Amidst increasing concerns about plastic pollution’s impacts on ecology and health,nanoplastics are gaining global recognition as emerging environmental hazards.This review aimed to examine the complex molecular consequences and underlying fundamental toxicity mechanisms reported from the exposure of diverse aquatic organisms to nanoplastics.Through the comprehensive examination of transcriptomics,proteomics,and metabolomics studies,we explored the intricate toxicodynamics of nanoplastics in aquatic species.The review raised essential questions about the consistency of findings across different omics approaches,the value of combining these omics tools to understand better and predict ecotoxicity,and the potential differences in molecular responses between species.By amalgamating insights from 37 omics studies(transcriptome 22,proteome six,and metabolome nine)published from 2013 to 2023,the review uncovered both shared and distinct toxic effects and mechanisms in which nanoplastics can affect aquatic life,and recommendations were provided for advancing omics-based research on nanoplastic pollution.This comprehensive review illuminates the nuanced connections between nanoplastic exposure and aquatic ecosystems,offering crucial insights into the complex mechanisms that may drive toxicity in aquatic environments.

A trait-based approach to assess climate change sensitivity of freshwater invertebrates across Swedish ecoregions

Freshwater habitats and organisms are among the most threatened on Earth, and freshwater ecosystems have been subject to large biodiversity losses. We developed a Climate Change Sensitivity （CCS） indicator based on trait information for a selection of stream- and lake-dwelling Ephemeroptera, Plecoptera and Trichoptera taxa. We calculated the CCS scores based on ten species traits identified as sensitive to global climate change. We then assessed climate change sensitivity between the six main ecoregions of Sweden as well as the three Swedish regions based on lilies. This was done using biological data from 1,382 stream and lake sites where we compared large-scale （ecoregional） patterns in climate change sensitivity with potential future exposure of these ecosystems to increased temperatures using ensemble-modelled future changes in air temperature. Current （1961-1990） measured temperature and ensemble-modelled future （2100） temperature showed an increase from the northernmost towards the southern ecoregions, whereas the predicted temperature change increased from south to north. The CCS indicator scores were highest in the two northernmost boreal ecoregions where we also can expect the largest global climate change-induced increase in temperature, indicating an unfortunate congruence of exposure and sensitivity to climate change. These results are of vital importance when planning and implementing management and conservation strategies in freshwater ecosystems, e.g., to mitigate increased temperatures using riparian buffer strips. We conclude that traits information on taxa specialization, e.g., in terms of feeding specialism or taxa having a preference for high altitudes as well as sensitivity to changes in temperature are important when assessing the risk from future global climate change to freshwater ecosystems [Current Zoology 60 （2）： 221-232, 2014].

Characteristics of plankton Hg bioaccumulations based on a global data set and the implications for aquatic systems with aggravating nutrient imbalance

The bioaccumulation of mercury(Hg)in aquatic ecosystem poses a potential health risk to human being and aquatic organism.Bioaccumulations by plankton represent a crucial process of Hg transfer from water to aquatic food chain.However,the current understanding of major factors affecting Hg accumulation by plankton is inadequate.In this study,a data set of 89 aquatic ecosystems worldwide,including inland water,nearshore water and open sea,was established.Key factors influencing plankton Hg bioaccumulation(i.e.,plankton species,cell sizes and biomasses)were discussed.The results indicated that total Hg(THg)and methylmercury(MeHg)concentrations in plankton in inland waters were significantly higher than those in nearshore waters and open seas.Bioaccumulation factors for the logarithm of THg and MeHg of phytoplankton were 2.4–6.0 and 2.6–6.7 L/kg,respectively,in all aquatic ecosystems.They could be further biomagnified by a factor of 2.1–15.1 and 5.3–28.2 from phytoplankton to zooplankton.Higher MeHg concentrations were observed with the increases of cell size for both phyto-and zooplankton.A contrasting trend was observed between the plankton biomasses and BAF_(MeHg),with a positive relationship for zooplankton and a negative relationship for phytoplankton.Plankton physiologic traits impose constraints on the rates of nutrients and contaminants obtaining process from water.Nowadays,many aquatic ecosystems are facing rapid shifts in nutrient compositions.We suggested that these potential influences on the growth and composition of plankton should be incorporated in future aquatic Hg modeling and ecological risk assessments.

Total mercury in wild fish in Guizhou reservoirs, China

The health hazard of mercury （Hg） compounds is internationally recognized, and the main pathways for methylmercury （MeHg） intake in humans are through consumption of food, especially fish. Given the large releases of Hg to the environment in China, combined with the fast development of hydropower, this issue deserves attention. Provided similar mobilization pathways of Hg in China as seen in reservoirs in North America and Europe one should expect increased Hg contamination in relation to future hydropower reservoir construction in this country. This study presents total Hg （THg） concentrations in wild fish from six Guizhou reservoirs, China. The THg concentrations in fish were generally low despite high background levels in the bedrock and depositions from local point sources. The over all mean ± SD concentration of THg was （0.066 ± 0.078） μg/g （n = 235）. After adjusting for among-reservoir variation in THg, there were significant differences in THg among functional groups of the fish, assumed to re？ect trophic levels. Predicted THg- concentration ratios, retrieved from a mixed linear model, between the functional groups were 9：4：4：1 for carnivorous, omnivorous, planktivorous and herbivorous fish. This result indicated that MeHg accumulation may prevail even under circumstances with short food chains as in this Chinese water system. No fish exceeded recommended maximum THg limit for human consumption set by World Health Organization and the Standardization Administration of China （0.5 μg/g fish wet weight （ww））. Only six fish （2.5%） exceeded the maximum THg limit set by US Environmental Protection Agency （0.3 μg/g fish ww）.

Transport and fate of mercury under different hydrologic regimes in polluted stream in mining area

Seepage from Hg mine wastes and calcines contains high concentrations of mercury （Hg）. Hg pollution is a major environmental problem in areas with abandoned mercury mines and retorting units. This study evaluates factors, especially the hydrological and sedimentary variables, governing temporal and spatial variation in levels and state of mercury in streams impacted by Hg contaminated runoff. Samples were taken during different flow regimes in the Wanshan Hg mining area in Guizhou Province, China. In its headwaters the sampled streams/rivers pass by several mine wastes and calcines with high concentration of Hg. Seepage causes serious Hg contamination to the downstream area. Concentrations of Hg in water samples showed significant seasonal variations. Periods of higher flow showed high concentrations of total Hg （THg） in water due to more particles being re-suspended and transported. The concentrations of major anions （e.g., Cl-, F-, NO3- and SO4^2-） were lower during higher flow due to dilution. Due to both sedimentation of particles and dilution from tributaries the concentration of THg decreased from 2100 ng/L to background levels （〈 50 ng/L） within 10 km distance downstream. Sedimentation is the main reason for the fast decrease of the concentration, it accounts for 69% and 60% for higher flow and lower flow regimes respectively in the upper part of the stream. Speciation calculation of the dissolved Hg fraction （DHg） （using Visual MINTEQ） showed that Hg（OH）2 associated with dissolved organic matter is the main form of Hg in dissolved phase in surface waters in Wanshan （over 95%）.

Levels and trends of poly-and perfluoroalkyl substances in the Arctic environment-An update

Poly-and perfluoroalkyl substances(PFASs)are important environmental contaminants globally and in the early 2000s they were shown to be ubiquitous contaminants in Arctic wildlife.Previous reviews by Butt et al.and Letcher et al.have covered studies on levels and trends of PFASs in the Arctic that were available to 2009.The purpose of this review is to focus on more recent work,generally published between 2009 and 2018,with emphasis on PFASs of emerging concern such as perfluoroalkyl carboxylates(PFCAs)and short-chain perfluoroalkyl sulfonates(PFSAs)and their precursors.Atmospheric measurements over the period 2006e2014 have shown that fluorotelomer alcohols(FTOHs)as well as perfluorobutanoic acid(PFBA)and perfluoroctanoic acid(PFOA)are the most prominent PFASs in the arctic atmosphere,all with increasing concentrations at Alert although PFOA concentrations declined at the Zeppelin Station(Svalbard).Results from ice cores show generally increasing deposition of PFCAs on the Devon Ice cap in the Canadian arctic while declining fluxes were found in a glacier on Svalbard.An extensive dataset exists for long-term trends of long-chain PFCAs that have been reported in Arctic biota with some datasets including archived samples from the 1970s and 1980s.Trends in PFCAs over time vary among the same species across the North American Arctic,East and West Greenland,and Svalbard.Most long term time series show a decline from higher concentrations in the early 2000s.However there have been recent(post 2010)increasing trends of PFCAs in ringed seals in the Canadian Arctic,East Greenland polar bears and in arctic foxes in Svalbard.Annual biological sampling is helping to determine these relatively short term changes.Rising levels of some PFCAs have been explained by continued emissions of long-chain PFCAs and/or their precursors and inflows to the Arctic Ocean,especially from the North Atlantic.While the effectiveness of biological sampling for temporal trends in long-chain PFCAs and PFSAs has been demonstrated,this does not apply to the C4eC8ePFCAs,perfluorobutane sulfonamide(FBSA),or perfluorobutane sulfonate(PFBS)which are generally present at low concentrations in biota.In addition to air sampling,sampling abiotic media such as glacial cores,and annual sampling of lake waters and seawater would appear to be the best approaches for investigating trends in the less bioaccumulative PFASs.

Decreasing mercury levels in consumer fish over the three decades of increasing mercury emissions in China

Fish consumption is the primary dietary route of human exposure to methylmercury.It has been well documented that elevated mercury concentration in fish in North America and Europe is linked to anthropogenic mercury emissions.China is the world’s largest producer,consumer,and emitter of mercury,as well as the world’s largest commercial fish producer and consumer.Although mercury pollution in fish in China is currently receiving much attention worldwide,its status remains largely unknown.Here,we conducted a meta-analysis on total mercury concentrations in marine and freshwater fish samples,covering 35,464 samples collected in China over the past 30 years.It is found that,opposite to the increasing emission and documented mercury contamination events,mercury levels in fish have gradually decreased in China over the past 30 years.The results were in sharp contrast to those found in North America and Europe.The mercury concentrations in fish were significantly anticorrelated with the fish catch and fish aquaculture and were inverse to trophic levels.Overfishing and the short lifecycle of aquaculture fish,both reducing the trophic level and the duration of mercury accumulation,were the most likely causes leading to the decline of mercury concentrations found in fish in China.