Seasonal variation, sources, and gas/particle concentrations of PCBs and OCPs at high altitude suburban site in Western Black Sea Region of Turkey

Air monitoring of organochlorine pesticides (OCPs) in Bursa Türkiye: Levels, temporal trends and risk assessment

Monitoring concentration levels of persistent organic pollutants (POPs) is required to evaluate the effectiveness of international regulations to minimize the emissions of persistent organic pollutants (POPs) into the environment. In this manner, we evaluated the spatial and temporal variations of 22 organochlorine pesticides (OCPs) using polyurethane foam passive air samplers at ten stations in Bursa in 2017 and 2018. The highest concentration value for Σ22OCPs was detected in Ağaköy (775 pg/m3) and Demirtaş (678 pg/m3) sampling sites, while the lowest value was observed in Uludağ University Campus (UUC, 284 pg/m3) site. HCB, γ-HCH, Endo I, and Mirex were the most frequently detected OCPs, which shows their persistence. Diagnostic ratios of β-/(α + γ)-HCH have pointed to historical and possible illegal OCP usage in the study area. The seasonality of air concentrations (with spring and summer concentrations higher than winter and autumn concentrations) was well exhibited by α-HCH, β-HCH, ɣ-HCH, HCB, Endo I, and Mirex but not aldrin, dieldrin, and α-chlordane (CC). Levels of OCPs detected in ambient air in the current study were relatively similar to or lower than those reported in previous studies conducted in Türkiye. Back trajectory analysis was applied to identify the possible sources of OCPs detected in the sampling regions. The Clausius-Clapeyron approach was used to investigate the temperature dependence of OCP gas-phase atmospheric concentrations. The data showed that long-range atmospheric transport affects ambient air OCP concentrations in the study area.

The effect of military conflict zone in the Middle East on atmospheric persistent organic pollutant contamination in its north

This study aimed to investigate long-range atmospheric transport of selected POPs released due to the effects of military conflicts in regions to the south of Turkey's borders. Ten locations were selected to deploy passive air samplers at varying distances to the border on a southeast-west transect of the country, proximity-grouped as close, middle, and far. Sampling campaign included winter and transition months when desert dust transport events occur. Hypothesis of the study was that a decreasing trend would be observed with increasing distance to the border. Group comparisons based on statistical testing showed that PBDE-183, Σ₄₅PCB, and dieldrin in winter; PBDE-28, PBDE-99, PBDE-154, p,p'-DDE, Σ₁₄PBDE, and Σ₂₅OCP in the transition period; and PBDE-28, PBDE-85, PBDE-99, PBDE-154, PBDE-190, PCB-52, Σ₄₅PCB, p,p'-DDE, and Σ₂₅OCP over the whole campaign had a decreasing trend on the transect. An analysis of concentration ratio to the background showed that long-range atmospheric transport impacted the study sites, especially those of close group in comparison to the local sources. Back-trajectory analyses indicated that there was transport from the conflict areas to sites in the close-proximity group, while farther sampling locations mostly received air masses from Europe, Russia, and former Soviet Union countries, followed by North Africa, rather than the military conflict areas. In consequence, decrease in concentrations with distance and its relation to molecular weight through proportions, diagnostic ratios, analysis of concentration ratio to the background, and back-trajectory analyses support the effect of transport from the military-conflict area to its north.

Evidence of stockpile contamination for legacy polychlorinated biphenyls and organochlorine pesticides in the urban environment of Cyprus (Eastern Mediterranean): Influence of meteorology on air level variability and gas/particle partitioning based on equilibrium and steady-state models

The present study investigated comprehensively the atmospheric occurrence and fate of an extensive range of polychlorinated biphenyls (PCBs; forty-two congeners), organochlorine pesticides (OCPs; twenty-seven emerging and legacy agrochemicals) and polycyclic aromatic hydrocarbons (PAHs; fifty parent and alkylated members, including the non USEPA-16 listed toxic ones), in both gas and particulate phase of the scarcely monitored atmosphere over Cyprus for the first time. Parent-metabolite concentration ratios suggested fresh application for dichlorodiphenyl-trichloroethanes (DDTs), dicofol, hexachlorocyclohexanes, endosulfan and chlorothalonil, particularly during spring (April-May). Regressions of logarithms of partial pressure against ambient temperature revealed that secondary recycling from contaminated terrestrial surfaces regulates the atmospheric level variability of PCBs, DDTs, aldrin, chlordane, dicofol, heptachlor and endosulfan. Enthalpies of surface-air exchange (∆H_SA) calculated from Clausius-Clapeyron equations were significantly correlated to vaporization enthalpies (∆H_V) determined by chromatographic techniques, corroborating presence of potential stockpile-contaminated sites around the study area. The Harner-Bidleman equilibrium model simulating urban areas, and the Li-Jia empirical model, predicted better the partitioning behavior of PAHs (<four-ring parent and alkylated members), PCBs (<hexa-chlorobiphenyls), and OCPs, respectively. For heavier PAHs and PCBs, partitioning coefficients (K_P) were inadequately predicted by the Li-Ma-Yang steady-state model, probably due to local human activities and regional transport in the study area.

Selected Persistent Organic Pollutants in Ambient Air in Turkey: Regional Sources and Controlling Factors

As a result of its unique location, Turkey receives air masses from Europe, Russia, Middle East, and Africa, making it an important place in terms of long-range atmospheric transport (LRT) of contaminants. Atmospheric levels of 22 organochlorine pesticides (OCPs), 45 polychlorinated biphenyls (PCBs), and 14 polybrominated diphenyl ethers (PBDEs) were measured in two metropolitan cities, Istanbul and Izmir, on a weekly basis from May 2014 to May 2015. Dichlorodiphenyltrichloroethane (DDT) and its derivatives were dominant OCP species, followed by isomers of hexachlorocyclohexane (HCH) at both sites. The annual mean concentration of ∑DDX (sum of o,p'-DDT, p,p'-DDT, o,p'-DDD, p,p'-DDD, o,p'-DDE, and p,p'-DDE) was 82 pg/m³ for Istanbul and 89 pg/m³ for Izmir, while these levels were about 46 pg/m³ for ∑HCHs (sum of α-, β-, γ-, and δ-HCH) at both of the sites. At both stations, tri- and tetra-PCBs and tetra- and penta-PBDEs were dominant congeners. The temperature dependence indicates that both LRT and local contaminated areas contribute to the elevated levels. A Lagrangian particle dispersion model (FLEXPART) showed a few potential source regions in northern Africa and Middle East, southern-southwestern and eastern Europe including Russia, as well as from local domestic metropolitan areas.

Atmospheric polychlorinated biphenyls in a non-metropolitan city in northern India: Levels, seasonality and sources

Recent studies from India reported polychlorinated biphenyls (PCBs) associated with incomplete combustion processes. In this study we have monitored atmospheric PCBs in Agra, a non-metropolitan city of northern India. During first month of summer and winter of 2017, polyurethane foam based passive air sampler (PUF-PAS) was deployed at each of 14 locations across urban, suburban and rural transects and one background site. Range of Σ₂₅PCBs varied between 25 and 1433 pg/m³ (Avg ± Stdev: 460 ± 461) in summer and 26-205 pg/m³ (Avg ± Stdev: 106 ± 59) in winter. Mean Σ₂₅PCBs concentration, showed an urban > suburban > rural trend in summer while, in winter a rural > urban > suburban trend was observed. PCB-52 was the dominant congener and after excluding this congener no significant difference was observed between summer and winter PCB concentrations. Using a combination of K-means cluster and principal component analysis (PCA) four major source types were identified. Open burning source accorded 80% of atmospheric PCBs, majorly indicator PCBs while the remaining 20% was contributed by atmospheric transport, petrogenic combustion and biomass burning. From the ten days back trajectory of the air mass it can be suggested that atmospheric transport from the hotspots resulted in a minor percentage of dioxin like PCBs in Agra. Maximum TEQs was accorded by PCB-77 (30%) and it is consistent with previous observations from Agra. Levels observed in the current study are well within the public health guideline based on inhalation unit risk (10 ng/m³) and United States Environmental Protection Agency's regional screening level high risk tier (4.9 ng/m³) for ambient air.

Quantitative analyses of selected polychlorinated biphenyl (PCB) congeners in water, soil, and sediment during winter and spring seasons from Msunduzi River, South Africa

The lack of information and the need for knowledge on the organic pollutants within the area of KwaZulu-Natal together with the global problem of water supply have prompted our investigation into the analyses of eight polychlorinated biphenyl (PCB) congeners in the Msunduzi River of KwaZulu-Natal, South Africa. Soil, sediment, and water samples were collected at ten different sites along the river during winter and spring seasons. Soil and sediment samples were extracted using ultra sonication with dichloromethane while water samples were liquid-liquid extracted using dichloromethane. All sample extracts were cleaned-up using a multi-layer silica gel column and analyzed with gas chromatography-mass spectrometry. Quality assurance measures were also determined. The percentage recoveries for water were 53-128 for all the PCBs analyzed, while sediment recoveries ranged between 69 and 105%. The highest total concentrations of the PCBs in sediment were 214.21-610.45 ng/g dw at the Du Toit sampling site and 30.86-444.43 ng/g dw basis at the wastewater treatment inlet for winter and spring, respectively. Soil PCB concentrations were 76.53-397.75 ng/g dw at the Msunduzi Town sampling site and 20.84-443.49 ng/g (dry weight) at the Du Toit sampling site for winter and spring, respectively. In addition, high PCB concentrations were found in effluent of the wastewater treatment inlet compared to other sampling sites, which ranged between 0.68-22.37 and 2.53-35.69 ng/mL for winter and spring seasons, respectively. In all the sampling sites selected for this study, Du Toit afforded the highest PCB concentration levels and the lowest was after chlorination at the Darvill wastewater treatment plant. The results presented are new and it is the first study of organic pollutants such as PCBs that has been carried out on this river.

Effects of sampling interval on the passive air sampling of atmospheric PCBs levels

In this study, we collected Polychlorinated biphenyls (PCBs) using passive air samplers (PASs), between February 4, 2013 and February 2, 2014, with the sampling periods ranging from 10 to 60 days. The samples were collected with PASs that contained polyurethane foam (PUF). With these samples, 87 PCB congeners were analyzed. Sampling coefficient (R) values for the four seasons were calculated using both the high volume air sampler (HVAS) and PAS samples collected with the same time interval. The average of the annual concentrations of 87 PCB congeners, calculated using the R values specific to this study, was 234 ± 175 pg/m³. PCB congeners with 3- and 4- chlorines were dominant. The samples were collected at the same time interval but at different times to represent accumulation in the PASs. The linear regression coefficients (r) of the PCB mass accumulated in PASs against time ranged from 0.89 and 0.97 indicating that accumulation was linear. Moreover, the concentrations of the PCB congeners were statistically correlated with atmospheric conditions.

Particle size distribution and gas-particle partitioning of polychlorinated biphenyls in the atmosphere in Beijing, China

Size-fractionated samples of urban particulate matter (PM; ≤1.0, 1.0-2.5, 2.5-10, and >10 μm) and gaseous samples were simultaneously obtained to study the distribution of polychlorinated biphenyls (PCBs) in the atmosphere in Beijing, China. Most recent investigations focused on the analysis of gaseous PCBs, and much less attention has been paid to the occurrence of PCBs among different PM fractions. In the present study, the gas-particle partitioning and size-specific distribution of PCBs in atmosphere were investigated. The total concentrations (gas + particle phase fractions) of Σ₁₂ dioxin-like PCBs, Σ₇ indicator PCBs, and ΣPCBs were 1.68, 42.1, and 345 pg/m³, respectively. PCBs were predominantly in the gas phase (86.8-99.0 % of the total concentrations). The gas-particle partition coefficients (K _p ) of PCBs were found to be a significant linear correlated with the subcooled liquid vapor pressures (P _L⁰) (R ² = 0.83, P < 0.01). The slope (m _r ) implied that the gas-particle partitioning of PCBs was affected both by the mechanisms of adsorption and absorption. In addition, the concentrations of PCBs increased as the particle size decreased (>10, 2.5-10, 1.0-2.5, and ≤1.0 μm), with most of the PCBs contained in the fraction of ≤1.0 μm (53.4 % of the total particulate concentrations). Tetra-CBs were the main homolog in the air samples in the gas phase and PM fractions, followed by tri-CBs. This work will contribute to the knowledge of PCBs among different PM fractions and fill the gap of the size distribution of particle-bound dioxin-like PCBs in the air.

POPs in a major conurbation in Turkey: ambient air concentrations, seasonal variation, inhalation and dermal exposure, and associated carcinogenic risks

Semi-volatile organic compounds were monitored over a whole year, by collection of gas and particle phases every sixth day at a suburban site in Izmir, Turkey. Annual mean concentrations of 32 polychlorinated biphenyls (∑₃₂PCBs) and 14 polycyclic aromatic hydrocarbons (∑₁₄PAHs) were 348 pg/m³ and 36 ng/m³, respectively, while it was 273 pg/m³ for endosulfan, the dominant compound among 23 organochlorine pesticides (OCPs). Monte Carlo simulation was applied to the USEPA exposure-risk models for the estimation of the population exposure and carcinogenic risk probability distributions for heating and non-heating periods. The estimated population risks associated with dermal contact and inhalation routes to ∑₃₂PCBs, ∑₁₄PAHs, and some of the targeted OCPs (α-hexachlorocyclohexane (α-HCH), β-hexachlorocyclohexane (β-HCH), heptachlor, heptachlor epoxide, α-chlordane (α-CHL), γ-chlordane (γ-CHL), and p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT)) were in the ranges of 1.86 × 10^-16-7.29 × 10^-9 and 1.38 × 10^-10-4.07 × 10^-6, respectively. The inhalation 95th percentile risks for ∑₃₂PCBs, ∑₁₄PAHs, and OCPs were about 6, 3, and 4-7 orders of magnitude higher than those of dermal route, respectively. The 95th percentile inhalation risk for ∑₃₂PCBs and OCPs in the non-heating period were 1.8- and 1.2-4.6 folds higher than in the heating period, respectively. In contrast, the 95th percentile risk levels for ∑₁₄PAHs in the heating period were 4.3 times greater than that of non-heating period for inhalation, respectively. While risk levels associated with exposure to PCBs and OCPs did not exceed the acceptable level of 1 × 10^-6, it was exceeded for 47 % of the population associated with inhalation of PAHs with a maximum value of about 4 × 10^-6.

Determination of Atmospheric PCB Level Variations in Continuously Collected Samples

Polychlorinated biphenyls (PCBs) were measured in ambient air samples (n = 48) that were collected for a 2- to 3-day period in each season (winter, spring, summer, fall) of 2013. The samples were collected on the Campus of Uludag University, which is in a semirural region. The samples were collected using a high-volume air sampler. The gas and particle phase concentrations of 87 PCB congeners (Σ87PCB) were measured in these samples. The average gas and particle phase concentrations of the Σ87PCB were calculated to be 293 ± 257 and 52 ± 56 ng/m(3), respectively. However, the results of short-term measurements showed that the variation among the measurements in the gas phase was up to 39-fold and up to 84-fold in the particle phase. These results demonstrated that the ambient air PCB concentrations were not stable and changed dramatically on a daily basis. Therefore, it was clear that a small number of samples could not be representative of the entire region. Furthermore, the obtained concentrations showed differences that depended on the meteorological conditions and long distance transportation. The sampling indicated that PCB homologues with 3 or 4 chlorines were dominant.

Evaluation of background soil and air polychlorinated biphenyl (PCB) concentrations on a hill at the outskirts of a metropolitan city

Air and soil sampling was conducted inside a forested area for 22 months. The sampling location is situated to the north of a metropolitan city. Average atmospheric gas and particle concentrations were found to be 180 and 28 pg m(-3) respectively, while that of soil phase was detected to be 3.2 ng g(-1) on dry matter, The congener pairs of PCB#4-10 had the highest contribution to each medium. TEQ concentration was 0.10 pg m(-3), 0.07 pg m(-3), 21.92 pg g(-1), for gas, particle and soil phases, respectively. PCB#126 and PCB#169 contributed to over 99% of the entire TEQ concentrations for each medium. Local sources were investigated by conditional probability function (CPF) and soil/air fugacity. Landfilling area and medical waste incinerator, located to the 8 km northeast, contributed to ambient concentrations, especially in terms of dioxin-like congeners. The industrial settlement (called Dilovasi being to the east southeast of 60 km distant) contributed from southeast direction. Further sources were identified by potential source contribution function (PSCF). Sources at close proximity had high contribution. Air mass transportation from Aliaga industrial region (being to the southwest of 300 km distant) moderately contributed to ambient concentrations. Low molecular weight congeners were released from soil body. 5-CBs and 6-CBs were close to equilibrium state between soil/air interfaces. PCB#171 was close to equilibrium and PCB#180 was likely to evaporate from soil, which constitute 7-CBs. PCB#199, representing 8-CBs deposited to soil. 9-CB (PCB#207) was in equilibrium between soil and air phases.

Gas-particle distributions, sources and health effects of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) in Venice aerosols

Air samples were collected in Venice during summer 2009 and 2012 to measure gas and particulate concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs). PCB-11, considered a marker for non-Aroclor contamination of the environment, was found for the first time in the Venetian lagoon and in Europe. An investigation on sources has been conducted, evidencing traffic as the major source of PAHs, whereas PCBs have a similar composition to Aroclor 1248 and 1254; in 2009 a release of PCN-42 has been hypothesized. Toxicological evaluation by TCA and TEQ methods, conducted for the first time in Venice air samples, identified BaP, PCB-126 and PCB-169 as the most important contributors to the total carcinogenic activity of PAHs and the total dioxin-like activity of PCBs and PCNs.

Ambient polychlorinated biphenyl levels and their evaluation in a metropolitan city

In this study, summer and autumn ambient PCB concentrations were investigated in metropolitan city of Istanbul. 84 congeners were targeted from di-CBs to nona-CBs on both particle and gaseous phases. Gaseous ambient concentrations were determined to be 372 ± 134 pg·m(-3), while on the particle phase this value was 49 ± 17 pg·m(-3), corresponding to an average of 420 pg·m(-3). About one-tenth of all PCBs lay in ambient aerosols, while 90% of all comprise 2-, 3-, 4-, and 5-CBs. Measured ambient concentrations of each congener group were tested against meteorological data. The di-CB concentrations were independent of ambient temperature while northerly winds lead to an increase in their concentrations, which was an indicator of considerable contribution to di-CB concentrations from the medical waste incineration plant in Istanbul. In contrast, other congeners' concentrations were found to be correlated with southerly winds. Being an inland sea and having been contaminated, for years, by industrial discharges along the coastline, volatilization from Marmara Sea was considered as the most probable source of other congeners. PSCF analysis was run with 12-hour trajectories to locate possible local sources and check these results. Gas/particle partitioning was applied using three different models. mr and br values for log PL(0) model were determined as -0.23 ± 0.09 and -3.25 ± 0.38, respectively. For absorption based log Koa model, m and b values were calculated as 0.23 ± 0.08 and -4.73 ± 0.83, respectively.

The influence of climate change on the global distribution and fate processes of anthropogenic persistent organic pollutants

The effect of climate change on the global distribution and fate of persistent organic pollutants (POPs) is of growing interest to both scientists and policy makers alike. The impact of warmer temperatures and the resulting changes to earth system processes on chemical fate are, however, unclear, although there are a growing number of studies that are beginning to examine these impacts and changes in a quantitative way. In this review, we examine broad areas where changes are occurring or are likely to occur with regard to the environmental cycling and fate of chemical contaminants. For this purpose we are examining scientific information from long-term monitoring data with particular emphasis on the Arctic, to show apparent changes in chemical patterns and behaviour. In addition, we examine evidence of changing chemical processes for a number of environmental compartments and indirect effects of climate change on contaminant emissions and behaviour. We also recommend areas of research to address knowledge gaps. In general, our findings indicate that the indirect consequences of climate change (i.e. shifts in agriculture, resource exploitation opportunities, etc.) will have a more marked impact on contaminants distribution and fate than direct climate change.