Occurrence of liquid crystal monomers in indoor and outdoor air particle matters (PM10): Implications for human exposure indoors.

Liquid crystal monomers (LCMs) are potentially persistent, bioaccumulating, and toxic substances. However, limited data are available on the occurrence of LCMs in indoor and outdoor air particle matter (PM10) in residential areas. Herein, residential areas near an e-waste dismantling center (Guiyu Town, Shantou City), as well as areas away from the e-waste site (Jiedong District, Jieyang City) were selected as the sampling areas. PM10 was collected from the indoor environments of Guiyu (IGY) and Jieyang (IJY), as well as those from the outdoor environments (OGY and OJY) using the high-volume air samplers (TH-10000C). The levels of 57 LCMs in PM10 were analyzed, and the highest concentrations of LCMs were found in IGY (0.970-1080 pg/m3), followed by IJY (2.853-455 pg/m3), OGY (0.544-116 pg/m3) and OJY (0.258-35.8 pg/m3). No significant difference was observed for LCM levels in indoor PM10 between the two areas (p > 0.05), which were significantly higher than those in outdoors (p < 0.05), indicating that the release of electronic products in general indoor environments is a source of LCMs that cannot be ignored. The compositions of LCMs in outdoors were not consistent with those of indoors. The correlation analysis of individual LCMs suggested potential different sources to the LCMs in indoor and outdoor environments. The median daily intake values of Σ46LCMs via inhalation were estimated as 0.440, 1.46 × 10-2, 0.170 and 1.19 × 10-2 ng/kg BW/day for adults, and as 2.27, 2.60 × 10-2, 0.880 and 2.10 × 10-2 ng/kg BW/day for toddlers, respectively, indicating much higher exposure doses of LCMs indoors compared with the outdoors, and much higher doses for toddlers compared with adults (p < 0.05). These results reveal the potentially adverse effects of LCMs on vulnerable populations, such as toddlers, in indoor environments.

Development and validation of an HPLC-MS/MS method for the simultaneous analysis of volatile organic compound metabolites, hydroxylated polycyclic aromatic hydrocarbons, and 8-hydroxy-2'-deoxyguanosine in human urine.

Humans are widely and concurrently exposed to volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). However, few studies have reported the internal co-exposure levels of these chemicals in occupational and general populations. Specifically, the associations revealed between the urinary levels of metabolites of VOCs (mVOCs), hydroxylated PAHs (OH-PAHs), and oxidative stress biomarkers for humans remain limited. In this study, a method based on solid-phase extraction (SPE) and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was developed for the simultaneous analysis of 22 mVOCs, 12 OH-PAHs, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in human urine samples. The method was validated with all target analyte accuracies and precisions in the range of 76 %-120 % and 1 %-14 % at three levels of spiked urine samples, respectively. The limit of detection (LOD) and limit of quantification (LOQ) of the target analytes were 0.01-0.34 ng/mL and 0.01-7.57 ng/mL, respectively. And the method was applied to measure urinary levels of target analytes from 38 petrochemical workers in Guangzhou, South China. Except for 3-hydroxy-benzo[a]pyrene, all target analytes were detected in the urine samples. The average levels were 0.05-12.6 ng/mL for individual OH-PAHs, 0.20-73620 ng/mL for individual mVOCs, and 1.00 ng/mL for 8-OHdG. Additionally, 3-hydroxy-phenanthrene, 1-hydroxy-pyrene, 6-hydroxy-chrysene, N-acetyl-S-(trichlorovinyl)-L-cysteine, 2-methylhippuric acid, thiodiacetic acid, trans, trans-Muconic acid, and N-acetyl-S-(3,4-dihydroxybutyl)-L-cysteine had statistically significant positive effects on 8-OHdG levels, while 1-hydroxy-naphthalene, 1,2-dihydroxybenzene, and hippuric acid showed a negative effect on 8-OHdG, indicating these metabolites could lead to synergistic or antagonistic oxidative DNA damage. This study provides a robust analytical method that permits a comprehensive assessment of co-exposure to PAHs and VOCs and their potential adverse health effects.

Spatial distribution, impact factors, and potential health implications of trace elements in human hair from capital residents in China.

We analyzed the levels, spatial distribution, impact factors, source apportionment, and potential health implications of trace elements (V, Zn, Cu, Mn, Ni, Mo, and Co) in 1202 human hair samples of urban residents aged 4-55 from 29 cities in China. The median values of seven trace elements in hair were found in the following increasing order: Co (0.02 µg/g) < V (0.04 µg/g) < Mo (0.05 µg/g) < Ni (0.32 µg/g) < Mn (0.74 µg/g) < Cu (9.63 µg/g) < Zn (157 µg/g). The spatial distribution of these trace elements in the hair from the six geographical subdivisions varied depending on the exposure sources and impact factors. Principal component analysis (PCA) revealed that Cu, Zn, and Co in the hair samples of urban residents were primarily derived from food, whereas V, Ni, and Mn were attributed to industrial activities and food. Majority of the hair samples (up to 81%) from North China (NC) exceeded the recommended value for V content, whereas up to 59.2%, 51.3%, and 31.6% samples from Northeast China (NE) exceeded the recommended values for Co, Mn, and Ni contents, respectively. The levels of Mn, Co, Ni, Cu, and Zn were significantly higher in female hair than those in male hair, whereas the levels of Mo were higher in male than in female hair (p < 0.01). Furthermore, significantly higher Cu/Zn ratios were observed in the hair of male residents than those in the female residents (p < 0.001), indicating a higher health risk for male residents.

Tissue-specific and stereoselective accumulation of Dechlorane Plus isomers in two predator fish in a laboratory feeding study.

The tissue-specific bioaccumulation of Dechlorane Plus (DP) isomers was investigated in two predator fish species (redtail catfish, RF; and oscar fish, OF) that were feeding on tiger barb (TB), which was exposed to syn-DP and anti-DP isomers. The biotransformation potential of DP isomers was examined by in vitro metabolism using fish liver microsomes. No difference in accumulation behaviors of DP isomers was observed between RF and OF, and the accumulation of both syn- and anti-DP isomers exhibiting a linear increase trend with the exposure time in all fish tissues. The assimilation efficiencies and depuration rates for syn-DP and anti-DP were determined to be the highest in the liver. Biomagnification factors (BMFs) for both syn-DP and anti-DP were higher than one in the serum and gastrointestinal tract of fish, whereas were less than one in the other tissues. The wet-weight concentrations of DP isomers in tissues were significantly correlated with the lipid contents in both fish species, indicating that the tissue distribution of DP isomers occurred through passive diffusion to the lipid compartments in vivo. Tissue-specific compositions of DP isomers were observed, with anti-DP selectively accumulating in the liver, gonad, serum, and gills, whilst syn-DP in the carcass and GI tract. However, after being normalized of all tissues, the fish showed no selective accumulation of DP isomers during the exposure period, and selective accumulation of syn-DP was observed during the depuration period. No potential DP metabolites were detected in the fish tissues and in vitro metabolism systems. The main cause of this stereoselective DP isomer accumulation could have been the selective excretion of anti-DP isomer through the fish feces.

Analysis of polybrominated diphenyl ethers, hexabromocyclododecanes, and legacy and emerging phosphorus flame retardants in human hair.

Human hair has been identified as a non-invasive alternative matrix for assessing the human exposure to specific organic contaminants. In the present study, a solvent-saving analytical method for the simultaneous determination of 8 polybrominated diphenyl ethers (PBDEs), 3 hexabromocyclododecanes (HBCDDs), 12 phosphorus flame retardants (PFRs), and 4 emerging PFRs (ePFRs) has been developed and validated for the first time. Hair sample preparation protocols include precleaning with Milli-Q water, digestion with HNO3/H2O2 (1:1, v/v), liquid-liquid extraction with hexane:dichloromethane (4:1, v/v), and fractionation and cleanup on a Florisil cartridge. The method was validated by using two levels of spiked hair samples of 3 replicates for each spiking group. Limits of quantification (LOQs) were 0.12-22.4 ng/g for all analytes, average values of accuracies were ranging between 88 and 115%, 82-117%, 81-128%, and 81-95% for PBDEs, HBCDDs, PFRs, and ePFRs, respectively; and precision was also acceptable (RSD < 20%) for all analytes. Eventually, this method was applied to measure the levels of the targeted analytes in hair samples of e-waste dismantling workers (n = 14) from Qingyuan, South China. Median values ranged between 3.00 and 18.1 ng/g for PBDEs, 0.84-4.04 ng/g for HBCDDs, 2.13-131 ng/g PFRs, and 1.49-29.4 ng/g for ePFRs, respectively. PFRs/ePFRs constitute the major compounds in human hair samples, implying the wide use of PFRs/ePFRs as replacements of PBDEs and HBCDDs, as well the potential high human exposure risks of PFRs/ePFRs. Overall, this work will allow to a comprehensive assessment of human exposure to multiple groups of FRs using hair as a non-invasive bioindicator.

Short-term variability in levels of urinary phosphate flame retardant metabolites in adults and children from an e-waste recycling site.

In the present study, urine samples (n = 258) were collected from adults (n = 42) and children (n = 22) in an electronic waste (e-waste) recycling site. The concentrations and compositions of six di-esters, or the metabolites of phosphate flame retardants (PFRs), were measured at different time points on consecutive days. Bis(2-chloroethyl) phosphate (BCEP), dibutyl phosphate (DBP), bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), and diphenyl phosphate (DPHP) were detected in more than 50% of urine samples. The median concentrations of BCEP, DBP, BDCIPP, and DPHP were 2.43-4.80, 0.09-2.65, 0.46-0.89, and 0.66-1.83 ng/mL in adult urine samples, respectively. For children, the median concentrations of BCEP, DBP, BDCIPP, and DPHP were 1.23, 0.08, 0.06, and 0.29 ng/mL in morning urine samples, and 1.86, 0.12, 0.14, and 0.27 ng/mL in nightfall urine samples, respectively. Nightfall urine had generally higher levels of di-esters than those in morning urine for both adults and children (p < 0.05). Children had significantly lower concentrations of di-esters than adults, indicating the occupational exposure risks of PFRs for adults. Significant correlations were observed in levels of BDCIPP (3 out of 6 groups of samples) and DPHP (2 out of 6 groups of samples) in couples (p<0.05). Significant correlations between parents and boys were only observed in BCEP levels in nightfall urine samples, and in DBP levels in morning urine samples (p<0.05). The results suggest that di-ester concentrations in e-waste recycling workers are highly variable depending on the time that samples are collected, which could further influence the estimation of human exposure to PFRs.

[Liver and Kidney Function of E-waste Dismantling Workers and Potential Influencing Factors].

High levels of exposure to heavy metals and persistent organic pollutants (POPs) by e-waste dismantling workers has attracted increasing attention, but the health conditions of the workers are seldom reported. The liver and kidney functions of the workers were studied by comparing the blood indicators of the worker group with those of the control group. Moreover, factors affecting the liver and kidney functions, such as the sexuality, age, and working time, were identified using correlation analysis. The ratio of aspartate transaminase and alanine aminotransferase (AST/ALT) and the direct bilirubin (DBIL) of the workers were significantly lower than the control group but the abnormal rate of liver and kidney remained the same in both groups. The abnormal rates of liver and kidney were higher in men than in women. ALT, AST/ALT, and urea nitrogen (BUN) increased with age while creatinine (CREA) increased with working time. The factors of liver and kidney damage caused by POPs and DBIL can be used as the indicators of the damage caused by multi-factors.

Urinary metabolites of phosphate flame retardants in workers occupied with e-waste recycling and incineration.

Urinary metabolites of phosphate flame retardants (PFRs) were determined in workers from an electronic waste (e-waste) recycling site and an incineration plant, in order to assess the PFR exposure risks of workers occupied with e-waste recycling and incineration. Bis(2-chloroethyl) phosphate (BCEP), bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), and diphenyl phosphate (DPHP) were the most frequently detected chemicals (82-93%). The median concentrations of BCEP, BDCIPP, and DPHP were 1.77, 0.23, and 0.70 ng/mL, and 1.44, 0.22, and 0.11 ng/mL in samples from the e-waste site and the incineration plant, respectively. Dibutyl phosphate (DBP) was detected in all samples from the incineration plant, with a median level of 0.30 ng/mL. The concentrations of BDCIPP (r = -0.31, p < 0.05) were significantly correlated with the occupational exposure time rather than age in workers from the e-waste site. Negative and significant correlations were also observed between the concentrations of BCEP (r = -0.42, p < 0.05), BDCIPP (r = -0.37, p < 0.05), and DPHP (r = -0.37, p < 0.05) and occupational exposure time rather than age in workers from the incineration plant. No gender differences were observed in levels of PFR metabolites in urine samples (p > 0.05). Concentrations of BDCIPP in female were significantly correlated with occupational exposure time (r = -0.507, p < 0.01). Concentrations of PFR metabolites in male were not significantly correlated with age or occupational exposure time (p > 0.05). Overall, the workers with occupational exposure to PFRs had different profiles of urinary PFR metabolites. The age, occupational exposure time, and gender seemed not to be main factors mediating the exposure to PFRs for workers occupied with e-waste recycling and incineration.

An investigation and evaluation on species and characteristics of pathogenic microorganisms in Chinese local hospital settings.

There are currently great concerns about the level of bacterial contamination in hospitals, as well as resistance to antimicrobial agents. The species and characteristics of microbes in Chinese hospitals are closely related to healthcare safety and the prevention and control of infections. However, data on the exposure of patients to microbes in Chinese hospitals are limited. The present study investigated the genera of microorganisms in Chinese hospitals. We evaluated their characteristics, such as antibiotic susceptibility, tolerance to disinfectants, and toxicity, using silkworms (Bombyx mori) as an animal model. Twenty-six distinct bacterial strains were isolated, and their genera were determined by sequencing their 16S rDNA regions. Twenty-five strains were resistant to one or more antibiotics, and six strains were resistant to multiple antibiotics. The results of minimal inhibitory concentration testing showed that eight strains were resistant to a chlorine-containing disinfectant, and 12 strains were resistant to Povidone-iodine. Following the injection of bacterial cultures into the silkworm hemolymph, 15 strains killed all of the silkworms within 5 d. Additionally, bacterial strain 14 killed all of silkworms within 12 h with a median lethal dose of 4 × 10(4) colony-forming units/larva. This study provides useful information for healthcare safety in Chinese hospitals.