Atmospheric deposition of trace elements to Daya Bay, South China Sea: Fluxes and sources

Dry deposition fluxes and inhalation risks of toxic elements in total suspended particles in the Bohai Rim region: Long-term trends and potential sources

Long-term changes in dry deposition fluxes (DDF) and health risks for toxic elements (TE) in total suspended particles (TSP) in the Bohai Rim region are important for assessing control effects of pollution sources. Thus, we investigated the trends in DDF and concentrations for TSP and TE and health risks of TE in eight cities in the region from 2011-2020. TSP concentration and DDF showed general downward trends. Compared to the before Clear Air Action Plan (BCAAP, 2011-2012) period, concentration and DDF of TE over the Clear Air Action Plan (CAAP, 2013-2017) period substantially decreased, with the highest decrease rates in Zn, Cd, and Cr. During the study period, non-carcinogenic (HI) and total carcinogenic (TCR) risks for children and adults were 0.09 and 0.04, and 1.54 × 10-5 and 2.65 × 10-5, respectively, with Cr6+ and As being dominant contributors. Compared to the BCAAP period, HI and TCR over the CAAP period decreased by 36.8 % and 32.4 %, respectively. However, their risks increased over the Blue Sky Protection Campaign (BSPC, 2018-2020) period. Potential source contribution function suggested substantial changes in potential risk areas over different control periods, with the BSPC primarily being on land and the Yellow Sea.

The anthropogenic effects on organic matter in sediment core based on Bayesian mixing model: a case study of Daya Bay

Sediment is an important carrier of evidence about environmental evolution which receives huge volumes of organic material originated from both anthropogenic and natural sources. In this study, based on sedimentary chronology, the vertical trends of particle size distribution, total organic carbon (TOC), total nitrogen (TN), and their stable isotopes (δ13C, δ15N) in the sediment core of the nuclear power sea in southwest Daya Bay were analyzed, and the distribution characteristics and contribution ratios of different sources of organic matter in the sedimentary environment over the past 70 years were resolved using a Bayesian mixing model (MixSIAR). TOC, TN, δ13C, and δ15N ranged from 0.89 to 1.56%, 0.09 to 0.2%, - 22.3 to - 20.6‰, and 4.38 to 6.51‰, respectively. The organic matter in the sediment is controlled by a mixture of terrestrial input and marine autochthonous, the proportion of organic matter from terrestrial sources increases, while that from marine sources decreases in the sediment core, which persists from 1960 to 2000, yet organic matter from marine sources still dominates. The first signs of increased primary productivity occurred in 1960, and it was primarily due to agricultural activity. After the 1980s, the rapid increase in population around Daya Bay, the construction of nuclear power plants, the rise of aquaculture, and the quick expansion of industrial bases were all major factors that changed the ecological environment of Daya Bay.

Submarine groundwater discharge and associated metal elements into an urbanized bay

In this study, geochemical tracers (radium isotopes) and heavy metals (Pb, Zn, Cd, Cr and As) were analyzed to derive the submarine groundwater discharge (SGD) and associated metal fluxes during four seasons in an urbanized bay (Daya Bay, China). Results showed that Pb and Zn were the main pollutants in bay water. SGD was found to exhibit an obvious seasonal trend (autumn > summer > spring > winter). Such seasonal patterns may be related to the hydraulic gradient between groundwater level and sea level, storm surges and tidal range. SGD was a dominant source of marine metal elements, contributing 19 %-51 % of the total inputs of metals into Daya Bay. The bay water was classified as slight pollution to heavy pollution, which could be linked to SGD-derived metal fluxes. This study provides a better understanding of the important role that SGD plays in metal budgets and ecological environments of coastal waters.

Atmospheric dry deposition fluxes of trace metals over the Eastern China Marginal Seas: Impact of emission controls

Atmospheric deposition is an important exogenous input of trace metals to Eastern China Marginal Seas (ECMS), which is strongly affected by human activities. With emission control practices implemented in China, it still remains unknown what changes have taken place in the atmospheric dry depositions of the trace metals over ECMS. This study aimed to estimate the atmospheric dry depositions of Zn, Pb, Cu, and Cd over ECMS via Weather Research and Forecasting Model-Community Multiscale Air Quality Modeling System (WRF-CMAQ) in the two winter periods of January 2012 and January 2019 as well as to explore the impacts of emission control on the depositions. The anthropogenic metal emissions from China, the Korean Peninsula, Japan, and marine ships were investigated in this study. In 2012, the dry deposition fluxes of Zn, Pb, Cu, and Cd over ECMS were in the ranges of 0.50-3.4 μg m^-2 d^-1, 0.22-1.9 μg m^-2 d^-1, 0.14-0.90 μg m^-2 d^-1, and 12-88 ng m^-2 d^-1, respectively. The deposition fluxes of the four metals over Bohai Sea (BS) and Yellow Sea (YS) were 2-3 times those over East China Sea (ECS). Outflow of polluted air masses from East Asia increased the metal depositions by 3- 5-fold relative to clear days. Compared with 2012, a 5-85 % reduction in the metal depositions over ECMS were estimated in 2019, largest reductions were found over YS and BS. Meteorological variation was able to decrease or increase the metal depositions. However, the emission control only caused a reduction in the entire study region. The metal inputs to the sea were significantly lower from the ship emissions than from the continental anthropogenic emissions, although the proportion of the ship emissions in the total metal depositions rose slightly from 2012 to 2019.

Effects of atmospheric deposition on heavy metals accumulation in agricultural soils: Evidence from field monitoring and Pb isotope analysis

Atmospheric deposition is an essential pathway of heavy metals (HMs) from the atmosphere to soils, while few studies assess the effects and contributions of atmospheric deposition on HMs accumulations in agricultural soils from the field and regional scales. In this study, eleven representative field monitoring sites from industrial areas, agricultural areas, and reference site in a typical rapid industrial development region were selected to determine the effects of atmospheric deposition on soil HMs accumulation. Industrial activities significantly increased the deposited particles flux from atmospheric deposition, with annual particles fluxes in industrial areas being 1.83 and 1.90 times higher than in agricultural areas and reference site, respectively. Although the HMs deposition fluxes had decreased significantly with time by literature comparison, the deposition fluxes of Cd and Pb were still at high levels in this study area. Precipitation was the key factor affecting seasonal variations of atmospheric HMs deposition. Lead isotope analysis indicated that atmospheric Pb originated from coal combustion, and atmospheric deposition was the primary source of Pb contamination in agricultural soil adjacent to industries. This study provided insight into the effects of atmospheric deposition on agricultural soil HMs accumulations at the regional scale and an important theoretical basis for source-preventing soil HMs contamination in industrial developed and other similar areas.

Sources and spatial variations of heavy metals in offshore sediments of the western Pearl River Estuary

The concentrations of six heavy metals (Cd, Cr, Cu, Pb, Zn, and As) in offshore surface sediments of western Pearl River Estuary were analyzed to investigate their sources and spatial variations using factorial kriging analysis. Three-scale spatial variations in heavy metal concentrations were identified and separated: nugget, local, and regional scale, which indicated sample errors, anthropogenic pollution and natural variation, respectively. Anthropogenic heavy metals varied sharply and heterogeneous at range of 60 km. Maoming Port, Hailing Bay and coastal area northeastern Hainan Island were potential polluted areas of Cd, Cr, Cu, Pb, Zn and As, also the Nandu River, Baoling River and Wanquan River estuaries were potential polluted areas of As. These polluted areas ranged up to 60 km in size and tended to extend with currents. The natural heavy metals varied continuously and relatively homogeneous at range of 180 km, which was dominated by riverine input and paleo-sea-level changes.

Speciation and source changes of atmospheric arsenic in Qingdao from 2016 to 2020 - Response to control policies in China

Arsenic (As) is a toxic pollutant in the atmosphere. The atmospheric As concentration is high over the East Asian continent. At present, there is less research on the long-term trend of atmospheric arsenic pollution, which is not conducive to understanding its behavior. Total suspended particulate matter (TSP) samples were collected in Qingdao in autumn and winter from 2016 to 2020 to analyze total arsenic (TAs), As(V) and As(III). The interannual variation patterns, influencing factors and health risks of arsenic concentrations in aerosols were discussed. The results showed that As(V) is the dominant species of arsenic in aerosols. The average concentration of TAs gradually decreased and the proportion of As(III) increased during autumn and winter from 2016 to 2020. The levels of TAs, As(V) and As(III) in aerosols increased during the heating period and on polluted days. Negative correlation between TAs/TSP and TSP indicated that higher concentrations of TSP in the atmosphere would reduce the content of TAs in particulate matter. The increase of secondary aerosol particles played a dilution effect. Mobile source emissions, biomass and coal combustion were main sources of atmospheric arsenic. The distribution range of large potential sources of atmospheric arsenic decreased from 2016 to 2020, and concentrated, mainly in parts of Shandong province and its offshore areas. Local sources contributed the most to atmospheric arsenic pollution in Qingdao in autumn and winter. TAs, As(V) and As(III) posed a low non-carcinogenic risk and a negligible carcinogenic risk to adults and children. This study reveals the influence of strict air pollution control policies on the speciation and source of arsenic in aerosols.

Atmospheric wet deposition of trace elements in Bangladesh: A new insight into spatiotemporal variability and source apportionment

The interaction between water vapor and natural/anthropogenic airborne particles deposits a massive amount of trace elements in the ecosystem. As the principal source region of the Indian monsoon originated from the Bay of Bengal, atmospheric trace elements in Bangladesh have impacted atmospheric wet deposition along the pathway, even reaching the headwaters in the Asian water tower. However, no study reports the atmospheric wet deposition of trace elements at the spatiotemporal scale. Thus, this study investigated the concentration, sources, and deposition of eighteen trace elements (Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Rb, Sr, Mo, Cd, Sn, Sb, Ba, and Pb) from 232 precipitation samples at four sites in Bangladesh. Results showed that the VWM concentrations of the eighteen measured trace elements ranged from 0.03 to 535.6 μg L^-1. Zn, Fe, and Al were the principal elements of the atmosphere at four sites with mean values of 207.9 ± 227.8, 18.2 ± 9.3, and 16.3 ± 6.8 μg L^-1, respectively. Besides, the eighteen trace elements showed significant variation in spatial scale with distinct seasonality. Enrichment factors of Zn, Sb, and Cd indicated serious anthropogenic influences. The major sources of trace elements were fossil fuel combustion, brick kilns, crustal dust, fugitive Pb, metal smelters, and battery recycling. Both the concentration and precipitation amount played a pivotal role in the deposition. Most of the air masses during the monsoon season came from marine sources passing over southern India and Sri Lanka. Meanwhile, the air masses during the non-monsoon season were from West Asia and the northwestern Indian subcontinent. The air masses are transported over a long range and deposit massive amounts of particulate matter in the Third Pole Himalayan region. This first-hand work on spatiotemporal variation provides a reference dataset for future targeting of the scientific community and policymakers for the development of strategies and action plans.

Solubility of aerosol minor and trace elements in Xiamen Island, Southeast China: Size distribution, health risk and dry deposition

Aerosol element solubility is essential to evaluate the damage to the environment and human health. In this work, the size distribution of total and soluble elements in eight particle size ranges with diameter <0.25, 0.25-0.44, 0.44-1.0, 1.0-1.4, 1.4-2.5, 2.5-10, 10-16 and >16 μm was investigated in Xiamen Island, southeast China from March 2018 to June 2020. The results showed that both total and soluble elements exhibited significant size dependence without obvious seasonal variations, and their relative contributions to PM₁ mass were much lower than in particles larger than 1 μm. The correlations between some elements in soluble fraction were quite different from those in total fraction and the correlations also varied with particle size due to their different solubility. The solubility of Al, Fe, Ag and Cr was relatively low compared with other elements. Moreover, the solubility of Na, Mg, Ca, Mn and Ag was less dependent on particle size while Al, Fe and other trace elements exhibited the highest solubility in PM₁ and the lowest in PM_>10. Overall, the solubility of elements is primarily a function of aerosol origin and size. The carcinogenic risks of metal exposure via inhalation for children (3.31 × 10^-6) and adults (4.42 × 10^-6) were slightly higher than the guideline of cancer risk with >60 % from V. As for non-carcinogenic risk, the hazard index values for children and adults were 1.59 and 0.53, respectively, with Mn, V and Ni together accounting for >85 % of the risk. >85 % of the size-dependent dry deposition fluxes of the selected soluble elements over the Xiamen Bay were contributed by particles larger than 10 μm due to their high deposition velocities. The atmospheric inputs of bioavailable Fe and Cu to the sea exceeded the required amounts relative to inorganic nitrogen to meet the growth of phytoplankton.

Comparison of Pollution Levels, Biomagnification Capacity, and Risk Assessments of Heavy Metals in Nearshore and Offshore Regions of the South China Sea

Seawater and fish were collected from nearshore (Pearl River Estuarine, PRE) and offshore (middle of the South China Sea, MSCS) regions of the South China Sea (SCS) to determine the heavy metals (HMs) pollution status and biomagnification characteristics. Results show that Cu in PRE seawater was moderately contaminated. Overall pollution risk of seawater were PRE (3.32) > MSCS (0.56), whereas that of fish was MSCS (0.88) > PRE (0.42). δ¹³C and δ¹⁵N exhibited distinguished characteristics for PRE and MSCS fish, indicating the diverse energy sources, nitrogen sources, and food web structures of nearshore and offshore regions. Cu was biomagnified whereas Pb and Ni were biodiluted in offshore fish. Hg presented significant biomagnification in both of nearshore and offshore fish. Finally, the target hazard quotient of Hg (1.41) in MSCS fish exceeded the standard limit, which was posed by high Hg concentration and consumption rate of offshore fish.

Atmospheric Wet Iron, Molybdenum, and Vanadium Deposition in Chinese Terrestrial Ecosystems

Iron (Fe), molybdenum (Mo), and vanadium (V) are the main components of the three known biological nitrogenases, which constrain nitrogen fixation and affect ecosystem productivity. Atmospheric deposition is an important pathway of these trace metals into ecosystems. Here, we explored the deposition flux, spatiotemporal pattern, and influencing factors of atmospheric wet Fe, Mo, and V deposition based on China Wet Deposition Observation Network (ChinaWD) data from 2016 to 2020. Our results showed that atmospheric wet Fe, Mo, and V deposition was 7.77 ± 7.24, 0.16 ± 0.11, and 0.13 ± 0.12 mg m^-2 a^-1 in Chinese terrestrial ecosystems, respectively, and revealed obvious spatial patterns but no significant annual trends. Wet Fe deposition was significantly correlated with the soil Fe content. Mo and V deposition was more affected by anthropogenic activities than Fe deposition. Wet Mo deposition was significantly affected by Mo ore reserves and waste incineration. V deposition was significantly correlated with domestic biomass burning. This study quantified wet Fe, Mo, and V deposition in China for the first time, and the implications of atmospheric trace metal deposition on biological nitrogen fixation were discussed.

Temporal distribution patterns of metals in water, sediment, and components of the trophic structure in a tropical coastal lagoon of the Gulf of Mexico

Trophic transfer and bioaccumulation of trace metals have a profound impact on the structure and function of coastal areas; however, the metal accumulation patterns in detritus-based food webs and the influence of climatic variability have not been thoroughly investigated. The Tampamachoco Lagoon (Gulf of Mexico) is a coastal system impacted by emissions from a thermoelectric plant. We evaluated the spatial-temporal distribution patterns of Al, Cd, Hg, Cr, Cu, and Pb in water, sediments, and in organisms categorized by trophic levels (TLs), trophic guilds, and habitat preferences. The sediments had the highest concentrations of metals with no significant differences between seasons. The indices of geo-accumulation and potential ecological risk classified sediments as "moderately contaminated", evidencing a threat to human health through consumption of detritivores and filter-feeders. The lowest TLs (filter-feeders and detritivorous) reached the maximum Metal Pollution Index in the rainy season. According to discriminant analyses of metals and species, omnivorous and zoobentivorous organisms were associated with Hg during the rainy and dry seasons; while Al, Cd, and Cu were related to low TLs, and seston was associated with Pb. Food web magnification factor analysis showed that: (a) Pb, Cu, and Cr were biodiluted as trophic levels increased; (b) Cd and Hg showed temporal biomagnification trends; (c) Al, Pb, Cu, and Cd showed significant biodilution from the lowest TL to intermediate TLs; and (d) Hg was transferred from the lowest to intermediate TLs with clear biomagnification effects.

Long-term wet precipitation of PM2.5 disturbed the gut microbiome and inhibited the growth of marine medaka Oryzias melastigma

Wet precipitation, as an important process of geochemical cycling and the most effective way of cleaning fine atmospheric particles (PM_2.5), can introduce the toxic substances in the atmosphere into the water environment. The adverse effect of wet precipitation of PM_2.5 on marine fish is still unclear. In this study, PM_2.5 samples were collected from six locations along coastal areas of the south China sea for 30 days and used to simulate the impacts of multiday discontinuity wet precipitation of PM_2.5 on marine medaka (Oryzias melastigma) in the case of 30 days discontinuity heavy rain (rainfall ≥ 7.6 mm/h and persist 1 h each day). Results showed that wet precipitation of PM_2.5 significantly inhibited the body weight gain of fish. In accordance, the size and number of lipid droplets in liver of the exposed groups were lower than those in normal control (NC) group. The expressions of genes involving in lipid degradation including lipoprotein lipase gene (LPL) and carnitine palmitoyltransferase gene (CPT) were up-regulated after exposure. The composition, diversity and function of gut microbiome were affected by wet precipitation of PM_2.5. PM_2.5 from industrial areas that have higher concentrations of metal profiles show more obvious impacts than PM_2.5 from agricultural leisure areas that possessed lower concentrations. All together, the results indicated that wet precipitation of PM_2.5 can decrease the diversity of gut microbiome, affect the lipid metabolism, and finally suppress the growth of marine medaka. It confirmed the potential ecological risks of long-term rainfall in air pollution areas to the aquatic organisms.

Trace Elements and Their Variation with pH in Rain Water in Arid Environment

Climate change in Kuwait has resulted in temperature fluctuations, frequent dust storms, and noticeable changes in the amount of precipitation. Pollutants released into the atmosphere from various sources affect the chemical composition of rainwater and impact its usability. The present study on rainwater focused on the determination of trace elements, sources, and their variation with respect to change in temperature and pH. The samples were collected from 12 different locations in both industrial and urban regions during significant rain events (n = 31) from November 2018 to March 2019 and samples were analyzed for trace elements in ICP-OES using standard USEPA 200.7 method. The mean concentration of the 16 elements analyzed followed the trend: Co < Cd < Cr < Mo < V<Ni < Pb < As < Se < Fe < Cu < Mn < Zn < Al < Ba < Sr and were inferred to be within the WHO permissible limits of drinking water. The analytical results revealed that Strontium (Sr) had the highest mean concentration (188 μg/L) followed by barium (Ba), aluminum (Al), and zinc (Zn) with mean concentrations of 95.2 μg/L, 30.4 μg/L, and, 16.6 μg/L respectively. The sources of contamination in rainwater were identified by calculating the enrichment factor (EF) using element concentration reported in Kuwait dust and from continental crustal values. EF for Fe, V, Ni, and Cr were below 10, indicating purely crustal sources. Ni, Zn, Cu, and Mn exhibited values between 10 and 100, reflecting industrial sources of contamination. EF for Sr was greater than 100, due to inputs from anthropogenic sources. A strong association between Al and pH along with correlation between Sr, Cr, Cu, Ni, Mo, V, and meteorological parameters was revealed from statistical analysis. Furthermore, pH Redox Equilibrium C programming (PHREEQC) was used to simulate changes in pH and temperature in rainwater to predict the resultant variations in trace element concentrations. There was no significant change observed in pH with rise in temperature, but the concentration of trace elements varied with change in pH. The concentration of V, Cr, and Al were most sensitive to pH variations. The results indicated that industrial emissions, fuel combustion, and dust in Kuwait are the primary sources of Al, Sr, Mn, Zn, and Ba in the rainwater samples. Since, the concentrations of these elements are relatively low, rainwater in Kuwait could be harvested for drinking and domestic purposes and used for recharging aquifers.

PM2.5 and Trace Elements in Underground Shopping Districts in the Seoul Metropolitan Area, Korea

We measured PM_2.5 in 41 underground shopping districts (USDs) in the Seoul metropolitan area from June to November 2017, and associated 18 trace elements to determine the sources and assess the respiratory risks. The PM_2.5 concentrations were 18.0 ± 8.0 μg/m³ inside USDs, which were lower than 25.2 ± 10.6 μg/m³ outside. We identified five sources such as indoor miscellanea, soil dust, vehicle exhaust/cooking, coal combustion, and road/subway dust, using factor analysis. Almost 67% of the total trace element concentration resulted from soil dust. Soil dust contribution increased with the number of stores because of fugitive dust emissions due to an increase in passers-by. Vehicle exhaust/cooking contribution was higher when the entrances of the USDs were closed, whereas coal combustion contribution was higher when the entrances of the USDs were open. Although miscellanea and coal combustion contributions were 3.4% and 0.7%, respectively, among five elements with cancer risk, Cr and Ni were included in miscellanea, and Pb, Cd, and As were included in coal combustion. The excess cancer risk (ECR) was the highest at 67 × 10^-6 for Cr, and the ECR for Pb was lower than 10^-6, a goal of the United States Environmental Protection Agency for hazardous air pollutants.

Impact of elemental composition of particulate matter in the airshed of a University Farm on the local air quality

The impact of particulate matter on the ambient air quality of Landmark University Farm was assessed using deposition fluxes of Trace elements (TEs) in the airshed of the farm. Deposition gauges were employed to collect both dry and wet deposition samples of particulate matter between 2018 and 2019. Elemental compositions of particulates collected during the sampling period were analyzed using Energy Dispersive X-ray Fluorescence Spectroscopy (ED-XRF). The deposition fluxes of crustal and anthropogenic trace elements were also determined using standard methods. Results showed that in dry season, iron has the highest mean concentration (3283.61 mg/kg), while chromium has the lowest (0.023 mg/kg). On the other hand, in wet season, silicon and nickel have the highest and lowest mean concentrations of 159.34 mg/kg and 0.01 mg/kg respectively. Although the concentrations of these metals were higher in the dry season than wet season, there was no statistical significant difference between the mean concentrations of the elements measured in each season of the year (p > 0.05). The compositions of some of the elements in the particulate matters were found to be far above the recommended exposure limits prescribed by OSHA. The study concluded that the elemental composition of particulate matter in the airshed of the University Farm adversely impacts the ambient air quality of the Community.

Evidence of Natural and Anthropogenic Impacts on Rainwater Trace Metal Geochemistry in Central Mexico: A Statistical Approach

Trace metals Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd, and As were determined on a monthly basis in a total of 52 rain samples collected from six different locations in the central region of Mexico during March 2016–April 2017. The average concentrations of trace metals (mg/L) in the rainwater samples showed an order of Zn (0.873) > Fe (0.395) > Mn (0.083) > Cr (0.041) ≥ Cu (0.041) > Pb (0.031) > Ni (0.020) > Co (0.013) > As (0.0003) > Cd (0.002). The differences observed in metal concentrations are related to variations in the influence of continental air masses, local transport, regional advection, and the solubility of trace metals. High concentrations of metals were observed in the months of March to May at all sites, probably due to the less extensive removal of air/air pollutants. The values obtained from the enrichment factor (EF) per metal showed relatively high values for Cd, Zn, Cu, Pb, Co, Ni, and Cr, suggesting anthropogenic origin. Pearson’s correlation matrix validated the distribution of trace metal sources and their relationships with local/regional meteorological characteristics. This paper presents relevant basic information for the evaluation of the toxic potential of rainwater and the possible health risks when using this source of water for human consumption.

The Evaluation of Air Quality in Albania by Moss Biomonitoring and Metals Atmospheric Deposition

The air quality of Albania is evaluated by trace metals atmospheric deposition using moss biomonitoring method. Bryophyte moss (Hypnum cupressiforme Hedw.) samples were collected during August and September 2015 from 55 sampling points distributed over the entire territory of Albania. The concentrations of Cr, Cu, Fe, Ni, Pb, V, and Zn in moss samples was determined by ICP-AES, ETAAS (As and Cd), and CVAAS (Hg) analysis. Spatial distribution and temporal trend of the moss elements is discussed in this study. Different variability was found in moss metal concentrations that may reflect their spatial distribution patterns and may identify the location of the areas with high contamination of each element. Compared with the measurements of moss collected in 2010, significant differences were found in the concentrations of As, Cr, Cu, Hg, Ni, Pb, and Zn. The differences between two moss surveys may reflect changes in the bioavailability of the elements resulting from wet and dry deposition respectively during 2015 and 2010 moss biomonitoring survey. The pollution loading index that was applied to judge the content of metal contamination indicated moderate pollution throughout Albania. Examination of the potential ecological risk found that As, Cd, Cr, Hg, Ni, and Pb pose the highest potential ecological risks particularly in the areas with high metal contents. Factor analysis applied to investigate the probable sources of metals in the environment suggested that Al and Fe likely originated from natural sources. As, Cd, Hg, Pb, Cu, Zn, Ni, and Cr likely originated from anthropogenic sources associated with long-range transport, transboundary pollution and local emission sources.

Distribution and transport of heavy metals in estuarine-inner shelf regions of the East China Sea

This study analyzes the distribution and transportation of heavy metals in surface sediments by determining the concentrations of 6 heavy metals (Cr, Zn, Ni, Pb, Cu, and Cd) based on 164 surface sediments collected from the East China Sea (ECS). The results indicated that concentrations of heavy metals were higher in the south than the north with a clear boundary near 30° N. The distributions of the six heavy metals could be divided into four groups that corresponded well with different sediment components, suggesting that hydrodynamic sorting processes play an important role in the selective transportation of sedimentary heavy metals. In addition, the spatial distributions of heavy metals were more consistent with fine-grained sediments having a grain size lower than 32 μm. Heavy metal concentrations were slightly higher than found in previous studies conducted from 2002 to 2010. In addition, their spatial patterns have changed drastically compared to data from 2006, suggesting that intensive inland human activities have had a profound impact on heavy metal transportation and distribution in the estuarine & inner-shelf regions of the ECS.

Metal wet deposition in the Three Gorges Reservoir (TGR) region of Southwest China

Metal wet deposition has become an environmental concern because of its threats to soil or water quality and human health. This study was to collect rainfall waters in 2016 from seven sites, representing urban, town, rural, and wetland, within the Three Gorges Reservoir (TGR) region of Southwest China, determine the metal concentration and flux (Zn, Mn, Cu, As, Cd, Pb), and identify their possible sources. Results indicated that Zn was the most abundant metal with a concentration of 16.92 μg L^-1 in fall and 19.91 μg L^-1 in winter and flux of 4.71 mg m^-2 in fall, while Cd was the least with a monthly mean concentration of 0.02-0.37 μg L^-1. Among the seven sites, urban (FL) had the highest values of both concentrations of metals (Zn, Cu, Pb) and fluxes of metals (Mn, As), which significantly differed from the other sites. Component and redundancy analysis suggested that fossil fuel and biomass combustion be a potential metal source. Enrichment factors, box model, and potential ecological risk index showed that the TGR water quality could face a high risk due to wet metal deposition, especially Cd. Data could provide a valuable aid in mitigating metal pollution, developing the best watershed management practices, as well as safeguarding water quality and human health in the TGR region or other reservoir regions.