Preliminary study of possible relationships between exposure to PCDD/Fs and dl-PCBs in ambient air and the length of life of people

Temporal, spatial, and seasonal variations in airborne PCDD/F and dl-PCB concentrations around Bien Hoa hot spot, Vietnam, and health risk assessments

Passive air samplers were used to monitor polychlorodibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorobiphenyls (dl-PCBs) between 2020 and 2022 in four residential areas around Bien Hoa hot spot (BHS) including Trung Dung (TD), Tan Phong (TP), Quang Vinh (QV), and Buu Long (BL). The total toxic equivalents of PCDD/Fs and dl-PCBs (∑TEQs) were highest in the TD area, from 284 to 642 fg TEQ/PUF day. Next was the QV area, where ∑TEQs ranged from 229 to 569 fg TEQ/PUF day. Then, ∑TEQs varied from 205 to 503 fg TEQ/PUF day in the TP area. The lowest ∑TEQs were between 179 and 385 fg TEQ/PUF day in the BL area. The temporal, spatial, and seasonal variations in concentrations of PCDD/Fs and dl-PCBs were related to the prevailing wind direction and the distance from each area to the dioxin hot spot. The average ∑TEQs for all four areas surrounding BHS in the dry season (423 fg TEQ/PUF day) were 1.4 times higher than in the rainy season (303 fg TEQ/PUF day). Health risk assessments from airborne dioxin exposure were estimated using the average daily doses through inhalation (ADDI). The ADDI for residents surrounding BHS ranged from 14.6 to 208 fg TEQ/kg BW/day. The ADDI values by areas were as follows: 23.2-208 fg TEQ/kg BW/day in the TD, 18.7-184 fg TEQ/kg BW/day in the QV, 16.7-163 fg TEQ/kg BW/day in the TP, and 14.6-125 fg TEQ/kg BW/day in the BL. These ADDI values remained within and below the 10% threshold of the WHO-recommended tolerable daily intake (100-400 fg TEQ/kg BW/day). It is necessary to control the excavation activities inside the BHS and cover the temporary storage sites of dioxin-contaminated materials to minimize the emissions of PCDD/Fs and dl-PCB into the ambient air.

Temporal variations in airborne PCDD/F and dl-PCB concentrations surrounding the dioxin-remediated areas in Da Nang, Vietnam, and health risk assessments

The air pollution levels from polychlorodibenzo-p-dioxins/polychlorodibenzofurans (PCDD/Fs) and dioxin-like polychlorobiphenyls (dl-PCBs) in three residential areas located north, west, and south of the Da Nang airport were determined by using passive air samplers containing polyurethane foam (PUF) discs with 3-month sampling intervals from 2017 to 2020. The total toxic equivalents (∑TEQs) of the PCDD/Fs and dl-PCBs, using WHO2005-TEFs, were highest north of the airport (134 to 10610 fg WHO-TEQ/PUF day, with an average of 1108 fg WHO-TEQ/PUF day). The ∑TEQs were lower west of the airport, between 159 and 381 fg WHO-TEQ/PUF day and averaged 230 fg WHO-TEQ/PUF day. The lowest ∑TEQs occurred south of the airport, with ranges of 76 and 331 fg WHO-TEQ/PUF day and an average of 152 fg WHO-TEQ/PUF day. Construction activities, including excavation and transportation of dioxin-contaminated soil north of the airport, have increased airborne PCDD/F and dl-PCB contamination and health risks. The average daily doses of PCDD/Fs and dl-PCBs through inhalation (ADDA) for residents located north of the airport were the highest (10.9 to 3434 fg WHO-TEQ/kg BW/day and average: 597 fg WHO-TEQ/kg BW/day). Residents located west of the airport faced lower health risks (13-123 fg WHO-TEQ/kg BW/day and average: 39 fg WHO-TEQ/kg BW/day). Residents south of the airport were exposed to a minimum of 6.2-107 fg WHO-TEQ/kg BW/day, with an average of 28 fg WHO-TEQ/kg BW/day. The maximum and average ADDA values for residents north of the airport exceeded 10% of the tolerable daily intake (TDI) recommended by the WHO (100-400 fg WHO-TEQ/kg BW/day). In comparison, all the ADDA values for residents located west and south of the airport were less than and within 10% of the TDI.

Concentrations of PCDD/Fs and dl-PCBs in ambient air in Hanoi, Vietnam, between 2017 and 2021, and health risk assessments

The concentrations and seasonal and temporal variations in polychlorodibenzo-p-dioxins/polychlorodibenzofurans (PCDD/Fs) and dioxin-like polychlorobiphenyls (dl-PCBs) in ambient air from November 2017 to September 2021 were investigated via passive air samplers containing polyurethane foam (PUF) discs in three residential areas: the Cau Giay (CG) urban, Quang Minh (QM) industrial-suburban, and Ba Vi (BV) rural areas, Hanoi, Vietnam. The average total toxic equivalents (TEQs) of PCDD/Fs and dl-PCBs (∑TEQs), using WHO2005-TEFs, were highest in the QM area (506 fg WHO-TEQ/PUF day) and ranged from 317 to 752 fg WHO-TEQ/PUF day. Compared to that in the QM area, the average ∑TEQs were lower in the CG area, ranging between 372 and 615 fg WHO-TEQ/PUF day with an average value of 482 fg WHO-TEQ/PUF day. The average ∑TEQs were lowest in the BV area, ranging from 121 to 414 fg WHO-TEQ/PUF day with an average of 231 fg WHO-TEQ/PUF day. PCDD/F and dl-PCB air pollution increased during spring and winter. The highest seasonal average ∑TEQs in the CG area was 534 fg WHO-TEQ/PUF day in winter. The highest average ∑TEQs in the QM and BV areas were 653 and 280 fg WHO-TEQ/PUF day in spring, respectively. The average daily dose (ADD) values of PCDD/Fs and dl-PCBs through inhalation for adults in the three areas were minimal (9.9-96.2 fg WHO-TEQ/kg body weight (BW)/day) and below the 10% threshold of the tolerable daily intake (TDI) value recommended by the WHO (100-400 fg WHO-TEQ/kg BW/day). For children, the ADD values (15.1-244 fg WHO-TEQ/kg BW/day) were less than and within 10% of the recommended TDI value.

Toxicity of polychlorinated biphenyls in aquatic environments - A review

The assessment of polychlorinated biphenyls (PCBs) and their congeners resulting from the pollution of all environmental media is inherently related to its persistence and ubiquitous nature. In principle, determination of this class of contaminants are limited to the determination of their concentrations in the various environmental matrices. For solving many problems in this context, knowledge of the emission sources of PCBs, transport pathways, and sites of contamination and biomagnification is of great benefit to scientists and researchers, as well as many regulatory organizations. By far the largest amounts of PCBs, regardless of their discharged points, end up in the soil, sediment and finally in different aquatic environments. By reviewing relevant published materials, the source of origin of PCBs in the environment particularly from different pollution point sources, it is possible to obtain useful information on the nature of different materials that are sources of PCBs, or their concentrations and their toxicity or health effects and how they can be removed from contaminated media. This review focuses on the sources of PCBs in aquatic environments and critically reviews the toxicity of PCBs in aquatic animals and plants. The review also assesses the toxicity equivalency factors (TEFs) of PCBs providing valuable knowledge to other scientists and researchers that enables regulatory laws to be formulated based on selective determination of concentrations regarding their maximum permissible limits (MPLs) allowed. This review also supplies a pool of valuable information useful for designing decontamination technologies for PCBs in media like soil, sediment, and wastewaters.

Toxic Organic Contaminants in Airborne Particles: Levels, Potential Sources and Risk Assessment

In the last years, many studies have focused on risk assessment of exposure of workers to airborne particulate matter (PM). Several studies indicate a strong correlation between PM and adverse health outcomes, as a function of particle size. In the last years, the study of atmospheric particulate matter has focused more on particles less than 10 μm or 2.5 μm in diameter; however, recent studies identify in particles less than 0.1 μm the main responsibility for negative cardiovascular effects. The present paper deals with the determination of 66 organic compounds belonging to six different classes of persistent organic pollutants (POPs) in the ultrafine, fine and coarse fractions of PM (PM < 0.1 µm; 0.1 < PM < 2.5 µm and 2.5 < PM < 10 µm) collected in three outdoor workplaces and in an urban outdoor area. Data obtained were analyzed with principal component analysis (PCA), in order to underline possible correlation between sites and classes of pollutants and characteristic emission sources. Emission source studies are, in fact, a valuable tool for both identifying the type of emission source and estimating the strength of each contamination source, as useful indicator of environment healthiness. Moreover, both carcinogenic and non-carcinogenic risks were determined in order to estimate human health risk associated to study sites. Risk analysis was carried out evaluating the contribution of pollutant distribution in PM size fractions for all the sites. The results highlighted significant differences between the sites and specific sources of pollutants related to work activities were identified. In all the sites and for all the size fractions of PM both carcinogenic and non-carcinogenic risk values were below acceptable and safe levels of risks recommended by the regulatory agencies.

Long-term monitoring of PCDD/Fs in soils in the vicinity of a hazardous waste incinerator in China: Temporal variations and environmental impacts

Campaigns from 2008 to 2016 are carried out to study temporal variations and environmental impacts of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/Fs) in soils in the vicinity of a new hazardous waste incinerator (HWI) in China. Results indicate that after 8-year operation of HWI, the geometrical means of both the total concentrations and the TEQ values of PCDD/Fs in soils decrease from 1280 ng·kg^-1 and 3.08 ng WHO-TEQ·kg^-1 to 568 ng·kg^-1 and 2.70 ng WHO-TEQ·kg^-1, respectively, showing generally limited impact on soils within 7.5 km. Temporal changes of PCDD/Fs congener profiles trend to profiles in combustion sources. Considering the whole studied area, results of principal component analysis between soils and emission sources show that instead of HWI, other sources including open burning, traffic, and cement plant are more responsible for PCDD/Fs accumulation. The modeling results of AERMOD indicate the dominant roles of wind velocities and directions on the deposition of PCDD/Fs emitted from HWI. The largest PCDD/Fs increase value in soils predicted by integrating AERMOD and a reservoir model is very limited after 25 years (2.03 × 10^-5 ng WHO-TEQ·kg^-1), indicating relatively minor impacts of HWI on surrounding soils, but the noticeable impact on area downwind from the stack in short distance (e.g., within 0.5 km) should be recognized.

PCDDs, PCDFs and PCBs in locally produced foods as health risk factors in Silesia Province, Poland

Dioxins (PCDDs), furans (PCDFs) and polychlorinated biphenyls (PCBs) emitted into the environment can accumulate in foods and become a significant source of dietary exposure for consumers of these compounds. This study aims to assess the dietary exposure of the residents in a rural area of the Silesia region in southern Poland to PCDDs, PCDFs and PCBs. The goal is to estimate cancer and non-cancer health risks due to the consumption of foods of animal origin. The area has relatively higher concentration of PCDDs, PCDFs and PCBs in the air in comparison to large industrialized cities of the Silesia province. Three popular foods of animal origin, namely free-range chicken meat, free-range chicken eggs, and cow milk produced in the farms were used. The control samples were the same foods from the local grocery stores. Two exposure scenarios were considered: Firstly that residents consumed free-range foods and secondly that the food items were purchased from stores in the study area. In the first scenario, exposure to concentrations of PCDDs, PCDFs, and dioxin-like PCBs (dl-PCBs) yielded evidence of elevated cancer and non-cancer risks. The hazard quotient (HQ) was 71.3 for non-cancer risk and 7.5 × 10^-3 for cancer risk. The health risk from exposure to PCDDs, PCDFs and dl-PCBs in the second scenario was 6.9 × 10^-4 and HQ = 0.8, respectively. Implementation of educational activities in the study area is needed to increase the resident's awareness of the risks associated with the emissions of chlorinated persistent organic pollutants to the environment, including aspects such as the main sources of the emission and how to avoid exposure to these compounds.

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.