Development of Lead Source-specific Exposure Standards Based on Aggregate Exposure Assessment: Bayesian Inversion from Biomonitoring Information to Multipathway Exposure

Exposure of children to lead is of great concern, and the exposure standards for different media are important for protecting public safety. However, these media-specific standards often fail to ensure the safety of children even when environmental lead levels are lower than the quality standards since humans are often exposed to lead via multiple pathways. To establish exposure standards to protect children from hazards associated with exposure to lead, an analytical tool for assessing aggregate exposure to lead based on Bayesian hierarchical model was developed, and then was used to update the external lead exposure of diet, paint, soil, air and drinking water using the blood lead levels in Chinese children aged 1–6 years. On the basis of updated external exposure, the source allocations for diet, paint, soil, air, and drinking water in China were 65.80 ± 7.92%, 16.98 ± 7.88%, 13.65 ± 5.05%, 3.36 ± 1.75%, and 0.20 ± 0.14%, respectively. Based on the estimated source allocations, the exposure standards were evaluated to be 0.2 μg/m³, 24.25 mg/kg, 0.027 μg/L, 0.051 μg/mg, 0.042 μg/mg, 38.02 μg/mg for air, soil, water, grains, vegetables, and paint, respectively. Since the standards setting procedure was based on the multipathway aggregate exposure assessment of lead, the newly proposed exposure standards should ensure the safety of children

Determination and Source Apportionment of Five Classes of Steroid Hormones in Urban Rivers

We developed an original analytical method for monitoring five estrogens, nine androgens, nine progestogens, six glucocorticoids, and one mineralocorticoid in one water sample using liquid chromatography-electrospray tandem mass spectrometry, and then 45 river, 13 discharging sites, and 4 composite effluent samples were analyzed to reveal their occurrence and sources in urban rivers. Of the 45 river samples, androgens were the dominant steroids detected (total concentrations up to 480 ng/L), followed by glucocorticoids (up to 52 ng/L), progestogens (up to 50 ng/L), and estrogens (up to 9.8 ng/L). The summed concentration for each class of detected hormones in 13 discharging site samples was higher than that in river samples, up to 1887 ng/L for androgens, 390 ng/L for glucocorticoids, 75 ng/L for progestogens, and 25 ng/L for estrogens. A principal component analyses with multiple linear regression based on the profiles of all target compounds was applied to identify the source apportionment and to predict the contribution from different sources. It was found that 62.7% of the mean summed hormones were contributed by freshly discharged untreated sewage, 29.4% by treated sewage and/or naturally attenuated untreated sewage, and 7.9% by an unknown source, possibly pharmaceutical manufacturing plants

Occurrence of Natural and Synthetic Glucocorticoids in Sewage Treatment Plants and Receiving River Waters

This paper first reports the occurrence of six glucocorticoids (prednisone, prednisolone, cortisone, cortisol, dexamethasone, and 6α-methylprednisolone) in sewage treatment plants (STPs) and receiving rivers by establishing a method for analyzing glucocorticoids in complex environmental waters. For the various types of aqueous matrices considered, the absolute recoveries were from 73 to 99%, and limits of quantification were below 0.2 ng/L. Among the seven STPs studied, the average concentrations of prednisone, prednisolone, cortisone, cortisol, dexamethasone, and 6α-methylprednisolone in influents were, respectively, 2.6 ± 2.1, 3.0 ± 1.6, 30 ± 21, 39 ± 26, 1.2 ± 0.70, and 0.62 ± 0.65 ng/L, and their percent removals were 99 ± 3.1, 78 ± 8.8, 99 ± 1.2, 98 ± 2.5, 99 ± 1.8, and 100 ± 0%, respectively. The lower removal of prednisolone was found to be due to its relatively low efficiency of biodegradation, especially in anoxic and aerobic units. The frequently detected glucocorticoids in effluents were prednisolone, cortisol, and cortisone with average concentrations 0.56 ± 0.06, 0.50 ± 0.33, and 0.26 ± 0.10 ng/L. In the receiving waters, the Tonghui and Qing Rivers, the concentrations of these compounds in some samples were much higher than those in their corresponding STP effluents; these differences depended on the sampling date, suggesting that there was random discharging of untreated wastewaters into these rivers. In addition, the ratio between the combined concentrations of two natural glucocorticoids (cortisol and cortisone) and the concentration of one synthetic glucocorticoid, prednisolone, was found to be a potential index to reflect the wastewater discharging

Determination and Occurrence of Retinoids in a Eutrophic Lake (Taihu Lake, China): Cyanobacteria Blooms Produce Teratogenic Retinal

Besides retinoic acids (RAs), some retinoids such as retinal (RAL) and retinol (ROH), which are considered as RA precursors in vertebrates, are also reported to be teratogenic agents. In this study we investigated four RA precursors including RAL, ROH, retinyl palmitate, and β-carotene in the eutrophic Taihu Lake, China, by developing a sensitive analytical method. RAL and β-carotene were widely detected in natural cyanobacteria blooms and lake water. Intracellular concentrations of RAL and β-carotene in blooms were 9.4 to 6.9 × 10³ and 3.4 to 1.8 × 10⁵ ng L^–1, respectively, and their concentrations in lake water were up to 1.4 × 10 ng L^–1 (RAL) and 9.8 × 10² ng L^–1 (β-carotene). The good correlation between intracellular concentrations of RAL and RAs implied that RAL was involved in the production of RAs by cyanobacteria blooms. Further examination of 39 cyanobacteria and algae species revealed that most species could produce RAL and β-carotene. The greatest amount of RAL was found in <i>Chlamydomonas</i> sp. (FACHB-715; 1.9 × 10³ ng g^–1 dry weight). As the main cyanobacteria in Taihu Lake, many <i>Microcystis</i> species could produce high amounts of RAL and were thought to greatly contribute to the production of RAL measured in the blooms. Productions of RAL and β-carotene by cyanobacteria were associated with species, origin location, and growth stage. The results in this study present the existence of a potential risk to aquatic animals living in a eutrophic environment from a high concentration of RAL in cyanobacteria blooms and also provide a clue for further investigating the mechanism underlying the biosynthetic pathway of RAs in cyanobacteria and algae

Trophodynamics of Polybrominated Diphenyl Ethers in the Marine Food Web of Bohai Bay, North China

Polybrominated diphenyl ethers (PBDEs) are of great environmental concern due to the exponential increase of the concentrations in the environment, especially in high trophic level organisms, and the trophodynamics of these chemicals in aquatic food webs is an important criterion for assessing their ecological risk. This study analyzed 13 PBDEs in the zooplankton, five invertebrate species, six fish species, and one marine bird species collected from Bohai Bay. PBDE concentrations in organisms from Bohai Bay (ΣPBDEs: 0.15–32.8 ng/g lipid weight) were low compared with other marine organisms worldwide, and BDE-47 was the predominant compound in most samples, followed by BDE-28, BDE-99/BDE-100, and BDE-119. Correlation between lipid-normalized concentrations of PBDEs, and trophic levels determined by stable nitrogen isotope technologies confirmed that PBDEs were biomagnified in the marine food web. Significantly positive relationships were found for total PBDEs and four PBDE compounds (BDE-28, BDE-47, BDE-100, and BDE-119), and their trophic magnification factors (TMFs) were 3.53, 3.57, 7.24, 3.23, and 2.60, respectively. The concentration ratios between congeners (BDE-99/BDE-100 and BDE-99/BDE-47) were found to decrease with increasing trophic levels, suggesting that trophic-level-dependent concentrations ratios between BDE-99 and BDE-100 would be contributed by trophic level-dependent biotransformation between BDE-99 and BDE-47, and therefore resulting in the dominance of BDE-100 compared with BDE-99 and the relatively high trophic magnification of BDE-47 in the marine food web

Ubiquitous Occurrence of Fluorotelomer Alcohols in Eco-Friendly Paper-Made Food-Contact Materials and Their Implication for Human Exposure

The occurrence of fluorotelomer alcohols (FTOHs) was investigated in 94 food-contact materials (FCMs). We detected 6:2 FTOH (<0.60–1110 ng/g), 8:2 FTOH (<0.40–8490 ng/g), and 10:2 FTOH (<0.02–9350 ng/g) in most FCM samples, and four longer-chain C_14–20 FTOHs were, for the first time, identified in FCMs with relatively high concentrations (<0.02–8450 ng/g for 12:2 FTOH, <0.02–1640 ng/g for 14:2 FTOH, <0.02–372 ng/g for 16:2 FTOH, and <0.02–130 ng/g for 18:2 FTOH). There were three typical profiles of FTOHs that were dominated by 6:2 FTOH (95.6 ± 8.1% in 9 FCMs), 8:2 FTOH (50.9 ± 20.8% in 22 FCMs), and 10:2 FTOH (44.5 ± 20.9% in 30 FCMs), indicating the congener-specific usage of FTOHs for different commercial purposes. All nine detectable FCMs produced in the United States were dominated by 6:2 FTOH, which was significantly different from those produced in China. The median concentration of total FTOHs in eco-friendly paper tableware was 2990 ng/g, which was lower than in popcorn bags (18 200 ng/g) but much higher than other FCMs (<0.55–38.7 ng/g). FTOHs could migrate from paper bowls, with migration efficiencies of 0.004–0.24% into water, 0.004–0.24% into 10% ethanol, 0.009–2.79% into 30% ethanol, 0.06–13.0% into 50% ethanol (v/v) simulants, and 0.04–2.28% into oil. Migration efficiencies decreased with increasing carbon chain lengths of FTOHs

Isomer-Specific Trophic Transfer of Perfluorocarboxylic Acids in the Marine Food Web of Liaodong Bay, North China

Trophic transfers of perfluorocarboxylic acids (PFCAs) have been well studied in aquatic food webs; however, most studies examined PFCAs as single compounds without differentiating isomers. In this study, an in-port derivatization GC-MS method was used to determine PFCA (perfluorooctanoic acid, PFOA; perfluorononanoic acid, PFNA; perfluorodecanoate acid, PFDA; perfluoroundecanoate acid, PFUnDA; perfluorododecanoate acid, PFDoDA; perfluorotridecanoate acid, PFTriDA, and perfluorotetradecanoate acid, PFTeDA) structural isomers in 11 marine species including benthic invertebrates, fishes, and gulls collected in November 2006 from Liaodong Bay in China. The total concentrations of linear PFCAs were 0.35–1.10, 0.93–2.61, and 2.13–2.69 ng/g ww, and the corresponding percentages of branched PFCAs to linear PFCAs were 6.6–15.5%, 4.2–9.9%, and 4.5–6.0% in invertebrates, fishes, and birds, respectively. Except for linear PFOA, significant positive relationships were found between the concentrations of all the target linear PFCAs and trophic levels, and the trophic magnification factors (TMFs) ranged from 1.90 to 4.88. Positive correlations between the concentrations of branched PFCAs isomers and trophic levels were also observed but were without statistical significance. The relatively high biomagnification of linear isomers of PFCAs would lead to low percentages of branched PFCAs to total PFCAs in organisms at high trophic levels. This study for the first time clarified isomer-specific trophic transfers of PFCAs in a marine food web

Trophic Dilution of Polycyclic Aromatic Hydrocarbons (PAHs) in a Marine Food Web from Bohai Bay, North China

Trophic transfer of polycyclic aromatic hydrocarbons (PAHs) in aquatic ecosystems is an important criterion for assessing their ecological risk. This study analyzed 18 PAHs in phytoplankton/seston, zooplankton, five invertebrate species, five fish species, and one seabird species collected from Bohai Bay, and trophic transfer of the PAHs was determined in the food web, of which the length was approximately 4 on the basis of stable nitrogen isotope values. The concentrations of PAHs (2−64.5 ng/g wet weight) in the marine ecosystem were moderate compared with other marine organisms worldwide, and the PAH compositions exhibited species-specific profiles that were related to trophic levels in some organisms. Significant negative relationships were also found between trophic levels and lipid-normalized concentrations for 10 PAH compounds (acenaphthylene, anthracene, fluoranthene, pyrene, chrysene, benz[a]anthracene, benzo[b]fluoranthene + benzo[k]fluoranthene, benzo[e]pyrene, benzo[a]pyrene, and perylene), and their trophic magnification factors (TMFs) ranged from 0.11 for fluoranthene to 0.45 for acenaphthylene. These results confirm that PAHs undergo trophic dilution in the marine food web, which is likely to be the combined results of low assimilation efficiencies and efficient metabolic transformation at higher trophic levels

Behaviors of Glucocorticoids, Androgens and Progestogens in a Municipal Sewage Treatment Plant: Comparison to Estrogens

This work investigated the behaviors of seven glucocorticoids, eight androgens, and nine progestogens compared to six estrogens in a municipal sewage treatment plant (STP) in Beijing, China. Among all of the hormones considered, androgens were the dominant steroids detected in all samples (total concentrations up to 10 216 ± 912 ng/L for influents, 171 ± 10 ng/L for effluents, and 647 ± 52 ng/g for dehydrated sludge samples), followed by estrogens (102 ± 8 ng/L, 14 ± 2 ng/L, and 14 ± 1 ng/g), progestogens (57 ± 6 ng/L, 8 ± 2 ng/L, and 13 ± 3 ng/g), and glucocorticoids (42 ± 2 ng/L, 0.7 ± 0.1 ng/L, and 1.2 ± 0.3 ng/g). With the exception of 19-nor-4-androstene-3,17-diol (NAD, 67%), removal rates for androgens were relatively high (98−99%), while those for glucocorticoids, estrogens, and all progestogens except 6α-methylhydroxyprogesterone (MHPT) were 85−99%, 78−99%, and 73−96%, respectively. Glucocorticoids, androgens, and progestogens were mainly removed by degradation as with estrogens, while different behaviors were observed in the aerated grit chamber, anaerobic tank, anoxic tank, and aerobic tank units. Many of the detected glucocorticoids, androgens, and progestogens were eliminated in the anaerobic tank, but estrogens were largely degraded in the aerobic one. Significant increases in the mass of 21α-hydroxyprogesterone (21-HPT) and MHPT in the anaerobic tank and anoxic tank, respectively, were due to deconjugation

Evaluating a Tap Water Contamination Incident Attributed to Oil Contamination by Nontargeted Screening Strategies

The present study applied nontargeted screening techniques as a novel approach to evaluate the tap water samples collected during the “4.11” tap water pollution incident occurred on April 11, 2014 in Lanzhou in west China. Multivariate analysis (PCA and OPLS-DA) of about 3000 chemical features obtained in extracts of tap water samples by ultrahigh-pressure liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) analysis showed significantly different chemical profiles in tap water from pollution regions versus reference regions during the event. These different chemical profiles in samples from different regions were not observed in samples collected during the nonpollution period. The compounds responsible for the differences in profiles between regions were identified as naphthenic acids (NAs) and oxidized NAs (oxy-NAs) after the sample extracts underwent bromination to explore saturations, dansylation to identify hydroxylations and corresponding MS/MS mode analysis. A consistent finding was further observed in the targeted analysis of NA mixtures, demonstrating that the Lanzhou “4.11” tap water pollution incident could be attributed to oil spill pollution, and NA mixtures would be a marker for oil contamination. Such evaluations can help to rapidly discriminate pollution sources in accidental pollution events and contribute to regular water monitoring management of water safety issues