Probabilistic human health risk assessment of PCDD/Fs near municipal solid-waste incinerator using Monte Carlo analysis coupled with triangular fuzzy numbers.

PCDD/Fs are dioxins produced by waste incineration and pose risks to human health. We aimed to detail the health risks of airborne and soil PCDD/Fs near a municipal solid-waste incinerator (MSWI) for the surrounding population and develop a new model that improves upon existing methods. Thus, we conducted field sampling and then investigated a MSWI in the Pearl River Delta (2016-2018). Our results showed that the carcinogenic and non-carcinogenic risk values of PCDD/Fs exposed to residents in nearby areas were acceptable, with hazard index (HI) values lower than 1.0 and a total carcinogenic risk lower than 1.0E-6. Notably, the results raised concerns regarding higher non-carcinogenic risks in children than in adults. Comparative analysis of the frequency accumulation diagram, accumulated probability risk, and the absolute value of error (δ) between the 95% confidence interval (CI) and the 90% CI of the Monte Carlo stochastic simulation-triangular fuzzy number (MCSS-TFN) and the MCSS model, respectively, demonstrated that the MCSS-TFN exhibited less uncertainty than the MCSS model, regardless of the health risk value of PCDD/Fs in ambient air or in soil. This observation underscores the superiority of the MCSS-TFN model over other models in assessing the health risks associated with PCDD/Fs in situations with limited data. Our new method overcomes the limited dataset size and high uncertainty in assessing the health risks of dioxin substances, providing a more comprehensive understanding of their associated health risks than MCSS models.

Human molybdenum exposure risk in industrial regions of China: New critical effect indicators and reference dose.

Evidence increasingly suggests molybdenum exposure at environmental levels is still associated with adverse human health, emphasizing the necessity to establish a more protective reference dose (RfD). Herein, we conducted a study measuring 15 urinary metals and 30 clinical health indicators in 2267 participants residing near chemical enterprises across 11 Chinese provinces to investigate their relationships. The kidney and cystatin-C emerged as the most sensitive organ and critical effect indicator of molybdenum exposure, respectively. Odds of cystatin-C-defined chronic kidney disease (CKD) in the highest quantile of molybdenum exposure significantly increased by 133.5% (odds ratio [OR]: 2.34, 95% CI: 1.78, 3.11) and 75.8% (OR: 1.76, 95% CI: 1.24, 2.49) before and after adjusting for urinary 14 metals, respectively. Intriguingly, cystatin-C significantly mediated 15.9-89.5% of molybdenum's impacts on liver and lung function, suggesting nephrotoxicity from molybdenum exposure may trigger hepatotoxicity and pulmonary toxicity. We derived a new RfD for molybdenum exposure (0.87 µg/kg-day) based on cystatin-C-defined estimated glomerular filtration rate by employing Bayesian Benchmark Dose modeling analysis. This RfD is significantly lower than current exposure guidance values (5-30 µg/kg-day). Remarkably, >90% of participants exceeded the new RfD, underscoring the significant health impacts of environmental molybdenum exposure on populations in industrial regions of China.

Why Do People Gain Belly Fat in Rural Areas? A Study of Urinary Metal(loid)s and Abdominal Obesity in China.

Obesity is prevalent in rural areas of China, and there are inconsistent findings regarding the association between metal(loid) exposure and the risk of obesity. Abdominal obesity (AOB), which reflects visceral fat abnormity, is a crucial factor in studying obesity-related diseases. We conducted a study measuring 20 urinary metal(loid)s, 13 health indicators, and the waist circumference (WC) in 1849 participants from 10 rural areas of China to investigate their relationships. In the single exposure models, we found that urinary chromium (Cr) was significantly associated with the odds of having AOB [adjusted odds ratio (OR) = 1.81 (95% confidence interval (CI): 1.24, 2.60)]. In the mixture exposure models, urinary Cr consistently emerged as the top contributor to AOB, while the overall effect of mixed metal(loid)s was positive toward the odds of having AOB [adjusted OR: 1.33 (95% CI: 1.00, 1.77)], as revealed from the quantile g-computation model. After adjusting for the effects of other metal(loid)s, we found that the elevation of apolipoprotein B and systolic blood pressure significantly mediated the association between urinary Cr and the odds of having AOB by 9.7 and 19.4%, respectively. Our results suggest that exposure to metal(loid)s is a key factor contributing to the prevalence of AOB and WC gain in rural areas of China.

Sorption of tetrabromobisphenol A onto microplastics: Behavior, mechanisms, and the effects of sorbent and environmental factors.

Microplastics (MPs) and halogenated organic pollutants coexist in ambient water and MPs tend to sorb organic pollutants from surrounding environments. Herein, a study on the sorption behavior of tetrabromobisphenol-A (TBBPA) onto four different MPs, namely, polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC) was carried out. Effects of MPs properties and environmental factors, including the type, surface charge and pore volume as well as the ionic strength (Ca2+) and humic acid (HA) on the sorption of TBBPA were discussed. Results showed that the sorption of TBBPA onto the MPs could reached an equilibrium within 24 h, and the sorption capacities decreased in the following order -PVC (101.85 mg kg-1) >PS (78.95 mg kg-1) >PP (58.57 mg kg-1) >PE (49.43 mg kg-1). Adsorption kinetics data fitted by intraparticle diffusion model revealed both surface sorption and intraparticle diffusion contributed, in the interfacial diffusion stage approximately 11-29% of TBBPA slowly diffused onto the surface of the MPs, and finally, in the intraparticle diffusion stage. The increase of Ca2+ concentration could promote the sorption of TBBPA by PE, PP, and PS, but no significant alteration for PVC. For all the four MPs, HA was found to exert a negative effect on TBBPA sorption. The adsorption was mainly driven by hydrophobic partition and electrostatic interactions.

Health implication of heavy metals exposure via multiple pathways for residents living near a former e-waste recycling area in China: A comparative study.

Herein, crop (vegetables and rice, n = 30), soil (n = 14), dust (n = 12), and PM10 (n = 25) samples were collected to assess the environmental quality of a former e-waste recycling area and evaluate the related health risks. In dust and PM10, the concentrations of heavy metals (Cd, Cu, Ni, Pb, and Zn) were lower than previously reported values, although the numbers for soil, vegetables, and rice remained high. The average accumulation factors of heavy metals in crops decreased in the order of Zn > Cd > Ni > Cu > Pb, and soil was identified as the largest contributor to crop pollution. Heavy metal ingestion largely occurred via rice consumption, which accounted for a significant fraction of the total average daily dose (ADD; 75.2-86.7% in children and 78.0-91.7% in adults), especially for Cd, Cu, Ni, and Zn. However, in the case of Pb, soil ingestion accounted for 48.9% of the ADD in adults, while in children, vegetable, rice, and dust ingestion accounted for 44.7%, 28.6%, and 23.7% of the ADD, respectively. The combined exposure hazard indices at the fifth, median, and 95th percentiles for all heavy metals were determined as 2.54, 9.40, and 40.1 for adults and as 3.75, 13.7, and 58.4 for children, respectively. In terms of health risk, crop consumption was identified as the major exposure pathway for both children and adults, featuring a contribution of 99.9%. In addition, the 95th percentile carcinogenic risks for Pb exceeded the acceptable level. Thus, this work shows that to reduce the health risk for local residents in the former e-waste area, more attention should be paid to soil repair.

A review of toxicity induced by persistent organic pollutants (POPs) and endocrine-disrupting chemicals (EDCs) in the nematode Caenorhabditis elegans.

Persistent organic pollutants (POPs) and endocrine disrupting compounds (EDCs) are almost ubiquitous in synthetic and natural sources; however these contaminants adversely impact ecosystems and humans. Owing to their potential toxicity, concerns have been raised about the effects of POPs and EDCs on ecological and human health. Therefore, toxicity evaluation and mechanisms actions of these contaminants are of great interest. The nematode Caenorhabditis elegans (C. elegans), an excellent model animal for environmental toxicology research, has been used widely for toxicity studies of POPs or EDCs from the whole-animal level to the single-cell level. In this review, we have discussed the toxicity of specific POPs or EDCs after acute, chronic, and multigenerational exposure in C. elegans. We have also introduced a discussion of the toxicological mechanisms of these compounds in C. elegans, with respect to oxidative stress, cell apoptosis, and the insulin/IGF-1 signaling pathway. Finally, we raised considered the perspectives and challenges of the toxicity assessments, multigenerational toxicity, and toxicological mechanisms.

Synthesis of methoxy-substituted picenes: substitution position effect on their electronic and single-crystal structures.

A series of picenes having methoxy groups was synthesized through Pd-catalyzed Suzuki-Miyaura couplings or Wittig reaction/intramolecular cyclization sequences, and their physicochemical properties and single-crystal structures were evaluated. The substitution position effects between the outer 1,12-, 2,11-, and 4,9-position and the inner 3,10-position are quite different; the former showed the same electronic structure as that of picene, but the latter results in a HOMO geometry different from those of picene and other methoxy picenes. In addition, crystal structures of four types of methoxy-substituted picenes 4a-c,e strongly depend on their substitution position and number of methoxy groups, which dramatically changes the structures from the fully anisotropic 1D π-stacked structure to a unique 3D herringbone structure due to steric hindrance of methoxy groups. The calculations of transfer integrals based on their single-crystal structures reveal that the methoxy picenes have intermolecular overlaps less effective than that of the parent nonsubstituted picene. These results are attributed not only to the packing structure but also to electronic structures such as the HOMO distribution. The preliminary OFET of the representative 4c,e showed hole mobilities significantly lower than that of picene due to their less effective intermolecular overlaps, as predicted by the calculated transfer integrals.

Copper-catalyzed decarboxylative C3-acylation of free (N-H) indoles with α-oxocarboxylic acids.

An efficient Cu-catalyzed decarboxylative C3-acylation of free (N-H) indoles using α-oxocarboxylic acids as acylating agents has been developed. This method was compatible with a variety of functional groups and provided an attractive alternative access to 3-acylindoles in moderate to high yields.

Health assessment based on exposure to microplastics in tropical agricultural soil.

Microplastic (MP) pollution of agricultural soils has caused global alarm over its widespread distribution and potential risks to terrestrial ecosystems and human health. This study assessed human health based on exposure to soil MPs through a comprehensive investigation of the factors influencing their occurrence and spatial distribution on Hainan Island, South China. The results showed that the abundance of soil MPs was 1128.6 ± 391.5 items·kg-1, whereas the normalized abundance of MPs based on using a power-law function was 19,261.4 items·kg-1. Regarding the extent of population exposure to agricultural soil MPs, the average daily exposure dose (pADD) model revealed that using mass as an indicator to assess the health risks associated with MP intake is more reliable than using abundance. However, abundance-based exposure assessments are also relevant because MPs with smaller particle sizes are more harmful to human health. Moreover, for adults, the normalized pADD values based on abundance and mass were 1.68E-02 item MPs·kg BW-1·d-1 and 7.23E-02 mg MPs·kg BW-1·d-1, respectively. Although the multidimensionality of MPs should be further aligned and quantified, the preliminary findings of this study contribute to the development of human health risk assessment frameworks for soil MPs.

Transcriptome-based approach to identify mechanisms underlying locomotor abnormality induced by decabromodiphenyl ethane in zebrafish larvae.

The brominated flame retardant decabromodiphenyl ethane (DBDPE) has been extensively used following restrictions on BDE-209 and thus, been frequently detected in aquatic environment. However, information on impact of DBDPE on fish development and the potential mechanisms remains scarce. In present study, developing zebrafish were employed as a study model. Embryos were exposed until 5 d to DBDPE at concentrations of 0, 3, 30, and 300 µg/L, following which the impact on larval development was investigated. DBDPE bioaccumulation and locomotor hyperactivity were observed in developing zebrafish exposed to DBDPE. Transcriptome and bioinformatics analyses indicated that pathways associated with cardiac muscle contraction and retinol metabolism were notably affected. The mechanisms of DBDPE to induce locomotor abnormality were further investigated by analyzing levels of retinol and retinol metabolites, eye and heart histology, heart rates, and ATPase activity. Our results indicate that locomotor hyperactivity observed in larvae exposed to DBDPE results from abnormal heartbeat, which in turn is attributable to inhibition of Na+/K+-ATPase activity. Furthermore, DBDPE did not change larval eye histology and contents of retinoid (retinol, retinal, and retinoic acid). This study provides insight into the mechanisms underlying DBDPE-induced developmental toxicity and highlights the need for addressing the environmental risks for aquatic organisms.

Identification and health risk evaluation of soil contaminated by polycyclic aromatic hydrocarbons at shale gas extraction sites based on positive matrix factorization.

The impact of shale gas extraction on surrounding environmental media remains unclear. In this study, the current state of contamination by polycyclic aromatic hydrocarbons (PAHs), which are high-frequency contaminants of shale gas, was investigated in the soil surrounding emerging shale gas development sites. The source analysis of PAHs was conducted in the soils of shale gas extraction sites using positive matrix factorization (PMF). The health risk assessment (HRA) was calculated for ingestion, dermal contact, and inhalation exposures, and the priority sources of PAHs in the soil were jointly identified by PMF and HRA to refine the contribution level of different individual PAHs to the carcinogenic risk. The results showed that both Sichuan and Chongqing mining site soils were contaminated to different degrees. Shale gas extraction has an impact on the surrounding soil, and the highest contributing source of PAHs in the mining site soil of Sichuan was anthropogenic activity, accounting for 31.6%, whereas that in the mining site soil of Chongqing was biomass combustion and mixed automobile combustion, accounting for 35.9%. At the two mining sites in Sichuan and Chongqing, none of the three exposure pathways (ingestion, dermal contact, and inhalation) posed a carcinogenic risk to children, whereas the dermal exposure pathway posed a carcinogenic risk to adults. Health risk assessments based on specific source assignments indicate that when managing soil pollution, the control of fossil fuel combustion and vehicular emissions should be prioritized.

Associations of urinary zinc exposure with blood lipid profiles and dyslipidemia: Mediating effect of serum uric acid.

The relationship between zinc (Zn) exposure and abnormal blood lipids including dyslipidemia is contentious. Serum uric acid (SUA) has been reported to be correlated to both Zn exposure and dyslipidemia. The underlying mechanisms of Zn exposure associated with blood lipids and the mediating effects of SUA remain unclear. Therefore, this study analyzed the data from Chinese 2110 adults (mean age: 59.0 years old) in rural areas across China to explore the associations of Zn exposure with blood lipid profiles and dyslipidemia, and to further estimate the mediating effects of SUA in these relationships. The study data showed that urinary Zn was associated with increased levels of blood lipid components triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C). Moreover, an increased risk of dyslipidemia was observed in the study participants who had higher urinary Zn levels. Compared with the first quartile, the fourth quartile of urinary Zn concentration corresponded to the increase of TG (ß = 0.20, 95 % CI: 0.12, 0.28), LDL-C (ß = 0.06, 95 % CI: 0.01, 0.10) and dyslipidemia risk (OR = 2.16, 95 % CI: 1.50, 3.10), respectively. Elevated urinary Zn was also associated with higher levels of SUA and hyperuricemia risk. The SUA levels were positively related to total cholesterol (TC), TG, LDL-C levels and dyslipidemia risk. Mediation analyses revealed that SUA mediated 31.75 %, 46.16 % and 19.25 % of the associations of urinary Zn with TG, LDL-C levels and dyslipidemia risk, respectively. The subgroup and sensitivity analyses confirmed the positive associations between urinary Zn and blood lipid profiles and the mediating effect of SUA. The national population-based study further enhanced our understanding of the associations between Zn exposure and blood lipid profiles and mediating effect of SUA among generally healthy, middle-aged, and elderly individuals.

Simultaneous determination of ten taste and odor compounds in drinking water by solid-phase microextraction combined with gas chromatography-mass spectrometry.

Taste and odor (T&O) problems in drinking water frequently occur because of many compounds present in the water, of which trans-1,10-dimethyl-trans-9-decalol (geosmin) and 2-methylisoborneol (MIB) are well-known. In this study, a fast and effective method was established for simultaneous determination of 10 T&O compounds, including geosmin, MIB, 2,4,6-trichloroanisole (TCA), 2-methylbenzofuran, 2-isopropyl-3-methoxypyrazine (IPMP), 2-isobutyl-3-methoxypyrazine (IBMP), cis-3-hexenyl acetate, trans,trans-2,4-heptadienal, trans, cis-2,6-nonadienal, and trans-2-decenal in water samples by headspace solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry. An orthogonal array experimental design was used to optimize the effects of SPME fiber, extraction temperature, stirring rate, NaCI content, extraction time, and desorption time. The limits of detection ranged from 0.1 to 73 ng/L were lower than or close to the odor threshold concentrations (OTCs). All the 10 T&O compounds were detected in the 14 water samples including surface water, treatment process water and tap water, taken from a waterworks in Lianyungang City, China. MB and geosmin were detected in most samples at low concentration. Six T&O compounds (IPMP, IBMP, trans,cis-2,6-nonadienal, 2-methylbenzofuran, trans-2-decenal, and TCA) were effectively decreased in water treatment process (sedimentation and filtration) that is different from cis-3-hexenyl acetate, MIB and geosmin. It is noted that the TCA concentrations at 15.9-122.3 ng/L and the trans,cis-2,6-nonadienal concentrations at 79.9-190.1 ng/L were over 10 times higher than their OTCs in tap water. The variation of the analytes in the all water samples, especially distribution system indicated that distribution system cannot be ignored as a T&O compounds source.

Development of human health criteria in China for benzo[a]pyrene: A comparison of deterministic and probabilistic approaches.

Human health water quality criteria (HHWQC) for benzo[a]pyrene (BaP) in Chinese rivers and lakes were established using both deterministic and probabilistic approaches. Results showed that the national bioaccumulation factor (BAF) values for BaP at trophic levels 2, 3, and 4 were 342 L/kg, 199 L/kg, and 196 L/kg, respectively. The probabilistic HHWQC for BaP was 0.00407 µg/L for both water and organisms consumption and 0.00488 µg/L for organisms consumption only, which provide a more adequate protection than the deterministic HHWQC. Approximately 32.1% of the studied waters in China exceeded the derived HHWQC, which is likely to have adverse health effects and need be considered more attention. The derived HHWQC for BaP is soly based on Chinese exposure-related activity patterns and field-measured BAFs in surface freshwaters in China, which is important to provide a scientific basis for establishing or revising water quality standards (WQS) and risk management of BaP in water.

Health risk assessment of trace metal(loid)s in agricultural soil using an integrated model combining soil-related and plants-accumulation exposures: A case study on Hainan Island, South China.

Traditional health risk assessment of trace metal(loid)s (TMs) in agricultural soil exclusively considers direct soil-related exposure and may underestimate the health risks they pose. In this study, the health risks of TMs were evaluated using an integrated model that combined soil-related and plant-accumulating exposures. A detailed investigation of common TMs (Cr, Pb, Cd, As, and Hg) coupled with probability risk analysis based on a Monte Carlo simulation was conducted on Hainan Island. Our results showed that, except for As, the non-carcinogenic risk (HI) and carcinogenic risk (CR) of the TMs were all within the acceptable ranges (HI < 1.0, and CR < 1E-06) for direct soil-related exposure to bio-accessible fractions and indirect exposure via plant accumulation (CR substantially lower than the warning threshold 1E-04). We identified crop food ingestion as the essential pathway for TM exposure and As as the critical toxic element in terms of risk control. Moreover, we determined that RfDo and SFo are the most suitable parameters for assessing As health risk severity. Our study demonstrated that the proposed integrated model combining soil-related and plant-accumulating exposures can avoid major health risk assessment deviations. The results obtained and the integrated model proposed in this study can facilitate future multi-pathway exposure research and could be the basis for determining agricultural soil quality criteria in tropical areas.

Identification and verification of PCDD/Fs indicators from four typical large-scale municipal solid waste incinerations with large sample size in China.

Monitoring PCDD/Fs emissions from municipal solid waste incinerations (MSWIs) is of paramount importance, yet it can be time-consuming and labor-intensive. Predictive models offer an alternative approach for estimating their levels. However, robust models specific to PCDD/Fs were lacking. In this study, we collected 190 PCDD/Fs samples from 4 large-scale MSWIs in China, with the average PCDD/Fs levels and TEQ levels of 0.987 ng/m3 and 0.030 ng TEQ/m3, respectively. We developed and evaluated predictive models, including traditional statistical methods, e.g., linear regression (LR) as well as machine learning models such as back propagation-artificial neural networks (BP ANN) and random forest (RF). Correlation analysis identified 2,3,4,7,8-PeCDF, 1,2,3,6,7,8-HxCDF, 2,3,4,6,7,8-HxCDF were better indicator congeners for PCDD/Fs estimation (R2 > 0.9, p < 0.001). The predictive results favored the RF model, exhibiting a high R2 value and low root mean square error (RMSE) and mean absolute error (MAE). Additionally, the RF model showed excellent prediction ability during external validation, with low absolute relative error (ARE) of 10.9 %-12.6 % for the three indicator congeners in the normal PCDD/F TEQ levels group (<0.1 ng TEQ/m3) and slightly higher ARE values (13.8 %-17.9 %) for the high PCDD/F TEQ levels group (>0.1 ng TEQ/m3). In conclusion, our findings strongly support the RF model's effectiveness in predicting PCDD/Fs TEQ emission from MSWIs.

Associations between trace level thallium and multiple health effects in rural areas: Chinese Exposure and Response Mapping Program (CERMP).

Thallium (Tl) is a cumulative high toxicant in the environment, but few studies have investigated the comprehensive health effects underlying chronic Tl exposure at trace levels. This study aims to evaluate the liver, kidney, lung and other potential health effects associated with chronic Tl exposure at trace levels in rural areas of China. Urinary Tl concentrations of 2883 adults from rural areas of 12 provinces in China were measured and 2363 participants were involved in the final analysis. Indicators of liver and kidney functions in the serum, as well as the lung function indicators, were determined in the participants. General linear regression and restricted cubic spline regression were combined to study the associations between urinary Tl and health indicators or outcomes. In this study, the detected rate of Tl in the urine of the participants was 97.28 %. When the urinary Tl concentration was ranged at the fourth quintile, the risk of having liver function disorder was 70 % higher [Odds ratio (OR) = 1.70 (95 % confidence intervals (CI): 1.30, 2.22)] in all the participants, whereas the farmers were more likely to have the disorder [OR = 2.08 (95 % CI: 1.49, 2.92)] than the non-farmers [OR = 1.20 (95 % CI: 0.77, 1.88)]. Nonlinear associations between most of the liver health indicators and urinary Tl were identified, of which serum bilirubin was strongly associated with the elevation of urinary Tl when its concentration was >0.40 µg/g creatinine. Besides, urinary Tl was negatively associated with lung health indicators. Our study proposes the safety re-assessment of the current exposure level of Tl in the environment, especially in rural areas of China.

Association of urinary exposure to multiple metal(loid)s with kidney function from a national cross-sectional study.

BACKGROUND: Arsenic (As), cadmium (Cd) and copper (Cu) are hazardous for kidney function, while the effects of selenium (Se) and zinc (Zn) were unexplored for the narrow safe range of intake. Interactions exists between these multiple metal/metalloid exposures, but few studies have investigated the effects. METHODS: A cross-sectional survey was performed among 2210 adults across twelve provinces in China between 2020 and 2021. Urinary As, Cd, Cu, Se and Zn were measured using inductively coupled plasma-mass spectrometry (ICP-MS). Serum creatinine (Scr) and N-acetyl-beta-D glucosaminidases (urine NAG) were quantified in serum and urine, respectively. Kidney function was evaluated by the estimated glomerular filtration rate (eGFR). We employed logistic regression and Bayesian kernel machine regression (BKMR) models to explore the individual and joint effects of urinary metals/metalloids on the risk of impaired renal function (IRF) or chronic kidney disease (CKD), respectively. RESULTS: Association was found between As (OR = 1.24, 95 % CI: 1.03, 1.48), Cd (OR = 1.65, 95 % CI: 1.35, 2.02), Cu (OR = 1.90, 95 % CI: 1.59, 2.29), Se (OR = 1.51, 95 % CI: 1.24, 1.85) and Zn (OR = 1.33, 95 % CI: 1.09, 1.64) and the risk of CKD. Moreover, we observed association between As (OR = 1.18, 95 % CI: 1.07, 1.29), Cu (OR = 1.14, 95 % CI: 1.04, 1.25), Se (OR = 1.15, 95 % CI: 1.06, 1.26) and Zn (OR = 1.12, 95 % CI: 1.02, 1.22) and the risk of IRF. Additionally, it was found that Se exposure may strength the association of urinary As, Cd and Cu with IRF. Furthermore, it is worth noting that Se and Cu contributed greatest to the inverse association in IRF and CKD, respectively. CONCLUSION: Our findings suggested that metal/metalloid mixtures were associated with kidney dysfunction, Se and Cu were inverse factors. Additionally, interactions between them may affect the association. Further studies are needed to assess the potential risks for metal/metalloid exposures.

Glutamatergic transmission associated with locomotion-related neurotoxicity to lindane over generations in Caenorhabditis elegans.

Organochlorine pesticide lindane in the environment and biota results in the potential risks on ecosystem and human health. Lindane can adversely affect the locomotion and nervous system, yet the potential neurotoxicity of lindane over generations remains uncertain. In this study, the neurotoxicity and underlying mechanisms in Caenorhabditis elegans (C. elegans) were investigated after parental (P0) exposure to lindane at environmentally relevant concentrations over generations. Exposure to lindane at concentrations of 10-100 ng/L significantly decreased body bends and head thrashes in P0 generation. Significant decrease of fluorescence labeled different neurotransmitters, and clear morphological changes by exposure to lindane at 10-100 ng/L suggested that lindane could induce the neuronal damage in C. elegans. During the transgenerational process, decreased locomotive behaviors were also observed in F1-F3 generations, and head thrashes returned to normal levels in F4 generation. Moreover, lindane exposure down-regulated the expression of dat-1, dop-1, glr-1 and mod-1genes, while up-regulated unc-30 gene in P0 generation, which recovered to normal levels in F4 generation. Interestingly, eat-4 continued to be regulated from inhibition to stimulation in P0-F4 generations, suggesting that glutamatergic transmission may more contribute to the neurotoxicity of lindane over generations.

Brominated flame retardants and heavy metals in common aquatic products from the pearl river delta, south china: Bioaccessibility assessment and human health implications.

Aquatic products are an important source of environmental pollutants to humans. This study was conducted to assess the bioaccessibility of selected brominated flame retardants and heavy metals in common aquatic products from the Pearl River Delta, South China, as well as associated human health risks. Based on a questionnaire survey, ten of the most consumed aquatic products were collected from local markets. The bioaccessibility of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCDDs), and heavy metals was assessed using an in vitro gastrointestinal model. Bioaccessibility of heavy metals (33.0-84.0%) and HBCDDs (38.5-68.4%) was significantly higher than that of PBDEs (13.4-65.4%). Total non-carcinogenic and carcinogenic risks from heavy metal consumption were much higher than the threshold values due to excessive abundances of arsenic in shellfish (HQ = 2.45, CR = 1.1 ×10-3). Furthermore, middle-aged populations and females were subjected to greater health risks due to different intakes of aquatic products among age and gender groups. Significant difference in bioaccessibility among analytes indicated that bioaccessibility of pollutants is non-negligible in health risk assessment. This is the first study systematically investigating health risks of aquatic products consumption and concludes that shellfish is a great cause for concern for the PRD residents.