Human health risk assessment of multiple contaminants due to consumption of animal-based foods available in the markets of Shanghai, China

A review of common statistical methods for dealing with multiple pollutant mixtures and multiple exposures

Traditional environmental epidemiology has consistently focused on studying the impact of single exposures on specific health outcomes, considering concurrent exposures as variables to be controlled. However, with the continuous changes in environment, humans are increasingly facing more complex exposures to multi-pollutant mixtures. In this context, accurately assessing the impact of multi-pollutant mixtures on health has become a central concern in current environmental research. Simultaneously, the continuous development and optimization of statistical methods offer robust support for handling large datasets, strengthening the capability to conduct in-depth research on the effects of multiple exposures on health. In order to examine complicated exposure mixtures, we introduce commonly used statistical methods and their developments, such as weighted quantile sum, bayesian kernel machine regression, toxic equivalency analysis, and others. Delineating their applications, advantages, weaknesses, and interpretability of results. It also provides guidance for researchers involved in studying multi-pollutant mixtures, aiding them in selecting appropriate statistical methods and utilizing R software for more accurate and comprehensive assessments of the impact of multi-pollutant mixtures on human health.

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.

Strategies for mitigation of pesticides from the environment through alternative approaches: A review of recent developments and future prospects

Chemical-based peticides are having negative impacts on both the healths of human beings and plants as well. The World Health Organisation (WHO), reported that each year, >25 million individuals in poor nations are having acute pesticide poisoning cases along with 20,000 fatal injuries at global level. Normally, only ∼0.1% of the pesticide reaches to the intended targets, and rest amount is expected to come into the food chain/environment for a longer period of time. Therefore, it is crucial to reduce the amounts of pesticides present in the soil. Physical or chemical treatments are either expensive or incapable to do so. Hence, pesticide detoxification can be achieved through bioremediation/biotechnologies, including nano-based methodologies, integrated approaches etc. These are relatively affordable, efficient and environmentally sound methods. Therefore, alternate strategies like as advanced biotechnological tools like as CRISPR Cas system, RNAi and genetic engineering for development of insects and pest resistant plants which are directly involved in the development of disease- and pest-resistant plants and indirectly reduce the use of pesticides. Omics tools and multi omics approaches like metagenomics, genomics, transcriptomics, proteomics, and metabolomics for the efficient functional gene mining and their validation for bioremediation of pesticides also discussed from the literatures. Overall, the review focuses on the most recent advancements in bioremediation methods to lessen the effects of pesticides along with the role of microorganisms in pesticides elimination. Further, pesticide detection is also a big challenge which can be done by using HPLC, GC, SERS, and LSPR ELISA etc. which have also been described in this review.

Unexpectedly high levels and health risks of atmospheric polychlorinated biphenyls in modern mechanical dismantling of obsolete electrical equipment: Investigations in a large integrated e-waste dismantling industrial estate

Large industrial estates for electrical and electronic waste (e-waste) mechanical dismantling and recycling are gradually replacing outmoded small factories and intensive domestic workshops for e-waste manual and chemical dismantling. However, the air pollution and health risks of persistent organic pollutants during the modern mechanical processing of e-waste, especially obsolete electrical equipment, still remain unclear. Here, unexpectedly high levels (409.3 ng/m3) and health risks of airborne polychlorinated biphenyls (PCBs) were found during the mechanical processing of obsolete electric equipment or parts in a large integrated dismantling industrial estate, which is comparable to or a dozen times higher than those reported during chemical processing. In contrast, the levels (936.0 pg/m3) and health risks of particulate polybrominated diphenyl ethers (PBDEs) were all lower than those of previous studies. PCB emissions (44.9-3300.5 ng/m3) varied significantly across six mechanical dismantling places specifically treating waste motors, electrical appliances, hardware, transformers, and metals, respectively. The high PCB content and mass processing number of obsolete electrical equipment probably result in the highest PCB emissions from the mechanical dismantling of obsolete motors, followed by waste electrical appliances and metals. The PCB non-cancer and cancer risks associated with inhalation and dermal exposure in different mechanical dismantling places were all above the given potential risk limits. In particular, the health risks of dismantling obsolete motor exceeded the definite risk levels. Little difference in PCB emissions and health risks between working and non-working time suggested the importance of PCB volatilization from most e-waste. Such high PCB emissions and health risks of PCBs undoubtedly posed a severe threat to frontline workers, but fortunately, they decreased significantly with the increasing distance from the industrial estate. We highlight that PCB emissions and associated health risks from obsolete electrical equipment with high PCB content during mechanical dismantling activities should be of great concern.

De-novo exposure assessment of heavy metals in commercially important fresh and dried seafood: Safe for human consumption

The heavy metals (HMs) in seafood are alarming due to their biomagnification in the food chain. The concentrations of As, Cd, Hg, Pb, Cr, and Ni in both fresh and dried fish were quantified, and the potential exposure and safe intake levels for human consumption were assessed by the European Commission (EC) and the Food Safety Standard Authority of India (FSSAI). HMs concentrations ranged from 0.003 mg/kg (Cr) to 2.08 mg/kg for (As) and 0.007 mg/kg (Hg) to 2.76 mg/kg (As). Cd, Hg, and Pb levels in fresh and dried fish were below the maximum residue limits (MRLs) set by the EC and FSSAI, which were 0.1 mg/kg, 0.5 mg/kg, and 0.3 mg/kg, respectively. Cr and As concentrations were also below the MRLs of 12 mg/kg and 76 mg/kg for aquatic products specified by FSSAI. The concentration of HMs in fresh and dried fish was found in the order of As > Cr > Ni > Pb > Cd > Hg and As > Cd > Cr > Ni > Pb > Hg, while the fresh and dried fishes contained HMs in the following order: E. areolatus > S. longiceps > L.lentjen > S. barracuda > E. affinis > S. javus and DA > DS > DR > DB > DSF. The metal pollution index (MPI) validates seafood is HMs free, while the single (Pi) and Nemerow integrated pollution index (Pnw) indicate that concentrations of Cd and As in fresh and dried fish have exceeded the threshold value. The target hazard quotient (THQ<1), hazard index (HI < 1), and target cancer risk (TCR<10-4) indicate that there are no non-carcinogenic and carcinogenic risks through the consumption of seafood and seafood products collected from the Tuticorin coast and marketed at the domestic and international levels. The preliminary findings emphasize the importance of formulating domestic legislation/government initiatives to promote seafood and its consumption. The attainment of this objective shall be facilitated by examining the levels of persistent organic pollutants (POPs) in seafood and evaluating its potential risk to consumers.

Occurrence and probabilistic risk assessment of polycyclic aromatic hydrocarbons in blood and urine of auto-mechanics in Akure Metro, Nigeria

This study provides baseline data on the concentration of polycyclic aromatic hydrocarbons (PAHs) in blood and urine samples of auto-mechanics, using Nigeria as a case study. Eighteen auto-mechanics participated in the study excluding two controls. The concentrations for the ΣPAHs across all participants (excluding control) ranged from 1.67 to 3.30 (2.17 ± 0.58) in blood with a significantly higher (P < 0.05) range of 7.61 to 10.76 (8.69 ± 1.00) in urine. The high molecular weight PAHs (4-6 rings) dominated the PAH profile in both blood (≥ 92%) and urine (≥ 87%) across all locations. Dibenz(a)anthracene was the most distributed PAH, while acenaphthene and indeno(1,2,3-cd)pyrene were the least distributed. The dermal route constituted approximately 99% of the total chronic exposure, followed by ingestion, and the least via inhalation. The hazard index (HI) was below the safe thresholds (HI = 1), suggesting non-carcinogenic PAH effects. However, all the participants including control samples had carcinogenic risk (CR) values above the acceptable level of 10^-6 in both blood and urine samples. The carcinogenic and mutagenic potencies were higher in urine than in blood. The results suggest less acute toxicity and more potential chronic effects. The computed elimination ratio (> 1) suggests low excretion in urine and a potentially harmful trend. Molecular diagnostic ratios and principal component analysis suggest mixed PAH sources. The study revealed biomonitoring solely dependent on blood analysis may greatly underestimate health risks due to PAH exposure. To the best of our knowledge, this study is the first to provide levels of PAHs in the blood and urine of Nigerian mechanics. Findings herein will support policymakers at all levels in re-focusing attention to the less prioritized professions that pre-disposes people to PAHs and other emerging pollutants in society.

Multi-omics analysis reveals BDE47 induces depression-like behaviors in mice by interfering with the 2-arachidonoyl glycerol-associated microbiota-gut-brain axis

2,2',4,4'-tetrabromodiphenyl ether (BDE47) is a foodborne environmental risk factor for depression, but the pathogenic mechanism has yet to be fully characterized. In this study, we clarified the effect of BDE47 on depression in mice. The abnormal regulation of the microbiome-gut-brain axis is evidenced closely associated with the development of depression. Using RNA sequencing, metabolomics, and 16s rDNA amplicon sequencing, the role of the microbiome-gut-brain axis in depression was also explored. The results showed that BDE47 exposure increased depression-like behaviors in mice but inhibited the learning memory ability of mice. The RNA sequencing analysis showed that BDE47 exposure disrupted dopamine transmission in the brain of mice. Meanwhile, BDE47 exposure reduced protein levels of tyrosine hydroxylase (TH) and dopamine transporter (DAT), activated astrocytes and microglia cells, and increased protein levels of NLRP3, IL-6, IL-1β, and TNF-α in the brain of mice. The 16 s rDNA sequencing analysis showed that BDE47 exposure disrupted microbiota communities in the intestinal contents of mice, and faecalibaculum was the most increased genus. Moreover, BDE47 exposure increased the levels of IL-6, IL-1β, and TNF-α in the colon and serum of mice but decreased the levels of tight junction protein ZO-1 and Occludin in the colon and brain of mice. In addition, the metabolomic analysis revealed that BDE47 exposure induced metabolic disorders of arachidonic acid and neurotransmitter 2-Arachidonoyl glycerol (2-AG) was one of the most decreased metabolites. Correlation analysis further revealed gut microbial dysbiosis, particularly faecalibaculum, is associated with altered gut metabolites and serum cytokines in response to BDE47 exposure. Our results suggest that BDE47 might induce depression-like behavior in mice through gut microbial dysbiosis. The mechanism might be associated with the inhibited 2-AG signaling and increased inflammatory signaling in the gut-brain axis.

Accumulation and biotransformation of the novel vanillin-derived pesticide, vanisulfane, in laying hens after dietary exposure

Vanisulfane is a novel plant antiviral agent with promising prospects to prevent and control viral crop diseases. However, human health risk assessment after vanisulfane exposure from animal-derived food products remains limited. To gain insight into the accumulation and biotransformation of vanisulfane in livestock, laying hens were dietary exposed to ¹⁴C-vanisulfane. Although more than 80 % of the applied dose was observed in the excreta, vanisulfane and its metabolites accumulated in tissues, especially the liver and kidney, and was found to be transferred to eggs. A total of eight metabolites associated with both phase I and phase II metabolism were identified via ¹⁴C tracing and LC-QTOF-MS. Phase I metabolism included oxidation, hydroxylation, dechlorination and demethylation, and phase II metabolism was associated with sulfonic acid and glucuronide conjugation. The high percentages of metabolites in laying hens' tissues and organs, illustrated the active biotransformation of vanisulfane in vivo, which suggests that the marker residues of vanisulfane should consider its major metabolites. A digestive model was also used to determine the digestive fate of vanisulfane. This study improves our understanding of vanisulfane accumulation and biotransformation in laying hens, which will be helpful for risk assessments of foods derived from animals exposed to pesticides.

Exposure to polycyclic aromatic hydrocarbons and the associations with oxidative stress in waste incineration plant workers from South China

Waste incineration is one of the most common emission sources of polycyclic aromatic hydrocarbons (PAHs), causing potential occupational exposure in waste incineration workers. However, relative investigations among waste incineration plant workers are still very limited, particularly in China. Therefore, we collected urine specimens from 77 workers in a waste incineration plant as the exposed group, and 101 residents as the control group in Shenzhen, China. Nine mono-hydroxylated PAH metabolites (OH-PAHs) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were measured, and their internal relationships were explored. The urinary levels of most OH-PAHs and 8-OHdG in the exposed group exhibited high levels versus another group (p < 0.05). We found negative associations between OH-PAHs and 8-OHdG in the control group (p < 0.05), while most of OH-PAHs were not associated with 8-OHdG in the exposed group, which indicated that the exposure to waste incineration could enlarge the level of individual oxidative stress damage. Nevertheless, PAHs were less likely to trigger obvious health risks in exposed workers through estimation of human intake and exposure risks. This study provides a reference for occupational PAH exposure and strengthen the need of health monitoring among incineration workers.

Human exposure to polybrominated diphenyl ethers (PBDEs) through the diet: An update of the scientific literature

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame-retardants (BFRs). As for other persistent organic pollutants, dietary intake (followed by dust inhalation) is the main route of human exposure to PBDEs. In 2012, we reviewed the scientific literature on the concentrations of PBDEs in foodstuffs and their dietary exposure. The current review is aimed at updating the results of recent studies (2012-2022) focused on determining the levels of PBDEs in food samples, as well as the dietary intake of these compounds. We have revised studies conducted over the world. The current information on the concentrations of PBDEs in food and their dietary intake is now much more notable than that available in our previous review, being China the country contributing with the highest number of studies. Because of the important differences in materials and methods used in the available studies, the comparison of results is certainly complicated. However, there seems to be a general trend towards a decrease in the levels of PBDEs in foods, and consequently, in the dietary intake of these contaminants. The lack of tolerable daily intakes of PBDEs is an issue that needs to be solved for assessing human health risks of these BFRs.

Exposure Routes and Health Risks Associated with Pesticide Application

Pesticides play an important role in agricultural development. However, pesticide application can result in both acute and chronic human toxicities, and the adverse effects of pesticides on the environment and human health remain a serious problem. There is therefore a need to discuss the application methods for pesticides, the routes of pesticide exposure, and the health risks posed by pesticide application. The health problems related to pesticide application and exposure in developing countries are of particular concern. The purpose of this paper is to provide scientific information for policymakers in order to allow the development of proper pesticide application technics and methods to minimize pesticide exposure and the adverse health effects on both applicators and communities. Studies indicate that there are four main pesticide application methods, including hydraulic spraying, backpack spraying, basal trunk spraying, and aerial spraying. Pesticide application methods are mainly selected by considering the habits of target pests, the characteristics of target sites, and the properties of pesticides. Humans are directly exposed to pesticides in occupational, agricultural, and household activities and are indirectly exposed to pesticides via environmental media, including air, water, soil, and food. Human exposure to pesticides occurs mainly through dermal, oral, and respiratory routes. People who are directly and/or indirectly exposed to pesticides may contract acute toxicity effects and chronic diseases. Although no segment of the general population is completely protected against exposure to pesticides and their potentially serious health effects, a disproportionate burden is shouldered by people in developing countries. Both deterministic and probabilistic human health risk assessments have their advantages and disadvantages and both types of methods should be comprehensively implemented in research on exposure and human health risk assessment. Equipment for appropriate pesticide application is important for application efficiency to minimize the loss of spray solution as well as reduce pesticide residuals in the environment and adverse human health effects due to over-spraying and residues. Policymakers should implement various useful measures, such as integrated pest management (IPM) laws that prohibit the use of pesticides with high risks and the development of a national implementation plan (NIP) to reduce the adverse effects of pesticides on the environment and on human health.

Urinary heavy metals in residents from a typical city in South China: human exposure and health risks

Although heavy metal pollution has developed into a major global environmental problem, most research has focused on specific elements, especially arsenic (As) and selenium (Se), and on the health risks to people in polluted areas or by occupation. This study investigated the urine of 480 participants from Guangzhou with a population of 18 million and targeted nine heavy metals: As, Se, chromium (Cr), manganese (Mn), nickel (Ni), cadmium (Cd), lead (Pb), antimony (Sb), and mercury (Hg). The heavy metals were widely detected, of which As, Se, Cd, and Pb all exceed 98%. Among the toxicants, As showed the highest concentration, followed by Se with 40.5 and 35.4 μg/L, respectively. The heavy metal levels from suburban subjects were generally higher than those in urban subjects (except for Sb), and the Cd level of males was lower than that of females. Concentrations were related to age, body mass index, alcohol consumption, and smoking. According to the health risk assessment, most subjects experienced potential non-carcinogenic risk from As, Cd, Se, and Hg, which accounted for 38.2%, 8.83%, 8.31%, and 3.38%, respectively. The carcinogenic risk of As and Cd surpassed the risk level of 10^-6, and 90.1% and 35.4% of the subjects, respectively, exceeded 10^-4, an unacceptable risk level. More attention to the high carcinogenic risk from heavy metals and the high detected levels of As and Cd is required.

Perchlorate and chlorate in breast milk, infant formulas, baby supplementary food and the implications for infant exposure

Perchlorate and chlorate are ubiquitous pollutants in various types of foodstuffs, drinking water and environmental compartments. They have raised great concerns due to potential adverse effects on human thyroid functions. Dietary intake is considered as the predominant pathway for human exposure to perchlorate and chlorate. Nevertheless, data on human exposure to the chemicals above remain limited, particularly for the most vulnerable populations such as infants. In the present study, 62 breast milks, 53 infant formulas, 88 baby supplementary food and 50 tap water samples were collected in South China and the levels of perchlorate and chlorate were measured in these samples. Perchlorate and chlorate were frequently detected in more than 90% of measured samples. In these different types of samples, the median concentrations of perchlorate were 0.65 μg/L, 0.61 μg/kg, 0.56 μg/kg and 1.18 μg/L, respectively, while the median concentrations of chlorate were 1.73 μg/L, 2.48 μg/kg, 2.67 μg/kg and non-detected, respectively. Health risk assessment using hazard quotient suggested that perchlorate and chlorate exposure in the sampled baby food are not expected to increase the risk of an adverse health effect. To our knowledge, this is the first study simultaneously investigating perchlorate and chlorate exposure in Chinese infants via food intake.

Human health risks estimations from polycyclic aromatic hydrocarbons in serum and their hydroxylated metabolites in paired urine samples

Polycyclic aromatic hydrocarbons (PAHs) are compounds with two or more benzene rings whose hydroxylated metabolites (OH-PAHs) are excreted in urine. Human PAH exposure is therefore commonly estimated based on urinary OH-PAH concentrations. However, no study has compared PAH exposure estimates based on urinary OH-PAHs to measurements of PAH levels in blood samples. Estimates of PAH exposure based solely on urinary OH-PAHs may thus be subject to substantial error. To test this hypothesis, paired measurements of parent PAHs in serum and OH-PAHs in urine samples from 480 participants in Guangzhou, a typical developed city in southern China, were used to investigate differences in the estimates of human PAH exposure obtained by sampling different biological matrices. The median PAH concentration in serum was 4.05 ng mL^-1, which was lower than that of OH-PAHs in urine (8.33 ng mL^-1). However, serum pyrene levels were significantly higher than urinary levels of its metabolite 1-hydroxypyrene. Concentrations of parent PAHs in serum were not significantly correlated with those of their metabolites in urine with the exception of phenanthrene, which exhibited a significant negative correlation. Over 28% of the participants had carcinogenic risk values above the acceptable cancer risk level of 10^-6. Overall, estimated human exposure and health risks based on urinary 1-hydroxypyrene levels were only 13.6% of those based on serum pyrene measurements, indicating that estimates based solely on urine sampling may substantially understate health risks due to PAH exposure.

Estimating the dietary exposure and risk of persistent organic pollutants in China: A national analysis

Substantial heterogeneities have been found in previous estimations of the risk from dietary exposures to persistent organic pollutants (POPs) in China, mainly due to spatiotemporal variations. To comprehensively evaluate the dietary risks of POPs listed in the Stockholm Convention, more than 27,580 data records from 753 reports published over the last three decades were examined. Respectively, for various food categories, the results obtained for the range of mean concentrations of POPs are as follows: total dichlorodiphenyltrichloroethanes (DDTs: 1.4-27.1 μg/kg), hexachlorocyclohexanes (HCHs: 1.8-29.3 μg/kg), polybrominated diphenyl ethers (PBDEs: 0.046-2.82 μg/kg), polychorinated biphenyls (PCBs: 0.05-7.57 μg/kg), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD&Fs: 2.9-210 pg toxic equivalent (TEQ)/kg), perfluorooctanoic acid (PFOA: 0.02-0.97 μg/kg), perfluoroctane sulfonate (PFOS: 0.00082-2.76 μg/kg) and short-chain chlorinated paraffins (SCCPs: 64-348.92 μg/kg). Temporal decreasing trends were observed for DDTs, HCHs, PBDEs, PCDD&Fs, and PFOA, with no significant change for other POPs. Meanwhile, the estimated daily intake for adults were 75.2 ± 43.6 ng/kg/day for DDTs, 123 ± 87 ng/kg/day for HCHs, 0.37 ± 0.17 pg TEQ/kg/day for PCDD&Fs, 17.8 ± 9.5 ng/kg/day for PCBs, 3.3 ± 1.8 ng/kg/day for PBDEs, 3.6 ± 1.9 ng/kg/day for PFOA, 3.3 ± 2.0 ng/kg/day for PFOS, and 2.5 ± 1.6 μg/kg/day for SCCPs. Furthermore, non-carcinogenic risks were the highest for PCBs (0.89) and PCDD&Fs (0.53), followed by PFOA (0.18), PFOS (0.17), HCHs (0.062), SCCPs (0.025), DDTs (0.0075), and PBDEs (0.00047). These findings illustrated that exposure to POPs declined due to the control policies implemented in China, while the cumulative risk of POPs was still higher than 1, indicating continuous efforts are required to mitigate associated contamination.

Risk Assessment of Cd, Cu, and Pb from the consumption of hunted meat: red-legged partridge and wild rabbit

The objective was to assess that potential health risk from Cd, Cu, and Pb, through the consumption of hunted red-legged partridge and wild rabbit meat, with special focus on the population of hunters and their relatives. Mineral content was analyzed by atomic absorption methods (F-AAS for Cu and GF-AAS for Cd and Pb) after microwave digestion of lyophilized samples. The average concentrations of these elements were 0.008 and 0.01 mg/kg for Cd; 1.41 and 1.63 mg/kg for Cu and 0.98 and 1.28 mg/kg for Pb in wild rabbit and red-legged partridge meat respectively. The dietary, risk assessment was performed by assuming two intake scenarios based on the obtained results of the survey on game meat consumption and the current maximum recommended intakes of Cd, Cu, and Pb, and then, the hazard quotients (THQ and TTHQ) were calculated. The data show that exposure to these metals from eating red-legged partridge and wild rabbit meat from a hunting provenance is relatively low and generally greater in the hunter population. The risk assessment revealed that moderate or low consumption of meat of these species does not offer a significant public health risk. Moreover, hazard quotients values for these metals of red-legged partridge and rabbit meat consumption in hunters and nonhunters are below 1. However, a high Pb content in the meat of these species and a high consumption may pose a greater health risk to hunters.

Co-exposure and health risks of parabens, bisphenols, triclosan, phthalate metabolites and hydroxyl polycyclic aromatic hydrocarbons based on simultaneous detection in urine samples from guangzhou, south China

Polycyclic aromatic hydrocarbons (PAHs) and certain ingredients in personal care products, such as parabens, bisphenols, triclosan and phthalate metabolites, have become ubiquitous in the world. Concerns of human exposure to these pollutants have increased during recent years because of various adverse health effects of these chemicals. Multiple compounds including parabens, bisphenols, triclosan, phthalate metabolites (mPAEs) and hydroxyl PAHs (OH-PAHs) in urine samples from Guangzhou were determined simultaneously to identify the human exposure pathways without external exposure data combined with data analysis, and the toxicants posed the highest risk to human health were screened in the present study. The detection frequencies for the chemicals exceeded 90%. Among the contaminants, mPAEs showed the highest concentrations, followed by OH-PAHs, with triclosan present at the lowest concentrations. Mono-n-butyl phthalate, methylparaben, bisphenol A, and hydroxynaphthalene represented the most abundant mPAE, parabens, bisphenol, and OH-PAH compounds, respectively. The present PAHs are mainly exposed to human through inhalation, while the chemicals added to personal care products are mainly exposed to human through oral intake and dermal contact. The urine samples from suburban subjects showed significantly higher OH-PAH levels than the urine samples from urban subjects, and females had lower OH-PAH levels than males. Urinary concentrations of the analyzed contaminants were significantly correlated with age, body mass index, residence time, as well as the frequencies of alcohol consumption and swimming. Risk assessments based on Monte Carlo simulation indicated that approximately 30% of the subjects suffered non-carcinogenic risks from mPAEs and OH-PAHs, with mPAEs accounting for 89% of the total risk.

A review on in-vitro oral bioaccessibility of organic pollutants and its application in human exposure assessment

Generally, human oral exposure assessments of contaminants have not considered the absorption factor in the human gastrointestinal tract, thus overestimating human exposure and associated health risk. Currently, more researchers are adding the absorption factor into human exposure assessment, and bioaccessibility measured by in-vitro methods is generally replacing bioavailability for estimation because of the cheap and rapid determination. However, no single unified in-vitro method is used for bioaccessibility measurement of organic pollutants, although several methods have been developed for these pollutants and have shown good in vitro-in vivo correlation between bioaccessibility and bioavailability. The present review has focused on the development of in-vitro methods, validation of these methods through in-vivo assays, determination of factors influencing bioaccessibility, application of bioaccessibility in human exposure assessment, and the challenges faced. Overall, most in-vitro methods were validated using bioavailability, and better in vitro-in vivo correlations were obtained when absorption sinks were added to the digestion solution to mimic dynamic absorption of organic chemicals by small intestine. Incorporating bioaccessibility into the estimation of human exposure by oral ingestion significantly decreases the estimated exposure dose. However, more investigations on bioaccessibility of hydrophobic organic compounds are urgently needed because many challenges for in-vitro methods remain to be overcome.

Co-exposure to polycyclic aromatic hydrocarbons and phthalates and their associations with oxidative stress damage in school children from South China

Monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs), phthalate metabolites (mPAEs), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in the urine of school children aged 8-11 years from Shenzhen, China were measured in order to investigate oxidative stress damage from co-exposure to PAHs and PAEs. The concentrations of OH-PAHs and mPAEs in urine were 0.36-36.5 (median: 3.86) and 9.48-1609 (median: 240) ng/mL respectively. Gender and age did not influence urinary concentrations of ΣOH-PAHs and ΣmPAEs, but geographical variations (i.e., urban versus suburban) were observed. Levels of 8-OHdG were positively correlated with urinary OH-PAHs and mPAEs, with correlation coefficients (r) varying between 0.160 and 0.365 (p < 0.05). OH-PAHs made a greater contribution to oxidative DNA damage than mPAEs when these two types of pollutants were present at the same concentrations. Human health risks were assessed using the hazard quotient and the hazard index for the cumulative risk of a complex of chemicals. The results demonstrated that risks from PAHs could be neglected, but that 29.5 % of school children may be subject to obvious health risks from PAEs, especially diethylhexyl phthalate.

Temporal trends of "old" and "new" persistent halogenated organic pollutants in fish from the third largest freshwater lake in China during 2011-2018 and the associated health risks

The study aimed to investigate temporal trends of "old" and "new" persistent halogenated organic pollutants (HOPs) in Taihu Lake, the third largest freshwater lake in China, and the associated health risks. Five fish species were consecutively collected from the lake every year during 2011-2018. HOPs including 37 polychlorinated biphenyls (PCBs), 10 organochlorine pesticides (OCPs), short- and medium-chain chlorinated paraffins (SCCPs and MCCPs), 19 polybrominated diphenyl ethers (PBDEs), and 10 new brominated flame retardants (NBFRs), were measured. The results showed that all the HOPs were detected, with MCCPs and NBFRs showing the highest and lowest concentrations, respectively. The levels of SCCPs and MCCPs were several orders of magnitude higher than those of the other HOPs. There were obvious increasing trends for SCCPs, MCCPs, and hexachlorobenzene, but a decreasing trend for PBDEs. No obvious increasing or decreasing trends were observed for the other HOPs. The present study indicated that the use of NBFRs to replace PBDEs was not yet clearly observed. Fish consumption did not result in non-carcinogenic risks, but posed low carcinogenic risks, with PCBs and DDTs being the highest-risk contaminants because of historical residues. This is the first study for the temporal variations of the HOPs in the lake.

Cancer risk and disease burden of dietary cadmium exposure changes in Shanghai residents from 1988 to 2018

Cadmium (Cd) is a widely distributed toxic metal, which is mainly exposed to humans through diet. The impact of dietary guidelines on the Chinese diet structure has indirectly led to changes in dietary Cd exposure. The Chinese Dietary Guidelines were issued in 1997 and revised in 2007. Based on the time between issuance and revision, this study examined the Cd contamination levels in Shanghai foods from 1988 to 2018 and evaluated cancer risk and disease burden of dietary Cd exposure accordingly. Over the time periods of 1988-1997, 1998-2007, and 2008-2018, it was found that Cd dietary exposure of Shanghai residents showed a trend of increasing and then decreasing (39.7, 44.7, and 36.4 μg/day, respectively). In contrast to cereals, the contribution rates of meat and vegetables to Cd exposure have gradually increased over time, and aquatic foods have become the main source of Cd exposure (40.6%). Although the non-cancer risk hazard quotients of dietary Cd exposure and the excess lifetime cancer risks (ELCR) are relatively low (HQ < 1, ELCR < 10^-4), 26.6% of Shanghai residents had a potential risk of kidney injury calculated by toxicokinetic model (TK model), and the disability adjusted life years (DALYs) have been rising (from 41.6 to 58.2). Results indicated that in the past three decades, changes of Cd contamination in food due to both limit standards and changes in dietary structure have influenced cancer risk and disease burden from Cd exposure in Shanghai residents. In summary, our study suggested that while regulating the contamination in foods, attention should also be paid to the potential impacts of dietary structure and guidelines on the exposure of pollutants.

Interrelationship of anthropogenic activity and parabens in fish from Taihu Lake during 2009-2017

Parabens are alkyl esters widely used as preservatives in foodstuffs, cosmetics, and pharmaceuticals. Taihu Lake is the third largest freshwater lake in China. However, there is no information available on the occurrence of parabens in Taihu Lake. To investigate contamination of parabens in Taihu Lake and the influence of human activities on contamination levels, 199 fish samples, comprising five species, were collected from Taihu Lake from 2009 to 2017. Five parabens, including methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), butylparaben (BuP), and benzylparaben (BeP), were quantitated using an isotope dilution LC-MS/MS method. The total concentrations of the five parabens ranged from 261 to 1710 pg/g wet weight (ww) with an average of 642 pg/g ww. The predominant compounds were MeP, EtP, and PrP, whose amounts accounted for more than 95% of the total amounts. No significant differences in the concentrations of parabens among the five fish species were observed, suggesting no interspecies differences in bioaccumulation of these compounds. Σ₅parabens in fish showed temporal variations with the means ranging between 532 and 772 pg/g ww during years. The levels of parabens were generally consistent with the economic development and urbanization rates of the regions surrounding Taihu Lake. The "typical" and "high" estimated daily intake (EDI) of parabens were 0.53 and 0.91 ng/kg-bw/day for children, and 0.46 and 0.79 ng/kg-bw/day for adults based on calculations using the means and the 95th concentrations, respectively. The EDIs were much lower than the reference dose values, suggesting that there are no obvious health risks posed by fish consumption.

Persistent Halogenated Organic Pollutants in Surface Water in a Megacity: Distribution Characteristics and Ecological Risks in Wuhan, China

Surface water pollution in megacities is strongly linked to human and environmental health, and surface water quality has deteriorated sharply recently because of increasing persistent halogenated organic pollutant (HOP) concentrations. In the present study, we collected 112 water samples from 14 lakes and 11 drinking water sources in Wuhan, China, and analyzed them for two typical groups of HOPs: polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). The mean values of the ΣPCB concentrations were 4.34 and 10.05 ng L^-1 in winter and summer, respectively. For ΣPBDE concentrations, the mean values were 0.88 and 1.53 ng L^-1 in winter and summer, respectively. The PCB and PBDE concentrations at most sites in summer were significantly higher than those in winter, probably because of heavy stormwater runoff in summer. The degree of urbanization predicted from the population density was positively correlated with ΣPCB concentrations in the drinking water sources in summer. PBDE and PCB composition analysis suggested the major sources were penta-BDE and Aroclor mixtures. Risk assessments showed the PBDEs in water from the Zhuankou site exceeded the threshold set by the European Union, which could result in adverse effects on aquatic organisms. Negligible noncarcinogenic risks were found for PCBs and PBDEs in the surface water with regard to drinking and bathing. However, the carcinogenic risks of PCBs for bathing in surface water were higher than the safe level of 1.00 × 10^-6, implying that the surface water in Wuhan is not safe for bathing.

Trace determination of carbamate pesticides in medicinal plants by a fluorescent technique

The safety issue of using carbamate pesticides in medicinal plants (MPs) has been a global concern and hence attracted attention of many researchers to develop analytical tools for trace pesticides detection. Derived from the fluorescence-based techniques, a rapid, convenient and efficient method for the detection of three carbamate pesticides, including carbofuran, aldicarb and methomyl has been developed by using core-shell QDs. By optimizing experimental parameters, the system demonstrated high detection sensitivities for the investigated carbamates, with the lowest detectable concentrations less than 0.05 μM. The molecular docking study indicated that the selected carbamate pesticides bound to the catalytic active site of acetylcholinesterase via π-π or H-π interactions, which also revealed the potential mechanism of the differences in inhibition strength among the three pesticides on AChE. Moreover, in order to investigate the applicability and reliability of the proposed method for the pesticide analysis in real sample with complex matrix, the matrix effects of eight common MPs have been systematically explored. These findings suggested that this technique was a simple, sensitive and reliable method for rapid determination of carbamate pesticides in real samples, especially those with complex matrices like MPs, vegetables, fruits, and other agricultural crops.

Concentrations of environmental organic contaminants in meat and meat products and human dietary exposure: A review

Meat and meat products is one of the most relevant food groups in an important number of human diets. Recently, the IARC, based on results of a number of epidemiological studies, classified the consumptions of red meat and processed meat as "probably carcinogenic to humans" and as "carcinogenic to humans", respectively. It was suggested that the substances responsible of the potential carcinogenicity would be mainly generated during meat processing, such as curing and smoking, or when meat is heated at high temperatures. However, the exposure to environmental pollutants through meat consumption was not discussed. The purpose of the present paper was to review recent studies reporting the concentrations of PCDD/Fs, DL-PCBs and PAHs in meat and meat products, as well as the human exposure to these pollutants through the diet. It is concluded that the health risks derived from exposure to carcinogenic environmental contaminants must be considered in the context of each specific diet, which besides meat and meat products, includes other foodstuffs containing also chemical pollutants, some of them with carcinogenic potential. Anyhow, meat and meat products are not the main food group responsible of the dietary exposure to carcinogenic (or probably carcinogenic) environmental organic pollutants.

Patulin and ochratoxin A co-occurrence and their bioaccessibility in processed cereal-based foods: A contribution for Portuguese children risk assessment

Patulin (PAT) and ochratoxin A (OTA) are well known enteropathogenic mycotoxins that are present in several foodstuffs. Processed cereal-based foods are among the first solid foods eaten by children, a particularly vulnerable population group. There is a lack of knowledge related to the co-occurrence of PAT and OTA in food intended for children consumption and their potential interactions during the digestion process. The present study aims to evaluate, for the first time, the co-occurrence of PAT and OTA in processed cereal-based foods for children consumption, the bioaccessibility of these two mycotoxins, and the contribution of the bioaccessibility data for human health risk assessment. PAT and OTA incidence were 75% and 50%, respectively. These mycotoxins co-occurred in 40% of analysed samples. Bioaccessibility assays revealed mean values of 52% and 56% for PAT, alone and combined with OTA; and 100% and 106% for OTA, alone and combined with PAT. Considering the human health risk assessment, and taking into account the co-occurrence and the bioaccessibility results, this study indicates a tolerable exposure to these mycotoxins representing a low risk for Portuguese children. The present work reinforces the importance of a holistic approach for risk assessment which gathers data from occurrence, exposure and bioaccessibility.

Seafood consumption among Chinese coastal residents and health risk assessment of heavy metals in seafood

The aims of the present study were to obtain the seafood dietary patterns of coastal residents, to determine the concentrations of heavy metals, and to evaluate the possible health risks caused by seafood intake. The daily food intakes of 24 types of seafood were collected from 738 participants from Xiamen, a southern Chinese coastal city, using food frequency questionnaire (FFQ) and dietary history method. One hundred and fifty-six samples of 14 types of highest intake seafood were collected from local markets for lead (Pb), cadmium (Cd), chromium (Cr), mercury (Hg), and arsenic (As) determination. Health risks via seafood consumption were evaluated by calculating the target hazard quotient (THQ) and the total hazard index (HI) for carcinogenic and non-carcinogenic effects recommended by the US Environmental Protection Agency. The results showed that the seafood daily intake of Xiamen residents was 61.5 (2.14, 115) g/day. The concentrations of Pb, Cd, Cr, Hg, and As in seafood were ND-0.45 mg/kg, ND-0.19 mg/kg, ND-0.80 mg/kg, ND-0.70 mg/kg, and 0.32-16.9 mg/kg, respectively. Concentrations of Cd and As in some samples were higher than national limitation standards. Consumption of 14 common types of seafood would not pose non-carcinogenic risk. However, some types, such as sparuslatus, oyster, and porphyra tenera, would form a carcinogenic risk. Regardless of a carcinogenic or non-carcinogenic risk, As posed the highest risk on humans. The observed HI value for non-carcinogenic effect of all metals in all seafood reached 0.69-2.20, and the metal orders of risk can be listed as As > Hg > Cr > Cd > Pb, reiterating the risk of As is a matter of concern in seafood from Xiamen markets.

[Recent Epidemiological Studies on Methylmercury, Mercury and Selenium]

More than sixty years has passed since the outbreak of Minamata disease, and high-level methylmercury contaminations now seem nonexistent in Japan. However, mercury has been continuously discharged from natural sources and industrial activities, and the health effects on children susceptible to methylmercury exposure at low levels, in addition to mercury contamination from mercury or gold mining areas in developing countries, become a worldwide concern. In this article, we provide a recent overview of epidemiological studies regarding methylmercury and mercury. The following findings were obtained. (1) Many papers on exposure assessment of methylmercury/mercury have been published since the Minamata Convention on Mercury was adopted in 2013. (2) The most crucial problem is child developmental neurotoxicity resulting from prenatal exposure to methylmercury, but its precise assessment seems to be difficult because most of such effects are neither severe nor specific. (3) Several problems raised in birth cohort studies (e.g., whether IQ deficits due to prenatal methylmercury exposure remain when the children become adults, or whether the postnatal exposure at low levels also causes such adverse effects in children) remain unsolved. (4) Concurrent exposure models of methylmercury, lead, polychlorinated biphenyls, aresenic, and organochlorine pesticides, as well as possible antagonists such as polyunsaturated fatty acids and selenium, should be considered in the study design because the exposure levels of methylmercury are extremely low in developed countries. (5) Further animal experiments and molecular biological studies, in addition to human studies, are required to clarify the mechanism of methylmercury toxicity.

Nutrients and contaminants in tissues of five fish species obtained from Shanghai markets: Risk-benefit evaluation from human health perspectives

Shanghai is a Chinese megacity in the Yangtze River Delta area, one of the most polluted coastal areas in China. The inhabitants of Shanghai have very high aquatic product consumption rates. A risk-benefit assessment of the co-ingestion of fish nutrients and contaminants has not previously been performed for Shanghai residents. Samples of five farmed fish species (marine and freshwater) with different feeding habits were collected from Shanghai markets in winter and summer. Fatty acids, protein, mercury, cadmium, lead, copper, polychlorinated biphenyls, hexachlorocyclohexanes, and dichlorodiphenyltrichloroethanes were measured in liver, abdominal fat, and dorsal, abdominal, and tail muscles from fish. Tolerable daily intakes and benefit-risk quotients were calculated to allow the benefits and risks of co-ingesting n-3 long-chain polyunsaturated fatty acids and contaminants to be assessed according to the cancer slope factors and reference doses of selected pollutants. All of the contaminant concentrations in the muscle tissues were much lower than the national maximum limits, but the livers generally contained high Hg concentrations, exceeding the regulatory limit. The organic pollutant and n-3 long-chain polyunsaturated fatty acid concentrations correlated with the lipid contents of the fish tissues, and were higher in carnivorous marine fish than in omnivorous and herbivorous freshwater fish. The tolerable daily intakes, risk-benefit quotients, and current daily aquatic product intakes for residents of large Chinese cities indicated that the muscle tissues of most of the fish analyzed can be consumed regularly without significant contaminant-related risks to health. However, attention should be paid to the potential risks posed by dichlorodiphenyltrichloroethane in large yellow croaker and Hg in tilapia. Based on the results of this study, we encourage people to consume equal portions of marine and freshwater fish.