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Variations in the distribution, source composition, mass inventory and burial flux of polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Pearl River Estuary (PRE) collected in 2011 and 2019 were analyzed to investigate the influence of the anthropogenic activities. Total concentrations of 16 priority PAHs in 2019 (200.40 ± 188.86 ng g−1 dry weight on average) were at the medium level among global bays/estuaries/coastal areas. In 2019, PAH concentrations have decreased by about 50% compared to 2011 and the dominant composition has changed from low- to high-molecular-weight PAHs. The qualitative and quantitative source apportionment analysis indicates that the dominant source of PAHs has shifted from petroleum (40.33%) in 2011 to traffic emission (44.17%) in 2019. The source variation in the PRE can be attributed to the transformation of the energy source structure from petrogenic to pyrogenic in the Pearl River Delta. The estimated PAH mass inventory of the top 5-cm sediment was 38.70 metric tons in 2019, which was about 41 metric tons lower than that in 2011. The average deposition fluxes have dropped from 418.91 ± 261.02 ng cm−2 yr−1 in 2011 to 215.52 ± 246.63 ng cm−2 yr−1 in 2019. The decreasing PAH concentration is related to the sediment coarsening and decline of total organic carbon. These findings in the PRE can be applied to other estuarine environments influenced by anthropogenic activities.

Plastics pose ecological and human health risks, with disposable contact lenses constituting a potential high-volume pollution source. Using sales data and an online survey of lens users (n = 416) ...

In this study, the occurrence, spatial distribution, potential sources, mass inventory, and ecological risk assessment of perfluoroalkyl acids (PFAAs) in surface sediments from the lower Yangtze River were investigated based on field and laboratory assays conducted in November 2019. The total concentrations of 13 target PFAAs (∑PFAAs) ranged from 13.83 to 20.33 ng/g dw, and perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) were predominant in the surface sediments with average concentrations of 2.89 and 4.07 ng/g dw, respectively. The ∑PFAAs concentrations in pore-water ranged from 23.30 to 58.81 ng/L, and PFOA and PFOS were predominant with mean concentrations of 6.29 and 5.04 ng/L, respectively. The profiles of PFAAs composition in surface sediments showed limited difference. Results of fugacity model revealed that PFOS was in relative equilibrium, whereas PFOA exhibited a diffusion trend from sediments to water body. Correlation analysis and positive matrix factorization demonstrated that the main sources of ∑PFAAs were electroplating and fast-food packaging, degradation products and textile, mixed sources, and PFOA-based products. The mass inventory of ∑PFAAs was estimated to be 1680.72 kg, and the results of ecological risk assessments based on equilibrium partition and species sensitivity distribution methods suggested that the hazards of PFAAs in sediments to local aquatic organisms are low. However, the evaluation methods and control measures of PFAAs in surface sediments are still limited, requiring further research.

Contamination by hexabromocyclododecanes (HBCDDs) in the soil environment is an ongoing concern because of their "specific exemption" on the production and use in China. In this study, spatial distribution, temporal trend, and diastereoisomer profiles of HBCDDs were examined in surface soils collected in Jinan, China. Concentrations of ΣHBCDD (sum of α-, β-, and γ-HBCDDs) in soils ranged from 1.70 to 228 ng/g dry weight (dw), with a mean value of 26.1 ng/g dw. Soils collected from e-waste dismantling sites (mean 146 ng/g dw) contained significantly higher concentrations of ΣHBCDD than those of urban (15.5 ng/g dw) and farmland soils (3.86 ng/g dw) (p 0.01). The temporal trend suggested that ΣHBCDD levels in the industrial area rose significantly between 2014 and 2019 (p 0.05), with an annual increase of 12%. An increase in ΣHBCDD levels was also observed in urban and farmland soil samples during the study period, although it did not reach a significant level (p 0.05). All surface soils were dominated by γ-HBCDD (mean 60.7% of total concentrations); however, the proportions of α-isomer increased from 28.7% in urban and rural soils to 43.4% in industrial soils. The calculated risk quotients of HBCDDs present in soils were at least 25-fold lower than the threshold limit value. The mean mass inventory of HBCDDs was approximately 2501 kg in the cultivated land of Jinan City; further studies are needed to discern the uptake of HBCDDs by crops and the fate of these chemicals in agricultural ecosystems.

The levels and distribution of tris-(2,3-dibromopropyl) isocyanurate (TBC) and hexabromocyclododecanes (HBCDs) in sediments in the intertidal zone of the New River Estuary were investigated. The concentration of TBC ranged from 2.78 to 35.1 ng·g−1dw, and the concentration of total HBCDs ranged from 10.3 to 43.5 ng·g−1dw. The composition of the three HBCD isomers, α-, β-, and γ-HBCD, was 6.23%, 8.00% and 85.8%, respectively. Moreover, the mass inventory of TBC, α-, β-, γ-HBCD, and total HBCDs in sediments were estimated to be about 1465.49, 124.64, 154.98, 1707.54, 1987.16 kg, respectively. Compared to previous studies, the concentrations of TBC and HBCDs in the intertidal zone of the New River Estuary were relatively high. Therefore, more concern of the potential public health and environmental risks of TBC and HBCDs is necessary.

This study comprehensively interprets the contamination status of organochlorine pesticides (OCPs) in the soils from Benevento provincial territory, southern Italy, and its implications for environmental health by means of a systematic grid sampling method and geostatistics. The total concentrations of OCPs in the soils ranged from 0.058 to 16.9 ng/g, with a geometric mean (GM) of 0.72 ng/g and an arithmetic mean (AM) of 1.71 ng/g. The levels of OCPs were dominated by p,p′-DDE, p,p′-DDD, HCB, contributing together to 73.5% of the total OCPs. The higher levels of HCB, DDTs, and HCHs found in southwestern, central and east Benevento provincial territory, all occurring adjacent to landfill sites. The residues of OCPs in soil are largely ascribed to their historical use. The OCP inventories in soils of Benevento provincial territory ranged from 0.13 to 4.84 metric tons, with GM = 0.42 metric tons and AM = 0.44 metric tons. The soil is likely to be a sink for DDTs under the influence of regional air transport from pollution hotspots and has the potential to release other chemicals with a high vapor pressure, e.g., HCB, HCHs, and α-Endosulfan. And the mean level of the air-soil exchange flux of HCB, HCHs, and DDTs is estimated to be −1.59, −0.72, and 0.10 ng/m2/day respectively. The potential ecological and human health risks caused by OCPs in the soils are deemed essentially negligible in Benevento provincial territory.

Surface sediment samples were collected from the Yangtze River Estuary (YRE) to the inner-shelf mud area of the East China Sea (ECS) for a comprehensive study of the sources and fates of polychlorinated biphenyls (PCBs) based on their spatial distribution, deposition flux, and mass inventory. The total concentrations of 32 PCBs (Σ32PCBs) varied from 0.3 to 11.9 ng/g dry weight. Under strong hydrodynamic conditions, the weak correlations between TOC or MD and Σ32PCB concentrations were observed in the YRE. In contrast, there were relatively well relationships of PCBs with TOC content and sediment grain size in the inner shelf of the ECS due to the influence of hydrological sorting from the YRE to the inner shelf of the ECS. This suggests that the Yangtze River input plays a considerable role in controlling the distribution of PCBs in the coastal ECS. Compared with the annual discharge of Σ32PCBs from the Yangtze River to the sea (3.21 t/yr), the deposition flux was estimated to be ~2.63 t/yr. Furthermore, a total mass inventory of 50 tons in the sediments suggests that the YRE and inner shelf mud of the ECS represents an important global sink of PCBs. Estimated 21–39% of sedimentary PCBs were derived from local emissions (mainly dismantling of electronic waste) aside from Yangtze River input. Higher proportions of penta-CBs were also observed near the central Zhejiang Coast, providing further evidence that the local emission from e-waste dismantling near the coast is a significant contributor to sedimentary PCBs in the coastal ECS.

We investigated the occurrence of brominated flame retardants (BFRs), organochlorine pesticides (OCPs), and polychlorinated biphenyls (PCBs) in the surface soils from the largest BFR-manufacturing and vegetable farming center (Shouguang) of North China. The total concentrations of BFRs ranged from 39.9 to 8,145 ng/g dry weight with a mean of 1,947 ng/g. The BFRs were dominated by decabromodiphenylethane (deca-BDEs) and tetrabromobisphenol A (TBBPA), with means of 1127 and 672 ng/g, respectively, followed by decabromodiphenyl ethane (DBDPE) (111 ng/g) and hexabromocyclododecanes (HBCD) (37.5 ng/g). This profile was generally consistent with the BFR production and use in China, except for TBBPA. Although the lower brominated BDEs (tri- through hepta-BDEs) in the soil may originate from technical deca-BDE mixtures as trace impurities and/or from the degradation of deca-BDEs, deca-BDE was shown to be persistent in the soil. The concentrations of OCPs (44 ng/g) were significantly lower than those of BFRs and displayed a spatial distribution opposite to that of BFRs, which was concentrated in the industrial zone. PCBs (with the lowest levels) showed a relatively uniform spatial distribution because of regional diffusive sources. The mass inventories for the entire land soil (20-cm) were estimated to be 1042, 26, and 3.7 t for BFRs, OCPs, and PCBs, respectively.

A spatially resolved, dynamic version of the Multimedia Urban Model (MUM) and the boundary layer forecast and air pollution transport model BLFMAPS were coupled to build Spatially Oriented MUM (SO-MUM), to estimate emissions and fate of POPs in an urban area on a 5 × 5 km(2) cell resolution. SO-MUM was used to back-calculate emissions from spatially resolved measured air concentrations of PCBs and PBDEs in Toronto, Canada. Estimated emissions of Σ(88)PCBs were 230 (40-480) kg y(-1), 280 (50-580) g y(-1) km(-2), or 90 (16-190) mg y(-1) capita(-1), and Σ(26)PBDEs were 28 (6-63) kg y(-1), 34 (7-77) g y(-1) km(-2), or 11 (2-25) mg y(-1) capita(-1). A mass inventory of penta- and octa-BDEs in Toronto was estimated to be 200 tonnes (90-1000 tonnes) or 80 (40-400) g capita(-1). Using this estimate and that of 440 (280-800) tonnes of PCBs, estimated emissions of Σ(88)PCBs and Σ(26)PBDEs per mass of chemical inventory in Toronto were 0.5 (0.05-1.6) and 0.1 (0.01-0.7) g y(-1) kg(-1), respectively. The results suggest annual emission rates of 0.04% and 0.01% from the mass inventories with downtown accounting for 30% and 16% of Toronto's chemical inventory and emissions of PCBs and PBDEs, respectively. Since total PBDE emissions are a function of mass inventory, which is proportional to building volume, we conclude that building volume can be used as a proxy to predict emissions. Per mass inventory emission rates were negatively related to vapor pressure within a compound class, but not consistently when considering all compound congeners.

The levels and distribution of tris-(2,3-dibromopropyl) isocyanurate (TBC) and hexabromocyclododecanes (HBCDs) of surface sediments in the Yellow River Delta wetland had been investigated. The concentrations of TBC and ∑ HBCDs ranged from 0.20 to 29.03 ng·g − 1 dw and below limits of detections (LODs) to 20.25 ng·g − 1 dw. The average composition profile of three HBCDs isomers were 10.1%, 6.1% and 83.8% for α-, β- and γ-HBCD, respectively. Moreover, correlation analysis indicated there are similar sources among three isomers and positive correlations between total organic carbon (TOC) content and concentrations of TBC and HBCDs. The mass inventory of TBC,α-, β-, γ-HBCD, ΣHBCDs in surface sediments of Yellow River Delta wetland were estimated about 725.50, 72.76, 44.29, 548.34, 665.39 kg. Therefore, further investigations on potential human health and environmental risk assessments of TBC and HBCDs were needed.

The distribution, inventory, and potential risk of organochlorine pesticides (OCPs), including Hexachlorocyclohexanes (HCHs) and Dichlorodiphenyltrichloroethanes (DDTs), and their correlation with soil properties and anthropogenic factors were investigated in soils of the Campanian Plain. The total concentrations of HCHs and DDTs ranged from 0.03 to 17.3 ng/g (geometric mean: GM = 0.05 ng/g), and 0.08-1231 ng/g (GM = 14.4 ng/g), respectively. In general, the concentration of OCPs in farmland and orchards was higher than on land used for non-agricultural purposes. There are significant differences in the concentration of OCPs in the soils across the region, more specifically, the Acerra-Marigliano conurbation (AMC) and Sarno River Basin (SRB) are recognized as severely OCP-contaminated areas. The recent application of technical HCHs and DDTs in large quantities appears unlikely in light of the ratio of α-HCH/β-HCH and p,p'-DDT/p,p'-DDE, and the prohibition of the use of these chemicals in Italy nearly forty years ago. The clear correlation between the concentration of DDTs and organic carbon suggests a typical secondary distribution pattern. The mass inventory of OCPs in soils of the Campanian Plain is estimated to have a GM of 17.3 metric tons. There is no clear evidence linking the impact of geographical distribution of OCPs on the incidence of cancer, and the 95% confidence interval of total incremental lifetime cancer risk (TILCR) data falls below the internationally accepted benchmark value of 1 × 10(-5).

This study was conducted with the aim of analyzing persistent organic pollutants i.e., PCBs, PBDEs, DPs and OCPs for sediment samples collected from Mehmood Booti Drain, Lahore, Pakistan that receives higher pollution loads from adjacent waste dumping site. Levels of ∑PCBs, ∑PBDEs, ∑DPs and ∑OCPs ranged between 5.9-62, 0.36-1.32, n.d.-0.02 and 0.96-18.07ngg(-1,) respectively. These levels were found to be comparable with other studies of local or global origin. Composition, spatial distribution and source profile indicated that Mehmood Booti waste dumping site was the major input source for sedimentary POPs pollution. The highest POPs deposition flux and mass inventory was attributed to PCBs and OCPs. Deposition flux indicated the input of 6E(-04), 5E(-05), 9E(-07) and 4E(-0)(4)t/yr of PCBs, PBDEs, DPs and OCPs into the Mehmood Booti Drain sediments which ultimately discharge into the River Ravi. Mass inventories suggested 1E(-02), 3E(-04), 7E(-06) and 3E(-03) metric tons PCBs, PBDEs, DPs and OCPs burden, respectively in the Mehmood Booti Drain sediments.

Concentrations of hexabromocyclododecanes (HBCDs) were determined in surface sediments of Shanghai, China. The concentrations of total HBCD diastereoisomers (ΣHBCD) ranged from 0.01 to 13.70 ng g(-1) dry weight (dw) with a mean value of 3.41 ng g(-1) dw, which was up to several orders of magnitude lower than those reported for sediments from European countries. The ΣHBCD concentrations in sediments from chemical/textile industrial or densely populated areas were generally higher than those from rural or less chemical/textile industrialized areas in Shanghai. A high proportion of α-HBCD was observed in sediment samples and was significantly higher than that of commercial HBCD products. This might be due to thermal isomerization from γ-HBCD to α-HBCD and slower degradation rate of α-HBCD compared to γ-HBCD in anaerobic conditions. The mass inventory of ΣHBCD in surface sediments of Shanghai was estimated at 164.4 kg, representing a significant source of HBCDs to the Shanghai environment. This indicates that further study on potential transfer of HBCDs from sediments to aquatic organisms and ecological risk assessments is required.

A large-scale survey on the area and depth stratified distribution of dichlorodiphenyltrichloroethane (DDT; mainly p,p'- and o,p'-dichlorodiphenyldichloroethylene (DDE)) contamination in the water column of the Southern California Bight (SCB) was conducted in 2003-2004 using a solid-phase microextraction-based sampling technique. Dissolved-phase DDEs were clearly widespread, with the central SCB containing the highest levels, and the Palos Verdes Shelf sediments have remained the dominant source of DDT compounds to the SCB. The p,p'- and o,p'-DDE concentrations ranged from0.073 to 2.6 ng/L and from0.043 to 0.26 ng/L, respectively, clearly elevated with respect to measured values from across the globe. DDEs were hypothesized to have been transported from the historically contaminated zone on the Palos Verdes Shelf to other areas via a repeated process of sediment resuspension/deposition and short-range advection. Total mass inventories were estimated at 14 and 0.86 kg for p,p'- and o,p'-DDE, respectively, for the sampled area, resulting in p,p'- and o,p'-DDE mass inventories for the entire SCB of 230 and 14 kg, respectively. Furthermore, total fluxes of p,p'-DDE were estimated to be in the range of 0.8 to 2.3 metric tons per year. These results suggest that the SCB has been and continues to be a significant source of DDT contamination to the global oceans.