Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in Zhejiang foods (2006-2015): Market basket and polluted areas

Polychlorinated dibenzo-p-dioxin and dibenzofuran contamination of free-range eggs: estimation of the laying hen's soil ingestion based on a toxicokinetic model, and human consumption recommendations

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are ubiquitous in the environment. The main route of human exposure is through food consumption. Soil contamination can be problematic for sanitary safety depending on the usage of the soil, such as farming. In case of environmental soil contamination with PCDD/Fs, hen's eggs may be contaminated due to soil ingestion by hens. For this reason, it is important to understand the parameters that influence eggs' contamination when hens are raised in contaminated areas. After the discovery of a contaminated area in Lausanne (Switzerland), we collected hens' eggs from ten domestic-produced eggs and one farm. Based on PCDD/F measurements of eggs and soil, and a toxicokinetic model, we estimated individual hen's soil intake levels and highlighted appropriate parameters to predict the dose ingested. Recommended weekly consumption for home-produced eggs was calculated based on the tolerable weekly intake proposed by EFSA in 2018. The most important parameter to assess the soil ingestion does not seem to be the soil coverage by vegetation but rather the hen's pecking behaviour, the latter being difficult to estimate objectively. For this reason, we recommend using a realistic soil ingestion interval to assess the distribution of egg PCDD/F concentration from free-range hens reared on contaminated soil. The addition of soil contamination in the toxicokinetic model can then be used to recommend to the general population weekly consumption of eggs. The consumption by adults of free-range eggs produced on land with soil containing >90 ng toxic-equivalent (TEQ)/kg dry soil should be avoided. Even with a low level of soil contamination (1-5 ng TEQ/kg dry soil), we would recommend consuming not more than 5 eggs per week for adults and no more than 2 eggs for children below 4 years old.

Protein, Essential Amino Acid, and Fatty Acid Composition of Five Target Fishery Species of Central Mediterranean Sea

The protein, essential amino acid, and fatty acid composition of European pilchard (Sardina pilchardus), European hake (Merluccius merluccius), surmullet (Mullus surmuletus), red mullet (Mullus barbatus), and deep water rose shrimp (Parapenaeus longirostris) from the central Mediterranean Sea were investigated. All the species showed an essential amino acid content of about 50% of total amino acids, while the protein and total fatty acids content varied from 19.9 to 24.8% and from 1.4 to 5.1%, respectively. The fatty acid profile mainly followed the order SFA (39.1-52.6%) > PUFA (21.0-39.3%) > MUFA (15.6-24.3%). Palmitic and stearic acids were predominant among saturated fatty acids (38-52% and 21-25%, respectively), while palmitoleic and oleic acids were the most represented of the total monounsaturated acids (10-21% and 55-68%, respectively). All the species, as expected, showed a more significant proportion of n-3 PUFA (EPA + DHA) of about 81-93% of the total PUFA, with the highest values was found in European pilchard. Also, several fat quality index values, such as n-6/n-3 ratio, PUFA/SFA, the index of atherogenicity (IA), the index of thrombogenicity (IT), the hypocholesterolemic/hypercholesterolemic ratio (HH), and fish lipid quality/flesh lipid quality (FLQ) were calculated to assess the nutritional quality. All the obtained results, along with the fat quality indexes, indicated the excellent nutritional values of the selected species.

Foraging animal origin food samples as passive indicators of dioxin-like POPs contamination in industry sites: Method development, characterisation and risk assessment

Titanium dioxide (TiO2) is an important industrial chemical, and studies suggest its major production route - the chloride process could lead to the generation of unintentional dl-POPs. However, no relevant studies assessed the occurrence of dl-POPs associated with TiO2 production in the industrial zones, which is mostly due to the ultra-trace level distribution of these compounds in environmental compartments. The present study explored the novel possibility of utilising foraging animal-origin foods as sensitive indicators for addressing this challenge and generated a globally beneficial dataset by assessing the background levels of dl-POPs in the vicinity of a TiO2 production house in Southern India. Systematic sampling of foraging cow's milk and free-ranging hen's eggs was carried out from the study site, and the dl-POPs assessments were conducted utilising an in-house developed cost-effective GC-MS/MS-based analytical methodology. The median dl-POPs levels in milk and egg samples were about 3 times higher than the control samples collected from farm-fed animals and retail markets. The contaminant loads in the foraging animal-origin food samples were further traced to their presence in environmental compartments of soil and sediment and admissible degree of correlations were observed in congener fingerprints. Elevated health risks were inferred for the population in the industrial zones with weekly intakes weighing about 0.15-17 times the European Food Safety Authority-assigned levels. The consumption of foraging cow's milk was observed to have a higher contribution towards the hazard indices and cancer risk estimates and were significantly higher (p < 0.05) for children. The study also presents a critical validation of the GC-MS/MS-based method for the purpose of regulatory monitoring of dl-POPs, which could be of practical significance in economies in transition.

Global trends of dioxin and dioxin-like PCBs in animal-origin foods: a systematic review and gap areas

Dioxins and dioxin-like polychlorinated biphenyls are a group of lipophilic compounds classified under persistent environmental pollutants (POPs). Significant sources of dioxin emissions include industrial effluents, open burning practices, and biomedical and municipal waste incinerators. These emissions will enter the food chain and accumulate in animal-origin foods (AOFs). A systematic review was conducted to analyze the global levels of dioxins and dioxin-like PCBs in AOFs using PRISMA guidelines 2020. The data on the dioxin contamination in AOFs were extracted from 53 publications based on their presence in eggs, meat and meat products, milk and dairy products, marine fish and fish products, and freshwater fish and crabs. A gap analysis was conducted based on the systematic review to understand the grey areas to be focused on the  future. No trend of dioxin contamination in AOFs was observed. A significant gap area was found in the need for nationwide data generation in countries without periodic monitoring of AOFs for dioxin contamination. Source apportionment studies need to be explored for the dioxin contamination of AOFs. Large-scale screening tests of AOFs using DR-CALUX based on market surveys are required for data generation. The outcomes of the study will be helpful for stakeholders and policyholders in framing new policies and guidelines for food safety in AOFs.

Health risk assessment and development of human health ambient water quality criteria for PCBs in Taihu Basin, China

Polychlorinated biphenyls (PCBs) are a class of typical persistent organic pollutants (POPs) with carcinogenicity and extensively found in diverse environmental mediums. The Taihu Basin is one of the most economically developed regions in China, and it has also caused a lot of historical legacy and unconscious emissions of PCBs, posing a threat to the health of people in the region. This study counted the concentrations of PCBs in five environmental media (water, soil, air, dust, and food) in the Taihu Basin from 2000 to 2020 and used Monte Carlo simulation to simulate the multi-channel exposure of PCBs in people of different ages (children, teenagers, and adults), and evaluated their noncarcinogenic and carcinogenic health risks. Finally, the human health ambient water quality standards (AWQC) for PCBs were obtained using regional exposure parameters and bioaccumulation factors. The results showed that the pollution of PCBs in the Taihu Basin was relatively serious in China. The concentration of PCBs in dust is higher than other environmental media. And exposure to water and food is the main exposure pathway for PCBs in the population of the region. Besides, PCBs pose no noncarcinogenic risk to people in this region, but their carcinogenic risk to residents exceeds the safety threshold. Among the three population groups, adults have the highest risk of cancer, and prevention measures need to be taken by controlling the intake of related foods and the concentration of PCBs in water. The following human health AWQC values of the PCBs in Taihu Basin is 3.2 × 10-9 mg/L.

The residues and health risk assessment of polychlorinated biphenyls (PCBs) in Pheretima (an earthworm-derived traditional medicine) from southeastern China

Minimal research exists on polychlorinated biphenyl (PCB) exposure from traditional Chinese medicines (TCMs), despite their significant contributions to domestic and international health protection. This study is the first to investigate the levels, profiles, and health risks of PCB residue in Pheretima, a typical TCM produced from earthworm. Seventy-seven Pheretima samples from different regions of China were analyzed for 45 PCB congeners. PCBs were found in all samples exhibiting species-dependent discrepancies. ∑45PCBs was ranging from 0.532 to 25.2 µg/kg (mean 4.46 µg/kg), with CB-11 being the most abundant congener contributing 71.8% ± 10.8% to ∑45PCBs, followed by CB-47, which were all non-Aroclor congeners called unintentionally produced PCBs (UP-PCBs). The average estimated daily intake of ∑45PCBs, ∑7ID-PCBs (indicative polychlorinated biphenyls), and CB-11 were 0.71, 0.04, and 0.51 ng/kg bw/d, respectively. The ∑HQ of PCBs in Pheretima samples was 2.97 × 10-4-2.46 × 10-2 (mean 2.77 × 10-3, 95th 4.21 × 10-3), while the ∑RQ ranged from 1.19 × 10-8 to 2.88 × 10-6 (mean 4.87 × 10-7, 95th 2.31 × 10-6). These findings indicate that Pheretima ingestion does not pose significant non-carcinogenic risks. However, certain individual samples exhibit an acceptable level of potential risks, particularly when considering that PCBs are recognized as endocrine disruptors and classified as probable carcinogens. These results contribute to the safety evaluation of traditional medicines and suggest the potential use of Pheretima as a bioindicator for PCB pollution. It is advisable to monitor UP-PCBs as indicator congeners and gather additional toxicological data.

Polychlorinated biphenyls in bovine milk from a typical informal electronic waste recycling and related source regions in southern India before and after the COVID-19 pandemic outbreak

For more than a decade, Chennai city in southern India has been evidenced with informal electronic waste (e-waste) recycling and open burning practices as the potential sources for polychlorinated biphenyls (PCBs). PCBs can bioaccumulate in livestock particularly cows grazing on the contaminated soil. The outbreak of the COVID-19 pandemic led to additional challenges associated with waste management practices. Hence this study aims to elucidate twenty-five PCB congeners in bovine milk from the previously reported PCB source regions in Chennai and the suburbs before and after about three years of the pandemic outbreak along electronic waste recycling (EWR), open burning dumps (OBD), and residential (RES) transects. The geomean concentration of Ʃ25PCBs in ng/g lipid weight (lw) followed a decreasing trend of EWR (13 ng/g lw) > OBD (8 ng/g lw) > RES (4 ng/g lw). Over 80 % of PCBs stemmed from EWR and OBD transects before and after the pandemic. However, a significant surge in the level of PCB-52 was observed in the OBD transect after the pandemic outbreak. Most toxic PCB congeners, PCB-126 and -169 were significant contributors to TEQs in EWR and OBD transects and can be reasoned with the burning of waste materials and mixed plastics in these transects. The highest average daily dose (ADD) exposure risk was for children from EWR and was significantly higher (p < 0.05) than other transects. Mean ADD-induced TEQ (6.6 pg TEQ/kg-bw/day) from the cows grazing around Kodungaiyur dumpsite slightly exceeded the EU guideline of 5.5 pg TEQ/kg-bw/day after the outbreak of the pandemic due to PCB-126. However, none of the samples exceeded the US FDA (1.5μg/g milk fat) recommendation limits for PCBs in milk fat. Prolonged exposure to such persistent organic pollutants interlinked with the burning of mixed waste in the open dumps can be a public health concern.

Levels, patterns and risk assessment of PCDD/Fs and dl-PCBs through dietary exposure in the Valencian Region (Spain)

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin like polychlorinated biphenyls (dl-PCBs) levels were measured in representative vegetable oils and animal origin foodstuffs collected in a Total Diet Study carried out in the Valencian Region (Spain). A total amount of 3,300 food samples were collected and grouped into 5 main food groups: vegetable oils, meat and meat products, eggs, milk and dairy products and fish and sea products. The samples were analysed using gas chromatography coupled to high-resolution mass spectrometry (GC-HRMS). The food group which presented the highest concentration in wet weight (ww) for the sum of PCDD/Fs and dl-PCBs was fish and sea products (0.5 pg TEQ g-1 ww), whereas meat and meat products (0.6 pg TEQ g-1 lipid) showed the highest levels expressed in lipid terms. Occurrence data of PCDD/F and dl-PCBs were combined with consumption data to estimate the dietary exposure of adults (>15 years) and children (6-15 years). Finally, the estimated weekly intake (EWI) was calculated using a deterministic approach and considering the food consumption of the population, with fish and sea products being the main food group contributor. Likewise, considering the worst-case scenario (Upper Bound, UB), average EWI were 1.8 and 3.4 pg TEQ kg-1 body weight (bw) week-1 for adults and children, respectively. For children, the average EWI was almost twice above the tolerable weekly intake (TWI) of 2 pg TEQ kg-1 bw week-1 set by EFSA in 2018. In terms of risk characterisation, the overall obtained results showed that 19 % of adults and 43 % of children may exceed the TWI when using UB.

Prenatal exposure to 209 PCBs in mother-infant pairs from two cities in China: Levels, congener profiles, and transplacental transfer

Prenatal exposure to polychlorinated biphenyls (PCBs) has been well researched, but studies covering all 209 congeners are limited. Recent literature suggests a shift in the dominant congeners and increasing levels of unintentionally-produced PCBs (UP-PCBs) in environmental samples in China. To investigate the exposure levels and profiles of PCBs in pregnant women and newborns, as well as the characteristics of transplacental transfer, we measured 209 PCBs in 80 pairs of maternal serum (MS) and cord serum (CS) from Hangzhou and Mianyang, China. The levels of ∑PCBs of participants in this study were lower than those in developed countries and followed the order of (ng/g lw): Hangzhou-MS (148) > Hangzhou-CS (107) > Mianyang-MS (63.8) > Mianyang-CS (57.9). UP-PCBs (mainly PCB-11) contributed around 50% of ∑PCBs in serum, which is consistent with the environmental samples. Environmental burden and dietary intake may account for the differences in the exposure levels, while the historical production and release may have impacted the homologue profiles. Prenatal exposure to PCB-126 was associated with increased birth weight (n = 80, adjusted β = 0.270, p = 0.030). The body burden of dioxin-like PCBs of newborns in Hangzhou was 82.4 pg TEQ/kg bw, suggesting certain health risks under WHO tolerable daily intake of 1-4 pg TEQ/kg bw. Log₁₀ K_OW was negatively correlated with log₁₀-transformed transplacental transfer efficiency (R² = 0.36, p < 0.001), serving its importance for PCBs' transplacental transfer. This study is the first to investigate maternal and fetal exposure to PCBs in China based on their levels, congener and homologue profiles, and potential adverse effects. Our findings help to provide insights into the processes and factors influencing the transplacental transfer of PCBs.

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.

Levels, enrichment characteristics and dietary intake risk of polychlorinated dibenzo-p-dioxin/furans in traditional smoked pork

The concentrations and TEQs of polychlorinated dibenzo-p-dioxin/furans (PCDD/Fs) in traditional smoked pork were significantly higher than those in raw pork, and mainly distributed in the surface layer. The main enriched congeners during traditional smoking were 2378-TCDF, 12378-PeCDF, 23478-PeCDF, 1234678-HpCDF, OCDF, 1234678-HpCDD and OCDD. The ability of each congener to transfer from the surface to the inner part was various. According to the dietary habits of local residents, PCDD/Fs in more than half of the traditional smoked pork samples posed a potential carcinogenic risk, and the risk in the surface samples were 1.02-10.2 times that of the corresponding inner samples. Some variables might be the important factors affecting the concentration of PCDD/Fs in smoked pork, such as the duration of smoking and the kind of fuel. It is recommended to achieve lower risk by reducing the consumption of smoked pork, especially the surface layer of smoked pork, and innovating traditional smoking technologies.

Endocrine-Disrupting Chemicals and Their Effects in Pet Dogs and Cats: An Overview

Over the past few decades, several pollutants classified as environmental endocrine-disrupting chemicals (EDCs) have become a matter of significant public health concern. Companion animals play a major role in human society, and pet ownership is substantially increasing worldwide. These intimate human-pet relationships imply sharing much of the same environment, thus including exposure to similar levels of EDCs in daily routine. Here, we review the current knowledge on the sources and routes of exposure to EDCs in domestic indoor and outdoor environments and discuss whether endocrine disruption is a health concern in pets. We summarize the phenomenon of endocrine disruption, providing examples of EDCs with a known impact on dog and cat health. Then, we propose an overview of the literature on the adverse effects of EDCs in domestic pets, with a special focus on the health of reproductive and thyroid systems. Finally, we explore the potential role of companion animals as unintentional sentinels of environmental exposure to EDCs and the implications for public health risk assessment in a "shared risk" scenario. Overall, this review supports the need for an integrated approach considering humans, animals, and the environment as a whole for a comprehensive assessment of the impact of EDCs on human and animal health.

Presence of novel and legacy flame retardants and other pollutants in an e-waste site in China and associated risks

Electrical and Electronic Equipment (EEE) residues and their management have been widely identified as potential sources of plasticizers and flame retardants to the environment, especially in non-formal e-waste facilities. This study evaluates the distribution, partitioning and environmental and human impact of organophosphate esters (OPEs), legacy polychlorinated biphenyls (PCBs), polybromodiphenyl ethers (PBDEs) and organochlorine pesticides (OCPs) in the e-waste recycling area of Baihe Tang village, in the Qingyuan county, Guangdong province, China. A plastic debris lump accumulated in a small pond during years was identified as the main source of pollution with ∑pollutants of 8400 μg/g dw, being OPEs the main contaminants detected, followed by PBDEs. This lump produced the contamination of water, sediments, soils and hen eggs in the surrounding area at high concentrations. Plastic-water and water-sediment partitioning coefficients explained the migration of OPEs to the water body and accumulation in sediments, with a strong dependence according to the K_OW. Triphenyl phosphate (TPhP), tricresyl phosphate (TCPs) and high chlorination degree PCBs produced a risk in soils and sediments, considering the lowest predicted no effect concentration, while the presence of PCBs and PBDEs in free range hen eggs exceeded the acceptable daily intake. OCPs were detected at low concentrations in all samples. The presence of organic contaminants in e-waste facilities worldwide is discussed to highlight the need for a strict control of EEE management to minimize environmental and human risks.

Use of different endpoints to determine the bioavailability of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in Sprague-Dawley rats

Liver, fat (adipose tissue), blood, and feces are common endpoints used to determine the bioavailability of persistent organic pollutants (POPs). However, it is not known whether the bioavailability of each endpoints is comparable or whether there is a comprehensive endpoint that can be used for all congeners for the measurement of bioavailability. In this study, we observed the accumulation and distribution of 10 polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and 18 polychlorinated biphenyls (PCBs) in different organs of Sprague-Dawley (SD) rats and calculated the bioavailability based on feces, liver, and fat endpoints. Our results indicated that PCB 126, PCB 169, and 50% of PCDD/F congeners were mainly accumulated in the liver, with a bioavailability ranging from 28.9 to 50.6%. On the other hand, higher chlorinated (> 5 Cl) PCB congeners were mainly accumulated in adipose tissues, with a bioavailability ranging from 20.1 to 82.2%, while lower chlorinated (< 5 Cl) pollutants, such as 2,3,7,8-TeCDF, 2,3,7,8-TeCDD, 1,2,3,7,8-PeCDF, and PCB 28, 52, 77, 81, were likely metabolized over 36% in rats during the 8-week experimental period. If we considered metabolization (degradation) as a type of bioavailable process, then the fecal endpoint was a feasible option. However, if we considered the selective accumulation behavior of some congeners in different organs/tissues, then there was no single comprehensive endpoint suitable for all congeners. Lastly, female rats showed significantly higher PCDD bioavailability than male rats at low dose level (0.2 ng/100 g b.w./d); however, the difference in PCB bioavailability between female and male rats was not significant.

A pilot evaluation on the toxicokinetics and bioaccumulation of polychlorinated naphthalenes in laying hens

Knowledge of the transfer features of polychlorinated naphthalenes (PCNs), a class of emerging persistent organic pollutants (POPs), is still lacking concerning the environment-feed-food transfer chain of farm animals. We conducted a controlled feeding experiment with laying hens fed fly ash-contaminated diets to investigate the toxicokinetics and bioaccumulation of PCNs (tri- to octa-CNs) in the hen eggs and tissues. The eggs showed increasing PCNs levels after 14 days of oral exposure, which gradually decreased during the 28-day depuration period but still exceeded the initial levels. The apparent one-compartment half-life of ∑₆₃PCNs in the eggs was 28.9 days, which was comparable to those of other dioxin-like compounds. The uptake and depuration rates of PCN congeners in the eggs were 0.002-0.010 and 0.016-0.079 days^-1 in eggs, respectively. The depuration rates were decreased with the n-octanol/water partition coefficients (logK_OW), indicating that the eggs retained more lipophilic congeners, whereas the uptake rates increased with the logK_OW, indicating the faster deposition of the more lipophilic PCNs in eggs during the exposure period. The transfer rates of PCN congeners ranged from 0.27%-23.0%, indicating the transfer potential of PCNs from feed to eggs. Additionally, the PCN distribution in the laying hens at the end of the exposure showed tissue-specific accumulation, with the high levels of PCNs in the liver, spleen, and ovum. Positive correlations between the transfer factors (C_tissue/C_feed) and the logK_OW suggested that more lipophilic PCN congeners tended to accumulate in the tissues. After quantitatively assessing the feed-to-food transfer of PCNs in laying hens, our results highlight the risk of exposure to PCNs in the food supply chain.

Persistent organic pollutants in foods, their interplay with gut microbiota and resultant toxicity

Persistent Organic Pollutants (POPs) have become immensely prevalent in the environment as a result of their unique chemical properties (persistent, semi-volatile and bioaccumulative nature). Their occurrence in the soil, water and subsequently in food has become a matter of concern. With food being one of the major sources of exposure, the detrimental impact of these chemicals on the gut microbiome is inevitable. The gut microbiome is considered as an important integrant for human health. It participates in various physiological, biochemical and immunological activities; thus, affects the metabolism and physiology of the host. A myriad of studies have corroborated an association between POP-induced gut microbial dysbiosis and prevalence of disorders. For instance, ingestion of polychlorinated biphenyls, polybrominated diphenyl ethers or organochlorine pesticides influenced bile acid metabolism via alteration of bile salt hydrolase activity of Lactobacillus, Clostridium or Bacteroides genus. At the same time, some chemicals such as DDE have the potential to elevate Proteobacteria and Firmicutes/Bacteriodetes ratio influencing their metabolic activity leading to enhanced short-chain fatty acid synthesis, ensuing obesity or a pre-diabetic state. This review highlights the impact of POPs exposure on the gut microbiota composition and metabolic activity, along with an account of its corresponding consequences on the host physiology. The critical role of gut microbiota in impeding the POPs excretion out of the body resulting in their prolonged exposure and consequently, enhanced degree of toxicity is also emphasized.

Insights into the toxicokinetic, tissue distribution and maternal transfer of polychlorinated dibenzo-p-dioxins/dibenzofurans in laying hens fed with dioxin-associated dietary

A controlled feeding experiment was conducted to investigate the toxicokinetic of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) in laying hens. The laying hens were fed with fly ash contaminated diets to replicate the typical environment-feed-chicken transfer chain in China. Levels of PCDD/Fs rapidly increased in the pectoralis, adipose tissue, liver and blood of laying hens with daily ingestion of dioxin-associated diets during the 14-days exposure period, and then a gradual decrease was observed in the 28-days depletion period. The depletion rates (k_d) of the toxic equivalent of PCDD/Fs (TEQ_PCDD/Fs) were 0.043, 0.031 and 0.030 day^-1 for pectoralis, liver and adipose tissue in the high-exposure group, respectively. The k_d of individual PCDD/Fs in liver increased with the numbers of chlorine and n-octanol/water partition coefficient (logK_OW), indicating that lower chlorinated congeners had higher half-lives in liver. Decreasing ratios of liver to adipose tissue for PCDD/Fs (L/AT) throughout the experiment suggested a tendency of equilibrium partitioning between liver and adipose tissue. Congener-specific sequestration of PCDD/Fs in liver was revealed by the positive correlation between L/AT ratios and logK_OW. Physiological bioconcentration factors of PCDD/Fs were estimated at the end of exposure, indicating the preferential accumulation of hexachlorinated congeners in most tissues. Furthermore, maternal transfer of PCDD/Fs was positively correlated with logK_OW, implying that more lipophilic congeners were transferred to egg along with the lipid circulation.

Toxic chemicals from uncontrolled e-waste recycling: Exposure, body burden, health impact

Uncontrolled electronic-waste (e-waste) recycling processes have induced serious environmental pollution and human health impacts. This paper reviewed studies on the wide range of toxic chemicals through the use of primitive recycling techniques, their transfer to various ecological compartments, and subsequent health impacts. Results indicated that local food items were heavily polluted by the pollutants emitted, notably heavy metals in vegetables, rice, fish and seafood, and persistent organic pollutants (POPs) in livestock. Dietary exposure is the most important exposure pathway. The associations between exposure to e-waste and high body burdens of these pollutants were evident. It seems apparent that toxic chemicals emitted from e-waste activities are causing a number of major illnesses related to cardiovascular, digestive and respiratory systems, according to the information provided by a local hospital (Taizhou, an e-waste recycling hot spot in China). More epidemiological data should be made available to the general public. It is envisaged that there are potential dangers of toxic chemicals passing on to the next generation via placental transfer and lactation. There is a need to monitor the development and health impacts of infants and children, born and brought up in the e-waste sites.

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

Studies on the human body burden of dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in populations around municipal solid waste incinerators (MSWIs) in China are limited. The objective of this study was to assess the potential adverse health effects of an 8-year MSWI on the surrounding population and identify possible exposure pathways. We hypothesized that the MSWI would result in different environmental impacts and population health outcomes between upwind and downwind of its 3 km vicinity. We conducted a 10-year retrospective mortality survey on the population surrounding the MSWI. Then, we selected 50 residents aged 50 years or older on each of the upwind and downwind sides of MSWI to test serum PCDD/Fs. Meanwhile, environmental and food exposures to PCDD/Fs were tested for selected residents. The age-adjusted mortality rates were significantly higher for residents downwind than upwind, but no significant difference was found in the standardized mortality ratio before and after the MSWI operation. The toxic equivalents (TEQ) and major congeners of PCDD/Fs were significantly higher in the sera of the downwind residents than in the upwind. The PCDD/Fs in air, soil, dust, and vegetables on the downwind side were not significantly different from those on the upwind side, but the mean concentrations of PCDD/Fs in downwind hen eggs was significantly higher than those from upwind. In conclusion, downwind residents living within 3 km of the MSWI had higher age-adjusted mortality and serum level of PCDD/Fs than upwind residents. This higher mortality rate among downwind residents was not associated with MSWI. However, the higher levels of PCDD/Fs in downwind hen eggs suggest that the downwind population dioxin exposure was related to their location.

Brominated and chlorinated contaminants in food (PCDD/Fs, PCBs, PBDD/Fs PBDEs): Simultaneous determination and occurrence in Italian produce

Validated methodology for the simultaneous determination of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) and polybrominated diphenyl ethers (PBDEs) in foods of animal origin is presented. Method performance indicators were equivalent or better than those required for the control of EU regulated (EU, 2017/644) PCDD/F and PCB congeners in these foods, and for risk assessment through dietary intake. The method uses a high (>90%) proportion of ¹³Carbon-labelled surrogates for internal standardisation combined with high resolution mass spectrometry that allow accurate quantitation, and this was confirmed by multiple successful participations in proficiency testing for PCDD/Fs, PCBs and PBDEs in food. The same validation and method performance requirements as used for PCDD/Fs were followed for PBDD/Fs. The analysis of a range of food samples (eggs, milk, fish, shellfish, pork, beef and poultry), showed the occurrence of all four classes of contaminants at varying concentration ranges. In general, PCBs were the most prominent contaminant, both, in terms of dioxin-like toxicity, as well as in the occurrence of non-dioxin-like congeners, an observation that concurs with those made in other studies on Italian foods. The levels of PCDD/F and PCB occurrence are consistent with a gradual decline in contamination as reported by some other similar studies. Although all the determined contaminants were detected in the sampled foods, there was poor correlation between the occurrences of the brominated and chlorinated contaminants, and between PBDEs and PBDD/Fs, but better associations were observed between the occurrences of the chlorinated contaminants.

Environmental contamination and human exposure of polychlorinated biphenyls (PCBs) in China: A review

Polychlorinated biphenyls (PCBs), together with 11 other organic compounds, were initially listed as persistent organic pollutants (POPs) by the Stockholm Convention because of their potential threat to ecosystems and humans. In China, many monitoring studies have been undertaken to reveal the level of PCBs in environment since 2005 due to the introduced stricter environmental regulations. However, there are still significant gaps in understanding the overall spatial and temporal distributions of PCBs in China. This review systematically discusses the occurrence and distribution of PCBs in environmental matrices, organisms, and humans in China. Results showed that PCB contamination in northern and southern China was not significantly different, but the PCB levels in East China were commonly higher than those in West China, which might have been due to the widespread consumption of PCBs and intensive human activities in East China. Serious PCB contamination was found in e-waste disassembling areas (e.g., Taizhou of Zhejiang Province and Qingyuan and Guiyu of Guangdong Province). Higher PCB concentrations were also chronicled in megalopolises and industrial clusters. The unintentionally produced PCBs (UP-PCBs) formed during industrial thermal processes may play an increasingly significant role in PCB pollution in China. Low PCB levels were recorded in rural and underdeveloped districts, particularly in remote and high-altitude localities such as the Tibetan Plateau and the South China Sea. However, these data are limited. Human exposure to PCBs is closely related to the characteristics of environmental pollution. This review also discusses existing issues and future research prospects on PCBs in China. For instance, the accumulation characteristics and migration regularities of PCBs in food webs should be further studied. More investigations should be undertaken to assess the quantitative relationship between external and internal exposure to PCBs. For example, bioaccessibility and bioavailability studies should be supplemented to evaluate human health risks more accurately.

Forty years studies on polychlorinated biphenyls pollution, food safety, health risk, and human health in an e-waste recycling area from Taizhou city, China: a review

E-waste generation has become a serious environmental challenge worldwide. Taizhou of Zhejiang Province, situated on the southeast coastline of China, has been one of the major e-waste dismantling areas in China for the last 40 years. In this review, we focused on the polychlorinated biphenyl (PCB) trends in environmental compartments, burden and impact to humans, food safety, and health risk assessment from Taizhou, China. The review suggested that PCBs showed dynamic trends in air, soil, water, biodiversity, and sediments. Soils and fish samples indicated higher levels of PCBs than sediments, air, water, and food items. PCB levels decreased in soils with the passage of time. Agriculture soils near the e-waste recycling sites showed more levels of total PCBs than industrial soils and urban soils. Dioxin-like PCB levels were higher in humans near Taizhou, suggesting that e-waste pollution could influence humans. Compared with large-scale plants, simple household workshops contributed more pollution of PCBs to the environment. Pollution index, hazard quotient, and daily intake were higher for PCBs, suggesting Taizhou should be given priority to manage the e-waste pollution. The elevated body burden may have health implications for the next generation. The areas with stricter control measures, strengthened laws and regulations, and more environmentally friendly techniques indicated reduced levels of PCBs. For environment protection and health safety, proper e-waste dismantling techniques, environmentally sound management, awareness, and regular monitoring are very important.

Polychlorinated dibenzo-p-dioxins and dibenzofurans in lotus from a lake historically polluted by the chlor-alkali industry: Occurrence, organ distribution and health risk from dietary intake

In this study, the organ distribution and exposure risk from dietary intake of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were investigated for lotus collected from Ya-er Lake, a lake in Hubei Province, Central China that was historically polluted by the chlor-alkali industry. The highest concentrations of PCDD/Fs were found in the main and fibrous lotus roots, with mean values of 48.9 ± 90.1 pg/g and 94.6 ± 143 pg/g, respectively. In all the investigated samples, Octa-CDD (OCDD) and Octa-CDF (OCDF) were the predominant congeners, at 26% and 17% of Σ₁₇ PCDD/Fs, respectively, followed by 1,2,3,4,6,7,8-HpCDF (9%). The distribution ratios of PCDD/Fs in adjacent lotus organs indicated that PCDD/Fs accumulated easily in edible organs, such as lotus seeds, membrane and leaves. The WHO-TEQ in the edible lotus organs and the probable daily intake (PDI) of lotus products by residents were calculated: the toxic equivalents in the lotus fruit parts reached a mean of 2 pg WHO-TEQ₂₀₀₅/g dw, and the mean weekly intake of lotus products for adolescents living around Ya-er Lake was 2.3 pg WHO-TEQ/kg bw/week. These results suggested that long-term consumption of lotus products from Ya-er Lake presents a health hazard to residents.

Reevaluation on accumulation and depletion of dioxin-like compounds in eggs of laying hens: Quantification on dietary risk from feed to egg

Updated assessment on transfer of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) from feed to food is essential for understanding human exposure risk. A controlled feeding experiment was conducted for laying hens to reevaluate the transfer characteristics of dioxin-like compounds from feed to egg. Two fortified diets (1.17 and 5.13 pg TEQ g^-1 dry weight), made by blending with fly ash, were fed to laying hens for 14 days, followed by 28-days depletion. Levels of ∑TEQ_{PCDD/Fs+DL-PCBs} in eggs rapidly increased once exposure started, reaching at 1.98 and 6.86 pg TEQ g^-1 lw at the end of exposure for low- and high-exposure groups, respectively, and dropped to under the European legislation (maximum levels: 5.0 pg TEQ g^-1 lw) after 28-days depletion. The quantitative depletions showed that the half-lives (T_1/2) of ∑TEQ_PCDD/Fs in eggs were 23 and 14 days for low- and high-exposure groups, respectively. The depletion and accumulation rates of PCDD/Fs were in the range of 0.026-0.151 and 0.005-0.016 day^-1, respectively, representing that the T_1/2 of PCDD/Fs in eggs ranged from 5 to 27 days. The depletion kinetics of DL-PCBs was not significant in egg. The hens with higher laying rates exhibited shorter T_1/2 of PCDD/Fs, implying that increasing laying rate could expedite the depletion of PCDD/Fs in egg. The T_1/2 of PCDD/Fs in egg were negatively correlated with the chlorine number, indicating that lower chlorinated congeners tended to be retained in the egg. Transfer rates of PCDD/Fs were in the range of 4-19%, which were lower than the previous results. These results were attributed to short exposure time and low bioavailability of PCDD/Fs in fly ash. Estimations of dietary intake highlighted the dietary risk of PCDD/Fs from feed to egg, which would pose limited adverse effects on human health.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in food and human dietary intake: An update of the scientific literature

It is well established that for non-occupationally exposed populations, dietary intake is, by far, the main way of human exposure to polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD/Fs), a family of environmental POPs with a well-known potential toxicity -including carcinogenicity-in humans. We here summarize the results of recent studies (2010-2021) (databases: Scopus and PubMed), focused on determining the levels of PCDD/Fs in food samples of different origins, as well as the dietary intake of these pollutants. We have revised studies conducted in various Asian, American and European countries. However, information is rather limited, with no recent data for most countries over the world. Due to the enormous differences in the methodologies of the studies, to conduct a detailed comparison of the results for the different regions and countries has not been possible. Notwithstanding, where data over time are available, important reductions have been observed. These reductions have been linked to the decreases in the environmental emissions of PCDD/Fs noted in recent years. Interestingly, reductions in the levels of PCDD/Fs in biological tissues are also occurring in parallel. In general, the tolerable daily/weekly/monthly dietary intakes of PCDD/Fs are not being currently exceeded where data are available.

Polychlorinated biphenyls (PCBs) in the colostrum samples from the Yangtze River Region: Exposure profile and risk assessment

Polychlorinated biphenyls (PCBs) may transfer into the neonates through the placental transfer and via breastfeeding after the delivery, thus might be harmful to the infant. Sixty colostrum samples in the Yangtze River Region were collected to investigate the concentration, distribution pattern, and enantiomer characteristic of the PCB exposure. Among all samples, over 90% of pollutants were tetra-to hepta-chlorinated PCBs. The sum concentration of the PCB was 512 (IQR: 322-856) ng g^-1 lipid weight. Enantiomer fraction (EF) of PCB 95 and PCB 149 was found lower than the racemic value, while EFs of PCB 45 and PCB 136 were found higher and near-racemic state, respectively. The concentration pattern and enantiomeric properties of the PCBs indicated that the mothers from Mianyang had a recent exposure to PCBs. Among all samples, similar exposure and metabolic pathways of the PCB congeners were observed. PCB exposure showed no significant correlation with the birth outcome of the infants, but 43.3% of the infants have potential health risks via breastfeeding.

Accumulation characteristics and estimated dietary intakes of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls in plant-origin foodstuffs from Chinese markets

The levels and accumulation characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were investigated in nine pools of representative plant-origin foodstuffs randomly collected from markets located in five regions of the Chinese mainland during 2018-2019. The collected foodstuffs consisted of cereals, beans, potatoes, leafy vegetables, root and stem vegetables, melon vegetables, legume vegetables, edible fungi, and mixed vegetable oil. In the fresh plant food pools, the concentrations of toxic equivalency (WHO-TEQ) were in the ranges of 0.9-14.5 pg/kg in upperbound (UB) scenario and 0.002-7.3 pg/kg in lowerbound (LB) scenario on a fresh weight basis; and TriCDFs and TeCBs were the predominant PCDD/F and PCB homologues, respectively. In the mixed vegetable oil, the WHO-TEQ concentrations were 129.4 pg/kg and 103.6 pg/kg on a lipid weight basis in UB and LB scenarios, respectively; and high-chlorinated PCDD/F and PCB homologues were much more abundant. The estimated plant food-borne dietary intakes of WHO-TEQ by a standard adult in the five surveyed regions were in the ranges of 3.39-4.20 and 1.57-2.13 pg WHO-TEQ/kg body weight/month in UB and LB scenarios, respectively. Among all surveyed regions, consumption of cereals and vegetable oil made up the primary contributions to the estimated dietary intakes of WHO-TEQ. TriCDFs accounted for 41.1-83.9% of the PCDD/Fs dietary intakes via consumption of plant foods, and TeCBs made up 61.2-73.0% of the PCBs dietary intakes via consumption of plant foods, suggesting that the potential toxic effects of TriCDFs and TeCBs on human health should be concerned.

Dioxins in breast milk of Chinese mothers: A survey 40 years after the e-waste recycling activities

In the past two decades, numerous studies on dioxin concentrations in breast milk have been conducted in China. However, information concerning dioxin concentrations in breast milk from women living in e-waste recycling sites remains limited. Thus, this study aimed to evaluate health risk owing dioxin intake in e-waste recycling areas in China. In 2015, 42 mothers were recruited from an e-waste recycling site, and the same number of mothers were recruited from a reference site. We collected 10-mL breast milk samples from each participant. Breast milk concentrations of polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs) were significantly higher in the exposed group than in the reference group. The total toxic equivalents (TEQ) of PCDDs/DFs were 9.68 pg/g lipid in the exposed group, a value two times higher than those in the reference group (4.18 pg/g lipid). The estimated daily intake (EDI) of PCDD/DFs was calculated to assess the risk of dioxins through breastfeeding. The infant EDI level was two times higher in the exposed group (54.21 pg TEQ/kg body wt/day) than in the reference group (23.41 pg TEQ/kg body wt/day). Our findings suggest that mothers and their breastfeeding infants living in an e-waste recycling site were exposed to higher dioxin concentrations than those living in a reference site.

Occurrence of dioxin-like POPs in soils from urban green space in a metropolis, North China: implication to human exposure

Urban green space is a special space for urban life and natural contact and has an important impact on human health. However, little information is available on dioxin-like persistent organic pollutants (POPs) in the soils from the specific areas. We measured the concentrations of polychlorinated naphthalenes (PCNs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polychlorinated biphenyls (PCBs) in the soils from urban green space in a metropolis, North China, and found total concentrations of PCDD/Fs, PCBs, and PCNs in the range of 11.5-91.4, 14.7-444, and 82.5-848 pg/g, respectively. It was worth to notice that the concentrations of PCDD/Fs in public park soil from urban center were significantly higher than those in the road greenbelts and resident lawns (Kruskal-Wallis test, p = 0.004). The source analysis indicated that sewage sludge from wastewater treatment plants were important sources of PCNs and PCDD/Fs in urban green land soils, and atmospheric deposition from municipal solid waste incinerator (MSWI) also play an important role in PCDD/F sources. The rough exposure risk evaluation showed that the residents were at a safe level with the daily doses being 0.172-3.144 fg/kg BW/day for children and 0.022-0.406 fg/kg BW/day for adult. Due to the complex and variable sources of PCDD/Fs in urban areas, dioxin-like POPs in urban green land should be given more attention to weaken human exposure.

Levels and patterns of polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls in foodstuffs of animal origin from Chinese markets and implications of dietary exposure

The concentrations and distribution profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were measured in representative animal origin foodstuffs randomly collected from markets located in five regions of the Chinese mainland during 2018-2019. The collected foodstuffs were classified into 11 pools consisting of pork, beef, mutton, poultry meat, chicken eggs, pure milk, mixed animal fat, fish, shrimp, shellfish, and cephalopods. The levels of tri-to octa-CDD/Fs (∑PCDD/Fs), tri-to deca-CBs (∑PCBs), and WHO-TEQ in the collected animal foods were found to be in the ranges of 0.4-14.3 pg/g, 0.04-2.8 ng/g, and 0.013-0.75 pg/g on a fresh weight basis, respectively. The concentrations of PCDD/Fs and PCBs in most of the animal food groups from coastal regions were obviously higher than those from inland regions. Remarkable differences in the homologue and congener distribution of PCDD/Fs and PCBs were observed between terrestrial and aquatic animal foods. The dietary intakes of WHO-TEQ via consumption of animal foods by a standard adult in the five regions were estimated to be in the range of 3.57-19.63 pg WHO-TEQ/kg body weight/month. Consumption of the aquatic animal food and pork categories contributed most of the estimated dietary intakes of WHO-TEQ in the coastal regions, whereas consumption of beef, mutton, and milk made up the primary contributions in Northwest region.

Polybrominated dibenzo-p-dioxins and furans (PBDD/Fs) in Italian food: Occurrence and dietary exposure

Human exposure to polychlorinated dioxins and furans (PCDD/Fs) through the dietary pathway is widely recognised and regulations in some regions of the world help to limit food contamination. Similar information on the analogous polybrominated dioxins and furans (PBDD/Fs) is scarce, partly due to the higher threshold to analytical access and unavailability of some standard materials. The analytical methodology developed here determined twelve planar PBDD/F congeners using ¹³Carbon labelled PBDD/F surrogates and high resolution mass spectrometric detection, and was extensively validated prior to the analysis of a range of commonly consumed Italian foods. The methodology also allowed simultaneous determination of PCDD/Fs and polychlorinated biphenyls (PCBs). The results show that PBDD/Fs occurred in different foods over a range of concentrations from <0.001 pg/g to 4.58 pg/g in fish. The dietary exposure (upper bound) of different Italian population groups, resulting from these occurrence levels was estimated using the toxic equivalency (TEQ) approach that is commonly used for dioxin-like contaminants and ranged from 0.17 to 0.42 pg TEQ/kg bodyweight/day (lower bound - 0.01 pg TEQ/kg bodyweight/day) depending on the population subgroup. Although precautionary, upper bound values may provide a more realistic estimate of toxicity as not all congeners and foods were measured. As expected, children were more highly exposed than adults due to lower body weight. These exposure levels were between a quarter and a third of that arising from the sum of PCDD/Fs and PCBs (0.61 to 1.38 pg WHO-TEQ/kg bodyweight/day), but they contribute to dioxin-like toxicity. If this data is considered in view of the revised tolerable dioxin-like dietary intake published by EFSA in 2018, it is evident that the tolerable weekly intake of 2 pg/kg bodyweight/week would be exceeded by some of the assessed population sub-groups, or all sub-groups if the cumulative intake is considered.

Activation of six lipocalins genes' transcription under PCB18 stress in OsTIL-silenced Oryza sativa L

The lipocalins genes have been assigned for involving in the responses of organisms to various stress factors. The function of lipocalins under PCB18 stress was addressed by pathway complementation in the Oryza sativa L. OsTIL-silenced mutant. The growth of wild type (WT) and OsTIL-silenced mutant (MT) callus were suppressed by PCB18, and MT varieties were inhibited more seriously than WT varieties. Meanwhile, only WT varieties showed "Hormesis" effect. Compared with WT (3 day > 90.0%, 6 day ≤45.5%), MT varieties kept high removing efficiency by HPLC analysis. Varied gene transcription after OsTIL silencing was demonstrated between two varieties, especially obvious under PCB stress. Silenced OsTIL induced more protective gene transcriptions by qPCR analysis, OsVDE at 3 day, OsCHL, OsZEP1, OsZEP2 and OsUN at 6 day and OsZEP2 at 9 day. PCB18 stress further irritated these genes transcription in MT varieties. The defense stagy in WT varieties was that the transcriptions of lipocalins were inhibited to reduce PCB18 accumulation and toxicity. OsTIL could effectively limit PCB18 accumulation and toxicity. After TIL lacking, OsCHL, OsZEP1, OsZEP2 and OsUN in mutant were strongly evoked to against PCB stress. Remarkably, OsUN and OsZEP2 gene expressions were responded to PCB18 stress in both two varieties.

Environmental and health impacts due to e-waste disposal in China - A review

E-waste is discarded and shipped mostly to developing countries located in Asian continent for disposal from other developed countries. Especially 70% of the world's e-waste ends up in Guiyu, a small town located in Guangdong Province of China. As little as 25% is recycled in formal recycling centers with adequate protection for workers and the other e-waste arrived in those areas is not handled in organized manner. As per reports only roughly 12.5% of e-waste is actually recycled, and the recycling efforts in those regions are primitive and result in toxic substances being leached into the surrounding ecosystems. In addition to persistent organic pollutants, there are many heavy metals found in the ground and river sediments in Guiyu, exceeding the threshold set to protect human health. Those areas are no longer suitable for growing food, and water is unsafe for drinking, due to the amount of toxins leached into the groundwater and land. Hazardous threats to environment and human health due to hazardous substances of e-waste all around China, as well as the current e-waste management were documented in this review. The article concludes with controlled contamination sources, and eco-friendly and efficient remediation technologies to solve e-waste problem in China.

Assessment of Air Pollution with Polychlorinated Dibenzodioxins (PCDDs) and Polychlorinated Dibenzofuranes (PCDFs) in Lithuania

Polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDD/F) are highly bioavailable in humans, either through direct inhalation or indirectly by trophic transfer from contaminated food or water. The main sources of pollution with PCDD/F include industrial and non-industrial combustion sources, like domestic contaminated wood burning, house fires, burning of leaves from trees, etc. When looking for alternative energy sources and reduced energy costs, solid waste incineration plants are intended to be built in the vicinity of urbanized areas, and thus, the need emerges for examination and prediction of to what extent the solid waste incineration plants might affect the surrounding ecosystem, air pollution, and human health. Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) (or simply PCDD/F congeners) belong to the group of semi-volatile organic compounds with environmental stability and long-range transfer in the ambient air. Dioxin isomers are highly toxic and may have carcinogenic and mutagenic effects in humans. PCDD/F is detected in air, water, sediment, plants and animals. PCDD/F is generally distributed in the particulate phase in ambient air. For solid waste incineration plant emissions, the distribution of PCDD/F particles into particles with a diameter of <10 μm is more than 81% of the total particulate matter, and more than 54% of the PCDD/F is distributed into particles with a diameter of <2.5 μm. The aim of this study is to investigate the sources of PCDD/F, emissions and potential hazards, i.e., a toxic equivalent in Lithuania. The measurements were performed in two largest cities of Lithuania Vilnius and Kaunas, where the level of PCDD/F discovered was from 0.015 to 0.52 pg/m3 and from 0.02 to 0.05 pg/m3, respectively. The sites for the monitoring were selected based on their proximity to the locations of the planned cogeneration power plants in these cities.

The relationship between perinatal exposure to dioxins and serum steroid hormone levels in preschool-aged children at an e-waste region in China

Perinatal exposure to dioxins affects steroid hormone synthesis. The purpose of the present study was to evaluate the associations between perinatal exposure to dioxins and serum steroid hormone levels in preschool-aged children from an e-waste recycling region in China. In the present study, we enrolled 50 pairs of mothers and infants from the Taizhou, Luqiao region in 2015. Of the 50 pairs of mothers and infants, 42 pairs participated in this study when the children were 4 years old. We measured breast milk dioxin concentrations using high-resolution gas chromatography/mass spectrometry. Additionally, we used liquid chromatography-tandem mass spectrometry to measure the concentrations of progesterone, testosterone, androstenedione (A-dione), and dehydroepiandrosterone (DHEA) in serum samples from the 4-year-old children. We used multivariate linear regressions to assess the associations between dioxin congeners and steroid hormones. Results were reported as beta estimates and 95% confidence intervals by bootstrapping. We observed sex-related differences between breast milk dioxins and serum steroid hormone levels in 4-year-old children. An increase in breast milk dioxins was associated with a decrease in testosterone in serum samples from boys. Similarly, an increase in breast milk dioxins was associated with a decrease in progesterone levels in serum samples from girls. However, dioxins were not associated with changes in the levels of testosterone, DHEA, or A-dione in girls. Based on these results, we conclude that perinatal exposure to dioxins modifies steroidogenesis in preschool-aged children. However, the long-term impact of dioxins requires further large-scale studies to assess these effects in school-going children and adolescents.

Mass Spectrometry for Analysis of Changes during Food Storage and Processing

Many physicochemical changes occur during food storage and processing, such as rancidity, hydrolysis, oxidation, and aging, which may alter the taste, flavor, and texture of food products and pose risks to public health. Analysis of these changes has become of great interest to many researchers. Mass spectrometry is a promising technique for the study of food and nutrition domains as a result of its excellent ability in molecular profiling, food authentication, and marker detection. In this review, we summarized recent advances in mass spectrometry techniques and their applications in food storage and processing. Furthermore, current technical challenges associated with these methodologies were discussed.

The association between dioxins and steroid hormones in general adult males: a cross-sectional study in an e-waste region of China

As observed among residents in electronic waste (e-waste) recycling areas, dioxins can disrupt the homeostasis of endocrine hormones and the balance of thyroid hormones. Few studies, however, have examined whether e-waste recycling activities influence steroid hormone equilibrium in the general adult male population. This study evaluated the association between steroid hormones and the physical burdens of dioxins in the general adult male population residing in an e-waste region. In September 2017, 74 adult males residing in an e-waste dismantling region were enrolled in the current study. Approximately 10 mL of blood was collected from each adult male, and the serum samples were separated through centrifugation. Then, the levels of dioxin and steroid hormones in the serum of the participants were measured. We treated dioxin levels as categorical variables in the general linear model according to quartiles (25, 50, and 75 percentile). Comparing the findings with a reference group (< 25th percentile), we noted significantly higher dehydroepiandrosterone (DHEA) level in men with low serum polychlorinated dibenzofuran-toxic equivalent (PCDFs-TEQ) level between 3.80 and 6.31 pg/g lipid (1933 vs. 1447 pg/ml) and low polychlorinated dibenzo-p-dioxins and dibenzofurans-TEQ (PCDD/PCDFs-TEQ) between 8.57 and 15.11 pg/g lipid (1996 vs. 1360 pg/ml). Moreover, a significantly higher androstenedione (A-dione) level was found in men whose serum PCDFs-TEQ ≥ 11.34 pg/g lipd (2404 vs. 1848). What's more, there were significantly higher 3β-hydroxysteroid dehydrogenase (3β-HSD) concentrations in low- and high-2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) groups (1.30-1.67 and ≥ 2.64 pg-TEQ/g lipid, respectively with 719 and 807 vs. 496, respectively). Our findings suggest that specific dioxin exposure may disturb normal DHEA, A-dione levels, and enzyme activity in the general adult male population in an e-waste region of China.

Cytotoxicity of 2,2',3,5',6-Pentachlorobiphenyl (PCB95) and its metabolites in the chicken embryo liver cells of laying hens

2,2',3,5',6-Pentachlorobiphenyl (PCB95) is known as a persistent pollutant that was found in eggs in China. PCB 95 can be metabolized into OH-PCB95 and MeO-PCB95 in liver microsomes. However, the toxicity and its mechanism of PCB95 or its metabolites have been little studied on laying hens. Herein, chicken embryo liver cells of laying hens were selected and treated with different levels of PCB95 and its two metabolites, and the EC₅₀ of PCB95, OH-PCB95, MeO-PCB95 was 80.85, 4.81 and 107.04 μg/mL respectively, indicating that OH-PCB95 is much more cytotoxic than PCB95 or MeO-PCB95. Targeted metabolomics was further used to study the effects of the parent compound and its metabolites on cell metabolism. The results showed that four primary types of glycerophospholipids were down-regulated after exposure to PCB95 and its metabolites, especially PE and PS (60% more than the control for PCB95, 40% for OH-PCB95, and less than 40% for MeO-PCB95). KEGG pathway analysis based on amino acid metabolism showed that PCB95 may mainly interfere with the amino acids involved in immune regulation (phenylalanine and tyrosine), and OH-PCB95 may be associated with genetic disoders (cysteine, methionine and purine metabolism). However, the metabolic pathways induced by MeO-PCB95 are quite different from those induced by PCB95 and OH-PCB95, affecting mainly D-glutamine and D-glutamate metabolism, alanine and glutamate metabolism, and arginine and proline metabolism; these pathways mainly regulate the elimination of excess purines and are involved in the synthesis of the amino acids required by cells. These results showed that OH-PCB95 has the highest toxicity on chicken embryo liver cells and MeO-PCB95 could be a detoxification product of PCB95 and OH-PCB95. This study contributes to the understanding of the different effects of PCB95 and its metabolites on cellular metabolism, and the data are helpful in evaluating the hepatotoxic effects of these compounds.

Health risks and source identification of dietary exposure to indicator polychlorinated biphenyls (PCBs) in Lanzhou, China

Polychlorinated biphenyls (PCBs) are widely present in multiple environmental media even long after the phaseout, posing a health risk to the general population. Dietary intake is the major exposure route of PCBs; however, information is limited regarding PCBs in food that people directly consume. This study aims to measure personal exposure to indicator PCBs, evaluate the health risks, and identify their sources in a typical metropolitan city in China. Multi-day food samples were collected from 21 subjects in Lanzhou, Gansu Province, in two seasons using the duplicate plate method. Samples were extracted and analyzed for seven indicator PCBs using gas chromatography/mass spectrometry. Average daily doses (ADDs) of ∑7PCBs were estimated using Monte Carlo analysis with food intake information. Results show that PCB-118 and PCB-180 were the major congeners in food samples with average concentrations of 1.42 and 1.11 ng/g, respectively. The average (± SD) ADD of ∑7PCBs was 26.47 ± 22.10 ng/kg day among adults aged 18-69 years and displayed small variation across age groups. Comparing with the chronic RfD of 7 ng/kg day, 67% of people had their ADDs exceeding this threshold. The median cancer risk was 5.52 × 10^-5, and 51% of residents had risks exceeding the action level of 10^-4. The principal component analysis identified waste incineration, gasoline engine production, and leakage of #1 PCBs as the major PCBs sources. In conclusion, a large portion of Lanzhou residents has high non-cancer and cancer risks from dietary exposure to PCBs, which warrants control actions targeting these major sources.

The health concern of polychlorinated biphenyls (PCBs) in a notorious e-waste recycling site

Polychlorinated biphenyls (PCBs) remain a relatively high level in e-waste recycling regions 3 decades after ban on use. Illegal recycling activities cunningly moved under the environmental law enforcement. Here, we analyzed PCBs in soils and plants from Guiyu, China (one of the world's largest recycling areas) to understand the relationship between PCBs pollution and the transition of recycling activities (locations and techniques). High concentrations of PCBs were found in soil and plant samples from emerging recycling sites, up to 234 ng g^-1 and 236 ng g^-1 (dry weight), respectively. The recycling activities, specifically the open burning process, would obviously aggravate the PCB pollution levels in its environment. The calculated values of estimated daily intake and hazard ratios of PCBs in dietary routes showed that health risks should be taken seriously.

Dioxin and PCB residues in meats from Italy: Consumer dietary exposure

In order to investigate PCB and PCDD/F concentrations and potential human health risk a study has been conducted in meat samples (beef, pork, chicken and turkey) purchased from Italian supermarkets. PCBs were dominant (41.8-77.7 ng g^-1 l.w.) with respect to PCDD/Fs (20.1-91.1 pg g^-1 l.w.). The levels were variable and largely dependent upon the type of meat. Accumulation pattern showed a distribution typically reported for meat. PCBs tended to decrease from lowest to highest congeners, while for PCDD/Fs the concentration profile was dominated by highly chlorinated dioxins and furans. Concentrations of PCDD/Fs plus dl-PCBs and indicator PCBs exceeding the EU maximum permissible levels were found in 23.3% and 53.3% of the samples, respectively. Exposure estimates to PCDD/Fs plus dl-PCBs (0.08-4.16 pg WHO-TEQs kg^-1 b.w. w.^-1) were within the new limit proposed by the EFSA's expert panel, except for pork sausage, showing a twofold higher value. Concerning the exposure derived from indicator PCBs, the maximum level set by different European countries (10 ng kg^-1 b.w. d.^-1) was surpassed solely via consumption of pork sausage (17.22 ng kg^-1 b.w. d.^-1), thought also the estimated intake from hamburger consumption (6.88 ng kg^-1 b.w. d.^-1) merits attention being close to guideline limit.

Associations between polychlorinated dibenzo-dioxins and polychlorinated dibenzo-furans exposure and oxidatively generated damage to DNA and lipid

Polychlorinated dibenzo-dioxins and polychlorinated dibenzo-furans (PCDD/Fs) have been reported to induce reactive oxygen species and oxidative stress, but the dose-response relationships have not been explored in molecular epidemiological studies. In this study, a total of 602 participants were recruited, comprising of 215 foundry workers, 171 incineration workers and 216 residents living more than 5 km away from the plants as the reference group. Individual PCDD/Fs exposures were estimated according to PCDD/Fs levels of working and living ambient air and daily foods. Urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-iso-prostaglandin-F2α (8-isoPGF2α) were determined to reflect oxidatively generated damage to DNA and lipid. Generalized linear models were used to access the associations between PCDD/Fs exposure and oxidative stress biomarkers. We found that PCDD/Fs exposure and urinary oxidative stress biomarkers of workers were all higher than those of the reference group. Significantly positive exposure-response relationships between individual PCDD/Fs exposures and urinary 8-oxodG and 8-iso-PGF2α were found. Each 1-unit increase in ln-transformed levels of PCDD/Fs exposure generated a 0.78 nmol/mmol creatinine increase in ln-transformed 8-oxodG and a 0.50 ng/mmol creatinine increase in ln-transformed 8-isoPGF2α in foundry workers, a 0.49 nmol/mmol creatinine increase in ln-transformed 8-oxodG and a 0.26 ng/mmol creatinine increase in ln-transformed 8-isoPGF2α in incineration workers, compared with the reference group. And such associations were not modified by tobacco use. Our findings could help to understand the dose-response relationships between PCDD/Fs and oxidatively generated damage to DNA and lipid, and provide an epidemiologic basis for conducting research on the carcinogenesis and other toxicity mechanisms of PCDD/Fs.

Effects of perinatal dioxin exposure on development of children: a 3-year follow-up study of China cohort

The purpose of this study was to investigate the longitudinal effects of perinatal exposure to dioxin on physical growth in a 3-year follow-up study. In 2015, 27 mother-infant pairs living in an electronic waste (e-waste) dismantling region and 35 pairs living in a control region were enrolled in the present study. Breast milk samples were collected at 4 weeks after birth. Physical growth, including weight, height, and head and chest circumferences, was measured at 6 months and 3 years of age. Dioxin levels in the breast milk were measured by gas chromatography/high-resolution mass spectrometry. Levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin and toxic equivalency values in maternal breast milk of polychlorinated dibenzodioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and PCDDs/PCDFs were significantly higher in women residing in the e-waste dismantling region. In 3-year-old boys, inverse associations were found between height and PCDDs-TEQ. In girls, positive associations were found between height and 2,3,7,8-TetraCDD, PCDDs-TEQ, and PCDDs/PCDFs-TEQ, and for weight and PCDDs-TEQ and PCDDs/PCDFs-TEQ at 3 years of age. In this study, sex-specific differences were observed in children, in whom dioxin exposure decreased growth in boys but increased growth in girls during the first 3 years of life.

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.

Carboxylated Multiwalled Carbon Nanotubes as Dispersive Solid-Phase Extraction Sorbent to Determine Eighteen Polychlorinated Biphenyls in Vegetable Samples by Gas Chromatography-Mass Spectrometry

A simple, rapid, and reliable method based on dispersive solid-phase extraction (d-SPE) and gas chromatography-mass spectrometry (GC-MS) was developed for quantitating polychlorinated biphenyls (PCBs) in vegetable samples. Parameters affecting both the extraction yields and cleanup efficiency, including the type and volume of extraction solvent, extraction time, type and volume of cleanup sorbent, and cleanup time, were optimized. Matrix effects were evaluated, and matrix-matched calibration was recommended. Under the optimized conditions, carboxylated multiwalled carbon nanotubes (MWCNTs-COOH), which exhibit excellent adsorption capabilities due to large surface area and unique structure, were employed as d-SPE sorbent to remove interfering substances, rather than the analytes, from vegetable samples. Satisfactory linear relationship was observed for all PCBs across a concentration range of 5-500 μg/kg with correlation coefficients no less than 0.9993. Four representative vegetables (cucumber, tomato, lettuce, and cabbage) were selected as matrices for method validation. Each matrix was spiked at concentrations of 5, 10, and 100 μg/kg to evaluate recoveries, which ranged from 84.5% to 116.5% with relative standard deviations (n=6) between 0.6% and 17.6%. The limits of detection and the limits of quantification ranged from 0.3 to 1.4 μg/kg and 0.8 to 4.5 μg/kg, respectively. Twelve real vegetable samples were analyzed using the proposed method. Three of the target PCBs were detected in one lettuce sample with the total concentration of 17.9 μg/kg.

Levels of PCDD/Fs in foodstuffs in Tarragona County (Catalonia, Spain): Spectacular decrease in the dietary intake of PCDD/Fs in the last 20 years

In this study, we determined the levels polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in 45 "composite" samples of food items belonging to 12 food groups. Foodstuffs were purchased in various locations of Tarragona County, Catalonia, Spain. The daily dietary intake of PCDD/Fs was subsequently estimated for the population living in that County. The highest toxic equivalent (WHO-TEQ) value corresponded to fish (0.103 ng/kg ww), followed by seafood (0.071 ng/kg ww) and eggs (0.070 ng/kg ww). In contrast, the lowest PCDD/F concentrations corresponded to vegetables, tubers, pulses, and fruits (each, 0.003 ng/kg ww). The current dietary intake of PCDD/Fs by the adult population was estimated in 8.54 pg WHO-TEQ/day, being fish and seafood the food groups with the greatest contribution to the dietary exposure of PCDD/Fs, followed by eggs, as well as by meat, oils and fats. The current study shows a continued decrease in the exposure to PCDD/Fs by the general population of Tarragona County since the first survey in the area conducted in 1998. The reduction observed in the last 20 years (from 210 pg I-TEQ/day to 8.54 pg WHO-TEQ/day) is certainly spectacular. The current daily intake (0.122 pg WHO-TEQ/kg bw) is also lower than most intakes recently reported in a number of regions and countries.

Toxicity of polyhalogenated dibenzo-p-furans in the light of nucleic acid bases interaction

Quantitative structure-activity relationship (QSAR) investigation utilizing quantum chemical descriptors under density functional theory is performed to predict the toxicity (pEC₅₀) of a series of polyhalogenated dibenzo-p-furans (PHDFs). PHDFs are very important concern to the researchers due to their presence and diverse effects in the environment. A successful two parameter QSAR model is developed with a combination of a global descriptor known as charge transfer (ΔN) between toxins and biosystem and a local descriptor as Fukui function (f_max⁺) for maximum nucleophilic attack at the toxin site. A systematic analysis is performed to identify the electron donation/acceptance nature of the considered PHDF compounds with the choice of a model biosystems comprising five different nucleic acid bases, namely Adenine, Thymine, Guanine, Cytosine and Uracil to identify proper ΔN descriptor. Accordingly, PHDFs are found to be electron acceptors with maximum charge transfer from Guanine and therefore, ΔN_G is utilized as the charge transfer parameter for all the toxins in the present work. The selected combination of global and local descriptors (ΔN_G andf_max⁺) are found to predict 93% of the observed toxicity (pEC₅₀) of the PHDFs. The developed QSAR model is tested for two different test sets: PHDFs and polyhalogenated biphenyls (PHBs) with about 90% of prediction of their toxicity values, which confirms the importance of the selected descriptors.