Time trends of persistent organic pollutants in spanish air

Occurrence and exposure risk assessment of organochlorine pesticides in two waterbird species from Honghu Lake Wetland, Central China

Monitoring and evaluating bird exposure to hazardous pollutants in wetlands are receiving considerable attention. In this study, the occurrence of 18 organochlorine pesticides (OCPs) in the muscle of bean geese (Anser fabalis) and common teals (Anas crecca) collected from Honghu Lake Wetland (HLW), Central China was studied. Additionally, an exposure risk assessment model was applied to obtain risk levels of OCPs to these birds through three oral routes (food intake, water drinking and soil ingestion). The results suggested that the most abundant OCPs detected in the muscle of waterbirds were DDTs (7.68-602 ng/g lipid weight), followed by HCHs (1.39-89.8 ng/g lipid weight). A significant difference (p < 0.05) existed between two species, but most of OCPs exhibited no statistically relationship with age or gender (p > 0.05). The compositional patterns of OCPs combined with ratios of certain metabolites to their parent compounds indicated that all OCPs in the HLW were largely from historical usage except heptachlor. The exposure risk assessment revealed that common teals with lighter weight had greater exposure risks than bean geese. Of the OCPs analyzed, DDTs could probably cause harm to target birds studied here. Exposure via food intake was identified to be significant while soil ingestion and water drinking contributed least, but they should still be concerned.

Application of Deconica castanella ligninolytic enzymatic system in the degradation of hexachlorobenzene in soil

Hexachlorobenzene (HCB) is a pollutant still found in the environment despite being widely banned. Considering that basidiomycetes are useful to degrade a variety of organochlorinated pollutants, we therefore report the influence of HCB on the ligninolytic enzymatic system of Deconica castanella. The inoculum was prepared with sugarcane bagasse and soybean flour and was added in soil with and without HCB (2000 mg kg soil^-1 ), 5% emulsion containing soybean oil and Tween 20 at proportion 9:1, v:v; with 70% moisture at 25°C. Fungal biomass was quantified by widely acknowledged growth biomarker ergosterol. The extraction of the enzymatic complex was performed and laccase, Mn-dependent peroxidase (MnP), and lignin peroxidase (LiP) activities were determined. Furthermore, HCB and its metabolites were quantified by gas chromatography and chlorides by potentiometric titration. Results evidenced that HCB did not interfere in fungal growth, though the only detected enzymatic activity was laccase. MnP and Lip were not detected during D. castanella growth in soil. The peak of laccase enzymatic activity occurred in the presence of HCB. In addition, the laccase exhibited thermostability. Therefore, we hereby shed light on the role of laccase in the degradation of HCB by an efficient low-cost and environmentally safe detoxification mechanism.

Levels and trends of perfluoroalkyl acids (PFAAs) in water (2013-2020) and fish from selected riverine basins in Spain

The aim of the present study was to assess the presence of perfluoroalkyl acids (PFAAs), namely perfluoroalkane sulfonates and perfluoroalkyl carboxylic acids, in Spanish river basins in order to: identify potential spatiotemporal variations; evaluate the effectiveness of the measures implemented for the reduction/elimination of these pollutants; verify the fulfillment of the Environmental Quality Standards (EQSs) in the European Union. PFOS and PFOA were determined in 116 water samples from four sites in the Duero basin, the largest in the Iberian Peninsula, collected seasonally from 2013 to 2020. In addition, 30 fish sample composites from the sample banks of Duero, Tagus, Ebro, Eastern Cantabrian and Catalonian basins were analyzed for 15 PFAAs. Median PFOS and PFOA concentrations were 0.72 and 0.42 ng/L, ranging from values below the limit of quantification (LOQ) to 81 and 22 ng/L, respectively. During the studied period, 51% of water samples were above the EQS of 0.65 ng/L for PFOS. In the case of fish, the PFOS range was <LOQ-59 with 33% of the samples above the EQS of 9.1 ng/g wet weight. Moreover, fish from the Tagus and Catalonian basins showed median concentrations above the EQS. Particularly, fish collected around highly populated areas such as Madrid and Barcelona showed the greatest PFAA concentrations. Overall, PFAA concentrations in water and fish increased significantly with population density suggesting urban areas as their main source. Although our results suggested decreasing tendencies for PFOS and PFOA in water, significant trends only could be confirmed at two sampling sites.

Main sources controlling atmospheric burdens of persistent organic pollutants on a national scale

National long-term monitoring programs on persistent organic pollutants (POPs) in background air have traditionally relied on active air sampling techniques. Due to limited spatial coverage of active air samplers, questions remain (i) whether active air sampler monitoring sites are representative for atmospheric burdens within the larger geographical area targeted by the monitoring programs, and thus (ii) if the main sources affecting POPs in background air across a nation are understood. The main objective of this study was to explore the utility of spatial and temporal trends in concert with multiple modelling approaches to understand the main sources affecting polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in background air across a nation. For this purpose, a comprehensive campaign was carried out in summer 2016, measuring POPs in background air across Norway using passive air sampling. Results were compared to a similar campaign in 2006 to assess possible changes over one decade. We furthermore used the Global EMEP Multi-media Modeling System (GLEMOS) and the Flexible Particle dispersion model (FLEXPART) to predict and evaluate the relative importance of primary emissions, secondary emissions, long-range atmospheric transport (LRAT) and national emissions in controlling atmospheric burdens of PCB-153 on a national scale. The concentrations in air of both PCBs and most of the targeted OCPs were generally low, with the exception of hexachlorobenzene (HCB). A limited spatial variability for all POPs in this study, together with predictions by both models, suggest that LRAT dominates atmospheric burdens across Norway. Model predictions by the GLEMOS model, as well as measured isomeric ratios, further suggest that LRAT of some POPs are dictated by secondary emissions. Our results illustrate the utility of combining observations and mechanistic modelling approaches to help identify the main factors affecting atmospheric burdens of POPs across a nation, which, in turn, may be used to inform both national monitoring and control strategies.

Atmospheric Occurrence of Organochlorine Pesticides and Inhalation Cancer Risk in Urban Areas at Southeast Brazil

Organochlorine pesticides (OCPs) have been produced for almost a century and some of them are still used, even after they have been proved to be toxic, persistent, bioaccumulative and prone to long-range transport. Brazil has used and produced pesticides in industrial scales for both agricultural and public health purposes. Urban and industrial regions are of special concern due to their high population density and their increased exposure to chemical pollution, many times enhanced by chemical production, application or irregular dumping. Therefore, we aimed to investigate the occurrence of OCPs in outdoor air of urban sites from two major regions of southeast Brazil. Some of these sites have been affected by OCP production and their irregular dumping. Deterministic and probabilistic inhalation cancer risk (CR) assessments were conducted for the human populations exposed to OCPs in ambient air. Ambient air was mainly affected by Ʃ-HCH (median = 340 pg m^-3) and Ʃ-DDT (median = 233 pg m^-3), the only two OCPs registered for domissanitary purposes in Brazil. OCP concentrations tended to be higher in summer than in winter. Dumping sites resulted in the highest OCP atmospheric concentrations and, thus, in the highest CR estimations. Despite of all limitations, probabilistic simulations suggested that people living in the studied regions are exposed to an increased risk of hepatic cancer. Infants and toddlers (0 < 2 y) were exposed to the highest inhalation CRs compared to other age groups. Other exposure pathways (such as ingestion and dermic uptake) are needed for a more comprehensive risk assessment. Moreover, this study also highlights the need to review the human exposure to OCPs through inhalation and their respective CR in other impacted areas worldwide, especially where high levels of OCPs are still being measured.

Unintentionally produced polychlorinated biphenyls in pigments: An updated review on their formation, emission sources, contamination status, and toxic effects

The formation, emission, environmental occurrence, and potential adverse effects of unintentionally produced polychlorinated biphenyls (PCBs) in pigments are reviewed, providing a comprehensive and up-to-date picture on these pollutants. PCBs are typically formed during manufacturing of organic pigments that involve chlorinated intermediates and reaction solvents, rather than those of inorganic pigments. Concentrations and profiles of PCBs vary greatly among pigment types and producers, with total PCB levels ranging from lower than detection limits to several hundred ppm; major components can be low-chlorinated (e.g., CB-11) or high-chlorinated congeners (e.g., CB-209). Pigment-derived PCBs can be released into the environment through different steps including pigment production, application, and disposal. They can contaminate atmospheric, terrestrial, and aquatic ecosystems, and then affect organisms living there. This situation garners scientific and public attention to nonlegacy emissions of PCBs and suggests the need for appropriate monitoring, management, and abatement strategies regarding these pollutants.

GAPS-megacities: A new global platform for investigating persistent organic pollutants and chemicals of emerging concern in urban air

A pilot study was initiated in 2018 under the Global Atmospheric Passive Sampling (GAPS) Network named GAPS-Megacities. This study included 20 megacities/major cities across the globe with the goal of better understanding and comparing ambient air levels of persistent organic pollutants and other chemicals of emerging concern, to which humans residing in large cities are exposed. The first results from the initial period of sampling are reported for 19 cities for several classes of flame retardants (FRs) including organophosphate esters (OPEs), polybrominated diphenyl ethers (PBDEs), and halogenated flame retardants (HFRs) including new flame retardants (NFRs), tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDD). The two cities, New York (USA) and London (UK) stood out with ∼3.5 to 30 times higher total FR concentrations as compared to other major cities, with total concentrations of OPEs of 15,100 and 14,100 pg/m³, respectively. Atmospheric concentrations of OPEs significantly dominated the FR profile at all sites, with total concentrations in air that were 2-5 orders of magnitude higher compared to other targeted chemical classes. A moderately strong and significant correlation (r = 0.625, p < 0.001) was observed for Gross Domestic Product index of the cities with total OPEs levels. Although large differences in FR levels were observed between some cities, when averaged across the five United Nations regions, the FR classes were more evenly distributed and varied by less than a factor of five. Results for Toronto, which is a 'reference city' for this study, agreed well with a more in-depth investigation of the level of FRs over different seasons and across eight sites representing different urban source sectors (e.g. traffic, industrial, residential and background). Future sampling periods under this project will investigate trace metals and other contaminant classes, linkages to toxicology, non-targeted analysis, and eventually temporal trends. The study provides a unique urban platform for evaluating global exposome.

Passive air sampling for semi-volatile organic chemicals

During passive air sampling, the amount of a chemical taken up in a sorbent from the air without the help of a pump is quantified and converted into an air concentration. In an equilibrium sampler, this conversion requires a thermodynamic parameter, the equilibrium sorption coefficient between gas-phase and sorbent. In a kinetic sampler, a time-averaged air concentration is obtained using a sampling rate, which is a kinetic parameter. Design requirements for kinetic and equilibrium sampling conflict with each other. The volatility of semi-volatile organic compounds (SVOCs) varies over five orders of magnitude, which implies that passive air samplers are inevitably kinetic samplers for less volatile SVOCs and equilibrium samplers for more volatile SVOCs. Therefore, most currently used passive sampler designs for SVOCs are a compromise that requires the consideration of both a thermodynamic and a kinetic parameter. Their quantitative interpretation depends on assumptions that are rarely fulfilled, and on input parameters, that are often only known with high uncertainty. Kinetic passive air sampling for SVOCs is also challenging because their typically very low atmospheric concentrations necessitate relatively high sampling rates that can only be achieved without the use of diffusive barriers. This in turn renders sampling rates dependent on wind conditions and therefore highly variable. Despite the overall high uncertainty arising from these challenges, passive air samplers for SVOCs have valuable roles to play in recording (i) spatial concentration variability at scales ranging from a few centimeters to tens of thousands of kilometers, (ii) long-term trends, (iii) air contamination in remote and inaccessible locations and (iv) indoor inhalation exposure. Going forward, thermal desorption of sorbents may lower the detection limits for some SVOCs to an extent that the use of diffusive barriers in the kinetic sampling of SVOCs becomes feasible, which is a prerequisite to decreasing the uncertainty of sampling rates. If the thermally stable sorbent additionally has a high sorptive capacity, it may be possible to design true kinetic samplers for most SVOCs. In the meantime, the passive air sampling community would benefit from being more transparent by rigorously quantifying and explicitly reporting uncertainty.

Organochlorine pesticides air monitoring near a historical lindane production site in Spain

The landfilling and dumping of persistent organic pollutants (POPs) and other persistent hazardous chemicals, such as hexachlorocyclohexane (HCH) isomers can have significantly adverse environmental consequences and cause contamination in soil, water, and atmosphere systems. Approximately 115,000 t of HCH wastes were generated by INQUINOSA Factory located in Sabiñánigo (Aragón, Spain) from 1975 to 1992, and were mainly dumped at Bailín and Sardas landfills. Under the frame of the project plan approved by the Government of Aragón, remediation and containment measures were implemented at the derelict production facility and landfill sites. To protect and assess the local environment, the concentrations of HCH isomers, pentachlorobenzene (PeCB) and hexachlorobenzene (HCB) in air were periodically monitored in the Sardas landfills and surroundings by passive sampling devices. The influence of meteorological parameters was evaluated, showing positive correlations between temperature and HCH and HCB concentrations. The highest HCH levels were detected in Sardas landfill and INQUINOSA Factory sites. PeCB values were statistically higher in Sardas landfill than in Sabiñánigo urban core, nevertheless, HCB concentrations were similar in both sampling points. Statistically positive correlations were found among HCH isomers in all sampling points, showing a major common source. The chlorobenzenes also correlated positively with each other. The α-/γ-HCH ratios were calculated (1.46 ± 1.25; mean ± S.D.), corroborating that concentrations detected were mainly originated from the historical production, storage and waste disposal of technical HCH.

Distribution, seasonal variation and inhalation risks of polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls and polybrominated diphenyl ethers in the atmosphere of Beijing, China

Spatial distribution, seasonal variation and potential inhalation risks of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were investigated in the atmosphere of Beijing, using passive air samplers equipped with polyurethane foam disks. Concentrations of ΣPCDD/Fs, ΣPCBs and ΣPBDEs ranged from 8.4 to 179 fg WHO₂₀₀₅-TEQ/m³, 38.6-139 and 1.5-176 pg/m³, respectively. PCDFs showed higher air concentrations than those of PCDDs, indicating the influence of industrial activities and other combustion processes. The non-Aroclor congener, PCB-11, was detected in air (12.3-99.4 pg/m³) and dominated the PCB congener profiles (61.7-71.5% to ∑PCBs). The congener patterns of PBDEs showed signatures from both penta-BDE and octa-BDE products. Levels of PCDD/Fs, PCBs and PBDEs at the industrial and residential sites were higher than those at rural site, indicating human activities in urban area as potential sources. Higher air concentrations of PCDD/Fs, PCBs and PBDEs were observed in summer, which could be associated with atmospheric deposition process, re-volatilization from soil surface and volatilization from use of technical products, respectively. Results of inhalation exposure and cancer risk showed that atmospheric PCDD/Fs, dioxin-like PCBs and PBDEs did not cause high risks to the local residents of Beijing. This study provides further aid in evaluating emission sources, influencing factors and potential inhalation risks of the persistent organic pollutants to human health in mega-cities of China.

Assessment of POPs in air from Spain using passive sampling from 2008 to 2015. Part II: Spatial and temporal observations of PCDD/Fs and dl-PCBs

Time series (2008-2015) of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in ambient air from the Spanish Monitoring Program were analyzed. A total of 321 samples were collected seasonally each year in 5 urban and 7 background sites by means of passive air sampling. Air concentrations were higher at urban than background sites (urban vs. background concentration ranges): PCDD/Fs (26.9-1010 vs. 20.0-357 fg/m³), non-ortho PCBs (0.113-3.14 vs. 0.042-2.00 pg/m³) and mono-ortho PCBs (0.644-41.3 vs. 0.500-32.8 pg/m³). Results showed significant decreases from 2009 for non-ortho PCBs and PCDD/Fs as well as for WHO₂₀₀₆-TEQs. These declines were sharper, and sometimes only significant, in urban places resulting in converging levels at urban and background sites for these pollutants at the end of the study period. In contrast, mono-ortho PCBs did not show any significant variation but a steady flat temporal behavior in their concentrations, suggesting the existence of different sources between mono-ortho and non-ortho PCBs. Seasonality was observed for air burdens of all these POPs. PCDD/Fs were mostly measured at higher concentrations in colder than in hot seasons, and the opposite was true for dl-PCBs. Seasonal variations for PCDD/Fs appeared to be related to changes in their sources (e.g. domestic heating, open burning) rather than to temperature per se. In contrast, environmental temperature dependent factors (e.g. increased partitioning into the gas phase) drove seasonal variations in dl-PCBs instead of seasonal changes in their sources. Regarding spatial patterns, significant greater levels of PCDD/Fs and dl-PCBs were generally found in cities compared to background areas, pointing out the role of densely populated areas as sources for these pollutants in Spain. As proven by our results, long-term monitoring activities are essential to assess and understand temporal behaviors for these POPs, as well as to evaluate the achievement of Stockholm Convention objectives.

Assessment of POPs in air from Spain using passive sampling from 2008 to 2015. Part I: Spatial and temporal observations of PBDEs

The Stockholm Convention (SC) on Persistent Organic Pollutants (POPs) calls for the Parties' effectiveness evaluation of those measures taken to meet the reduction and eventual elimination of POPs from the environment. With that goal, air concentrations of different POP families have been measured uninterruptedly since 2008 under the Spanish Monitoring Program (SMP) by means of passive air sampling. This work focuses on data for polybrominated diphenyl ethers (PBDEs) determined in a total of 321 samples collected seasonally each year in 5 urban and 7 background sites. Neither significant temporal trends nor significant seasonal variations for total PBDE air burdens were detected. In contrast, significant variations were found among PBDE congeners. Those related to the octa-PBDE formulation significantly decreased in the study period. However, PBDEs related to the penta-formulation showed steady concentrations while PBDE-209, the congener found at the greatest levels, showed increasing or steady levels in most sampling sites. Seasonal variations were also markedly different among congeners. Concentrations of the lightest PBDEs (tri- to penta-substituted) were highly influenced by ambient temperature (T), showing maximum values in summer probably due to higher volatilization rates compared to those of heavier PBDEs. Contrarily, no clear seasonal trends were found for hexa- to deca-PBDEs, which were negatively related to precipitation; thereby, indicating an efficient atmospheric wash out by wet deposition episodes. Regarding spatial patterns, overall significant greater PBDE levels were found in cities compared to background areas, pointing out the role of highly populated areas as sources for these pollutants in Spain. Yet and especially in the case of PBDE-209, our results suggested the presence of significant unknown sources of PBDEs in some background sites. Further monitoring efforts are needed to assess potential unknown sources in the sampling network as well as to ensure temporal trends of these pollutants in Spain.

Traditional and novel halogenated flame retardants in urban ambient air: Gas-particle partitioning, size distribution and health implications

Urban ambient air samples, including gas-phase (PUF), total suspended particulates (TSP), PM₁₀, PM_2.5 and PM₁ airborne particle fractions were collected to evaluate gas-particle partitioning and size particle distribution of traditional and novel halogenated flame retardants. Simultaneously, passive air samplers (PAS) were deployed in the same location. Analytes included 33 polybrominated diphenyl ether (PBDE), 2,2',4,4',5,5'-hexabromobiphenyl (BB-153), hexabromobenzene (HBB), pentabromoethylbenzene (PBEB), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), dechloranes (Dec 602, 603, 604, 605 or Dechorane plus (DP)) and chlordane plus (CP). Clausius-Clapeyron equation, gas-particle partition coefficient (K_p), fraction partitioned onto particles (φ) and human respiratory risk assessment were used to evaluate local or long-distance transport sources, gas-particle partitioning sorption mechanisms, and implications for health, respectively. PBDEs were the FR with the highest levels (13.9pgm^-3, median TSP+PUF), followed by DP (1.56pgm^-3), mirex (0.78pgm^-3), PBEB (0.05pgm^-3), and BB-153 (0.04pgm^-3). PBDE congener pattern in particulate matter was dominated by BDE-209, while the contribution of more volatile congeners, BDE-28, -47, -99, and -100 was higher in gas-phase. Congener contribution increases with particle size and bromination degree, being BDE-47 mostly bounded to particles≤PM₁, BDE-99 to > PM₁ and BDE-209 to > PM_2.5. No significant differences were found for PBDE and DP concentrations obtained with passive and active samplers, demonstrating the ability of the formers to collect particulate material. Deposition efficiencies and fluxes on inhaled PBDEs and DP in human respiratory tract were calculated. Contribution in respiratory track was dominated by head airway (2.16 and 0.26pgh^-1, for PBDE and DP), followed by tracheobronchial (0.12 and 0.02pgh^-1) and alveoli (0.01-0.002pgh^-1) regions. Finally, hazard quotient values on inhalation were proposed (6.3×10^-7 and 1.1×10^-8 for PBDEs and DP), reflecting a low cancer risk through inhalation.

Self-organizing maps for indications of airborne polychlorinated biphenyl (PCBs) and organochlorine pesticide (OCPs) dependence on spatial and meteorological parameters

This paper investigates the relation of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in air samples with meteorological parameters (temperature, atmospheric pressure and relative humidity) using the Kohonen self-organizing map (SOM). Both gas- and particle-adsorbed phase of 20 PCB congeners and 7 OCPs including the three new ones (α-HCH, β-HCH, and γ-HCH) listed in the Stockholm Convention were collected during a one-year period at urban locations in Zagreb (Croatia). Moving beyond existing studies, the SOM analysis showed that the meteorological characteristics of transient seasons such as spring had no influence on the dissimilarities in the behavior of PCBs and OCPs. Towards the identification of pollutant spatial patterns, the SOM did not isolate a clear phenomenon probably due to the absence of local pollution sources contributing to the elevated concentrations of these compounds. Overall, our results have shown that the SOM method, by recognizing significant differences among PCB and OCP seasonality, could be recommended in the analysis of pollutant distribution depending on temperature and atmospheric pressure.

Effects of room airflow on accurate determination of PUF-PAS sampling rates in the indoor environment

Accurate and precise interpretation of concentrations from polyurethane passive samplers (PUF-PAS) is important as more studies show elevated concentrations of PCBs and other semivolatile air toxics in indoor air of schools and homes. If sufficiently reliable, these samplers may be used to identify local sources and human health risks. Here we report indoor air sampling rates (Rs) for polychlorinated biphenyl congeners (PCBs) predicted for a frequently used double-dome and a half-dome PUF-PAS design. Both our experimentally calibrated (1.10 ± 0.23 m3 d-1) and modeled (1.08 ± 0.04 m3 d-1) Rs for the double-dome samplers compare well with literature reports for similar rooms. We determined that variability of wind speeds throughout the room significantly (P < 0.001) effected uptake rates. We examined this effect using computational fluid dynamics modeling and 3-D sonic anemometer measurements and found the airflow dynamics to have a significant but small impact on the precision of calculated airborne concentrations. The PUF-PAS concentration measurements were within 27% and 10% of the active sampling concentration measurements for the double-dome and half-dome designs, respectively. While the half-dome samplers produced more consistent concentration measurements, we find both designs to perform well indoors.

Gas/particle partitioning and particle size distribution of PCDD/Fs and PCBs in urban ambient air

Urban ambient air samples, including gas-phase (PUF), total suspended particulates (TSP), PM₁₀, PM_2.5 and PM₁ airborne particle fractions were collected to evaluate gas-particle partitioning and size particle distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs). Clausius-Clapeyron equation, regressions of logKp vs logP_L and logK_OA, and human respiratory risk assessment were used to evaluate local or long-distance transport sources, gas-particle partitioning sorption mechanisms, and implications for health. Total ambient air levels (gas phase+particulate phase) of TPCBs and TPCDD/Fs, were 437 and 0.07pgm^-3 (median), respectively. Levels of PCDD/F in the gas phase (0.004-0.14pgm^-3, range) were significantly (p<0.05) lower than those found in the particulate phase (0.02-0.34pgm^-3). The concentrations of PCDD/Fs were higher in winter. In contrast, PCBs were mainly associated to the gas phase, and displayed maximum levels in warm seasons, probably due to an increase in evaporation rates, supported by significant and strong positive dependence on temperature observed for several congeners. No significant differences in PCDD/Fs and PCBs concentrations were detected between the different particle size fractions considered (TSP, PM₁₀, PM_2.5 and PM₁), reflecting that these chemicals are mainly bounded to PM₁. The toxic content of samples was also evaluated. Total toxicity (PUF+TSP) attributable to dl-PCBs (13.4fg-TEQ₀₅ m^-3, median) was higher than those reported for PCDD/Fs (6.26fg-TEQ₀₅ m^-3). The inhalation risk assessment concluded that the inhalation of PCDD/Fs and dl-PCBs pose a low cancer risk in the studied area.

Long-term trends of atmospheric organochlorine pollutants and polycyclic aromatic hydrocarbons over the southeastern Tibetan Plateau

Long-term monitoring in remote regions is essential for revealing pollution trends at the global scale but relevant studies remain limited. In the present study, a six-year continuous monitoring of atmospheric persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) was carried out at Lulang in the southeastern Tibetan Plateau (TP). Average concentrations of hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), dichlorodiphenyltrichloroethanes (DDTs), polychlorinated biphenyls (PCBs) and PAHs were 13.5, 8.9, 41.7, 1.8pg/m³ and 6.2ng/m³, respectively. Obvious seasonality was found for all the target compounds. HCHs, DDTs and PCBs had their highest concentrations in summer (monsoon season) and lowest in winter, which is consistent with the fluctuation of the Indian monsoon. Meanwhile, HCB and 5-6-ring PAHs showed opposite variations, possibly induced by local sources and the westerly flow in winter. Declining trends were observed for most of the chemicals, except o,p'-DDE, HCB and PCBs. A declining trend in the α/γ-HCH ratio indicated a shift from technical HCHs to lindane. An increasing trend in the o,p'/p,p'-DDT ratio suggested a likely shift from technical DDTs to dicofol. For PAHs, the contribution from high-temperature combustion has increased recently. The half-lives of α-HCH, γ-HCH, o,p'-DDT, p,p'-DDT were 6.1, 108, 77.6 and 14.2years, respectively. The half-lives of γ-HCH, o,p'-DDT and p,p'-DDT were higher than those in the Arctic, indicating these compounds will persist in the TP for a longer period. The temporal trends in atmospheric POPs were possibly induced by emissions in India and likely driven by wind speed in Lulang. This study contributes toward a better understanding of the behavior and transport of POPs in the TP region.

Seasonal variations of PCDD/Fs congeners in air, soil and eggs from a Polish small-scale farm

The transfer of dioxin from the environment to the food is a problem in a consumers' health protection. The study aimed to determine the concentration of dioxins in free-range chicken eggs, air and soil samples, collected during 12 months on an individual small farm, located in Małopolska region, Poland. In the majority of analyzed eggs, the concentrations of dioxin exceeded several times the legal limit of 2.5 pg WHO-TEQ g-1fat. Seasonal changes in the PCDD/Fs congeners in egg, air and soil samples were studied. During the winter season, when the combustion processes of the solid fuel in domestic furnaces are intensive, the PM10 concentration in the Małopolska region exceeds the legal limit (50μg/m3) even eight times. In this period, eggs, air and soil samples showed a higher share of PCDFs with a specific contribution of 2,3,7,8-TCDF. During the summer months, in the egg, air and soil samples, the share of PCDDs is higher with dominant OCDD and 1,2,3,4,6,7,8-HpCDDs, showing the effect of other combustion processes such as grass utilization or burning plastic wastes in controlled fires. In August, the month of the highest average air temperature and lowest rainfall amount, the highest toxicity of PCDD/Fs in eggs (9.52pgWHO-TEQ g-1fat) was found. Due to the similarity of the shares of PCDD/Fs congeners in total WHO-TEQ value we can take into account the influence of toxicity of PCDD/Fs in the air and soil on the toxicity in the eggs.

Calibration and evaluation of PUF-PAS sampling rates across the Global Atmospheric Passive Sampling (GAPS) network

Passive air samplers equipped with polyurethane foam (PUF-PAS) are frequently used to measure persistent organic pollutants (POPs) in ambient air. Here we present and evaluate a method to determine sampling rates (R_S), and the effective sampling volume (V_eff), for gas-phase chemical compounds captured by a PUF-PAS sampler deployed anywhere in the world. The method uses a mathematical model that requires only publicly available hourly meteorological data, physical-chemical properties of the target compound, and the deployment dates. The predicted R_S is calibrated from sampling rates determined from 5 depuration compounds (¹³C PCB-9, ¹³C PCB-15, ¹³C PCB-32, PCB-30, and d₆-γ-HCH) injected in 82 samples from 24 sites deployed by the Global Atmospheric Passive Sampling (GAPS) network around the world. The dimensionless fitting parameter, gamma, was found to be constant at 0.267 when implementing the Integrated Surface Database (ISD) weather observations and 0.315 using the Modern Era Retrospective-Analysis for Research and Applications (MERRA) weather dataset. The model provided acceptable agreement between modelled and depuration determined sampling rates, with ¹³C PCB-9, ¹³C PCB-32, and d₆-γ-HCH having mean percent bias near zero (±6%) for both weather datasets (ISD and MERRA). The model provides inexpensive and reliable PUF-PAS gas-phase R_S and V_eff when depuration compounds produce unusual or suspect results and for sites where the use of depuration compounds is impractical, such as sites experiencing low average wind speeds, very cold temperatures, or remote locations.

New insight into the distribution pattern, levels, and risk diagnosis of FRs in indoor and outdoor air at low- and high-altitude zones of Pakistan: Implications for sources and exposure

Data regarding flame retardants (FRs) in indoor and outdoor air and their exposure to population are scarce and especially unknown in the case of Pakistan. The current study was designed to probe FR concentrations and distribution pattern in indoor and outdoor air at different altitudinal zones (DAZs) of Pakistan with special emphasis on their risk to the exposed population. In this study, passive air samplers for the purpose of FR deposition were deployed in indoor and outdoor air at the industrial, rural, and background/colder zones/sites. All the indoor and outdoor air samples collected from DAZs were analyzed for the target FRs (9.30-472.30 pg/m³), showing a decreasing trend as follows: ∑NBFRs > ∑PBDEs > ∑DP. However, significant correlations among FRs in the indoor and outdoor air at DAZs signified a similar source of FR origin that is used in different consumer goods. Furthermore, air mass trajectories revealed that movement of air over industrial area sources influenced concentrations of FRs at rural sites. The FR concentrations, estimated daily intake (EDI) and the hazard quotient (HQ), were recorded to be higher in toddlers than those in adults. In addition, indoor air samples showed higher FR levels, EDI and HQ, than outdoor air samples. An elevated FR concentrations and their prevalent exposure risks were recorded in the industrial zones followed by rural and background zones. The HQ for BDE-47 and BDE-99 in the indoor and outdoor air samples at different industrial and rural sites were recorded to be >1 in toddlers and adults, this further warrants a health risk in the population. However, FR investigation in indoor and outdoor air samples will provide a baseline data in Pakistan to take further steps by the government and agencies for its implementations.

Association between exposure to organochlorine compounds and maternal thyroid status: Role of the iodothyronine deiodinase 1 gene

INTRODUCTION

Exposure to organochlorine compounds (OCs) may interfere with thyroid hormone (TH) homeostasis. The disruption of the deiodinase (DIO) enzymes has been proposed as a mechanism of action.

AIM

To evaluate the association between exposure to OCs and TH status in pregnant women, as well as to explore the role of genetic variations in the DIO1 and DIO2 genes.

METHODS

The study population (n=1128) was composed of pregnant women who participated in the INMA Project (Spain, 2003-2006). Hexachlorobenzene (HCB), 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (4,4´-DDE), b-hexachlorocyclohexane (b-HCH), polychlorobiphenyl (PCB) congeners 138, 153 and 180, thyroid stimulating hormone (TSH), total triiodothyronine (TT3) and free thyroxine (FT4) were measured in serum samples taken during the first trimester of pregnancy (mean [standard deviation (SD)]: 13.5 [2] weeks of gestation). Polymorphisms in DIO1 (rs2235544) and DIO2 (rs12885300) were genotyped in maternal DNA. Sociodemographic and dietary characteristics were obtained by questionnaire.

RESULTS

A 2-fold increase in HCB was associated with lower TT3 (% change=-1.48; 95%CI: -2.36, -0.60). Women in the third tertile for b-HCH had lower TT3 (% change=-3.19; 95%CI: -5.64, -0.67). The interactions between DIO1 rs2235544 and PCB153 and b-HCH were statistically significant. The inverse association between PCB153 and TT3 was the strongest among women with AA genotype. Women with CC genotype presented the strongest inverse association between b-HCH and FT4.

CONCLUSION

Exposure to HCB and b-HCH was associated to a disruption in maternal TT3. The DIO1 rs2235544 SNP modified the association between exposure to some of the OCs (specifically b-HCH and PCB153) and maternal thyroid hormone levels. These results strengthen the hypothesis that DIO enzymes play a role in explaining the disruption of thyroid hormones in relation to exposure to OCs.

Assessment of seasonal variations in persistent organic pollutants across the region of Tuscany using passive air samplers

Concentrations of persistent organic pollutants (POPs) were measured for an entire year in the region of Tuscany, Italy. Passive air samplers consisting of polyurethane foam (PUF) disks were deployed over four sampling periods of 3-5 months from April 2008 to July 2009 in urban (n = 6) and rural (n = 4) sites. The aim of the study was to characterize the spatial and seasonal variations in selected POPs. The POP concentrations (pg m^-3) in the air were dominated by dichlorodiphenyltrichloroethane and metabolites (DDTs) and polychlorinated biphenyls (∑₇PCBs). DDTs, and ∑₇PCBs showed a clear decreasing urban > rural gradient. The concentrations of DDTs and PCBs were up to 10 and 6 times higher, respectively, in urban sites than in rural sites. ∑₇PCBs showed a significant correlation with the urbanized areas located <5 km around the sampling sites. For hexachlorocyclohexanes (HCHs), α-HCH concentrations were similar at both sampling sites and were found to be quite uniform during the four sampling periods. Seasonal fluctuations were observed for DDTs, and ∑₇PCBs, with the highest concentrations observed during period 4 (summer-spring); this is most likely due to a temperature-driven re-emission from local sources. These findings were also supported by an air back trajectory analysis in the study area. This study contributes new information about POP levels in the Italian atmosphere and demonstrates the feasibility of using PUF disks to simultaneously assess seasonal concentrations at different sampling sites.

Actinobacteria: Current research and perspectives for bioremediation of pesticides and heavy metals

Actinobacteria exhibit cosmopolitan distribution since their members are widely distributed in aquatic and terrestrial ecosystems. In the environment they play relevant ecological roles including recycling of substances, degradation of complex polymers, and production of bioactive molecules. Biotechnological potential of actinobacteria in the environment was demonstrated by their ability to remove organic and inorganic pollutants. This ability is the reason why actinobacteria have received special attention as candidates for bioremediation, which has gained importance because of the widespread release of contaminants into the environment. Among organic contaminants, pesticides are widely used for pest control, although the negative impact of these chemicals in the environmental balance is increasingly becoming apparent. Similarly, the extensive application of heavy metals in industrial processes lead to highly contaminated areas worldwide. Several studies focused in the use of actinobacteria for cleaning up the environment were performed in the last 15 years. Strategies such as bioaugmentation, biostimulation, cell immobilization, production of biosurfactants, design of defined mixed cultures and the use of plant-microbe systems were developed to enhance the capabilities of actinobacteria in bioremediation. In this review, we compiled and discussed works focused in the study of different bioremediation strategies using actinobacteria and how they contributed to the improvement of the already existing strategies. In addition, we discuss the importance of omic studies to elucidate mechanisms and regulations that bacteria use to cope with pollutant toxicity, since they are still little known in actinobacteria. A brief account of sources and harmful effects of pesticides and heavy metals is also given.