Characteristics, sources and health risk assessment of trace metals and polycyclic aromatic hydrocarbons in PM2.5 from Hefei, China.

Trace metals (TRs) and polycyclic aromatic hydrocarbons (PAHs) are major toxic components of fine particulate matter (PM2.5) and related to various health adverse outcomes. The study aims to get a better understanding of the contents, sources and risks of PM2.5-bounded TRs and PAHs in Hefei, China, during the period of 2019-2021. We collected 504 samples and measured twelve TRs and sixteen priority PAHs by inductively coupled plasma mass spectrometry and high-performance liquid chromatography. The annual mass concentrations of PM2.5 was fluctuated in the year of 2019-2021 at 50.95, 47.48 and 59.38 µg/m3, with seasonal variations in rank order of winter > spring > autumn > summer. The median concentrations of PM2.5-bounded Æ©TRs and Æ©PAHs were also fluctuated, 132.85, 80.93 and 120.27 ng/m3 for Æ©TRs, 2.57, 5.85 and 2.97 ng/m3 for Æ©PAHs, in the year of 2019, 2020 and 2021, respectively. Seasonal variations of Æ©TRs and Æ©PAHs show the highest concentration in winter. Positive matrix factorization was used for identified pollution emission sources, and TRs mainly originated from coal combustion, traffic emission and fugitive dust, while PAHs stemmed from biomass, diesel, gasoline and coal combustion. Health risk assessment indicated that adults were more vulnerable than children, the carcinogenic risk assessment of As and Cr manifested a certain degree of cancer risk (1.0 × 10-6 < CR < 1.0 × 10-4) in adults group, and health risks of TRs were higher than PAHs in Hefei. These findings suggest that PM2.5-bounded TRs and PAHs should be considered when making emission control strategies for air pollution, and winter, combustion sources and adults should achieve more policy attention to decrease exposure risks in Hefei.

Distribution and bioaccumulation of endocrine disrupting chemicals in water, sediment and fishes in a shallow Chinese freshwater lake: Implications for ecological and human health risks.

The occurrence, distribution and bioaccumulation of six endocrine disrupting compounds (EDCs) were investigated in water, sediment and biota samples from Luoma Lake, a shallow Chinese freshwater lake. Total concentrations of ∑phenolic EDCs were much higher than ∑estrogens EDCs in both waters and sediments. There were not obvious differences on the concentrations of target compounds [except nonylphenol (NP)] in upstream, lake and downstream locations, these may be suggested that they were mainly affected by non-point discharges in this area. However, the high concentration of NP in water may be associated with the discharge of rural domestic wastewater without thorough treatment. Furthermore, concentrations of NP were about 2-3 order magnitude higher than those of OP in both water and sediment compartments. Relatively higher bioaccumulation factors (BAF) were obtained for DES and EE2. Ecological risk assessment revealed greater risk of NP in surface water, which may pose a serious threat to aquatic ecosystems. The estrogen equivalent concentration (EEQ) of male were higher than those in female, and occurred in the order of city >rural-urban>countryside.

Sorption of tetracycline to varying-sized montmorillonite fractions.

The influence of particle sizes on sorption of tetracycline by clay minerals is poorly understood. In this study, montmorillonite clay fractions with varying particle sizes were prepared by successive centrifugation, and the effects of particle sizes on sorption of tetracycline were evaluated using an equilibrium dialysis method. Sorption isotherms were nearly overlapped for size fractions ranging from 6.38 to 16.00 µm, except for the finest clay fraction (0.41 µm). The relatively low sorption by the fraction with the smallest particles could be attributed to the colloidal nature and high edge-to-surface ratio, which could lead to reduced accessibility of tetracycline to sorption sites (particularly those at the edges). The impact of solution pH and coexisting Na and Ca ions on tetracycline sorption was found to differ between the finest fraction and other clay fractions. The results demonstrated for the first time that clay particle size greatly influenced tetracycline sorption to clay minerals and consequently might affect their transport and bioavailability in the environment.

Effect of heat treatment on sorption of polar and nonpolar compounds to montmorillonites and soils.

Batch sorption isotherms of 1,3,5-trichlorobenzene, 1,3,5-trinitrobenzene, and tetracycline to organic-free montmorillonites and soils receiving heat treatment (375°C for 24 h) were compared with those to unheated sorbents. Sorption of the nonpolar 1,3,5-trichlorobenzene to soil was lowered after the removal of humus by heating, consistent with the mechanism of hydrophobic partition into organic matter. For 1,3,5-trinitrobenzene, the enhanced sorption to heated soils was attributed to specific interactions with exchangeable cations facilitated by heating-induced irreversible partial dehydration of the clay interlayer. For tetracycline, an additional mechanism for sorption enhancement could be due to increased exposure of strong complexation sites on clay minerals after removal of the humic coating. These hypotheses were supported by the sorption data to heated and unheated Na-, K-, and Cs-saturated montmorillonites. The combustion method is commonly adopted to measure the content of black carbon in soils and sediments. However, findings from the present study indicate that combustion may greatly modify the structural properties of clay minerals, leading to misinterpreted sorption contributions of different soil components to sorption of polar or ionic compounds.

Sorption of aromatic ionizable organic compounds to montmorillonites modified by hexadecyltrimethyl ammonium and polydiallyldimethyl ammonium.

Environmental residues of aromatic ionizable organic compounds (AIOCs) have received considerable attention due to their potential human health and ecological risks. The main objective of this study was to investigate the key factors and mechanisms controlling sorption of a series of anionic and zwitterionic AIOCs (two aromatic sulfonates, 4-methyl-2,6-dinitrophenol, tetracycline, sulfamethoxazole, and tannic acid) to montmorillonites modified with hexadecyltrimethyl ammonium (HDTMA) and polydiallyldimethyl ammonium (PDADMA). Compared with naphthalene (a nonpolar and nonionic solute), all AIOCs showed stronger sorption (the sorbent-to-solution distribution coefficient was in the order of 10-10 L kg) to the two organoclays in spite of the much lower hydrophobicity, indicating the predominance of electrostatic interaction in sorption. The proposed electrostatic mechanism of the tested AIOCs was supported by the pH dependency of sorption to the two organoclays. The two organoclays manifested weaker sorption affinity but faster sorption kinetics for bulky AIOCs than commercial activated carbon, resulting from the high accessibility of sorption sites in the open, ordered clay interlayer. The findings of this study highlight the potential of using HDTMA- and PDADMA-exchanged montmorillonites as effective sorbents for AIOCs in water and wastewater treatments.

Spatial occurrence and composition profile of organophosphate esters (OPEs) in farmland soils from different regions of China: Implications for human exposure.

The environmental load of organophosphate ester (OPE) flame retardants has caused a series of problems due to their extensive use. The soil matrix, as an ultimate sink for organic pollution, plays a vital part in the fate of OPEs in the environment. In this study, the spatial occurrence, composition profile and health risk of 13 OPE species in farmland soils from four provinces of China were characterized. Excluding tris(2,3-dibromopropyl) phosphate (TDBPP) and ethylhexyl diphenyl phosphate (EHDPP), the remaining eleven OPEs had a high detection frequency (DF) ranging from 60% to 100%. The range of total OPE (ΣOPE) concentrations were 62.3-394 ng/g dry weight (dw), with a median of 228 ng/g dw. Among these OPEs, tris(2-ethylhexyl) phosphate (TEHP) with a median of 143 ng/g dw) was the predominant species, followed by tricresyl phosphate (TCP; median of 20.1 ng/g dw) and tris(2-chloroethyl) phosphate (TCEP; median of 17.9 ng/g dw). In terms of geographical distribution, significantly lower OPEs levels were found in samples from Heilongjiang (159 ± 47.0 ng/g dw) than in those of Guangxi (264 ± 66.0 ng/g dw), Henan (252 ± 74.5 ng/g dw) and Hubei (242 ± 52.8 ng/g dw) provinces. Principal component analysis and Spearman's correlations were used to reveal potential sources of OPEs in the different provincial regions. Health risk exposure to OPEs in farmland soils was at an acceptable level (<1.20 × 10-5 for non-carcinogenic risk to children as the most sensitive age group; and <6.47 × 10-10 for carcinogenic risk to adults as the most sensitive age group) at the present detected concentrations. However, TCEP and TEHP, the predominant risk contributors, should be paid more attention.

Characterization and health risk assessment of organophosphate esters in indoor dust from urban and rural domestic house and college dormitory in Nanjing, China.

Indoor dust is an important route of exposure for organophosphate esters (OPEs), which are associated with adverse health effects. In the present study, the pollution occurrence and potential health risks of 13 OPEs in indoor dust from urban homes, college dormitories, and rural homes in Nanjing were investigated. Most OPEs were detected in the tested samples. College dormitories dust samples showed significantly higher OPEs concentrations (132.31-1.61 × 103 ng/g), followed by that in urban homes (31.42-49.84 ng/g) and rural homes (51.19-309.75 ng/g). The Mann-Whitney U test found no significant difference in the total concentrations of OPEs except for some individual OPEs between urban and rural homes. Tris (2-chloroisopropyl) phosphate (TCPP) was the most abundant compound in all tested areas. Spearman correlation coefficients and principal component analysis indicated that OPEs might originate from different sources in three microenvironments. Estimated exposures for adults and children in all indoor dust were below the relevant reference doses. Additionally, TCPP was the primary contributors to the non-carcinogenic risk, ranging from 1.07 × 10-6 to 2.20 × 10-5. Tris (2,3-dibromopropyl) phosphate was the dominant carcinogenic risk contributor in indoor dust, with a range of 1.33 × 10-11 to 8.74 × 10-10. These results suggested that the health risk of OPEs was within acceptable limits in the tested areas.

Occurrence, distribution and health risk assessment of organophosphate esters in outdoor dust in Nanjing, China: Urban vs. rural areas.

With increasing use of organophosphate esters (OPEs) largely due to the phasing out of various brominated flame retardants, much more attention has been paid to their occurrence, distribution and potential health risks. In this study, we investigated the occurrence and distribution characteristics associated to their potential health risks of selected 13 OPEs in outdoor dust with a comparison between urban and rural areas in Nanjing, China as well as seasonal variations. Ten out of 13 OPEs showed higher concentrations in urban dust than those in rural dust (p < 0.05). Six OPEs congeners exhibited significantly different concentrations with seasonal variations (p < 0.01) in rural dust. Halogenated OPEs were the dominant group in both urban (median: 56.8%) and rural (median: 45.9%) dust, and tris(2-chloroisopropyl) phosphate (TCPP) was found to be the most abundant OPE in both urban (median: 48.7%) and rural (median:26.4%) dust. Principal component analysis with multiple linear regression (PCA-MLR) and spearman correlations showed the different sources of OPEs in urban and rural dust. The non-carcinogenic (Hazard Index, HI < 1.62 × 10-5) and carcinogenic risks (CR < 2.28 × 10-9) of ΣOPEs were much lower than the theoretical threshold of risk, revealing a negligible risk to local residents from the exposure of OPEs in outdoor dust.

Occurrence, distribution and risk assessment of organophosphate esters in surface water and sediment from a shallow freshwater Lake, China.

Organophosphate esters (OPEs) are ubiquitous in the environment and pose a potential threat to ecosystem and human health. This study investigated the concentrations, distributions and risk of 12 OPEs in surface water and sediment from Luoma Lake, Fangting River and Yi River. Solid-phase extraction (SPE) method were used to extract OPEs from water samples, ultrasonic process and SPE method were used to extract OPEs from sediment samples, and the extracts were finally analyzed using the HPLC-MS/MS. The results revealed that the median and maximum concentrations of ΣOPEs were 73.9 and 1066 ng/L in surface water, and were 28.7 and 35.9 ng/g in sediment, respectively. Tris(2-chloroethyl) phosphate (TCEP) and trimethyl phosphate (TMP) were the most abundant OPEs in the surface water with median concentrations of 24.3 and 16.4 ng/L in Luoma Lake, respectively. Triethyl phosphate (TEP) was the most abundant OPE in the sediment with a median concentrations of 28.9 ng/g. However, tricresyl phosphate (TCrP) and ethylhexyl diphenyl phosphate (EHDPP) predominantly contributed to the ecological risk with respective median risk quotients 0.07 and 0.01 for surface water in Luoma Lake. TEP and TCrP were the most significant contributors to the ecological risk with respective median risk quotients of 6.4 × 10-4 and 5.6 × 10-4 for sediment. It was also found that inflowing Fangting River could be the major pollution source to Luoma Lake. The no-cancer and carcinogenic risks of OPEs were lower than the theoretical threshold of risk. The study found that the ecological and human health risks due to the exposure to OPEs were currently acceptable. In other words, the Luoma Lake was relatively safer to use as a drinking water source in urban areas in the context of OPEs pollution.

Spatiotemporal distribution and risk assessment of organophosphate esters in sediment from Taihu Lake, China.

The occurrence and spatiotemporal distribution of 12 organophosphate esters (OPEs) were investigated in the sediments collected from Taihu Lake. Compared to the same lake in 2012 (3.4-14 ng/g dw), the concentrations of ∑12 OPEs in sediments ranged from 10.76 to 335.37 ng/g dw and from 8.06 to 425.39 ng/g dw in 2015 and in 2016, respectively, indicating that the OPEs levels in Taihu Lake have aggravated, recently. TEHP was the most abundant compound of the OPEs, which suggested that TEHP was the most widely used around Taihu Lake recently. The positive correlations between some of individual OPEs and the principal components analysis suggested the same potential sources for them. The strong positive correlation between ∑BPs and TOC content indicated that TOC content was one of the factors affected the distribution of ∑OPEs in the sediment. Risk quotient (RQ) for OPEs showed no high eco-toxicity risk in sediment for aquatic organisms.

Occurrence and partitioning behavior of organophosphate esters in surface water and sediment of a shallow Chinese freshwater lake (Taihu Lake): Implication for eco-toxicity risk.

Organophosphate esters (OPEs) are ubiquitous in the aquatic environment, which have been considered or suspected as carcinogens and neurotoxicants. In this study, the occurrence, spatial distribution, potential sources, partitioning character and potential risks of OPEs in the surface water and sediment collected from Taihu Lake were investigated. The concentrations of ∑12 OPEs varied from 1.0 × 102 to 1.7 × 103 ng/L for the surface water and from 8.1 to 4.2 × 102 ng/g dw for the sediment. Trimethyl phosphate (TEP) was the predominant congener in the surface water, while Tris(2-ethylhexyl) phosphate (TEHP) in the sediment. Positive correlations between OPEs indicated that they may have the same sources and/or similar environmental behavior. The pseudo-partitioning values of OPEs ranged from 0.59 to 6.5 × 104 L/kg. TEHP has the highest pseudo-partitioning coefficient, which indicated that TEHP inclined to be enriched in the sediment in Taihu Lake. Risk assessment (RQ) showed that individual OPEs in the surface water and sediment posed no/low risk to aquatic organisms, except 2-Ethylhexyl diphenyl phosphate (EHDPP) (moderate risk) in water.

Personal exposure and health risk assessment of carbonyls in family cars and public transports-a comparative study in Nanjing, China.

To evaluate passenger health risks associated with inhalation exposure to carbonyl compounds mainly emitted from decoration materials of vehicles, we tested the carbonyl concentrations in interior air of 20 family cars, 6 metro lines, and 5 buses in the city of Nanjing. To assess non-carcinogenic health risks, we compared the data to the health guidelines of China, US Environmental Protection Agency (EPA), and Office of Environmental Health Hazard Assessment (OEHHA), respectively. To assess carcinogenic risks, we followed a standard approach proposed by the OEHHA to calculate lifetime cancer risks (LCR) of formaldehyde and acetaldehyde for various age groups. The results showed that there are formaldehyde, acetaldehyde, and acrolein concentrations in 40, 35, and 50% of family car samples exceeded the reference concentrations (RfCs) provided by Chinese guidelines (GB/T 27630-2011 and GB/T 18883-2002). Whereas, in the tested public transports, concentrations of the three carbonyls were all below the Chinese RfCs. Fifty and 90% of family cars had formaldehyde and acrolein concentrations exceeding the guidelines of OEHHA. Only one public transport sample (one bus) possesses formaldehyde and acetaldehyde concentrations above the chronic inhalation reference exposure limits (RELs). Furthermore, the assessments of carcinogenic risk of formaldehyde and acetaldehyde showed that lifetime cancer risks were higher than the limits of EPA for some family cars and public transports. In the study, buses and metros appear to be relatively clean environments, with total carbonyl concentrations that do not exceed 126 µg/m3. In family cars, carbonyl levels showed significant variations from 6.1 to 811 µg/m3 that was greatly influenced by direct emissions from materials inside the vehicles. Public transports seemed to be the first choice for resident trips as compared to family cars. Graphical abstract ᅟ.

[Distribution Characteristics and Potential Risk of Bisphenol Analogues in Surface Water and Sediments of Lake Taihu].

In this study, seven bisphenol analogues were measured in water and sediment samples from Taihu Lake, and potential risk was evaluated. The results showed that BPF, BPS and BPA were the predominant components in water samples from Lake Taihu. In sediment, BPA was always predominant, followed by BPF and BPS, and there was a significant positive correlation between BPs and TOC content. In addition, the high concentration levels of BPF, BPS and BPA were distributed in the tributaries of Lake Taihu(S4-S10). The risk assessment of the target BPs showed that the combined risk quotients posed a low eco-toxicity to aquatic ecosystem, and there was no appreciable risk to human health from potential environmental exposure of drinking water.

Prenatal transfer of decabromodiphenyl ether (BDE-209) results in disruption of the thyroid system and developmental toxicity in zebrafish offspring.

Decabromodiphenyl ether (BDE-209) was one of most widely-used polybrominated diphenyl ether (PBDE) flame retardants and is frequently detected in both abiotic and biotic samples from environment. However, knowledge of its transgenerational risks is limited. Here, 4-month-old zebrafish were exposed to various concentrations of BDE-209 (0, 3, 30 or 300µg/L) for 28days and spawned in clean water without BDE-209. Concentrations of triiodothyronine (T3) and thyroxine (T4) as well as expressions of genes involved in the hypothalamic-pituitary-thyroid (HPT) axis were measured in offspring after exposure of adult zebrafish to BDE-209. BDE-209 was accumulated in adult fish and F1 eggs, which suggests transfer of this compound from adult fish to their offspring. Exposure of BDE-209 to parents resulted in developmental abnormalities in offspring and a significant decrease in T4 concentrations in F1 larvae 120h post-fertilization (hpf). Furthermore, expressions of several genes involved in the HPT axis were also altered. Expressions of thyroid hormone receptor α (tr-α), thyrotropin releasing hormone (trh), thyroid stimulating hormone ß (tsh-ß) and deiodinase 1 (dio 1) were significantly down-regulated in F1 individuals, while expressions of thyroid stimulating hormone receptor (tshr) and transthyretin (ttr) were significantly up-regulated. These results suggest that exposure of parent zebrafish to BDE-209 can cause developmental toxicity in offspring and disruption of the thyroid endocrine system of offspring.

Occurrence, distribution, and risk assessment of alkylphenols, bisphenol A, and tetrabromobisphenol A in surface water, suspended particulate matter, and sediment in Taihu Lake and its tributaries.

The occurrence and distribution of nine selected compounds were investigated in surface water, suspended particulate matter (SPM), and sediment in Taihu Lake and its tributaries. With the exception of 4-Butylphenol, all compounds were detected in at least two phases, and nonylphenol (NP) and 4-tert-Octylphenol (4-OP) were the predominant alkylphenols (APs) in the lake. A significant correlation was observed between NP and 4-OP, indicating that they may share the same source. Moreover, surface water phase was the dominant sink of Bisphenol A (BPA) in the aquatic environment. The concentrations of BPA between the surface water and SPM phases were closely related to each other. In addition, Tetrabromobisphenol A (TBBPA) exhibited relatively higher concentrations and detection frequencies in the SPM. Risk assessment revealed greater risk associated with the surface water than the sediment, indicating that the discharge of industrial wastewater and domestic sewage poses a serious threat to aquatic ecosystems.