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The concentrations of trace elements in atmospheric bulk depositions (wet plus dry) were investigated from two highly industrialised areas of Sicily (southern Italy) from June 2018 to July 2019, in order to recognise the main natural and anthropogenic sources. A side objective of this study was to improve the common sampling procedures and analytical methods used for monitoring trace elements in atmospheric deposition. The trace element VWM (Volume-Weighted Mean) concentrations ranged from less than 0.01 μg L−1 for trace elements such as Cs, Tl, and U, up to 24 μg L−1 for minor elements (Al, Zn, Sr), in the filtered aliquot, while they reached concentrations up to 144 μg L−1 for the same elements, in the unfiltered aliquot. Therefore, significant differences in concentrations between these two aliquots were found, particularly for Al, Fe, Ti, Zn, Cr, Pb, Se, Cs, and U. This implies that filtering operations may produce a consistent underestimation of concentrations of certain 'constituents' of the atmospheric deposition. Natural (marine spray, local and regional geogenic input, volcanic emanations) and anthropogenic sources (industrial emissions, auto vehicular traffic, and diffuse background pollution) which influence rainwater chemistry were identified. Enrichment factors (EFs), with respect to the upper crust composition, provided clear evidence of the different sources above mentioned: Ti, Fe, Al, Cs, Cr, Rb, and Co have low EFs (<1), and are referable to the (local and/or regional) geogenic input, while Se, Sb, Zn, B, Cd, Cu, Mo, Sr, As, with high EFs (>10), highlight the influence of marine and/or industrial sources. The study produced a novel dataset on the atmospheric deposition rate of several trace elements, which had never been studied in the investigated areas. Finally, a comparison of trace element deposition rates in the studied areas with the atmospheric deposition reported for 53 different sites, belonging to 20 different European nations, was made. The comparison showed that some elements, such as Al, V, Zn, and Mo had higher median deposition fluxes in the Sicilian sites than in European monitoring sites. [ABSTRACT FROM AUTHOR]

To reveal the secondary anthropogenic contribution and accumulation rate of heavy metals in highway-side soils, we studied soil heavy metals on three representative highways in Southeast China, with different traffic intensities, service years, land use patterns and distances from roads, with high-resolution sampling of soil profiles. Concentrations of soil Cu, Zn, Pb and Cd were measured. The comparison of concentrations in surface soils with original values and their vertical distributions shows that soils within 150 m of the highway side are contaminated by heavy metals, with surface accumulation and possible movement down the profiles. The transferring depth of heavy metals was 10–30 cm. The contribution ratios of heavy metals were 1.0–30.5% in the surface at 30 cm, with the sequence of Cd >> Cu > Zn > Pb. The accumulation rates were 1.27–2.03 kg Cu ha−1 y−1, 2.44–5.27 kg Zn ha−1 y−1, 0.71–1.40 kg Pb ha−1 y−1 and 0.010–0.018 kg Cd ha−1 y−1 in soils within 50 m range. Furthermore, the accumulation of these metals varied with the traffic intensity, service years and land use patterns. Soils under forest have less heavy metal accumulation, which suggests a protective forest to set beside highways at a distance of at least 50 m to prevent soils from being contaminated. [ABSTRACT FROM AUTHOR]

The concentrations of trace elements in atmospheric bulk depositions (wet plus dry) were investigated from two highly industrialised areas of Sicily (southern Italy) from June 2018 to July 2019, in order to recognise the main natural and anthropogenic sources. A side objective of this study was to improve the common sampling procedures and analytical methods used for monitoring trace elements in atmospheric deposition. The trace element VWM (Volume-Weighted Mean) concentrations ranged from less than 0.01 μg L−1 for trace elements such as Cs, Tl, and U, up to 24 μg L−1 for minor elements (Al, Zn, Sr), in the filtered aliquot, while they reached concentrations up to 144 μg L−1 for the same elements, in the unfiltered aliquot. Therefore, significant differences in concentrations between these two aliquots were found, particularly for Al, Fe, Ti, Zn, Cr, Pb, Se, Cs, and U. This implies that filtering operations may produce a consistent underestimation of concentrations of certain ‘constituents’ of the atmospheric deposition. Natural (marine spray, local and regional geogenic input, volcanic emanations) and anthropogenic sources (industrial emissions, auto vehicular traffic, and diffuse background pollution) which influence rainwater chemistry were identified. Enrichment factors (EFs), with respect to the upper crust composition, provided clear evidence of the different sources above mentioned: Ti, Fe, Al, Cs, Cr, Rb, and Co have low EFs (10), highlight the influence of marine and/or industrial sources. The study produced a novel dataset on the atmospheric deposition rate of several trace elements, which had never been studied in the investigated areas. Finally, a comparison of trace element deposition rates in the studied areas with the atmospheric deposition reported for 53 different sites, belonging to 20 different European nations, was made. The comparison showed that some elements, such as Al, V, Zn, and Mo had higher median deposition fluxes in the Sicilian sites than in European monitoring sites.

An extensive chemical investigation of fog water's chemical composition, as well as source characterization, were carried out during the winter season (December to February) at an outflow location (Bhola, Bangladesh) of the Indo-Gangetic Plain (IGP). Characterization of the source involved correlational analysis, enrichment factor analysis, estimation of percentage sources, and air mass trajectory analysis. The average pH of fog water in Bhola was found to be 7.03 ± 0.02, demonstrating that acid-neutralizing components were successful in neutralizing acidifying species. The concentrations of the water-soluble ions were determined, and they were in the following order: Ca2+ > NO3− > Cl− > Na+ > SO42− > NH4+ > Mg2+ > K+ > F− > HCO3−. Of the six trace elements (Fe, Zn, Mn, Cu, Ni, Cr, Pb) that were analyzed, Zn ions were found in the highest concentration, followed by Mn ions. Neutralization factor analysis showed that the key neutralization components of fog-water were Ca2+ and NH4+. Enrichment factor (EF) calculation revealed the anthropogenic origin of NO3−, SO42−, Zn, Mn, and Cu. The percentage source contributions of NO3− (99.74%), SO42− (84.02%), and Cl− (8.30%) further support the anthropogenic origin. Backward air mass trajectory analysis was performed using the NOAA-HYSPLIT model. Long-range transport of contaminants over the IGP area was found to have a profound impact on the chemical composition of fog on the Bhola coast. This research has provided novel findings for the chemical characterization of fog water and the detection of its source at IGP outflow, and highlighted the anthropogenic contributions to local air pollution, as well as the transboundary influence on local air quality. [ABSTRACT FROM AUTHOR]

Coal mining and coal combustion in thermal power plants (TPPs) are the major anthropogenic sources of arsenic (As) contamination in many different industrial regions. In this study of industrial regions of West Bengal and Singrauli, it is observed that there is an anthropogenic contribution to the contamination from As-bearing coal. Up to 14.53 mg/kg of As is obtained in coal of West Bengal which also has very high average Fe concentration (16,095 mg/kg) along with high concentration of Cu, Mn and Hg. Similar observations are also found in Singrauli Industrial Region where 3.14 mg/kg of As with very high concentration of Fe 43,867 mg/kg along with high Cu, Mn and Hg concentration is found in coal samples. This low-grade bituminous coal contains arsenopyrite as observed by SEM–EDX. Arsenopyrite is converted to arsenolite upon combustion in these TPPs as observed in XRD. The fly ash has average As concentration of 1.53 mg/kg for West Bengal and 2.38 mg/kg for Singrauli Industrial Region and high concentration of toxic elements. The soil near these TPPs and mining areas is enriched in As, Fe, Hg, Cu and Mn. Not only As but high concentrations of Fe, Hg, Mn are also observed from analysis of water which relates to the anthropogenic inputs. The dissolution of arsenolite in reducing environments caused by periodic flooding releases As into water. Hence, the As contamination in the study area also has anthropogenic origin from coal consumption in TPPs. [ABSTRACT FROM AUTHOR]

To reveal the secondary anthropogenic contribution and accumulation rate of heavy metals in highway-side soils, we studied soil heavy metals on three representative highways in Southeast China, with different traffic intensities, service years, land use patterns and distances from roads, with high-resolution sampling of soil profiles. Concentrations of soil Cu, Zn, Pb and Cd were measured. The comparison of concentrations in surface soils with original values and their vertical distributions shows that soils within 150 m of the highway side are contaminated by heavy metals, with surface accumulation and possible movement down the profiles. The transferring depth of heavy metals was 10–30 cm. The contribution ratios of heavy metals were 1.0–30.5% in the surface at 30 cm, with the sequence of Cd >> Cu > Zn > Pb. The accumulation rates were 1.27–2.03 kg Cu ha−1 y−1, 2.44–5.27 kg Zn ha−1 y−1, 0.71–1.40 kg Pb ha−1 y−1 and 0.010–0.018 kg Cd ha−1 y−1 in soils within 50 m range. Furthermore, the accumulation of these metals varied with the traffic intensity, service years and land use patterns. Soils under forest have less heavy metal accumulation, which suggests a protective forest to set beside highways at a distance of at least 50 m to prevent soils from being contaminated.

The driving mechanism of Arctic amplification (AA) is so complex that no consistent and definitive conclusion has been formed yet. In particular, the internally and externally driven trends of AA have not been distinguished using observation-based methods. Given that the Arctic is more sensitive than other regions to anthropogenic greenhouse gas increases and other external forcings, we focus on separating anthropogenically driven trends from the Arctic surface air temperature (SAT) changes during 1979–2017 to quantify the contribution of anthropogenic effects on AA, with detection and attribution converted to probability distribution functions. Results indicate that the Arctic coast of the Siberian Great Plains, from the Barents Sea to the Kara Sea and eastward to the Bering Strait, has been warming most significantly, and is mainly dominated by anthropogenically driven trends. From 1979 to 2017, the minimum anthropogenically driven warming in most parts of the Arctic Ocean exceeds 2℃, especially the Kara Sea area, where the anthropogenically driven warming is significant, reaching 4℃. In addition, the minimum anthropogenic contributions exceed 60% in most parts of the Arctic Circle and are more than 80% of the warming trend in (75–90° N, 150–180° W). In 140° W–140° E Arctic region, the anthropogenically driven trend is the most remarkable, at 0.82℃ / decade, accounting for 84.5% of the measured warming trend. Meanwhile, the anthropogenically driven trend accelerates most rapidly in this area (0–140° W, 60–90° N). [ABSTRACT FROM AUTHOR]

The role of COVID-19 pandemic lockdown in improving air quality was reported extensively for land regions globally. However, limited studies have explored these over oceanic areas close to high anthropogenic activities and emissions. The Bay of Bengal (BoB) basin is one such region adjacent to the highly populated South Asian region. We find that Aerosol Optical Depth (AOD) over the BoB declined by as much as 0.1 or 30% during the peak lockdown of April 2020 compared to long-term climatology during 2003–2019. Simultaneously, the sea surface temperature (SST) rose by 0.5–1.5°C over the central and north-western parts of the BoB with an average increase of 0.83°C. We show that up to 30% of this observed warming is attributable to reduced atmospheric aerosols. The study highlights the importance of anthropogenic emissions reduction due to COVID lockdown on short-term changes to SST over ocean basins with implications to regional weather.

Rivers engage in carbon cycle by transporting the dissolved products of weathering of rocks to the oceans, and this process is sensitive to the global climatic changes. The present study was carried out with an objective of estimating the spatial and temporal variation in carbon consumption due to rock weathering in Cauvery, which is a major non-perennial tropical river in the peninsular India. The samples of all the rock types of this river basin were collected and subjected to mineralogical analysis. The water samples from this river were collected three times a year from 2013 to 2017 at 28 locations and were analysed for pH, EC and major ions. The spatiotemporal variations in the chemistry of river water were used to understand the amount of carbon dioxide consumed by rock weathering. The contribution of weathering to dissolved load of the river was higher followed by the contribution of anthropogenic activities and rainfall. The contribution of silicate weathering is dominant during the high river flow, whereas during low flow time periods, the contribution of carbonate weathering is on par with silicate weathering. The carbon consumption due to weathering in the Cauvery river was higher when the flow was significant, and it was lower during summer months. It is also evident that the carbon consumption is high in the upper and middle regions of the basin due to the weathering of gneissic and granodiorite rocks. Thus, the carbon consumption and flux in this basin are dynamic, both spatially and temporally. The east flowing rivers draining through the peninsular India, which is mostly composed of massive rocks, also functions as carbon sink, thus benefitting the environment by reducing the excess CO2 in the atmosphere. [ABSTRACT FROM AUTHOR]

An extensive chemical investigation of fog water’s chemical composition, as well as source characterization, were carried out during the winter season (December to February) at an outflow location (Bhola, Bangladesh) of the Indo-Gangetic Plain (IGP). Characterization of the source involved correlational analysis, enrichment factor analysis, estimation of percentage sources, and air mass trajectory analysis. The average pH of fog water in Bhola was found to be 7.03 ± 0.02, demonstrating that acid-neutralizing components were successful in neutralizing acidifying species. The concentrations of the water-soluble ions were determined, and they were in the following order: Ca2+ > NO3− > Cl− > Na+ > SO42− > NH4+ > Mg2+ > K+ > F− > HCO3−. Of the six trace elements (Fe, Zn, Mn, Cu, Ni, Cr, Pb) that were analyzed, Zn ions were found in the highest concentration, followed by Mn ions. Neutralization factor analysis showed that the key neutralization components of fog-water were Ca2+ and NH4+. Enrichment factor (EF) calculation revealed the anthropogenic origin of NO3−, SO42−, Zn, Mn, and Cu. The percentage source contributions of NO3− (99.74%), SO42− (84.02%), and Cl− (8.30%) further support the anthropogenic origin. Backward air mass trajectory analysis was performed using the NOAA-HYSPLIT model. Long-range transport of contaminants over the IGP area was found to have a profound impact on the chemical composition of fog on the Bhola coast. This research has provided novel findings for the chemical characterization of fog water and the detection of its source at IGP outflow, and highlighted the anthropogenic contributions to local air pollution, as well as the transboundary influence on local air quality.

Differentiating contribution of natural sources and anthropogenic inputs to soil element concentrations can provide important basis for pollution and risk assessments. Fifty-five surface soil samples were collected from farmland (n = 33) and forest land (n = 22) in the Leizhou Peninsula for the measurement of trace elements (Cr, Co, Ni, Cu, Zn, As, Pb, and Cd) concentrations. It was found that soil Cr, Ni, Cu, Zn and Cd concentrations were significantly higher in farmland soils than in forest soils (p < 0.05). Industrial discharges accounted for the increase in Cr, Co, Ni, and Cu concentrations with mean contribution rates of 10.9%, 29.4%, 23.2%, and 25.3%, whereas agricultural activities contributed significantly (14.6%−92.4%) to soil Cd levels. The pollution levels of individual element based on a geo-accumulation index, and enrichment and contamination factors roughly followed a decreasing order of Cd > Co ≈ Cu ≈ Ni ≈ Cr > Zn ≈ As ≈ Pb. Severe contamination was found near industrial areas, which resulted in a moderate or considerable ecological risk. Soil Cr mainly derived from weathering process of basaltic rocks and industrial sources resulted in non-carcinogenic hazard and carcinogenic risk indices up to 2.47 and 2.79 × 10–4, respectively, near industrial areas, leading to that children suffered more from higher non-carcinogenic and carcinogenic risks than adults. [ABSTRACT FROM AUTHOR]

Abstract Surface water quality has been greatly affected by anthropogenic activities around the world in the past decades. Scientists and policymakers should pay close attention to quantify historical change in human impacts on aquatic environment. An effective method for reconstructing the historical input of anthropogenic organic matters in aquatic environment is urgently required. Here, five sediment cores from the Huaihe River were analyzed for n -alkanes (C 8 –C 40) and isoprenoid alkanes (pristane and phytane) using gas chromatography–mass spectrometry (GC–MS). Sixty years (1955–2014) sedimentary history of n -alkanes was reconstructed using 210Pb method. The evaluation of wax n -alkanes percentage (WNA) indicated that the terrestrial higher plant input was predominant in most samples. The main anthropogenic sources were the petroleum hydrocarbon, fossil fuel combustion and the discharge of industrial wastewater and domestic sewage. The results of principal component analysis-multiple linear regression (PCA-MLR) indicated that the respective contributions of anthropogenic and biogenic sources to sedimentary organic matters were 47.8% and 48.1% in the Huaihe River. Furthermore, the anthropogenic contribution displayed a decrease trend from 1991 to 2014, which probably attributed to the effective pollution control measures taken by the local government. However, the anthropogenic contribution was still considerable during this period. Thus, the government should pay attention to organic pollution control in the Huaihe River sediments continuously. In summary, this study provides an effective method for reconstructing the historical change in anthropogenic contribution to sedimentary organic matters in rivers, which can probably be applied to other aquatic environment around the world. Graphical abstract Unlabelled Image Highlights • Developed a method to reconstruct the historical anthropogenic OM input in rivers • Lipid biomarkers were analyzed in sediment cores from the Huaihe River basin. • Quantitatively estimated the anthropogenic contribution to sedimentary OM • Attention to organic pollution control of Huaihe River sediments can't be reduced. [ABSTRACT FROM AUTHOR]

Anthropogenic influences can modulate the low‐frequency variability of extreme precipitation and increase the likelihood of flooding events. It is not, however, clear how much and in what manner the low-frequency variability has changed in recent decades as global warming has intensified. Here, we investigate the contribution of anthropogenic influences to the time evolution of extreme precipitation anomalies in different seasons using Coupled Model Intercomparison Project Phase 6 (CMIP6) and CMIP5 model simulations and observations over Europe. Our results show a latitudinal dependence of changes in extreme precipitation anomalies for all seasons due to anthropogenic impacts. While the contribution of anthropogenic influences to extreme precipitation anomalies at low latitudes (60°) latitudes. Without the offsetting effect of anthropogenic aerosols, anthropogenic emissions of greenhouse gases alone should have produced larger anomalies than observed. For all seasons, the more extreme the precipitation, the larger the anthropogenic influences.

The Oualidia lagoon provides important ecosystem services, such as fishing, aquaculture, tourism and high biological and ecological productivity. Many indices have been developed to evaluate environmental risks and to estimate the anthropogenic contribution of potentially toxic elements (PTE) in surficial sediments. The results show that the concentrations of the PTE found in surface sediments due to the anthropogenic activities in the area (urban effluents, aquaculture and agricultural areas) are significantly higher than those from the local background and sediment quality guidelines (SQGs). The potential ecological and biological risk index present satisfactory results. However, the sites near to the areas where anthropogenic activities are developed present 49% probability of toxicity, while the rest of the lagoon, present 9% to 21% probability of toxicity and low potential ecological risk, except for Hg where the risk was considered to be considerable. The PTE are mainly originated from the anthropogenic activities; nevertheless, anthropogenic contributions represent up to 69% of the total sediment of content, but it depends on the PTE: Cd (16%), Ni (38%), Zn (41%), Cr (43%), Cu (56%), Hg (68%), Pb (69%). Compared with the Sub-basin soils, the PTE are higher than 80%, hence the sub-basin feeds the lagoon by these elements (PTE). [ABSTRACT FROM AUTHOR]

Major elements and trace metals in suspended sediments along transect stations of the Mandovi and Zuari estuaries showed three types of distribution: (a) high concentrations of most metals (Al, Fe, Mn, Cr, Pb, Cu, Ni, Zn, Co, Sc, Mo, and U) in the upper estuary and their decreasing concentrations seaward in every season, (b) lower concentrations of some metals (Mg, Cr, Zr, V, Al, Th) in the upper estuary and bay and their increased concentrations in the lower estuary, and (c) higher concentrations of some metals (Cu, Ni, Zn, Pb, and Cr) in the upper estuary and bay and their decreased concentrations in the lower estuary. Mn was the most significant pollutant in both the estuaries. The Zn, Cr, Fe, and Mo in Mandovi during the monsoon and post-monsoon and, Pb, Ni, and Cr in Zuari during the post- and pre-monsoons were in the range 'moderately to heavily polluted.' The pollution load index of metals was high at upstream stations, with higher values in Mandovi during monsoon and Zuari during the post- and pre-monsoons. Most trace metals were correlated with Fe and Mn indicating their association primarily with Fe-Mn ore material. The principal component analysis indicated natural and anthropogenic inputs and the latter was predominantly related to ore material in both the estuaries. The distribution factor was high for Al, Mg, Zr, Th, and U in < 2-μm fraction and Cr, Cu, Ni, Zn, Co, V, Sc, and Zr in 2-4-μm size fraction sediments suggesting two sources of sediments. More than 60% concentrations of all trace metals were associated with < 2-μm fraction sediments. The distribution of trace metals along transect was affected by the physico-chemical conditions of the estuary, grain size of sediments, and anthropogenic contribution of metals. [ABSTRACT FROM AUTHOR]

The determination of the anthropogenic impact on the thermal regime of a megalopolis is discussed. The nominal boundaries of the megalopolis thermal effects are determined taking into account orographic and landscape effects and the variability of temperature difference between the center of the city and its suburbs. It is proposed to use the data of stations located within 40-50 km from the urban agglomeration boundaries for calculating the anthropogenic component of the urban heat island. The parameters of the heat island in Moscow are determined from the measurement data on maximum and minimum daily surface air temperature in 2012-2016, and their significant seasonal and intradaily variability is revealed. It is corroborated that anthropogenic causes for the higher air temperature in Moscow as compared with suburbs during the cold season are the release and loss of heat of heating systems; in the absence of snow cover the anthropogenic effect of these sources is enhanced by the thermal radiation of the urban surface. [ABSTRACT FROM AUTHOR]

In this study, the distribution of heavy metals (Co, Cr, Cu, Ni, Zn and Pb) in a sediment core from the Ganga (Hooghly) River estuary has been investigated. The data on concentrations of heavy metals, together with the concentrations of Al, Fe, Mn, carbonate, organic carbon (C) and nitrogen (N), have been used to understand (1) the phase association of metals, (2) their geochemical cycling in the sediment column and (3) if metals are enriched by anthropogenic contributions. The metals show significant positive correlations with Fe and Mn, indicating that Fe-Mn oxyhydroxide phases are the major host of metals in the sediment core. This observation together with significant negative correlations of Fe, Mn and the heavy metals with (C/N) provides the evidence for diagenetic redistribution of metals in the sediment column and their partitioning into the Fe-Mn oxyhydroxides. The increasing upward exchangeable Mn concentrations and association of metals with Fe and/or Mn in the exchangeable phases provide the supporting evidence for digenetic remobilization of the metals and their cycling with the Fe-Mn oxyhydroxides. Down-core variations of the metal concentrations generally match with that of Mn and Fe. The results of calculations for enrichment factors (EF) show that EF > 1.5 for Pb in the sediment core, suggestive of non-crustal sources. The elevated concentrations of Pb with EF > 1.5 in the sediment samples of the effluent water that drain into the estuary suggest that industries are an important source of Pb to the Hooghly River estuary sediments. The results and observations of this study suggest that an assessment of temporal variation of metal pollution in estuaries will require understanding of phase association and cycling of metals in the sediment column. [ABSTRACT FROM AUTHOR]

Quantification of the anthropogenic contribution for the pollution is important for the management of the environment. In this study, water samples from the Bian River in Suzhou, northern Anhui Province, China have been collected and analyzed for eight kinds of trace metal concentrations, and then analyzed by statistical methods for quantifying the natural and anthropogenic contributions. The results indicate that the water samples have mean concentrations of Cr > Cu > Ni > V > Zn > Ti > Co > Mn, and the medium coefficients of variations indicate that the water in the Bian River has not been dramatically affected by human activities. Factor analysis has identified three sources responsible for the trace metal concentrations, including two natural/geological sources and one anthropogenic source. Three sources have also been determined by Unmix model, and the anthropogenic contributions for the total Ti, V, Cr, Mn, Co, Ni, Cu and Zn are 25.3%, 26.7%, 31.3%, 58.9%, 28.1%, 32.1%, 42.4% and 32.5%, respectively. [ABSTRACT FROM AUTHOR]

Total suspended particulate (TSP) samples were collected at a pristine island (Huaniao) in northern East China Sea (ECS) between Mar. 2011 and Jan. 2013 and analyzed for the concentrations of major ions and trace elements. Aerosol sources and the distribution of source regions are identified using positive matrix factorization (PMF) and potential source contribution function (PSCF) methods. It is found that aerosols over Huaniao Island are contributed by six main factors including primary industrial emissions (11.3%), secondary aerosol (22%), oxalate-associated aerosol (15.7%), sea salt (36.7%), ship emission (6.3%) and mineral dust (8.1%). Anthropogenic source contribution to the resolved aerosol mass reached the highest (76.6%) and lowest (18%) values in January 2013 and August 2012 respectively, strongly influenced by the prevailing winds of East Asian monsoon. The main source regions of secondary aerosol are southeastern Hebei and Shandong, which is consistent with the most intensive distribution of coal-fired power plants and the largest emission of precursors in this area. Oxalate-associated aerosol is produced primarily along the coastal line. Primary industrial emissions mainly originate from southwestern Shandong and Yangtze River Delta. [ABSTRACT FROM AUTHOR]

Anthropogenic activities have significantly enhanced atmospheric metal inputs to the ocean, which has potentially important consequences for marine ecosystems. This study assesses the potential of Zn and Cu isotope compositions to distinguish between natural and anthropogenic atmospheric inputs of these metals to the surface ocean. To this end, the isotopic compositions of Zn and Cu in aerosols collected from the eastern tropical Atlantic Ocean on the GEOTRACES GA06 cruise are examined. Enrichment factors and fractional solubility measurements indicate the presence of a significant anthropogenic component in the aerosols collected furthest from the North African dust plume for both Zn and Cu. The mean δ65Cu NIST SRM 976 for the fully digested aerosols is +0.07 ± 0.39 ‰ (n = 9, 2 SD), which is indistinguishable from the lithogenic value, and implies that Cu isotopes are not an effective tracer of aerosol sources in this region. The mean δ66Zn JMC-Lyon value for the aerosols that underwent a total digestion is +0.17 ± 0.22 ‰ (n = 11, 2 SD). The aerosols leached with ammonium acetate have similar Zn isotope compositions, with a mean of +0.15 ± 0.16 ‰ (n = 7, 2 SD). The aerosols were collected in a region with prevalent mineral dust but, despite this, exhibit isotopically lighter Zn than lithogenic Zn with δ66Zn ≈ +0.3 ‰. When coupled with the previously published Pb isotope data, the aerosols exhibit coupled Zn-Pb isotope systematics that are indicative of mixing between mineral dust (δ66Zn = +0.28 ‰ and 206Pb/207Pb = 1.205) and anthropogenic emissions (δ66Zn = −0.22 ‰ and 206Pb/207Pb = 1.129). This demonstrates the potential of Zn isotopes to trace atmospheric Zn inputs from anthropogenic sources to the surface ocean. [ABSTRACT FROM AUTHOR]

Oxygen isotope ratio (δ 18 O) and concentrations of Al, Na + , methanesulfonic acid (MSA), SO 4 2 − , and selenium (Se) in a continuous series of 70 snow samples from a 3.2-m snow pit at a site in northwestern Greenland were determined using ultraclean procedures. Well-defined depth profiles of δ 18 O, Al, and sea-salt-Na + allowed the determination of chronology of the snow pit that spanned approximately 6 years from spring 2003 to summer 2009. Se concentrations were at a low pg/g level, ranging from 7.2 to 45 pg/g, and exhibited high variability with generally higher values during winter and spring and lower values during summer and fall. Very high crustal enrichment factors (EF c ) of Se averaging approximately 26,600 for the entire time period indicate a small contribution from crust dust. High Se/MSA ratios are generally observed in the winter and spring snow layers, in which the Se concentrations were relatively high (> 20 pg/g). This suggests that a significant component of the Se present in the snow layers is of anthropogenic origin. During the summer season, however, high EF c values are accompanied with low Se/MSA, indicating an increased contribution of marine biogenic sources. Significant correlations between Se, Al, and non-sea-salt SO 4 2 − highlight that significant inputs of Se to the snow are likely controlled by the seasonality in the transport efficiency of anthropogenic Se from the source regions to the site. Based on the seasonal changes in Se concentrations, Se/MSA, and Se/S ratios observed in the samples, the input of anthropogenic Se to the site appears to be governed by the long-range transportation of Se emitted from coal combustion in East Asian countries, especially in China. [ABSTRACT FROM AUTHOR]

Clay minerals and Sr–Nd isotopes of suspended particulate matter (SPM) and bottom sediment were investigated along transect stations of the Mandovi and Zuari estuaries, western India to determine the provenance and role of estuarine processes on their distribution. Kaolinite and illite, followed by minor goethite, gibbsite and chlorite were present in SPM and bottom sediment at all stations, both during monsoon and pre-monsoon. Smectite occurred in traces at river end stations but its contents increased downstream in both estuaries. Smectite contents were much higher in Zuari than in Mandovi estuary. The 87 Sr/ 86 Sr ratios and ɛNd of SPM were higher than those in hinterland rocks and laterite soils. The Sr ratios were highest at river end stations of both estuaries and decreased sharply seaward. The Sm/Nd ratios of SPM and sediment were close to that of iron ore material flushed into the estuaries. The mean ɛNd of SPM and sediment were similar in both estuaries. It is suggested that the smectite is formed in coastal plains and its distribution downstream is controlled by lithology and drainage basin of rivers. Abundant kaolinite and high Sr ratios reflect chemical weathering and lateritization of source rocks. Sr isotopic ratios along transects are influenced by changes in salinity, organic matter and turbidity. High and near identical ɛNd values along transect stations of both estuaries suggest that the Nd isotopic compositions are influenced by the lateritization of source rocks and anthropogenic contribution of ore material. [ABSTRACT FROM AUTHOR]

A total of 260 soil profiles were analyzed to estimate the anthropogenic contribution to total Hg content of soils in the Guangdong province by using the enrichment factor method. The results revealed that soil Manganese (Mn) as the reference element was appropriate for establishing the enrichment factor and assessing anthropogenic contribution to soil total Hg. The anthropogenic enrichment factors (EFs) suggested that some hotspots (EFs > 4) related to the anthropogenic Hg export can be identified, such as some mining of polymetallic ore in northern areas, coal exploitation in eastern areas, gold mine in western areas, and some chlor-alkali plants along the coast in the study area. The results of anthropogenic Hg contribution indicated that about 70% of the study areas suffer obvious anthropogenic Hg interference, of which anthropogenic Hg contribution to soil total Hg content was up to 72-90% in 20% of the study areas. [ABSTRACT FROM AUTHOR]

Atmospheric deposition of dust is suspected to have a significant impact on biogeochemical processes in high-nutrient-low-chlorophyll waters of the open ocean. In this study, we report time series of atmospheric deposition samples collected over two years at three different sites on Kerguelen and Crozet Islands in the Southern Indian Ocean. Total atmospheric deposition fluxes were measured for a large suite of elements (Al, As, Ba, Ca, Ce, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Na, Nd, Ni, Pb, Rb, S, Si, Sr, Ti, U, V, and Zn). Most of them are identified as coming from sea-salt or crustal sources, but enrichment factor variabilities of Pb, As, Cr, Cu, and V highlight an anthropogenic contribution during the austral winter for these five elements. For Al, Fe, Mn, and Si, deposition fluxes are similar for both Kerguelen and Crozet Islands. Fluxes for the other non-sea-salt elements exhibit differences below a factor of five with a decreasing gradient from Crozet to Kerguelen. [ABSTRACT FROM AUTHOR]

Abstract: Background: Because of concern about the recently increasing levels of biological Hg in some areas of the Arctic, we examined the literature concerning the long-term changes of Hg in humans and selected Arctic marine mammals and birds of prey since pre-industrial times (i.e. before 1800A.D.), to determine the anthropogenic contribution to present-day Hg concentrations and the historical timing of any changes. Methods: Mercury data from published articles were extracted on historical and pre-industrial concentrations as percentages of the recent maximum, as well as the man-made contribution was calculated and depicted in a uniform manner to provide an overview of the development over time. Results and discussion: Trends of [Hg] in hard tissues such as teeth, hair and feathers consistently showed that there had been an order-of-magnitude increase of [Hg] in Arctic marine foodweb-based animals that began in the mid- to late-19th Century and accelerated in the 20th Century. The median man-made contribution to present-day Hg concentrations was 92.4% ranging from 74.2 to 94.4%. Confidence in our data was increased by accompanying data in some studies on stable isotopes (δ 13C, δ 15N), which allowed us to normalize where necessary for changes in animal trophic position and feeding location over time, and by careful attention to the possibility of sample chemical diagenesis (Hg contamination or loss) which can alter the Hg content of ancient hard tissues. Conclusions: Wildlife hard tissue matrices provide consistent information with respect to the steep onset of Hg exposure of Arctic wildlife beginning in the latter half of the 19th Century. Today the man-made contribution was found to be above 92%. Stable isotope analyses provide important information to normalize for possible changes in diet over time, and are highly relevant to include when interpreting temporal trends, baseline concentrations as well as man-made anthropogenic contribution of Hg. [Copyright &y& Elsevier]

As a form of land degradation, soil erosion directly threatens the sustainability of natural resources and the environment. The impacts of humans on soil erosion are profound and complex, especially in the areas with frequent human activities. Moreover, the great variability of human activities at the spatial and time scales precludes a comprehensive understanding of how humans affect regional erosion. This study evaluated soil erosion by water from 1985 to 2015 occurring in South China, which is densely populated and has been intensively exploited, based on the Chinese Soil Loss Equation (CSLE) and multisource data including remote sensing images, meteorological station information and geographic data. A quantitative method combining traceability thinking and residual trend approach was employed to distinguish the relative contributions of climate change and human activities. The results showed that the average amount of soil erosion exhibited a significant decreasing trend from 1985 to 2015, which was consistent with the national water census data and previous studies. Anthropogenic factors played a more vital role than natural variables in the evolution of soil erosion, the multiyear average contribution of which was 63.90%. The area in which anthropogenic factors alleviated soil erosion covered approximately 83.70% of the study area. These results indicate that soil and water conservation practices have made outstanding contributions to the reduction of soil erosion in South China. However, the impacts of the expansion of building land and the development of plantations on aggravating soil erosion cannot be ignored. For future soil erosion control, we observed the diminishing marginal effect of investments in soil and water conservation, and a higher governance potential in the severely eroded regions, which made the severely eroded poor land a primary for comprehensive ecological management. This study aims to provide valuable insights for decision makers in South China to better understand the impacts of humans on the evolution of soil erosion and could provide scientific support for reducing regional soil loss and enhancing the sustainable development of the ecological environment. • Soil erosion in South China exhibited a clearly decreasing trend from 1985 to 2015. • Anthropogenic factors played a more impactful role than natural variables. • The effect of human activities was more likely to mitigate erosion. • Some meaningful soil and water conservation strategies were proposed. [ABSTRACT FROM AUTHOR]

The results of a 8 year survey of wet and dry depositions collected in Bologna (Northern Italy) are presented and discussed: monthly fluxes of the main ions (hydrogen, sodium, potassium, calcium, magnesium, ammoniacal and nitrate nitrogen, sulphate and chloride) have been registered and statistically discussed. The trend of hydrogen ion, whose largest correlation in the global deposition was found with sulphate, is clearly downwards, with peaks mainly in winter months. By means of a data factor analysis, three main sources to explain the variability of the deposition chemistry were recognized: an anthropogenic contribution (particularly represented by NO3 −, SO4 2−, H+), the sea spray (Na+, Cl− and, to a lesser extent, K+ and Mg2+) and a terrigenous fraction, particularly characterized by higher Ca2+ concentration; however, some concentration peaks of this ion have been found in association with some episodes of Saharan dust transportation. [ABSTRACT FROM AUTHOR]

Rivers engage in carbon cycle by transporting the dissolved products of weathering of rocks to the oceans, and this process is sensitive to the global climatic changes. The present study was carried out with an objective of estimating the spatial and temporal variation in carbon consumption due to rock weathering in Cauvery, which is a major non-perennial tropical river in the peninsular India. The samples of all the rock types of this river basin were collected and subjected to mineralogical analysis. The water samples from this river were collected three times a year from 2013 to 2017 at 28 locations and were analysed for pH, EC and major ions. The spatiotemporal variations in the chemistry of river water were used to understand the amount of carbon dioxide consumed by rock weathering. The contribution of weathering to dissolved load of the river was higher followed by the contribution of anthropogenic activities and rainfall. The contribution of silicate weathering is dominant during the high river flow, whereas during low flow time periods, the contribution of carbonate weathering is on par with silicate weathering. The carbon consumption due to weathering in the Cauvery river was higher when the flow was significant, and it was lower during summer months. It is also evident that the carbon consumption is high in the upper and middle regions of the basin due to the weathering of gneissic and granodiorite rocks. Thus, the carbon consumption and flux in this basin are dynamic, both spatially and temporally. The east flowing rivers draining through the peninsular India, which is mostly composed of massive rocks, also functions as carbon sink, thus benefitting the environment by reducing the excess CO 2 in the atmosphere.