PCDD/Fs in plasma of individuals living near a hazardous waste incinerator. A comparison of measured levels and estimated concentrations by PBPK modeling

Decreasing temporal trends of polychlorinated dibenzo-p-dioxins and dibenzofurans in adipose tissue from residents near a hazardous waste incinerator

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are very toxic chemicals which are emitted in waste incineration and whose exposure has important adverse effects for the human health. In 2019, adipose tissue samples were collected from 15 individuals with a median age of 61 years, who had been living near a hazardous waste incinerator in Constantí (Spain). The content of PCDD/Fs in each sample was analyzed. The results were compared with data from previous studies, conducted before (1998) and after (2002, 2007 and 2013) the facility started to operate, and based on populations of similar age. In 2019, the mean concentration of PCDD/Fs in adipose tissue was 6.63 pg WHO-TEQ/g fat, ranging from 0.95 to 12.95 pg WHO-TEQ/g fat. A significant reduction was observed with respect to the baseline study (1998), when a mean PCDD/Fs concentration of 40.1 pg WHO-TEQ/g fat was found. Moreover, the current level was much lower than those observed in the 3 previous studies (9.89, 14.6 and 11.5 pg WHO-TEQ/g fat in 2002, 2007 and 2013, respectively). The body burdens of PCDD/Fs were strongly correlated with age. The significant reduction of PCDD/Fs levels in adipose tissue fully agreed with the decreasing trend of the dietary intake of PCDD/Fs by the population of the zone (from 210.1 pg I-TEQ/day in 2018 to 8.54 pg WHO-TEQ/day in 2018). Furthermore, a similar decrease has been also observed in other biological, such as breast milk and plasma. The current data in adipose tissue, as well as those in other biological monitors, indicate that the population living near the HWI is not particularly exposed to high levels of PCDD/Fs. However, biomonitoring studies cannot differentiate the impact of the HWI emissions from food consumption patterns. This question can be only solved by conducting complementary investigations and contrasting the results of monitoring and epidemiological studies.

Concentrations of persistent organic pollutants in blood of the Spanish population: Temporal trend

The present article reviews the human biomonitoring studies conducted in Spain to assess exposure to persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), polybrominated diphenyl ethers (PBDEs), and per- and poly-fluoroalkyl substances (PFAS). In general terms, important variations in POPs concentrations between Spanish regions and specific populations were observed, while no associations between exposure to POPs and adverse health outcomes were found. Moreover, occupational exposure seems not to be a risk factor with regards to POPs exposure in the Spanish population. The present review highlights the importance of conducting human biomonitoring studies to find possible associations between POPs and adverse health effects.

PCDD/Fs in paired hair and serum of workers from a municipal solid waste incinerator plant in South China: Concentrations, correlations, and source identification

Human hair has been widely used to evaluate the exposure to drugs and organic pollutants. However, reports on the relationship between polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzo-p-furans (PCDFs) in hair and the body burden of PCDD/Fs are limited. In this study, the association between PCDD/Fs in paired hair and serum samples from workers was examined in a municipal solid waste incinerator (MSWI) plant in South China. Fly ash and flue gas from the MSWI plant were also analyzed to determine the source apportionment of PCDD/Fs in the hair. The median international toxic equivalents (I-TEQs) of ΣPCDD/F in serum and hair were 28.0 pg TEQ/g (lipid weight) and 0.30 pg TEQ/g (dry weight), respectively. The indicator congener of PCDD/Fs for the TEQ levels was 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) in both hair and serum, the concentrations of which both exhibited significant and strong linear dependence on the total TEQ levels (p < 0.01, R² = 0.966 and R² = 0.670, respectively). Significant positive correlations were found in the 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin (HxCDD) and octachlorodibenzo-p-dioxin (OCDD) levels between the hair and serum samples (p < 0.05). Flue gas (which is an external source) was identified as the primary source of PCDD/Fs in human hair. Blood and flue gas were accountable for, on average, 37% and 61% of the PCDD/Fs in hair, respectively.

Health risk of childhood exposure to PCDD/Fs emitted from a municipal waste incinerator in Zhejiang, China

This study aimed to evaluate the body burdens of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and their associated health impacts toward school-age children living near a municipal waste incinerator (MWI). A total of 82 children from the exposure area and 49 from the control area were recruited. We measured blood PCDD/F levels, conducted comet assays, calculated the percentage of 5-methylcytosine (%5-mC) and 5-hydroxymethylcytosine (%5-hmC), performed flow cytometry, measured hormonal levels, and analyzed hematological parameters. We also examined 17 congeners of PCDD/Fs in environmental samples, namely, eggs, rice, water, soil, and PM_2.5. The mean blood levels of ΣPCDD/Fs and TEQ-ΣPCDD/Fs were statistically higher in the exposure group than in the control group (3.40 vs. 2.77 pg/g wet weight and 0.40 vs. 0.28 pg WHO-TEQ/g wet weight, respectively; p < 0.05). By contrast, the %5-mC and %5-hmC levels were statistically lower in the exposure group than in the control group (1.15% vs. 4.66% and 0.22% vs. 0.30%, respectively; p < 0.01), whereas the mean % tail DNA was statistically higher in the exposure group than in the control group (10.10% vs. 8.28%, p < 0.01). The mean blood levels of ΣPCDD/Fs and TEQ-ΣPCDD/Fs were both negatively correlated with %5-mC (r = -0.245 and r = -0.217, respectively; p < 0.01) but not with %5-hmC and % tail DNA (p > 0.05). Furthermore, the mean ΣPCDD/F levels in eggs and soil obtained from the exposure area were statistically higher than those of the samples obtained from the control area (31.08 vs. 4.32 pg/g dry weight and 1026.04 vs. 674.97 pg/g dry weight, respectively). In conclusion, children living near the MWI may suffer genetic and epigenetic modifications, such as DNA damage or global DNA hypomethylation due to the MWI-emitted PCDD/Fs and other contaminants.

Concentrations of PCDD/Fs in Human Blood: A Review of Data from the Current Decade

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD/Fs) are environmental pollutants with great persistence, the capacity of bioaccumulation, and well known important toxic effects in humans and animals. Incinerators of hazardous, municipal and medical waste, chlorine bleaching of paper pulp, cement plants, and the traffic of motor vehicles are the most frequent emission sources of these compounds. The diet, followed at a great distance by inhalation, is generally the main way of human exposure to PCDD/Fs. Human biomonitoring is of great importance to prevent potential adverse effects derived from exposure to chemicals such as PCDD/Fs. In relation to this, blood is among the most used biological monitors. In the current review, we have summarized the recent information (2000–2009) published in the scientific literature (databases: Scopus and PubMed) on the concentrations of PCDD/Fs in blood samples of non-occupationally exposed populations, as well as in some groups of occupationally exposed individuals. We have revised a number of studies conducted in various African, American, Asian and European countries, and Australia. Unfortunately, the information is quite limited. No data are available for most countries over the world. Based on the results here reviewed, where available, the current health risks for the general populations do not seem to be of concern. Moreover, taking into account the important reductions observed in the levels of PCDD/Fs in foodstuffs, new decreases in the concentrations of PCDD/Fs in blood—and other biological tissues—are very probable in the immediate years.

Monitoring dioxins and furans in plasma of individuals living near a hazardous waste incinerator: Temporal trend after 20 years

The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in 40 plasma samples of individuals living in zones under potential influence of the emissions of a hazardous waste incinerator (HWI) (Tarragona County, Catalonia, Spain). Samples corresponded to subjects of different gender, age and specific areas of residence. The levels of PCDD/Fs were compared to those obtained in a baseline study (1998), as well as in previous surveys (2002, 2007 and 2012). The current mean concentration of PCDD/Fs in plasma was 6.79 pg I-TEQ/g lipid, which was significantly lower than the baseline concentration (27.0 pg I-TEQ/g lipid). A significant decrease was also observed in comparison to the results obtained in 2002 and 2007 (15.7 and 9.4 pg I-TEQ/g, respectively), while the current PCDD/F levels were similar to those obtained in 2012 (6.18 pg I-TEQ/g lipid). This important reduction in plasma PCDD/F levels is in accordance with the decreasing trend in the daily dietary intake of PCDD/Fs, which diminished from 210.1 pg I-TEQ (baseline) to 8.54 pg WHO-TEQ (current). OCDD was the predominant congener in plasma, while 2,3,7,8-TeCDD and 1,2,3,4,7,8,9-HpCDF showed the lowest levels. Based on the above results, as well as other recent data on the levels of PCDD/Fs in human milk, we conclude that the presence of the HWI does not mean additional and significant risks -as regards to PCDD/F exposure-for the population living in the neighborhood of the facility.

Health risk assessment of trihalomethanes mixtures from daily water-related activities via multi-pathway exposure based on PBPK model

In this study, the concentrations of trihalomethanes (THMs) in tap water and direct drinking water were analyzed, and based on the human behavior patterns and building parameters, the concentrations of THMs in indoor air were simulated with the water-air concentration conversion model. In addition, concentrations of THMs in human tissues were predicted based on physiologically based pharmacokinetic (PBPK) model, and the health risk of THMs for participants were estimated. Furthermore, the carcinogenic risk of mixtures according to the method proposed by USEPA and PBPK model based method were calculated and compared. The concentrations of chloroform, bromodichloromethane, dibromochloromethane and bromoform in tap water were 11.28-16.21, 4.83-6.28, 0.81-1.32 and 0.08-0.21 μg/L, and those in direct drinking water were 3.29-6.88, 0.35-0.47, 0.03-0.08 and 0.04-0.08 μg/L, respectively. The results of water-air concentration conversion model demonstrated that pollutants in air had a strong correlation with water-related activities. Multi-pathway PBPK model showed that THMs concentrations in liver, kidney and richly perfused tissue were higher than those in other tissues. The results of risk assessment showed that the mean risk levels of mixtures were 1.69 × 10^-4 and 1.72 × 10^-4 calculated by the USEPA recommended method and PBPK based method, which seriously exceeded the acceptable level. TCM and BDCM were the major risk factors, and inhalation was the main exposure route of THMs.

Development of a PBPK Model for Silver Accumulation in Chub Infected with Acanthocephalan Parasites

Simultaneous presence of metals and parasites in fish might lead to potential risks to human health. Parasites might influence metal accumulation and disturb detoxification in fish, thereby affecting biomarkers of fish responses as well as metal biomagnification in humans. It is, therefore, of importance to take into account parasite infection when investigating metal accumulation in fish. However, mechanisms of metal accumulation and distribution in fish-parasite systems are not integrated into current approaches. The present study proposes a new physiologically based pharmacokinetic model for mechanistic simulation of metal partitioning between intestinal parasites and their hosts. As a particular case, Ag accumulation in the system of chub Squalius cephalus and the acanthocephalan Pomphorhynchus tereticollis was investigated. As a novelty, fish cardiac output and organ-specific blood flow distribution were incorporated in our model. This approach distinguishes the current model from the ones developed previously. It also facilitates model extrapolation and application to varying conditions. In general, the model explained Ag accumulation in the system well, especially in chub gill, storage (including skin, muscle, and carcass), and liver. The highest concentration of Ag was found in the liver. The accumulation of Ag in the storage, liver, and gill compartments followed a similar pattern, i.e., increasing during the exposure and decreasing during the depuration. The model also generated this observed trend. However, the model had a weaker performance for simulating Ag accumulation in the intestine and the kidney. Silver accumulation in these organs was less evident with considerable variations.

Concentrations of PCDD/Fs in the neighborhood of a hazardous waste incinerator: human health risks

In 1996-1998, a wide surveillance program was initiated in the vicinity of a new hazardous waste incinerator (HWI) placed in Constantí (Catalonia, Spain), which started its regular operations in 1999. The program was aimed at assessing the environmental impact of the facility on the surrounding environment, as well as to evaluate the potential risks for the population living in the neighborhood. Since then, among other measurements, the concentrations of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) have been periodically determined in soil and herbage samples. This study shows the results, corresponding to the period 2013-2016. Data were compared with those obtained in the baseline survey (1996-1998), as well as with those of the previous survey (2011-2012). The median PCDD/F concentrations in soils were 0.44 and 0.33 ng toxic equivalent (I-TEQ)/kg in 2015 and 2016, respectively, with a significant decrease in relation to the baseline survey, and a non-significant decrease between 2015 and 2016. In turn, PCDD/F levels in vegetation showed some fluctuations over time, being the concentrations of PCDD/Fs in 2013 very similar to those found in 2012 (1.11 and 1.23 ng I-TEQ/kg, respectively). These concentrations notably decreased along the three last campaigns (0.16, 0.23, and 0.17 ng I-TEQ/kg in 2014, 2015, and 2016, respectively). These changes would be more related to a number of environmental factors rather than to a variation of PCDD/F emissions by the HWI. With respect to human health risks, exposure to PCDD/Fs in the area under potential influence of the HWI is not of concern, as the current environmental concentrations of PCDD/Fs do not mean additional carcinogenic or non-carcinogenic risks for the local population.

Characteristics of molecular weight distribution of dissolved organic matter in bromide-containing water and disinfection by-product formation properties during treatment processes

The characteristics of dissolved organic matter (DOM) and bromide ion concentration have a significant influence on the formation of disinfection by-products (DBPs). In order to identify the main DBP precursors, DOM was divided into five fractions based on molecular weight (MW), trihalomethane formation potential and haloacetic acid formation potential were determined for fractions, and the change in contents of different fractions and total DBPs during treatment processes (pre-chlorination, coagulation, sand filtration, disinfection) were studied. Moreover, the relationship between bromide concentration and DBP generation characteristics in processes was also analyzed. The results showed that the main DBP precursors were the fraction with MW <1kDa and fraction with MW 3-10kDa, and the DBP's generation ability of lower molecular weight DOM (<10kDa) was higher than that of higher molecular weight DOM. During different processes, pre-chlorination and disinfection had limited effect on removing organics but could alter the MW distribution, and coagulation and filtration could effectively remove organics with higher MW. For DBPs, trihalomethanes (THMs) were mainly generated in pre-chlorination and disinfection, while haloacetic acids (HAAs) were mostly generated during pre-chlorination; coagulation and sand filtration had little effect on THMs but resulted in a slight removal of HAAs. In addition, the results of ANOVA tests suggested that molecular sizes and treatment processes have significant influence on DBP formation. With increasing bromide concentration, the brominated DBPs significantly increased, but the bromine incorporation factor in the processes was basically consistent at each concentration.

Did municipal solid waste landfill have obvious influence on polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in ambient air: A case study in East China

Municipal solid waste (MSW) landfill was a main way to disposal of MSW and almost 95% of MSW was disposed by landfills in the world. In order to understand the influence of MSW landfill on polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in surrounding atmosphere, 42 ambient air samples were collected and analyzed from surrounding sites, background site, upwind site and downwind site of a MSW landfill in East China. The results of present study were summarized as follows. (1) The total concentrations of PCDD/Fs (∑PCDD/Fs) in ambient air from surrounding sites, background site, upwind site and downwind site were 2.215±1.004, 2.058±0.458, 2.617±1.092 and 1.822±0.566pgNm^-3, respectively. (2) The toxic equivalent concentrations (TEQ) of PCDD/Fs in ambient air from surrounding sites, background site, upwind site and downwind site were 0.103±0.017, 0.096±0.015, 0.120±0.024 and 0.108±0.014pg I-TEQNm^-3, respectively. (3) The congener profiles, ∑PCDD/Fs and TEQ between background atmosphere and surrounding atmosphere of landfill did not show statistically significant difference. (4) The ∑PCDD/Fs and TEQ in ambient air of downwind site were not higher than that of upwind site, suggesting that studied landfill did not have obvious influence on PCDD/Fs in ambient air from downwind site. (5) The 95th percentile carcinogenic risk (CR) of PCDD/Fs in ambient air from surrounding sites, background site, upwind site and downwind site were 8.03×10^-9, 7.57×10^-9, 9.69×10^-9 and 8.15×10^-9, respectively, which were much lower than the threshold value of CR (10^-6), suggesting that studied landfill did not influence the CR of PCDD/Fs in surrounding atmosphere and negligible cancer risk occurred. (6) The non-carcinogenic risk (non-CR) analysis indicated that landfill did not have influence on the non-CR of PCDD/Fs in surrounding atmosphere and no obvious non-carcinogenic effects developed.

Composition profiles and health risk of PCDD/F in outdoor air and fly ash from municipal solid waste incineration and adjacent villages in East China

In present study, composition profiles and health risk of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in outdoor air and fly ash from domestic waste treatment center (DWTC) were studied. In addition, the composition profiles and health risk of PCDD/F in outdoor air from adjacent villages were researched and used to quantitatively analyze the difference between onsite workers and adjacent villagers. Moreover, the difference between old intake method and new inhalation dosimetry method in the process of assessing the health risk of PCDD/Fs in outdoor air was quantitatively compared and analyzed. The results of this study were summarized as follows. (1) The 95th percentile carcinogenic risk (CR) and non-carcinogenic risk (non-CR) for onsite workers and adjacent villagers were much lower than the threshold values of 10(-6) and 1.0, respectively, suggesting no potential health risk. (2) The 95th percentile CR for onsite workers was 1.27×10(-8) and was 64.8 times higher than that of adjacent villagers (1.99×10(-10)). (3) The 95th percentile non-CR for onsite workers and adjacent villagers were 1.37×10(-4) and 1.31×10(-7), respectively. (3) Accidental ingestion of fly ash was the largest contributor to CR and non-CR for onsite workers, contributing 62.98% and 64.04% to CR and non-CR, respectively. (4) The CR and non-CR of PCDD/Fs in outdoor air for onsite workers and adjacent villagers which calculated by old intake method was much higher than the results from new inhalation dosimetry method. The results quantitatively showed the levels and potential risks of PCDD/Fs posed by a DWTC site, which can be helpful to predict the influence from DWTC sites and promote the management of DWTC in China.

Health risks for the population living in the vicinity of an Integrated Waste Management Facility: screening environmental pollutants

We performed a screening investigation to assess the human health risks of the Integrated Waste Management Facility (IWMF: mechanical-biological treatment (MBT) plant plus municipal solid waste incinerator (MSWI); Ecoparc-3) of Barcelona (Spain). Air concentrations of pollutants potentially released by the MBT plant (VOCs and bioaerosols) and the MSWI (trace elements, PCDD/Fs and PCBs) were determined. Trace elements, PCDD/Fs and PCBs were also analyzed in soil samples. The concentrations of trace elements and bioaerosols were similar to those previously reported in other areas of similar characteristics, while formaldehyde was the predominant VOC. Interestingly, PCDD/F concentrations in soil and air were the highest ever reported near a MSWI in Catalonia, being maximum concentrations 10.8 ng WHO-TEQ/kg and 41.3 fg WHO-TEQ/m(3), respectively. In addition, there has not been any reduction in soils, even after the closure of a power plant located adjacently. Human health risks of PCDD/F exposure in the closest urban nucleus located downwind the MSWI are up to 10-times higher than those nearby other MSWIs in Catalonia. Although results must be considered as very preliminary, they are a serious warning for local authorities. We strongly recommend to conduct additional studies to confirm these findings and, if necessary, to implement measures to urgently mitigate the impact of the MSWI on the surrounding environment. We must also state the tremendous importance of an individual evaluation of MSWIs, rather than generalizing their environmental and health risks.

A PBPK model to estimate PCDD/F levels in adipose tissue: comparison with experimental values of residents near a hazardous waste incinerator

This study was aimed at determining the concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in 15 samples of adipose tissue from subjects who had been living in the vicinity of a hazardous waste incinerator (HWI). The results were compared with levels obtained in previous surveys carried out in 1998 (baseline study), 2002 and 2007. The current (2013) concentrations of PCDD/Fs in adipose tissue ranged from 2.8 to 46.3 pg WHO-TEQ/g fat (mean and median concentrations: 11.5 and 7.4 pg WHO-TEQ/g fat, respectively), being significantly lower (64%) than those observed in 1998. In contrast, no significant differences in the mean PCDD/F concentrations were noted in the period 2002-2013. The significant decrease of the PCDD/F content in fat, also noted in other biological monitors such as plasma and breast milk, is in agreement with the reduction in the dietary intake of PCDD/Fs found in the same area of study. Similarly to other investigations across Europe, an increase of PCDD/F levels in adipose tissue in relation to age was observed, while no significant differences were noted according to gender. A multicompartmental physiologically-based pharmacokinetic (PBPK) model was also applied to estimate the levels of PCDD/Fs in adipose tissue. When comparing the modeled and experimental concentrations of PCDD/Fs in that tissue, very similar values were obtained for the four surveys, which indicates this can be a reliable tool to predict the internal dose of PCDD/Fs.