Wet deposition of persistent organic pollutants (POPs) in Izmir, Turkey

Temperature dependence of the rain-gas and snow-gas partition coefficients for nearly a thousand chemicals

Compared to the particle-gas partition coefficients (KPG), the rain-gas (KRG) and snow-gas (KSG) partition coefficients are also essential in studying the environmental behavior and fate of chemicals in the atmosphere. While the temperature dependence for the KPG have been extensively studied, the study for KRG and KSG are still lacking. Adsorption coefficients between water surface-air (KIA) and snow surface-air (KJA), as well as partition coefficients between water-air (KWA) and octanol-air (KOA) are vital in calculating KRG and KSG. These four basic adsorption and partition coefficients are also temperature-dependent, given by the well-known two-parameters Antoine equation logKXY = AXY + BXY/T, where KXY is the adsorption or partition coefficients, AXY and BXY are Antoine parameters (XY stand for IA, JA, WA, and OA), and T is the temperature in Kelvin. In this study, the parameters AXY and BXY are calculated for 943 chemicals, and logKXY can be estimated at any ambient temperature for these chemicals using these Antoine parameters. The results are evaluated by comparing these data with published experimental and modeled data, and the results show reasonable accuracy. Based on these coefficients, temperature-dependence of logKRG and logKSG is studied. It is found that both logKRG and logKSG are linearly related to 1/T, and Antoine parameters for logKRG and logKSG are also estimated. Distributions of the 943 chemicals in the atmospheric phases (gas, particle, and rain/snow), are illustrated in a Chemical Space Map. The findings reveal that, at environmental temperatures and precipitation days, the dominant state for the majority of chemicals is the gaseous phase. All the AXY and BXY values for logKSG, logKRG, and basic adsorption and partition coefficients, both modeled by this study and collected from published work, are systematically organized into an accessible dataset for public utilization.

Surfactant-enhanced mobilization of persistent organic pollutants: Potential for soil and sediment remediation and unintended consequences

This review aims to provide an overview of the sources and reactions of persistent organic pollutants (POPs) and surfactants in soil and sediments, the surfactant-enhanced solubilisation of POPs, and the unintended consequences of surfactant-induced remediation of soil and sediments contaminated with POPs. POPs include chemical compounds that are recalcitrant to natural degradation through photolytic, chemical, and biological processes in the environment. POPs are potentially toxic compounds mainly used in pesticides, solvents, pharmaceuticals, or industrial applications and pose a significant and persistent risk to the ecosystem and human health. Surfactants can serve as detergents, wetting and foaming compounds, emulsifiers, or dispersants, and have been used extensively to promote the solubilization of POPs and their subsequent removal from environmental matrices, including solid wastes, soil, and sediments. However, improper use of surfactants for remediation of POPs may lead to unintended consequences that include toxicity of surfactants to soil microorganisms and plants, and leaching of POPs, thereby resulting in groundwater contamination.

Fugacity-based analysis of polycyclic aromatic hydrocarbon pollution in Izmit Bay, Turkey: An analytical framework for assessment with limited data

An analytical framework was proposed for analyzing long-term chemical pollution in a coastal region with limited environmental data. The framework consists of compiling and synthesizing the available knowledge including the chemical's properties and the environmentally relevant data, as well as the data obtained by past monitoring studies. The gathered data is analyzed to assess multimedia fate of the pollutant by using fugacity-based intermedia transport calculations. Uncertainty analysis by applying Monte Carlo simulations is an integrated part of the framework. Dispersion factor (k) values were adopted, enabling a unified and intuitive way to define lognormal uncertainty distributions. The proposed framework was applied to polycyclic aromatic hydrocarbon (PAH) pollution in Izmit Bay, a coastal region in Turkey, impacted by industrialization and population growth. The analysis showed the importance of atmospheric pollution as a PAH source and indicated that Izmit Bay sediments may be at steady state for most PAHs.

Occurrence and Risk Assessment of Polybrominated Diphenyl Ethers in Surface Water and Sediment of Nahoon River Estuary, South Africa

The concentrations, potential sources, and compositional profile of PBDEs in the surface water and sediment of Nahoon Estuary, East London, South Africa, were investigated with solid-phase extraction and ultra-sonication, respectively, followed by gas-chromatography-electron capture detection. The seasonal range of the contaminants’ concentrations in water and sediment samples in spring season were ∑PBDE 329 ± 48.3 ng/L (25.32–785 ng/L) and ∑PBDE 4.19 ± 0.35 ng/g dw (1.91–6.57 ng/g), but ∑PBDE 62.1 ± 1.50 ng/L (30.1–110 ng/L) and ∑PBDE 65.4 ± 15.9 ng/g dw (1.98–235 ng/g) in summer, respectively. NH1 (first sampling point) was the most contaminated site with PBDE in the Estuary. The potential source of pollution is attributed to the stormwater runoff from a creek emptying directly into the Estuary. This study’s dominant PBDE congener is BDE-17, ranging from below detection limit to 247 ng/L and 0.14–32.1 ng/g in water and sediment samples, respectively. Most detected at all the sites were BDE-17, 47, 66, and 100. Most BDE-153 and 183 are found in sediment in agreement with the fact that higher brominated congeners of PBDE adsorb to solid materials. There was no correlation between the congeners and organic carbon and organic matter. However, the human health risk assessment conducted revealed that the PBDE concentration detected in the estuary poses a low eco-toxicological risk. Nevertheless, constant monitoring should be ensured to see that the river remains safe for the users, as it serves as a form of recreation to the public and a catchment to some neighbourhoods.

Rain Amplification of Persistent Organic Pollutants

Scavenging of gas- and aerosol-phase organic pollutants by rain is an efficient wet deposition mechanism of organic pollutants. However, whereas snow has been identified as a key amplification mechanism of fugacities in cold environments, rain has received less attention in terms of amplification of organic pollutants. In this work, we provide new measurements of concentrations of perfluoroalkyl substances (PFAS), organophosphate esters (OPEs), and polycyclic aromatic hydrocarbons (PAHs) in rain from Antarctica, showing high scavenging ratios. Furthermore, a meta-analysis of previously published concentrations in air and rain was performed, with 46 works covering different climatic regions and a wide range of chemical classes, including PFAS, OPEs, PAHs, polychlorinated biphenyls and organochlorine compounds, polybromodiphenyl ethers, and dioxins. The rain-aerosol (KRP) and rain-gas (KRG) partition constants averaged 105.5 and 104.1, respectively, but showed large variability. The high field-derived values of KRG are consistent with adsorption onto the raindrops as a scavenging mechanism, in addition to gas-water absorption. The amplification of fugacities by rain deposition was up to 3 orders of magnitude for all chemical classes and was comparable to that due to snow. The amplification of concentrations and fugacities by rain underscores its relevance, explaining the occurrence of organic pollutants in environments across different climatic regions.

Polybrominated diphenyl ethers in the environmental systems: a review

PBDEs are human-influenced chemicals utilized massively as flame retardants. They are environmentally persistent, not easily degraded, bioaccumulate in the biological tissue of organisms, and bio-magnify across the food web. They can travel over a long distance, with air and water being their possible transport media. They can be transferred to non-target organisms by inhalation, oral ingestion, breastfeeding, or dermal contact. These pollutants adsorb easily to solid matrices due to their lipophilicity and hydrophobicity; thus, sediments from rivers, lakes, estuaries, and ocean are becoming their major reservoirs aquatic environments. They have low acute toxicity, but the effects of interfering with the thyroid hormone metabolism in the endocrine system are long term. Many congeners of PBDEs are considered to pose a danger to humans and the aquatic environment. They have shown the possibility of causing many undesirable effects, together with neurologic, immunological, and reproductive disruptions and possible carcinogenicity in humans. PBDEs have been detected in small amounts in biological samples, including hair, human semen, blood, urine, and breastmilk, and environmental samples such as sediment, soil, sewage sludge, air, biota, fish, mussels, surface water, and wastewater. The congeners prevailing in environmental samples, with soil being the essential matrix, are BDE 47, 99, and 100. BDE 28, 47, 99, 100, 153, 154, and 183 are more frequently detected in human tissues, whereas in sediment and soil, BDE 100 and 183 predominate. Generally, BDE 153 and 154 appear very often across different matrices. However, BDE 209 seems not frequently determined, owing to its tendency to quickly breakdown into smaller congeners. This paper carried out an overview of PBDEs in the environmental, human, and biota niches with their characteristics, physicochemical properties, and fate in the environment, human exposure, and health effects.

Legacy and alternative flame retardants in typical freshwater cultured fish ponds of South China: Implications for evolving industry and pollution control

The production and usage of polybrominated diphenyl ethers (PBDEs) has been gradually phased out and the application of alternative halogenated flame retardants (AHFRs) has been continuously increased. It is essential to understand how the evolving flame retardants industry has affected the occurrence and flux of legacy and alternative flame retardants so that better pollution control measures can be made accordingly. Air, rainwater, inflowing river water, pond water, pond sediment, fish feed, and fish collected from freshwater cultured fish ponds (FWCFPs) within the Pearl River Delta, South China were analyzed for PBDEs and AHFRs. Concentrations of AHFRs in air (range; median: 7.8-870; 210 pg m^-3), rainwater (0.88-65; 4.8 ng L^-1), and sediment (19-120; 54 ng g^-1 dry weight (d.w.)) were one order of magnitude higher than those of PBDEs in air (12-98; 21 pg m^-3), rainwater (0.18-15; 0.70 ng L^-1), and sediment (1.5-9.6, 2.9 ng g^-1 d.w.) (t-test; p < 0.05). Decabromodiphenyl ether and decabromodiphenylethane were the predominant BDE and AHFR components, respectively, agreeing well with the production and usage patterns of flame retardants in China. The average input fluxes of AHFRs to the FWCFPs via dry deposition, wet deposition, net air-water exchange, and feeding (38.6, 20.6, and 2.14, μg m^-2 yr^-1) were one order of magnitude higher than those of PBDEs (3.44, 5.17, and -10.1, μg m^-2 yr^-1). Elevated occurrence and input fluxes of AHFRs suggested that aquaculture production is potentially facing a new challenge from alternative flame retardants. Atmospheric dry and wet deposition are important input sources of AHFRs to the FWCFPs. Feeding is an important input pathway for both PBDEs and AHFRs. Pollution control measures should be modified to accommodate the evolving flame retardants industry.

Accumulation and influencing factors of novel brominated flame retardants in soil and vegetation from Fildes Peninsula, Antarctica

The concentrations and distributions of nine novel brominated flame retardants (NBFRs) were analyzed in soil, lichen (Usnea aurantiaco-atra), and moss (Sanionia uncinata) samples collected from the Chinese Antarctic Great Wall Station and surrounding Fildes Peninsula area in west Antarctica. Total NBFR concentrations ranged from 61.2-225 pg/g dry weight (dw) in soil, 283-1065 pg/g dw in moss, and 135-401 pg/g dw in lichen, respectively. Decabromodiphenyl ethane (DBDPE) was the dominant NBFR in all samples, accounting for 65.2%, 50.1%, and 72.4% of cumulative NBFR concentration in soil, moss, and lichen, respectively. The concentrations of NBFRs in plant samples were higher than those in soil, which may be related to plant bioaccumulation. Significant log/log-linear correlations (p < 0.05) were found between the concentrations of BEHTEBP and total organic carbon (TOC) in soil, and between DBDPE and lipid content in mosses, indicating that TOC and lipid content potentially affect certain NBFRs in Antarctic soil and moss. This study presents the first report on NBFR contamination in soil and various vegetation in Antarctica.

First report on polybrominated diphenyl ethers in the Iranian Coral Islands: Concentrations, profiles, source apportionment, and ecological risk assessment

Coral reefs are challenged by multiple stressors due to the growing industrialization. Despite that, data on their environment are still scarce, and no research is yet performed on polybrominated diphenyl ethers in the Persian Gulf area. Seeking to fill in this gap, the present study aims to determine spatio-vertical distributions, source apportionment and ecological risk of polybrominated diphenyl ethers in the sediment cores and seawater samples from ten coral reef Islands in the Persian Gulf, Iran. Σ₁₂PBDEs concentrations ranged from 0.42 ± 0.04 to 47.14 ± 1.35 ng g^-1 dw in sediments, and from 1.17 ± 0.06 to 7.21 ± 1.13 ng L^-1 in seawater. The vertical polybrominated diphenyl ethers distribution varied significantly among the sampling stations and different depths with a decreasing trend towards the surface and peaks around 12-20 cm. Both in the seawater and sediment samples, elevated polybrominated diphenyl ethers loadings were observed in highly industrialized areas. Deca-bromodiphenyl ether-209 was the predominant congener along the sediment cores, whereas Tetra-bromodiphenyl ether-47 and Penta-bromodiphenyl ether-100 dominated in seawater samples. Commercial Deca-bromodiphenyl ether mixture was found to be the major source of polybrominated diphenyl ethers. Penta-bromodiphenyl ether was revealed to be the major ecological risk driver in the study area: it posed medium to high-risk quotient to sediment dwelling organisms. This study indicated that coral reefs are playing an important role in retaining polybrominated diphenyl ethers and highlighted the need to manage polybrominated diphenyl ethers contamination in the coral reef environment.

Spatial Distribution of Novel and Legacy Brominated Flame Retardants in Soils Surrounding Two Australian Electronic Waste Recycling Facilities

Informal recycling of electronic waste (e-waste) has been shown to cause significant brominated flame retardant (BFR) contamination of surrounding soils in a number of Asian and West African countries. However, to the authors' knowledge, there have been no published studies demonstrating polybrominated diphenyl ether (PBDE) and novel brominated flame retardant (NBFR) soil contamination from regulated "formal" e-waste processing facilities in developed countries. This study reports on PBDEs (-28, -47, -99, -100, -153, -154, -183, and -209) and NBFRs (PBT, PBEB, HBB, EH-TBB, BTBPE and DBDPE) in 36 soil samples surrounding two Australian e-waste recycling plants and a further eight reference soils. Overall ∑PBDE concentrations ranged 0.10-98 000 ng/g dw (median; 92 ng/g dw) and ∑NBFRs ranged ND-37 000 ng/g dw (median 2.0 ng/g dw). Concentrations in soils were found to be significantly negatively associated with distance from one of the e-waste facilities for ∑penta-BDEs, BDE-183, BDE-209, and ∑NBFR compound groups. ANOVA tests further illustrated the potential for e-waste recycling to significantly elevate concentrations of some BFRs in soils over distances up to 900 m compared to references sites. This study provides the first evidence of soil contamination with PBDEs and NBFRs originating from formal e-waste recycling facilities in Australia, which may have implications for e-waste recycling practices throughout the world.

Critical review of soil contamination by polybrominated diphenyl ethers (PBDEs) and novel brominated flame retardants (NBFRs); concentrations, sources and congener profiles

Polybrominated diphenyl ethers (PBDEs) have been used in a broad array of polymeric materials such as plastics, foams, resins and adhesives to inhibit the spread of fires since the 1970s. The widespread environmental contamination and well documented toxic effects of PBDEs have led to bans and voluntary withdrawals in many jurisdictions. Replacement novel brominated flame retardants (NBFRs) have, however, exhibited many of the same toxic characteristics as PBDEs and appear to share similar environmental fate. This paper presents a critical review of the scientific literature regarding PBDE and NBFR contamination of surface soils internationally, with the secondary objective of identifying probable pollution sources. An evaluation of NBFR distribution in soil was also conducted to assess the suitability of the newer compounds as replacements for PBDEs, with respect to their land contamination potential. Principle production of PBDEs and NBFRs and their consequent use in secondary polymer manufacture appear to be processes with strong potential to contaminate surrounding soils. Evidence suggests that PBDEs and NBFRs are also released from flame retarded products during disposal via landfill, dumping, incineration and recycling. While the land application of sewage sludge represents another major pathway of soil contamination it is not considered in this review as it is extensively covered elsewhere. Both PBDEs and NBFRs were commonly detected at background locations including Antarctica and northern polar regions. PBDE congener profiles in soil were broadly representative of the major constituents in Penta-, Octa- and Deca-BDE commercial mixtures and related to predicted market place demand. BDE-209 dominated soil profiles, followed by BDE-99 and BDE-47. Although further research is required to gain baseline data on NBFRs in soil, the current state of scientific literature suggests that NBFRs pose a similar risk to land contamination as PBDEs.

Atmospheric bulk deposition of polycyclic aromatic hydrocarbons in Shanghai: Temporal and spatial variation, and global comparison

Atmospheric deposition leads to accumulation of atmospheric polycyclic aromatic hydrocarbons (PAHs) on urban surfaces and topsoils. To capture the inherent variability of atmospheric deposition of PAHs in Shanghai's urban agglomeration, 85 atmospheric bulk deposition samples and 7 surface soil samples were collected from seven sampling locations during 2012-2014. Total fluxes of 17 PAHs were 587-32,300 ng m^-2 day^-1, with a geometric mean of 2600 ng m^-2 day^-1. The deposition fluxes were categorized as moderate to high on a global scale. Phenanthrene, fluoranthene and pyrene were major contributors. The spatial distribution of deposition fluxes revealed the influence of urbanization/industrialization and the relevance of local emissions. Meteorological conditions and more heating demand in cold season lead to a significant increase of deposition rates. Atmospheric deposition is the principal pathway of PAHs input to topsoils and the annual deposition load in Shanghai amounts to ∼4.5 tons (0.7 kg km^-2) with a range of 2.5-10 tons (0.4-1.6 kg km^-2).

Spatial variation of PAHs and PCBs in coastal air, seawater, and sediments in a heavily industrialized region

Concurrent coastal seawater (n = 22), sediment (n = 22), and atmospheric samples (n = 10) were collected in the Aliaga industrial region, Turkey, to explore the spatial variation, sources, and air-seawater exchange of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). Seawater Σ₁₆PAH concentrations (particle + dissolved) ranged between 5107 and 294,624 pg L^-1, while Σ₄₁PCB concentrations were in the range of 880-50,829 pg L^-1. Levels in sediments were highly variable ranging between 35.5-49,682 and 2.7-2450 μg kg^-1 in dry weight for Σ₁₆PAHs and Σ₄₁PCBs, respectively. Atmospheric concentrations varied between 1791-274,974 and 104-20,083 pg m^-3 for Σ₁₆PAHs and Σ₄₁PCBs, respectively. Sediment organic matter (OM) content and levels of Σ₁₆PAHs and Σ₄₁PCBs correlated weakly (r ² = 0.19-0.23, p < 0.05) suggesting that the spatial variations of PAHs and PCBs were mainly affected by local sources rather than their sorption to OM. The geographical distribution of PAH and PCB concentrations in air, seawater, and sediment and factor analysis on the sediment levels pointed out that the major sources in the region are steel plants, petroleum refinery, petrochemical complex, ship breaking, loading/unloading activities at the ports, vehicular emissions, and fossil fuel combustion emissions. The direction of the air-seawater exchange was also explored by estimating seawater fugacity fractions of PAHs and PCBs. For PAHs, the number of cases implying deposition (43.0%) and volatilization (39.5%) was similar, while for PCBs, the number of cases implying volatilization (60.4%) was much higher compared to deposition (21.6%). Fugacity fractions were generally <0.36 (deposition) at the sites close to industrial and ship breaking activities where the highest seawater and sediment levels were measured, implying that atmospheric deposition is an important mechanism affecting seawater and sediment PAH and PCB levels.

Historical records and sources of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in sediment from a representative plateau lake, China

The PAH and OCP concentrations in sediment cores collected from a deep lake were measured and evaluated chronologically. The results indicated that the PAH and OCP concentrations significantly increased from the 1950s to the 1990s and subsequently decreased to recent years. Integrated molecular diagnostic ratios indicated that the predominant petrogenic sources occurred from the 1950s-1980s. Petroleum and fuel combustion dominated the source of contamination more recently as a result of energy structure changes in this region. Additionally, HCHs and DDTs were the dominant OCP compounds, making up a majority of the total OCPs present (>85%). HCHs accounted for a larger ratio of the OCPs between the 1950s and 1980s, suggesting that HCHs were the dominant POPs in this period. DDTs then became dominant in the 1980s and later. High α/γ-HCH ratios suggested that the emission and conversion of local technical HCHs were the predominant HCHs source. The ratios of (DDE + p,p'-DDD)/DDTs and p,p'-DDT/DDTs indicated that the DDTs mainly originated from historical input. In addition, the dramatic decrease since the 1980s may be the result of China's banning of DDTs. However, DDTs were still present in the 1990s, suggesting DDTs were still used in this region and beyond.

Simulations of graphitic nanoparticles at air-water interfaces

The free energy associated with transferring a set of fullerene particles through a finite water layer is calculated using explicit solvent molecular dynamic simulations. Each fullerene particle is a carbon network of one or more spheroidal shells of graphitic carbon, and include single-shell (single-wall) or nested multi-shelled (nano-onions) structures ranging from 6 to 28 Å in radius. Corresponding changes in energy suggest a stronger affinity of carbon nano-onions for water compared to their single-shelled analogues. In the case of multi-shelled structures, the free energy profiles display a global minimum only in the bulk liquid indicating a high affinity of multi-shelled fullerene for complete hydration. Single-wall particles however, display a minimum at the air-water interface and for particles larger than 2 nm this minimum is a global minimum possessing a lower energy compared to the particle's state of complete hydration. While the propensity for single-shell particles to adsorb to the air-interface may increase with increasing particle size, there is an indication based on line tension calculations that larger single-shell particles may actually exhibit enhanced wetting compared to their smaller analogues.

Risk assessment of PBDEs and PAHs in house dust in Kocaeli, Turkey: levels and sources

Indoor dust samples were collected from 40 homes in Kocaeli, Turkey and were analyzed simultaneously for 14 polybrominated diphenyl ethers (PBDEs) and 16 poly aromatic hydrocarbons (PAHs) isomers. The total concentrations of PBDEs (Σ₁₄PBDEs) ranged from 29.32 to 4790 ng g^-1, with a median of 316.1 ng g^-1, while the total indoor dust concentrations of 16 PAHs (Σ₁₆PAHs) extending over three to four orders of magnitude ranged from 85.91 to 40,359 ng g^-1 with a median value of 2489 ng g^-1. Although deca-PBDE products (BDE-209) were the principal source of PBDEs contamination in the homes (median, 138.3 ng g^-1), the correlation in the homes was indicative of similar sources for both the commercial penta and deca-PBDE formulas. The PAHs diagnostic ratios indicated that the main sources of PAHs measured in the indoor samples could be coal/biomass combustion, smoking, and cooking emissions. For children and adults, the contributions to ∑₁₄PBDEs exposure were approximately 93 and 25 % for the ingestion of indoor dust, and 7 and 75 % for dermal contact. Exposure to ∑₁₆PAHs through dermal contact was the dominant route for both children (90.6 %) and adults (99.7 %). For both groups, exposure by way of inhalation of indoor dust contaminated with PBDEs and PAHs was negligible. The hazard index (HI) values for BDE-47, BDE-99, BDE-153, and BDE-209 were lower than the safe limit of 1, and this result suggested that none of the population groups would be likely to experience potential health risk due to exposure to PBDEs from indoor dust in the study area. Considering only ingestion + dermal contact, the carcinogenic risk levels of both B2 PAHs and BDE-209 for adults were 6.2 × 10^-5 in the US EPA safe limit range while those for children were 5.6 × 10^-4 and slightly higher than the US EPA safe limit range (1 × 10^-6 and 1 × 10^-4). Certain precautions should be considered for children.