High mortality and high PCDD/Fs exposure among residents downwind of municipal solid waste incinerators: A case study in China

Serum metabolism distribution in individuals exposed to dioxins: A case study of residents near the municipal solid waste incinerators in China

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) have attracted considerable attention owing to their environmental persistence, bioaccumulation, and high toxicity. This study aimed to investigate changes in serum metabolites following exposure to PCDD/Fs and to reveal a novel pathogenesis of PCDD/Fs. Serum samples were collected from 75 residents living near a municipal solid waste incinerator in China to analyse the relationship between PCDD/Fs and serum metabolic components. The serum level in the low-exposure group [19.07 (13.44-23.89) pg-TEQ/L] was significantly lower than that in the high-exposure group [115.60 (52.28-592.65) pg-TEQ/L]. Non-targeted metabolomic studies based on liquid chromatography-high resolution mass spectrometry have been applied to the metabolomic analysis of serum. Thirty-seven metabolites with significant differences among the different groups were identified as biomarkers. Pathway analysis revealed that high dioxin exposure perturbed various biological processes, including glycerol phospholipid metabolism and the interconversion of pentose and glucuronate. The results of a population health survey showed that the serum dioxin concentration in patients with diabetes was significantly higher than that in the control population. These findings suggest that dioxin exposure is associated with several potential adverse health risks, including inflammation, diabetes, and cardiovascular disease, through metabolic changes.

Serum PCDD/F levels in metropolitan populations living near a municipal solid waste incinerator in Eastern China

Ambient exposure to polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) is suspected to cause adverse human health outcomes. Herein, serum samples from 40 residents in the neighborhood of a municipal solid waste incinerator (MSWI) in the metropolitan area were measured for PCDD/Fs. The mean toxic equivalent (TEQ) concentration of total PCDD/Fs in human serum samples was 16.8 pg TEQ/g lipid. Serum PCDD/F levels were significantly higher in residents adjacent to the MSWI than in those from areas far from the emission source (p < 0.01). In addition, there were no significant associations between serum PCDD/Fs levels and factors, such as gender, age, and BMI in donors. For non-occupationally exposed populations, OCDD and 1,2,3,7,8-PeCDD in serum are available as indicators of total PCDD/Fs and total TEQ, respectively. The atmospheric PCDD/Fs levels were within a relatively low range in areas upwind and downwind of the MSWI. The results of the principal component analysis showed a distinct difference in PCDD/F congener patterns between air and serum samples, suggesting inhalation exposure could have a limited influence on the human body burden. Our findings will deepen the current knowledge of endogenous PCDD/F exposure in urban populations, and also facilitate public health protection strategies near MSWIs.

PCDD/F and DL-PCB exposure among residents upwind and downwind of municipal solid waste incinerators and source identification

Understanding the environmental and human impacts associated with polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) exposure from municipal solid waste incinerators (MSWIs) is challenging because information on ambient and dietary exposure levels, spatial characteristics, and potential exposure routes is limited. In this study, 20 households from two villages located on the upwind and downwind sides of a MSWI were selected to characterize the concentration and spatial distribution of PCDD/F and DL-PCB compounds in ambient and food samples, such as dust, air, soil, chicken, egg, and rice samples. The source of exposure was identified using congener profiles and principal component analysis. Overall, the dust and rice samples had the highest and lowest mean dioxin concentrations, respectively. Significant differences were observed (p < 0.01) in PCDD/F concentrations in chicken samples and DL-PCB concentrations in rice and air samples between the upwind and downwind villages. The exposure assessment indicated that the primary risk source was dietary exposure, especially from eggs, which had a PCDD/F toxic equivalency (TEQ) range of 0.31-14.38 pg TEQ/kg body weight (bw)/day, leading to adults in one household and children in two households exceeding the World Health Organization-defined threshold of 4 pg TEQ/kg bw/day. Chicken was the main contributor to the differences between upwind and downwind exposure. Based on the established congener profiles, the exposure routes of PCDD/Fs and DL-PCBs from the environment to food to humans were clarified.

PCDD/Fs in indoor environments of residential communities around a municipal solid waste incineration plant in East China: Occurrence, sources, and cancer risks

Prolonged exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) can pose several adverse outcomes on human health. However, there is limited information on public health associated with indoor PCDD/F exposure in residential environments. Here, we examined PCDD/F concentrations in indoor air and indoor dust samples obtained from households near a municipal solid waste incineration (MSWI) plant. Our measurements revealed that the toxic equivalent (TEQ) concentrations of PCDD/Fs in indoor air ranged from 0.01 to 0.05 pg TEQ/m³, which were below intervention thresholds (0.6 pg TEQ/m³). Additionally, the TEQ concentrations of PCDD/Fs in indoor dust ranged from 0.30 to 11.56 ng TEQ/kg. Higher PCDD/F levels were found in household dust in the town of Taopu compared to those in the town of Changzheng. Principal component analysis (PCA) of PCDD/Fs suggested that waste incineration was the primary source of PCDD/Fs in indoor air, whereas PCDD/Fs in indoor dust came from multiple sources. The results of the health risk assessment showed the carcinogenic risk due to indoor PCDD/F exposure was higher for adults than for nursery children and primary school children. The carcinogenic risks of PCDD/Fs for age groups residing near the MSWI plant were all less than the risk threshold (10^-5). Our findings will help to better understand the levels of PCDD/F exposure among urban populations living in residential communities around the MSWI plant and to formulate corresponding control measures to reduce probabilistic risk implications.

National and provincial dioxin emissions from municipal solid waste incineration in China

China presently lacks an up-to-date regional inventory of dioxin emissions from municipal solid waste incineration (MSWI), although MSWI has grown rapidly in recent decades. Based on dioxin concentrations from the official website for governments and enterprises, we created an inventory of dioxin emissions from 29 areas in mainland China. MSWI released a total of 22.56 g I-TEQ of dioxins in 2020. According to Monte Carlo simulation, the dioxin emissions with 95 %, 75 %, and 50 % certainty are 17.03-31.62, 19.24-27.71, and 20.43-25.96 g I-TEQ, respectively. Notably, Guangdong, Zhejiang, and Jiangsu provinces accounted for 38.8 %. The primary regions with considerable dioxin emission per capita and density are Zhejiang and Shanghai. Furthermore, Jilin and Heilongjiang provinces are the top two regions in terms of dioxin emissions per unit of billion gross domestic product. These indicators were affected significantly by the quantity of MSW generated and incinerated (MSWGI), capacity and operating years of incinerators, and degrees of air pollution control devices (APCDs). Dioxin emission factors (EFs) were about 100 times lower in 2020 than in 2004. Note, however, that there is a gap in dioxin EFs between China and European nations. We have proposed that MSW source classification, stable operation conditions of incinerators and APCDs, categories of incinerators selection, and technological upgrading should be China's major measures to curb dioxin emissions. Moreover, with the future increment in the quantity of MSWGI, it is essential to completely reinvent the dioxin monitoring program.