The distribution characteristics and potential sources of polybrominated diphenyl ethers (PBDEs) and alternative brominated flame retardants (aBFRs) were investigated in 54 surface sediment samples from four bays (Taozi Bay, Sishili Bay, Dalian Bay, and Jiaozhou Bay) of North China's Yellow Sea. Of the 54 samples studied, 51 were collected from within the four bays and 3 were from rivers emptying into Jiaozhou Bay. Decabromodiphenylethane (DBDPE) was the predominant flame retardant found, and concentration ranged from 0.16 to 39.7 ng g−1 dw and 1.13–49.9 ng g−1 dw in coastal and riverine sediments, respectively; these levels were followed by those of BDE 209, and its concentrations ranged from n.d. to 10.2 ng g−1 dw and 0.05–7.82 ng g−1 dw in coastal and riverine sediments, respectively. The levels of DBDPE exceeded those of decabromodiphenyl ether (BDE 209) in most of the samples in the study region, whereas the ratio of DBDPE/BDE 209 varied among the four bays. This is indicative of different usage patterns of brominated flame retardants (BFRs) and also different hydrodynamic conditions among these bay areas. The spatial distribution and composition profile analysis indicated that BFRs in Jiaozhou Bay and Dalian Bay were mainly from local sources, whereas transport from Laizhou Bay by coastal currents was the major source of BFRs in Taozi Bay and Sishili Bay. Both the ∑PBDEs and ∑aBFRs (sum of pentabromotoluene (PBT), 2,3-diphenylpropyl-2,4,6-tribromophenyl ether (DPTE), pentabromoethylbenzene (PBEB), and hexabromobenzene (HBB)) were at low concentrations in all the sediments. This is probably attributable to a combination of factors such as low regional usage of these products, atmospheric deposition patterns, coastal currents transportation patterns, and degradation processes for higher BDE congeners. This paper is the first study that has investigated the levels of DBDPE in the coastal sediments of China's Yellow Sea.

The occurrence and spatial distribution of polychlorinated naphthalenes (PCNs) were investigated in sediments, upland and paddy soils from the Liaohe River Basin. Concentrations of ΣPCNs were in the range of 0.33–12.49 ng g⁻¹ dry weight (dw) in sediments and 0.61–6.60 ng g⁻¹ dw in soils, respectively. Tri-CNs and tetra-CNs were the dominating homologues. An increasing trend of PCNs contamination was found in sediments with the rivers flowing through industrial areas and cities. Soils collected near cities exhibited higher abundance of PCNs than that of rural areas. The distribution of PCNs was related to the local industrial activities, rather than total organic carbon. Positive matrix factorization (PMF) was used for the source apportionment of PCNs in sediments and paddy soils. The result of PMF indicated that PCNs in sediments and paddy soils were mainly from the industrial processes, with additional contributions from the historical use of Halowax 1014 and atmospheric deposition.

While the spatial distributions of heavy metals in farmland soil of China have been comprehensively delineated, their temporal trends are rarely investigated but are important for environmental risk management. In this study, the current status and temporal trends of heavy metals in the farmland soil of Yangtze River Delta (YRD) were evaluated through field survey and meta-analysis. The field survey conducted in 2014 showed that the concentrations of Cd, Pb, Cu, Zn, and Ni in the farmland topsoil were 0.23 ± 0.14, 37.63 ± 15.60, 25.83 ± 41.62, 88.38 ± 43.30, and 29.21 ± 12.41 mg kg−1 (mean ± standard deviation), respectively. The heavy metals showed relatively higher concentrations on the borders among Zhejiang, Jiangsu, and Shanghai. In the meta-analysis, we selected 68 published studies related to heavy metal pollution in farmland topsoil of YRD from 2000 to the year (2014) when the field survey was conducted. The results show an increasing trend for Cd (p < 0.05; 0.0081 mg kg−1 year−1), a decreasing trend for Cu (p < 0.05; -0.80 mg kg−1 year−1), and no significant trend for Pb (p = 0.155), Zn (p = 0.746), and Ni (p = 0.305). The increasing rate of Cd from the meta-analysis is consistent with the rate (0.0013 mg kg−1 year−1) derived from the mass balance calculation for Cd, where atmospheric deposition originated from intensive coal combustion is considered as the main source of Cd in the topsoil. The decreasing trend of Cu is likely due to largely reduced application of copper-based agrochemicals. Environmental regulation and soil remediation are needed to protect food safety and ecosystem from heavy metal pollution, especially Cd.

The quantification of atmospheric deposition flux is essential for assessment of its impact on ecosystems. We present an advanced approach for the estimation of the spatial pattern of atmospheric nitrogen deposition flux over the Czech forests, collating all available measured data and model results. The aim of the presented study is to provide an improved, more complete, more reliable and more realistic estimate of the spatial pattern of nitrogen deposition flux over one country. This has so far usually been based on measurements of ambient NOx concentrations as dry deposition proxy, and NH4+ and NO3− in precipitation as wet deposition proxy. For estimation of unmeasured species contributing to dry deposition, we used the CAMx Eulerian photochemical dispersion model, coupled with the Aladin regional numeric weather prediction model. The contribution of fog and dissolved organic nitrogen was estimated using a geostatistical data driven model. We prepared individual maps for particular components applying the most relevant approach and then merged all layers to obtain a final map representing the best estimate of nitrogen deposition over the Czech Republic. Final maps accounting for unmeasured species clearly indicate that the approach used so far may result in a substantial underestimation of nitrogen deposition flux. Our results showed that nitrogen deposition over the Czech forested area in 2008 was well above 2 g N m−2 yr−1, with almost 70% of forested area receiving 3–4 g N m−2 yr−1. NH3 and gaseous HNO3, contributing about 80%, dominated the dry nitrogen deposition. Estimating the unmeasured nitrogen species by modeled values provides realistic approximations of total nitrogen deposition that also result in more realistic spatial patterns that could be used as input for further studies of likely nitrogen impacts on ecosystems.

Fullerenes are carbon based nanoparticles that may enter the environment as a consequence of both natural processes and human activities. Although little is known about the presence of these chemicals in the environment, recent studies suggested that soil may act as a sink. The aim of the present work was to investigate the presence of fullerenes in soils collected in The Netherlands. Samples (n = 91) were taken from 6 locations and analyzed using a new developed LC-QTOF-MS method. The locations included highly trafficked and industrialized as well as urban and natural areas. In general, C60 was the most abundant fullerene found in the environment, detected in almost a half of the samples and at concentrations in the range of ng/kg. Other fullerenes such as C70 and an unknown structure containing a C60 cage were detected to a lower extent. The highest concentrations were found in the proximity of combustion sites such as a coal power plant and an incinerator, suggesting that the nanoparticles were unintentionally produced during combustions processes and reached the soil through atmospheric deposition. Consistent with other recent studies, these results show that fullerenes are widely present in the environment and that the main route for their entrance may be due to human activities. These data will be helpful in the understanding of the distribution of fullerenes in the environment and for the study of their behavior and fate in soil.

Copper (Cu) and zinc (Zn) isotope ratios can be used to fingerprint sources and dispersion pathways of pollutants in the environment. Little is known, however, about the potential of δ65Cu and δ66Zn values in liquid and solid forms of atmospheric deposition to distinguish between geogenic, industrial, local and remote sources of these potentially toxic base metals. Here we present Cu-Zn deposition fluxes at 10 mountain-top sites in the Czech Republic, a region affected by extremely high industrial emission rates 25 years ago. Additionally, we monitored isotope composition of Cu and Zn in vertical and horizontal atmospheric deposition at two sites. We compared δ65Cu and δ66Zn values in snow and rime, extracted by diluted HNO3 and concentrated HF. Cu and Zn isotope signatures of industrial pollution sources were also determined. Cu and Zn deposition fluxes at all study sites were minute. The mean δ65Cu value of atmospheric deposition (−0.07‰) was higher than the mean δ65Cu value of pollution sources (−1.17‰). The variability in δ65Cu values of atmospheric deposition was lower, compared to the pollution sources. The mean δ66Zn value of atmospheric deposition (−0.09‰) was slightly higher than the mean δ66Zn value of pollution sources (−0.23‰). The variability in δ66Zn values of atmospheric deposition was indistinguishable from that of pollution sources. The largest isotope differences (0.35‰) were observed between the insoluble and soluble fractions of atmospheric deposition. These differences may result from different sources of Cu/Zn for each fraction. The difference in isotope composition of soluble and insoluble particles appears to be a promising tool for pollution provenance studies in Central Europe.

Although urban horticulture provides multiple benefits to society, the extent to which these vegetables are contaminated by the absorption of chemical elements derived from atmospheric deposition is unclear. This study was designed to evaluate the influence of air pollution on leafy vegetables in community gardens of Sao Paulo, Brazil. Vegetable seedlings of Brassica oleracea var. acephala (collard greens) and Spinacia oleracea (spinach) obtained in a non-polluted rural area and growing in vessels containing standard uncontaminated soil were exposed for three consecutive periods of 30, 60 and 90 days in 10 community gardens in Sao Paulo and in one control site. The concentrations of 17 chemical elements (traffic-related elements and those essential to plant biology) were quantified by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Tillandsia usneoides L. specimens were used as air plant biomonitors. The concentrations of As, Cd, Cr and Pb found in vegetables were compared to the recommended values for consumption. Principal Component Analysis (PCA) was used to cluster the elemental concentrations, and Generalized Linear Models (GLMs) were employed to evaluate the association of the factor scores from each PCA component with variables such as local weather, traffic burden and vertical barriers adjacent to the gardens. We found significant differences in the elemental concentrations of the vegetables in the different community gardens. These differences were related to the overall traffic burden, vertical obstacles and local weather. The Pb and Cd concentrations in both vegetables exceeded the limit values for consumption after 60 days of exposure. A strong correlation was observed between the concentration of traffic-related elements in vegetables and in Tillandsia usneoides L. An exposure response was observed between traffic burden and traffic-derived particles absorbed in the vegetables. Traffic-derived air pollution directly influences the absorption of chemical elements in leafy vegetables, and the levels of these elements may exceed the recommended values for consumption.

Estuaries and coastal areas strongly influenced by terrestrial inputs resulted from anthropogenic activities. To study the distributions, origins, potential transport and burden of organochlorine compounds (OCs) from river to marginal sea, organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were investigated in surface sediments collected from a subtropical estuary (Jiulong River Estuary, JRE) and the inner shelf of adjacent Western Taiwan Strait (WTS). The concentrations of OCPs and PCBs were from 5.2 to 551.7 and 1.0–8.1 ng g−1 (dry weight), respectively. OCP concentrations in the JRE were higher than in adjacent WTS, and a decreasing trend with the ascending distance from the estuary to the open sea was observed. Concentrations of DDTs were quite high in the upper reach of the estuary, inferred from antifouling paint on fishing boats of a local shipping company. According to established sediment quality guidelines, DDTs in the JRE posed potential ecological risk. HCHs in the estuary were mainly derived from the weathered HCHs preserved in the agriculture soils via local major river runoffs.OCPs patterns showed that OCPs in the south coast of WTS were resulted from local sources via river input, while OCPs in the north coast attributed to the long-range transport derived by the Fujian-Zhejiang Coastal Current.Minor variations of PCB concentrations and homologs indicated that PCBs were not the main pollutant in the agricultural region, consistent lighter PCBs reflected industrial PCBs were transported via atmospheric deposition derived by East Asia Monsoon. Moreover, the primary distribution pattern founded for DDTs and the considerable mass inventories and burdens calculated (258.1 ng cm−2 and 10.4 tones for OCPs) that higher than Pearl River Delta and Yangtze River Delta, together suggested that the contaminated sediments in the study area may be a potential source of OCPs to the global ocean.

Reconstructing the history of metal deposition in Singapore lake sediments contributes to understanding the anthropogenic and natural metal deposition in the data-sparse Southeast Asia. To this end, we present a sedimentary record of Pb, Pb isotopes and eleven other metals (Ag, As, Ba, Cd, Co, Cr, Cu, Ni, Tl, U and Zn) from a well-dated sediment core collected near the depocenter of MacRitchie Reservoir in central Singapore. Before the 1900s, the sedimentary Pb concentration was less than 2 mg/kg for both soil and sediment, with a corresponding 206Pb/207Pb of ∼1.20. The Pb concentration increased to 55 mg/kg in the 1990s, and correspondingly the 206Pb/207Pb decreased to less than 1.14. The 206Pb/207Pb in the core top sediment is concordant with the 206Pb/207Pb signal of aerosols in Singapore and other Southeast Asian cities, suggesting that Pb in the reservoir sediment was mainly from atmospheric deposition. Using the Pb concentration in the topmost layer of sediment, the estimated atmospheric Pb flux in Singapore today is ∼1.6 × 10−2 g/m2 yr. The concentrations of eleven other metals preserved in the sediment were also determined. A principal component analysis showed that most of the metals exhibit an increasing trend towards 1990s with a local concentration peak in the mid-20th century.

Mercury (Hg) concentrations in freshwater fish relates to aquatic Hg concentrations, which largely derives from soil stores of accumulated atmospheric deposition. Hg in catchment soils as a source for aquatic Hg is poorly studied. Here we test if i) peatland soils produce more methylmercury (MeHg) than forest soils; ii) total Hg (THg) concentrations in top soils are determined by atmospheric inputs, while MeHg is produced in the soils; and iii) soil disturbance promotes MeHg production. In two small boreal catchments, previously used in a paired-catchment forest harvest manipulation study, forest soils and peatlands were sampled and analysed for Hg species and additional soil chemistry. In the undisturbed reference catchment, soils were sampled in different vegetation types, of varying productivity as reflected in tree density, where historical data on precipitation and throughfall Hg and MeHg fluxes were available. Upper soil THg contents were significantly correlated to throughfall inputs of Hg, i.e. lowest in the tree-less peatland and highest in the dense spruce forest. For MeHg, top layer concentrations were similar in forest soils and peatlands, likely related to atmospheric input and local production, respectively. The local peatland MeHg production was documented through significantly higher MeHg-to-THg ratios in the deeper soil layer samples. In the disturbed catchment, soils were sampled in and just outside wheeltracks in an area impacted by forest machinery. Here, MeHg concentrations and the MeHg-to-THg ratios in the upper 5 cm were weakly significantly (p = 0.07) and significantly (p = 0.04) different in and outside of the wheeltracks, respectively, suggesting that soil disturbance promotes methylation. Differences in catchment Hg and MeHg streamwater concentrations were not explained by soil Hg and MeHg information, perhaps because hydrological pathways are a stronger determinant of streamwater chemistry than small variations in soil chemistry driven by disturbance and atmospheric inputs of Hg.