A review on the usage of POP pesticides in China, with emphasis on DDT loadings in human milk

Biodetector for chlordane using doped InP3 monolayers: a density functional theory study

Chlordane is a serious pollutant in the environment, and it is necessary to monitor chlordane levels using biodetectors. We performed first-principles calculations to investigate the adsorption of chlordane on Ag, Pd, and Au doped InP3 semiconductor monolayers. The results indicated that the adsorption energies of chlordane adsorbed on Ag, Pd, and Au doped InP3 are -7.961 eV, -6.328 eV, and -7.889 eV respectively. The band gaps of the doped InP3 monolayers underwent drastic changes after coming in contact with chlordane, the largest change in band gap occurred for Pd-doped InP3, where the band gap changed from 0.024 eV to 0.335 eV. The large change in band gap shows that the monolayer is sensitive to the molecule, making it a good biodetector. Our results conclude that Pd-doped InP3 stands out as the most promising biodetector for chlordane. This result will benefit environmental experimentalists in their further research.

Residual levels, phase distributions, and human health risks of OCPs in the middle reach of the Huai River, China

Are the residues of organochlorine pesticides (OCPs) in freshwater in China still of concern after prohibition and restriction for decades? The scarcity of monitoring data on OCPs in freshwater in China over the past few years has hampered understanding of this issue. In this study, water and suspended particulate matter (SPM) samples were collected from the middle reach of the Huai River for OCP analyses. Residues of ∑OCPs in water and SPM ranged from ND to 8.6 ng L-1 and 0.50 to 179 ng L-1, with mean concentrations of 1.7 ± 1.3 ng L-1 and 6.1 ± 31 ng L-1, respectively. ∑HCHs (α-, β-, γ-, and δ-HCH) and ∑HEPTs (heptachlor and heptachlor epoxide) were the most predominant pesticides in the dissolved phase and SPM, respectively, accounting for 43 ± 35% and 27 ± 29% of ∑OCPs. HCHs and heptachlor epoxide mainly existed in the dissolved phase, while heptachlor mainly existed in SPM. The isomeric composition pattern of HCHs in water differed from that in SPM. Briefly, β-HCH dominated in water, while δ-HCH dominated in SPM. However, the composition pattern of DDT and its metabolites in water was similar to that in SPM. o,p'-DDD and p,p'-DDE dominated in both water and SPM. The ratios of α-/γ-HCH and (DDD + DDE)/DDTs indicated that HCHs and DDTs were mainly derived from historical residues. Risk assessments indicated that OCPs may not pose carcinogenic and non-carcinogenic risks to residents.

Hidden risk of terrestrial food chain contamination from organochlorine insecticides in a vegetable cultivation area of Northwest Bangladesh

Organochlorine insecticide (OCI) exposures in terrestrial food chains from historical or current applications were studied in a vegetable production area in northwest Bangladesh. A total of 57 subsoil, 57 topsoil, and 57 vegetable samples, as well as 30 cow's milk samples, were collected from 57 farms. Multiple OCI residues were detected using GC-MS/MS with modified QuEChERS in 20 % of subsoils, 21 % of topsoils, 23 % of vegetables, and 7 % of cow's milk samples. Diversified OCI residues were detected in subsoils (17 residues with a concentration of 179.15 ± 148.61 μg kg-1) rather than in topsoils (3 DDT residues with a concentration of 25.76 ± 20.19 μg kg-1). Isomeric ratios indicate intensive historical applications of OCIs. According to Dutch and Chinese standards, the lower concentrations of individual OCI residues in the soil indicate negligible to slight soil pollution, assuming local farmers follow local pesticide use regulations. However, a maximum of 78.24 μg kg-1 ΣAldrines and 35.57 μg kg-1 ΣHCHs were detected (1-4 residues) in 60 % of brinjal, 28 % of cucumber, 29 % of sponge gourd, and 20 % of lady's finger samples, which could be a result of either historical or current OCI applications, or both. A strong positive correlation between aldrines in subsoils and cucurbit vegetables indicates greater bioaccumulation. Cow milk samples contained up to 6.96 μg kg-1 ΣDDTs, which resulted either from rationing contaminated vegetables or grazing on contaminated land. Individual OCI in both vegetables and cow's milk was below the respective maximum residue limits of US and FAO/WHO CODEX and poses little or no risk to human health. However, combined exposure to multiple pesticides could increase human health risks. A cumulative health risk assessment of multiple pesticide residues is suggested to assess the suitability of those soils for cultivation and grazing, as well as the safety of vegetables and cow's milk for human consumption.

Microbiology and Biochemistry of Pesticides Biodegradation

Pesticides are chemicals used in agriculture, forestry, and, to some extent, public health. As effective as they can be, due to the limited biodegradability and toxicity of some of them, they can also have negative environmental and health impacts. Pesticide biodegradation is important because it can help mitigate the negative effects of pesticides. Many types of microorganisms, including bacteria, fungi, and algae, can degrade pesticides; microorganisms are able to bioremediate pesticides using diverse metabolic pathways where enzymatic degradation plays a crucial role in achieving chemical transformation of the pesticides. The growing concern about the environmental and health impacts of pesticides is pushing the industry of these products to develop more sustainable alternatives, such as high biodegradable chemicals. The degradative properties of microorganisms could be fully exploited using the advances in genetic engineering and biotechnology, paving the way for more effective bioremediation strategies, new technologies, and novel applications. The purpose of the current review is to discuss the microorganisms that have demonstrated their capacity to degrade pesticides and those categorized by the World Health Organization as important for the impact they may have on human health. A comprehensive list of microorganisms is presented, and some metabolic pathways and enzymes for pesticide degradation and the genetics behind this process are discussed. Due to the high number of microorganisms known to be capable of degrading pesticides and the low number of metabolic pathways that are fully described for this purpose, more research must be conducted in this field, and more enzymes and genes are yet to be discovered with the possibility of finding more efficient metabolic pathways for pesticide biodegradation.

Temporal trends, sources, and ecological risk of residual organochlorine pesticides (OCPs) in sediment core from the Dongping Lake, North China

A sedimentary record of the 19 organochlorine pesticides (OCPs) pollutants from Dongping Lake, north China, is presented in this study. According to the dating of core sediment and OCP content analysis in samples, from 1904 to 2016, the total concentration of OCPs varied from undetectable levels (n.d.) to 33.1 ng/g. The OCP concentration was first detected in the samples of 1938, and then gradually increased to a peak level in 2000 thereafter decreased until 2016. Among the detected OCPs, hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) were the predominant and the most frequently detected contaminants in the core sediment, with concentrations ranging from n.d. to 16.9 ng/g and from n.d. to 8.8 ng/g, respectively. The distribution of OCPs in the sediments was affected by organic carbon concentration, showing a significant positive correlation (r = 0.93, p < 0.001), especially for HCHs (r = 0.98, p < 0.001). The source analysis showed that HCH contamination mainly derived from historical use of technical HCHs, while in recent years, it derived from lindane usage. DDT pollution was attributed to historical use of technical DDTs, as well as the microbial degradation of historic DDT residues. Finally, risk analysis was performed for OCPs in sediment cores based on sediment quality guidelines from the Canadian Council of Ministers of the Environment, showing that DDTs presented a high ecological toxicity risk during the period of 1959-2010.

Associations of polychlorinated biphenyl and organochlorine pesticide exposure with hyperuricemia: modification by lifestyle factors

Recent research has reported positive associations of exposure to polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) with hyperuricemia. However, most of these studies have primarily focused on the individual effects of PCB/OCP exposure. We aimed to explore the associations of both individual and combined PCB/OCP exposure with hyperuricemia and examine whether such associations could be modified by lifestyle factors. The cross-sectional study recruited 2032 adults between March and May 2019 in Wuhan, China. Logistic regression and weighted quantile sum (WQS) regression were applied to explore the relationship of individual and combined PCB/OCP exposure with hyperuricemia, while considering the modified effects of lifestyle factors. Of the 2032 participants, 522 (25.7%) had hyperuricemia. Compared with the non-detected group, the detected groups of PCB153 and PCB180 exhibited a positive association with hyperuricemia, with OR (95% CIs) of 1.52 (1.22, 1.91) and 1.51 (1.20, 1.90), respectively. WQS regression showed that PCB/OCP mixture was positively associated with hyperuricemia (OR: 1.31, 95% CI: 1.08, 1.58). PCB153/PCB180 exposure, combined with an unhealthy lifestyle, has a significant additive effect on hyperuricemia. Overall, PCB/OCP mixture and individual PCB153/PCB180 exposure were positively associated with hyperuricemia. Adherence to a healthy lifestyle may modify the potential negative impact of PCBs/OCPs on hyperuricemia.

Dichlorodiphenyltrichloroethane inhibits soil ammonia oxidation by altering ammonia-oxidizing archaeal and bacterial communities

Dichlorodiphenyltrichloroethane (DDT), a persistent organic pollutant, has known effects on natural microbes. However, its effects on soil ammonia-oxidizing microbes, significant contributors to soil ammoxidation, remain unexplored. To address this, we conducted a 30-day microcosm experiment to systematically study the effects of DDT contamination on soil ammonia oxidation and the communities of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). Our findings revealed that DDT inhibited soil ammonia oxidation in the early stage (0-6 days), but it gradually recovered after 16 days. The copy numbers of amoA gene of AOA decreased in all DDT-treated groups from 2 to 10 days, while that of AOB decreased from 2 to 6 days but increased from 6 to 10 days. DDT influenced the diversity and community composition of AOA but had no significant effect on AOB. Further, the dominant AOA communities comprised uncultured_ammonia-oxidizing_crenarchaeote and Nitrososphaera sp. JG1: while the abundance of the latter significantly and negatively correlated with NH 4+-N (P ≤ 0.001), DDT (0.001 < P ≤ 0.01), and DDD (0.01 < P ≤ 0.05) and positively correlated with NO3--N (P ≤ 0.001), that of the former significantly and positively correlated with DDT (P ≤ 0.001), DDD (P ≤ 0.001), and NH 4+-N (0.01 < P ≤ 0.05) and negatively correlated with NO3--N (P ≤ 0.001). Among AOB, the dominant group was the unclassified Nitrosomonadales in Proteobacteria, which showed significant negative correlation with NH 4+-N (0.01 < P ≤ 0.05) and significant positive correlation with NO3--N (0.001 < P ≤ 0.01). Notably, among AOB, only Nitrosospira sp. III7 exhibited significant negative correlations with DDE (0.001 < P ≤ 0.01), DDT (0.01 < P ≤ 0.05), and DDD (0.01 < P ≤ 0.05). These results indicate that DDT and its metabolites affect soil AOA and AOB, consequently affecting soil ammonia oxidation.

Quantification of insecticides in commercial seafood sold in East Asian markets: risk assessment for consumers

The extraction of 21 insecticides and 5 metabolites was performed using an optimized and validated QuEChERS protocol that was further used for the quantification (GC-MS/MS) in several seafood matrices (crustaceans, bivalves, and fish-mudskippers). Seven species, acquired from Hong Kong and Macao wet markets (a region so far poorly monitored), were selected based on their commercial importance in the Indo-Pacific region, market abundance, and affordable price. Among them, mussels from Hong Kong, together with mudskippers from Macao, presented the highest insecticide concentrations (median values of 30.33 and 23.90 ng/g WW, respectively). Residual levels of fenobucarb, DDTs, HCHs, and heptachlors were above the established threshold (10 ng/g WW) for human consumption according to the European and Chinese legislations: for example, in fish-mudskippers, DDTs, fenobucarb, and heptachlors (5-, 20- and tenfold, respectively), and in bivalves, HCHs (fourfold) had higher levels than the threshold. Risk assessment revealed potential human health effects (e.g., neurotoxicity), especially through fish and bivalve consumption (non-carcinogenic risk; ΣHQ_LT > 1), and a potential concern of lifetime cancer risk development through the consumption of fish, bivalves, and crustaceans collected from these markets (carcinogenic risk; ΣTCR > 10^-4). Since these results indicate polluted regions, where the seafood is collected/produced, a strict monitoring framework should be implemented in those areas to improve food quality and safety of seafood products.

Hormone receptor activities of complex mixtures of known and suspect chemicals in personal silicone wristband samplers worn in office buildings

Humans are exposed to increasingly complex mixtures of hormone-disrupting chemicals from a variety of sources, yet, traditional research methods only evaluate a small number of chemicals at a time. We aimed to advance novel methods to investigate exposures to complex chemical mixtures. Silicone wristbands were worn by 243 office workers in the USA, UK, China, and India during four work shifts. We analyzed extracts of the wristbands for: 1) 99 known (targeted) chemicals; 2) 1000+ unknown chemical features, tentatively identified through suspect screening; and 3) total hormonal activities towards estrogen (ER), androgen (AR), and thyroid hormone (TR) receptors in human cell assays. We evaluated associations of chemicals with hormonal activities using Bayesian kernel machine regression models, separately for targeted versus suspect chemicals (with detection ≥50%). Every wristband exhibited hormonal activity towards at least one receptor: 99% antagonized TR, 96% antagonized AR, and 58% agonized ER. Compared to men, women were exposed to mixtures that were more estrogenic (180% higher, adjusted for country, age, and skin oil abundance in wristband), anti-androgenic (110% higher), and complex (median 836 detected chemical features versus 780). Adjusted models showed strong associations of jointly increasing chemical concentrations with higher hormonal activities. Several targeted and suspect chemicals were important co-drivers of overall mixture effects, including chemicals used as plasticizers, fragrance, sunscreen, pesticides, and from other or unknown sources. This study highlights the role of personal care products and building microenvironments in hormone-disrupting exposures, and the substantial contribution of chemicals not often identifiable or well-understood to those exposures.

Chlorinated persistent organic pollutants in human breast milk in the Miyagi Prefecture disaster-affected area 1 year after the Great East Japan Earthquake of 2011

BACKGROUND

In the Great East Japan Earthquake of 11 March 2011, an earthquake and accompanying tsunami struck the Tohoku region of northeastern Japan. Buildings collapsed and the tsunami spread waste, including hazardous materials. This study aimed to determine the concentrations of persistent organic pollutants (POPs) in the breast milk of mothers living in the disaster-affected area of Sendai 1 year after the earthquake. Temporal trends in the POPs concentrations were evaluated by comparison with previous studies.

METHODS

One hundred breast milk samples were obtained from lactating mothers at a hospital in Sendai in 2012. The results were compared with those from other years to examine whether there were changes in the POPs concentrations after the earthquake. We measured polychlorinated biphenyls (PCBs) and organochlorine pesticides, such as chlordanes, using gas chromatography-mass spectrometer (GC-MS) with negative chemical ionization, and dichlorodiphenyl trichloroethane (DDT) and its metabolites using GC-MS with electron impact ionization.

RESULTS

The mean total PCBs (11 congeners), total chlordane, and total DDT concentrations were 76.2 ng/g lipid, 39.8 ng/g lipid, and 73.5 ng/g lipid, respectively. For the samples collected in 2012, the concentrations of POPs in breast milk showed minimal changes compared with results from previous years for samples collected at the same hospital in Sendai.

CONCLUSIONS

Our study demonstrates that 1 year after the earthquake and tsunami, the concentrations of chlorinated POPs in breast milk had not changed substantially.

Profiles and determinants of dicofol, endosulfans, mirex, and toxaphenes in breast milk samples from 10 prefectures in Japan

Human exposure to persistent organic pollutants (POPs) is reflected by POP concentrations in breast milk. Many studies of POPs in breast milk have been performed in Japan, but insufficient information is available about some legacy POPs (e.g., mirex and toxaphenes, included in the Stockholm Convention in 2001) and novel POPs (e.g., dicofol and endosulfans, included in the Stockholm Convention in 2019 and 2011, respectively). In this study, dicofol, endosulfan, mirex, and toxaphene concentrations in breast milk from 10 prefectures in Japan were determined. The samples were collected between 2005 and 2010, before Stockholm Convention restrictions on endosulfans and mirex were implemented. Common POPs (e.g., polychlorinated biphenyls) were also analyzed to allow the contamination statuses to be compared. The α-endosulfan and β-endosulfan concentrations were 0.26-13 and 0.012-0.82 ng/g lipid, respectively. The toxaphene #26 and #50 concentrations were <0.08-5.6 and < 0.1-8.5 ng/g lipid, respectively. The dicofol concentrations were <0.01-4.8 ng/g lipid. The mirex concentrations were <0.2-3.5 ng/g lipid. The α- and β-endosulfan concentrations on a lipid weight basis negatively correlated with the lipid contents of the milk samples (ρ = -0.65, p < 0.01 for α-endosulfan; ρ = -0.58, p < 0.01 for β-endosulfan). The toxaphene concentrations positively correlated with the lipid contents. The mirex concentrations positively correlated with the maternal age but negatively correlated with the maternal body mass index. No correlations between the dicofol concentrations and the factors were found. Principal component analysis divided the data into four groups, (1) chlordanes, dichlorodiphenyltrichloroethanes and related compounds, hexachlorobenzene, hexachlorocyclohexanes, hexachloroethane, and polychlorinated biphenyls, (2) endosulfans, (3) dicofol, dieldrin, and toxaphenes, and (4) bromodiphenyl ether 47. This indicated that bromodiphenyl ether 47, dicofol, endosulfans, and toxaphenes have different exposure routes or different kinetics to the other legacy POPs.

Using homing pigeons to monitor atmospheric organic pollutants in a city heavily involving in coal mining industry

Coal is the most extensively used fossil fuel in China. It is well documented that coal combustion detrimentally affected air quality, yet the contribution of coal mining activity to air pollution is still largely unknown. Homing pigeons have been applied to assess the occurrence of atmospheric pollutants within cities. Herein, we sampled homing pigeons from both urban and mining areas in a typical coal industry city (Datong, China) as biomonitors for assessing local air pollution. Target organic contaminants, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCPs) were frequently detected in lung, liver, and fat tissues of the pigeons. The pollutants were predominately accumulated in lung, validating that respiration was the main accumulation route for these compounds in homing pigeons. In addition, pathological damage examination in lung and liver tissues revealed that the exposure to atmospheric pollutants impaired pigeon health. While the concentrations of PCBs and OCPs were similar in pigeons from urban and mining areas, the concentrations of PAHs were higher in pigeons from urban area. In contrast, more elevated levels of PBDEs (particularly BDE-209) were found in the mining area, which was consistent with the greater pathological damages and particulate matter levels. Unlike coal combustion, coal mining activities did not increase atmospheric PAH exposure to homing pigeons, but intensified PBDE contamination along with increasing emission of particulate matters. Overall, homing pigeons are promising biomonitors for assessing the respiratory exposure and risk of atmospheric pollutants within cities.

Characteristics and Residual Health Risk of Organochlorine Pesticides in Fresh Vegetables in the Suburb of Changchun, Northeast China

In this study, eleven organochlorine pesticides (OCPs) in fresh vegetables in the Changchun suburb were investigated, and their potential health risks were evaluated. The average concentrations of OCPs in edible parts of vegetables were found in the following descending order: Σhexachlorocyclohexanes (ΣHCHs) (6.60 µg·kg^-1) > Σdichlorodiphenyltrichloroethanes (ΣDDTs) (5.82 µg·kg^-1) > ΣChlordanes (2.37 µg·kg^-1) > heptachlor (0.29 µg·kg^-1). Moreover, OCPs in different types of vegetables exceeded the maximum residue limits (MRLs), and the exceeding rates in various vegetables decreased in the following order: leafy vegetables (19.12%) > root vegetables (18.75%) > fruit vegetables (3.85%). The proportions of OCPs exceeding MRL in different vegetables were found in the following descending order: Welsh onion (22.50%) > radish (18.75%) > Chinese cabbage (14.29%) > pepper (6.90%) > cucumber (3.23%) > eggplant (2.94%) > tomato (2.78%). The sources' identification results showed that DDTs in vegetables came mainly from newly imported technical DDTs and dicofol, while HCHs originated mainly from lindane. For both adults and children, the average target hazard quotients (avg. THQ) were all less than 1, and the average hazard index (avg. HI) values were 0.043 and 0.036, respectively. There were no significant health risks associated with OCP exposure for the inhabitants of the study area.

Endocrine disrupting chemicals (EDCs) in environmental matrices: Occurrence, fate, health impact, physio-chemical and bioremediation technology

Endocrine disrupting chemicals (EDCs) are an emerging category of toxicity that adversely impacts humans and the environment's well-being. Diseases like cancer, cardiovascular risk, behavioral disorders, autoimmune defects, and reproductive diseases are related to these endocrine disruptors. Because these chemicals exist in known sources such as pharmaceuticals and plasticizers, as well as non-point sources such as agricultural runoff and storm water infiltration, the interactive effects of EDCs are gaining attention. However, the efficiency of conventional treatment methods is not sufficient to fully remediate EDCs from aqueous environments as the occurrence of EDC bioremediation and biodegradation is detected in remediated drinking water. Incorporating modification into current remediation techniques has to overcome challenges such as high energy consumption and health risks resulting from conventional treatment. Hence, the use of advanced psychochemical and biological treatments such as carbon-based adsorption, membrane technology, nanostructured photocatalysts, microbial and enzyme technologies is crucial. Intensifying environmental and health concerns about these mixed contaminants are primarily due to the lack of laws about acute concentration limits of these EDCs in municipal wastewater, groundwater, surface water, and drinking water. This review article offers evidence of fragmentary available data for the source, fate, toxicity, ecological and human health impact, remediation techniques, and mechanisms during EDC removal, and supports the need for further data to address the risks associated with the presence of EDCs in the environment. The reviews also provide comprehensive data for biodegradation of EDCs by using microbes such as fungi, bacteria, yeast, filamentous fungi, and their extracellular enzymes.

Organochlorine Pesticides and Polychlorinated Biphenyls in Sediment Impacted by Cage Aquaculture in the Volta Basin of Ghana

Seventeen organochlorine pesticides (OCPs) and seven indicator polychlorinated biphenyls (PCBs) residues in 80 sediment samples from four cage aquaculture farms on the Volta Basin were determined to find out the extent of their contamination as well as their risk to biota in the aquatic ecosystem. The extracted residues of the OCPs and PCBs were analysed on a gas chromatograph equipped with an electron capture detector and mass spectrometer, respectively. Eleven (11) OCPs: methoxychlor, δ-HCH, o,p'-DDD, α-endosulphan, β-HCH, o,p-DDE, p,p-DDE, p,p'-DDT, β-endosulphan, endrin, and heptachlor and seven (7) PCBs: PCB 18, PCB 28, PCB 52, PCB 101, PCB 138, PCB 153, and PCB 180 were detected in the sediments from the farms. The OCPs level ranged < LOD - 33.0 µg/kg. δ-HCH (8.154 ± 0.414 µg/kg), α-endosulphan (6.000 ± 1.414 µg/kg), o,p'-DDD (2.010 ± 1.46 µg/kg), endrin (13.867 ± 8.716 µg/kg), and α-endosulphan (0.503 ± 0.398 µg/kg) were predominant with frequencies of detection 100%, 45%, 68%, 92%, and 25% in fish farms A, B, C, D and controls, respectively. PCBs concentrations ranged 0.042-5.320 ng/g wet weight. PCB 153 recorded the highest concentration of 3.328 ± 1.700 ng/g in farm D. PCB 18 and PCB 180 dominated the profiles in the sediment from all the farms. The ecotoxicological risk of the OCPs and PCBs in the surface sediment using the SQGs indicated that ∑HCH in the sediment from all the farms except that the controls may pose a health risk to the benthic organisms. Therefore, a comprehensive remedial intervention is required to arrest the situation.

Not out of the woods yet: Signatures of the prolonged negative genetic consequences of a population bottleneck in a rapidly re-expanding wader, the black-faced spoonbill Platalea minor

The long-term persistence of a population which has suffered a bottleneck partly depends on how historical demographic dynamics impacted its genetic diversity and the accumulation of deleterious mutations. Here we provide genomic evidence for the genetic effect of a recent population bottleneck in the endangered black-faced spoonbill (Platalea minor) after its rapid population recovery. Our data suggest that the bird's effective population size, N_e , had been relatively stable (7500-9000) since 22,000 years ago; however, a recent brief yet severe bottleneck (N_e  = 20) which we here estimated to occur around the 1940s wiped out >99% of its historical N_e in roughly three generations. Despite a >15-fold population recovery since 1988, we found that black-faced spoonbill population has higher levels of inbreeding (7.4 times more runs of homozygosity) than its sister species, the royal spoonbill (P. regia), which is not thought to have undergone a marked population contraction. Although the two spoonbills have similar levels of genome-wide genetic diversity, our results suggest that selection on more genes was relaxed in the black-faced spoonbill; moreover individual black-faced spoonbills carry more putatively deleterious mutations (Grantham's score > 50), and may therefore express more deleterious phenotypic effects than royal spoonbills. Here we demonstrate the value of using genomic indices to monitor levels of genetic erosion, inbreeding and mutation load in species with conservation concerns. To mitigate the prolonged negative genetic effect of a population bottleneck, we recommend that all possible measures should be employed to maintain population growth of a threatened species.

Chemical contaminant exposures assessed using silicone wristbands among occupants in office buildings in the USA, UK, China, and India

Little is known about chemical contaminant exposures of office workers in buildings globally. Complex mixtures of harmful chemicals accumulate indoors from building materials, building maintenance, personal products, and outdoor pollution. We evaluated exposures to 99 chemicals in urban office buildings in the USA, UK, China, and India using silicone wristbands worn by 251 participants while they were at work. Here, we report concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and other brominated flame retardants (BFRs), organophosphate esters (OPEs), phthalates and phthalate alternatives, pesticides, and polycyclic aromatic hydrocarbons (PAHs). First, we found major differences in office worker chemical exposures by country, some of which can be explained by regulations and use patterns. For example, exposures to several pesticides were substantially higher in India where there were fewer restrictions and unique malaria challenges, and exposures to flame retardants tended to be higher in the USA and UK where there were historic, stringent furniture flammability standards. Higher exposures to PAHs in China and India could be due to high levels of outdoor air pollution that penetrates indoors. Second, some office workers were still exposed to legacy PCBs, PBDEs, and pesticides, even decades after bans or phase-outs. Third, we identified exposure to a contemporary PCB that is not covered under legacy PCB bans due to its presence as an unintentional byproduct in materials. Fourth, exposures to novel BFRs, OPEs, and other chemicals commonly used as substitutes to previously phased-out chemicals were ubiquitous. Fifth, some exposures were influenced by individual factors, not just countries and buildings. Phthalate exposures, for example, were related to personal care product use, country restrictions, and building materials. Overall, we found substantial country differences in chemical exposures and continued exposures to legacy phased-out chemicals and their substitutes in buildings. These findings warrant further research on the role of chemicals in office buildings on worker health.

DNA methylation changes induced by BDE-209 are related to DNA damage response and germ cell development in GC-2spd

Decabrominated diphenyl ether (BDE-209) is generally utilized in multiple polymer materials as common brominated flame retardant. BDE-209 has been listed as persistent organic pollutants (POPs), which was considered to be reproductive toxin in the environment. But it still remains unclear about the effects of BDE-209 on DNA methylation and the induced-male reproductive toxicity. Due to the extensive epigenetic regulation in germ line development, we hypothesize that BDE-209 exposure impacts the statue of DNA methylation in spermatocytes in vitro. Therefore, the mouse GC-2spd (GC-2) cells were used for the genome wide DNA methylation analysis after treated with 32 μg/mL BDE-209 for 24 hr. The results showed that BDE-209 caused genomic methylation changes with 32,083 differentially methylated CpGs in GC-2 cells, including 16,164 (50.38%) hypermethylated and 15,919 (49.62%) hypomethylated sites. With integrated analysis of DNA methylation data and functional enrichment, we found that BDE-209 might affect the functional transcription in cell growth and sperm development by differential gene methylation. qRT-PCR validation demonstrated the involvement of p53-dependent DNA damage response in the GC-2 cells after BDE-209 exposure. In general, our findings indicated that BDE-209-induced genome wide methylation changes could be interrelated with reproductive dysfunction. This study might provide new insights into the mechanisms of male reproductive toxicity under the environmental exposure to BDE-209.

Linking the past and present to predict the distribution of Asian crested ibis (Nipponia nippon) under global changes

Understanding how species' ecological niches adapt to environmental changes through time is critical for predicting the effect of future global change on endangered species. Yet few studies have incorporated knowledge of past niche shifting into the assessment of species' future fate in a changing world. In this study, we integrated the ecological niche dynamics into the species distribution modeling of the Asian crested ibis (Nipponia nippon) in East Asia. Specifically, we compared historical and present ecological niches of crested ibis in four-dimensional environmental space based on species occurrence and environmental data. We then employed a multi-temporal ecological niche model to estimate the potential geographical distribution of crested ibis under future climate and land-use changes. Our results show that crested ibis retained similar though not identical ecological niches over time. Compared to the historical baseline range, the current suitable habitat for crested ibis has been reduced by 39.6%. The effects of human activity outweigh those of climate change regarding the distribution of crested ibis. We conclude that the ecological niche of crested ibis was tended to be conservative, and future potentially suitable habitat may encounter northeastward and northwestward shift, and possibly expand by 18.7% referred to the historical range. The findings of our study are of clear importance for the conservation and successful reintroduction of crested ibis in East Asia.

Risk of dietary intake of organochlorine pesticides among the childbearing-age women: A multiple follow-up study in North China

Exposure to organochlorine pesticides (OCPs) can cause adverse health effects in the female population. We investigated the dietary OCP intake of childbearing-age women living in large agricultural areas of Northern China, as well as their associated health risks. Ten childbearing-age women were recruited during 2015-2016. Their weekly dietary intake diaries and food samples were collected over the course of five visits. The OCP residues of 322 food samples from seven categories (i.e., cereal, vegetable, fruit, fish, meat, egg, and milk) were analyzed by gas chromatography-mass spectrometry. The average concentrations of the total hexachlorocyclohexanes (ΣHCH), dichlorodiphenyltrichloroethanes and their metabolites (ΣDDX), endosulfans (ΣES), and dieldrin and endrin (ΣDrin) in all food categories were, overall, much lower than the maximum residue limits. Relative high mean residues of ΣDrin and ΣES were found in fruits (ΣDrin: 0.687 ng g-1 wet weight (w.w.), ΣES: 2.24 ng g-1 w.w.) and vegetables (ΣDrin: 0.690 ng g-1 w.w., ΣES: 2.11 ng g-1 w.w.). The estimated daily dietary intake (EDI) of these compounds was calculated, with mean levels of 10.6 (ΣES) > 4.37 (ΣDrin) > 1.51 (ΣHCH) > 0.850 (ΣDDX) ng kg-1 day-1. Women during the heating period (from January to March) tended to ingest more ΣHCH, ΣDDX, ΣDrin, and ΣES. Overall, women had no obvious non-carcinogenic and carcinogenic risks due to intake of OCPs, but 83.9% of them has potential carcinogenic risk, with estimated life carcinogenic risk (LCR) exceeding 10-6. Furthermore, women had a higher potential carcinogenic risk during the heating period (mean LCR: 1.33 × 10-5) than during the non-heating period (mean LCR: 8.50 × 10-6). ΣDrin was the dominant OCP responsible for health risks, followed by ΣHCH. We concluded that women in North China still have some dietary OCP intake, especially during the heating period.

Bioaccessibility dependence of dietary exposure to dichlorodiphenyltrichloroethane and its metabolites and hexachlorocyclohexane isomers and their induced health risk: A case study in Beijing City, China

Bioaccessibility is essential for evaluating dietary intake of contaminants. However, there is insufficient information on the dependence of dietary intake and risk assessment of dichlorodiphenyltrichloroethane and its metabolites (DDXs) and hexachlorocyclohexane isomers (HCHs) on bioaccessibility. Here, we investigated the bioaccessibilities of DDXs and HCHs in various foods and their influences on assessing exposure in the residents of Beijing City, China. Forty-three major foods in five types (fruit, vegetables, cereals, aquatic food, and meat) were sampled, and the bioaccessibility of DDXs and HCHs was evaluated using a static in vitro gastrointestinal digestion model. The bioaccessibility of DDXs in different food types ranked in the order of meat > vegetables > fruit > cereals > aquatic food, with mean ± standard deviation values of 62.2 ± 22.1%, 20.5 ± 10.6%, 12.4 ± 3.66%, 11.2 ± 9.69%, and 10.7 ± 4.97%, respectively. The highest average bioaccessibility of HCHs was found in meat (83.4 ± 14.2%), followed by fruit (41.0 ± 12.5%), vegetables (37.6 ± 18.1%), aquatic foods (24.2 ± 9.22%), and cereals (8.73 ± 4.07%). The estimated daily intakes (EDI) of the sum of DDXs and the sum of HCHs based on the bioaccessible concentration were only about 17% and 55% of the total EDI based on the residual concentration, respectively. Meat was found to play a more important role in EDI after bioaccessibility correction. The proportion of the population with potential non-carcinogenic and carcinogenic risks markedly decreased when considering bioaccessibility. It was concluded that bioaccessibility should be integrated into dietary exposure evaluation.

Sedimentary evolution of PAHs, POPs and ECs: Historical sedimentary deposition and evolution of persistent and emerging organic pollutants in sediments in a typical karstic river basin

Knowledge on the occurrence and distributions of organic compounds, especially PAHs, POPs and ECs, in karstic river basins is limited. This study aims to determine the depositional history and sources of PAHs, PCBs, OCPs, antibiotics, EDCs and phenolic compounds and the ecological risk they have in the Panyang River Basin, an area with a typical karstic landscape and a high-longevity population. Sediment core analysis was adopted, correlation and principal component analyses were conducted to analyze pollution sources, and lead isotope technology was implemented for dating analysis. The sediment core covered 108 years. PCBs were detected with concentrations ranging from 3.80 to 16.18 μg/kg in the core with two concentration peaks in 1950 and 2005 that were related to anthropogenic effects. Eight of the 20 targeted phenolic compounds were detected, with concentrations ranging from 0.42 to 1.10 mg/kg. All PAHs were detected in the cores, with concentrations from 12.91 to 37.80 μg/kg. They were mainly related to natural diagenetic processes and domestic and agricultural sources. The concentrations of different OCP compounds ranged from undetected to 213.43 μg/kg and were mainly related to agricultural activities and long-range transportation. These key findings can assist environmental planning and management in this river basin.

Pesticides driven pollution in Kuwait: The first evidence of environmental exposure to pesticides in soils and human health risk assessment

Soil pollution from pesticide residues is a key concern due to the high soil accumulation of pesticides and their human toxicity. Pesticide concentration of surface soil samples from the Sulaibiya agricultural field located in Kuwait was assessed in the present study. The study also investigated health risk assessment for both children and adults based on the residual concentrations. The average concentration of ƩOCPs (sum of organochlorine pesticides) along the present study was 3062 pg/g. The residual concentration of ƩOCPs was comparatively lower as compared to other locations around the world. Out of the 11 observed locations, A, B, and D locations indicated higher concentrations of ƩOCPs. The results indicated that DDT showed higher concentrations 692.87 pg/g in soil samples as compared to the other pesticides. Cancer risks of OCP via ingestion, dermal contact and inhalation of soil particles suggested that all stations were in a safe zone. However, locations A, B and D were closer to the low-risk band. The distribution pattern for each form of organochlorine pesticides (OCP) was different in Sulaibiya, indicating the non-simultaneous use of different groups of OCPs in this region. Multivariate statistical analysis based on cluster analysis identified three classes, 1, 2 and 3 of pesticides, suggesting these are from the same sources. Principle component analysis (PCA) showed that soil physicochemical properties influence the pesticides in soil samples. The results provides the baseline data of pesticides in soils from Kuwait.

Organochlorine Pesticide Ban Facilitated Reproductive Recovery of Chinese Striped Hamsters

Organochlorine pesticides (OCPs) have been used worldwide on an enormous scale over the last century but are banned globally due to environmental persistence and ecotoxicity in recent decades. The long-term effects of OCP ban for agricultural use in China since 1983 on the reproductive health of small terrestrial mammals have never been evaluated in the field. We examined the residue dynamics of OCPs and the reproductive performance of Chinese striped hamsters (Cricetulus barabensis) in North China Plain during 1983-2010 and concluded that the exposure levels of OCPs in hamsters drastically decreased from 2900 ± 740 to 25.2 ± 6.88 ng/g with an average half-life of 5.08 yrs, coinciding with the observed reproductive recovery of hamsters. The population-based reproductive performance of hamsters was significantly and negatively associated with OCP exposure levels after adjusting the contributions from climate and population density factors, indicating that the ban of OCPs has facilitated the reproductive recovery of hamsters by up to 81% contribution. Our findings suggest that the OCP ban is effective to restore reproduction of small terrestrial mammals. Integration of population biology and environmental science is essential to assess the impacts of persistent organic pollutants on ecological safety and biodiversity loss under accelerated global change.

Role of nanocatalyst in the treatment of organochlorine compounds - A review

Since a few centuries ago, organochlorine compounds (OCs) become one of the threatened contaminants in the world. Due to the lipophilic and hydrophobic properties, OCs always discover in fat or lipid layers through bioaccumulation and biomagnification. The OCs are able to retain in soil, sediment and water for long time as it is volatile, OCs will evaporate from soil and condense in water easily and frequently, which pollute the shelter of aquatic life and it affects the function of organs and damage system in human body. Photocatalysis that employs the usage of semiconductor nanophotocatalyst and solar energy can be the possible alternative for current conventional water remediation technologies. With the benefits of utilizing renewable energy, no production of harmful by-products and easy operation, degradation of organic pollutants in rural water bodies can be established. Besides, nanophotocatalyst that is synthesized with nanotechnology outnumbered conventional catalyst with larger surface area to volume ratio, thus higher photocatalytic activity is observed. In contrast, disadvantages particularly no residual effect in water distribution network, requirement of post-treatment and easily affected by various factors accompanied with photocatalysis method cannot be ignored. These various factors constrained the photocatalytic efficiency via nanocatalysts which causes the full capacity of solar photocatalysis has yet to be put into practice. Therefore, further modifications and research are still required in nanophotocatalysts' synthesis to overcome limitations such as large band gaps and photodecontamination.

Levels and profiles of persistent organic pollutants in breast milk in China and their potential health risks to breastfed infants: A review

Although some persistent organic pollutants (POPs) were prohibited or limited in use several decades ago, they are still frequently detected in the human body. The purpose of this study was to understand the levels and profiles of POPs in breast milk in China and assess their potential health risks among breastfed infants under six months of age. A literature review focused on China was performed for studies published from 2001 to 2020. The POP levels in breast milk along with other important variables were extracted, and then the average individual POP levels in breast milk were estimated. This review summarises the distribution of traditional and new POPs, including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), legacy brominated flame retardants (BFRs), perfluorinated compounds (PFCs), and chlorinated paraffins (CPs) and reported notably high levels of short-chain chlorinated paraffins and 1,1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p'-DDE) in breast milk. Although the levels of traditional POPs generally declined over time, especially p,p'-DDE and beta-hexachlorocyclohexane (β-HCH), women living in coastal areas, urban areas, and southern China still have a high body burden of certain POPs. In the present study, the estimated daily intake (EDI) of POPs through breastfeeding was used to evaluate the health risk for infants by comparing with acceptable levels. The findings suggested that infants born in coastal areas most likely suffered potential health risk from exposure to DDT, and the health risk of hexachlorobenzene (HCB) in infants in most nationwide regions remains a concern. More importantly, the EDI of PCBs for infants exceeds the safe limit on a national scale. Continuous surveillance of PCBs in breast milk is critical to evaluate the potential health effects on humans.

Evaluation of the concentration of the toxic 2,3,6,7-tetrachlorobiphenylene in air after an electrical material fire

It is known that when fires or explosions involve electrical systems, along with PCDDs and PCDFs, polychlorinated biphenylenes (PCBPs) are also produced. These chlorinated tricyclic aromatic pollutants were noticed in fire rubbles and after the World Trade Center destruction. However, the analytical difficulties in developing an efficient method have limited the knowledge of their environmental distribution. In light of the equipotency of 2,3,6,7-TeCBP and 2,3,7,8-TeCDD, PCBPs call for more accurate investigations. In this paper, for the first time, the level and persistence of 2,3,6,7-TeCBP have been investigated in air samples (both indoor and outdoor) after a fire broke out in an industrial building. GC-MS/MS analysis revealed that 2,3,6,7-TeCBP concentrations after the fire (3046 fg/m³ at the "epicentre") were remarkably higher than that of the 2,3,7,8-TeCDD. Moreover, the monitoring for over two years has demonstrated the persistent nature of this compound. 2,3,6,7-TeCBP was also analyzed in two different ambient air scenario: industrial and periurban areas and in both cases its concentrations were no matter of concern, confirming the correlation of 2,3,6,7-TeCBP with fire episodes. Collectively, 2,3,6,7-TeCBP, because of its toxicity, concentration and persistence, is a crucial compound in the evaluation of the health effects correlated with fires of electrical systems.

Exposure to multiclass pesticides among female adult population in two Chinese cities revealed by hair analysis

The high use of pesticides worldwide and the constant exposure of humans to these toxic-by-design chemicals have drawn the attention on the possible consequences on human health. However, information on the exposure of the general population to pesticides remain very limited in most countries, especially in urban areas. In the present work, hair analysis was conducted to investigate the exposure of 204 urban women living in two Chinese cities (Baoding and Dalian) to 110 pesticides and 30 metabolites of the following families: organochlorines, organophosphates, carbamates, pyrethroids, neonicotinoids, phenylpyrazoles, acid herbicides, urea herbicides and azoles. Results showed that 71 pesticides and 23 metabolites were found in the hair samples, with concentrations ranging up to 1070 pg/mg in hair. In each hair sample, the number of detected chemicals ranged from 25 to 50, demonstrating the cumulative exposure to pesticides among Chinese women in the studied regions. The concentrations of 38 chemicals (e.g., p-nitrophenol, diethyldithiophosphate, λ-cyhalothrin, permethrin, carbendazim and tebuconazole) were significantly different between women in Baoding and Dalian, indicating the regional differences in exposure to pesticide. Using a multiple regression analysis, we found that concentrations of a few dominant pesticides were associated with age, body mass index (BMI), cooking frequency and regions. These results can provide baseline information on exposure of female adult Chinese population to multiple pesticides and support future studies focused on the health effects associated with pesticide exposure.

A national-scale characterization of organochlorine pesticides (OCPs) in intertidal sediment of China: Occurrence, fate and influential factors

Organochlorine pesticides (OCPs) have been restricted for application for about 30 years in China. Intertidal zone is a sink for anthropogenic pollutants, and to better understand the current pollution status of OCPs in China, 324 surface sediment samples collected from 14 typical intertidal zones of China were analyzed for 22 OCPs. The total concentrations of OCPs ranged from 0.051 to 4141.711 ng/g, with DDTs and HCHs being the dominant components. Seasonal variations were not significant for most intertidal zones (p > 0.05), while significant spatial variations (p < 0.05) were found among 14 intertidal zones, with the highest OCPs concentrations detected in Jiulong Jiang (JLJ). The OCPs concentrations in intertidal sediments would rarely to frequently cause adverse biological effects and DDTs were the major threat. Apart from the historical usage of technical DDT and lindane, current usage of technical DDT and HCH were also implied, especially for intertidal zones such as Beidaihe (BDH) and Yingluo Wan (YLW). PCA analysis indicated that compounds within the same type of OCPs were from similar source, while different types of OCPs were generally from different sources and not used together. Our results further indicated that OCPs together with organic particles entered into the intertidal zones mainly through river input.

A survey of the secondary exposure to organophosphate and organochlorine pesticides and the impact of preventive factors in female villagers

Organophosphates (OPs) and organochlorine pesticides (OCPs) are two main types of pesticides that are widely used worldwide, and their toxicities have been reported in high-risk individuals, such as farmers and their wives. The aim of this study was to evaluate the levels of mentioned pesticides in farmers' wives (FWs) and compare them with the control group; we also aimed to assess the effect of personal health factors on the biochemical parameters. This case-control study was conducted on two FWs and control groups, consisting of 124 and 62 individuals, respectively. Serum levels of OCPs were measured using gas chromatography (GC) method. In addition, the activity of acetylcholine esterase (AChE), total antioxidant capacity (TAC), and serum levels of malondialdehyde (MDA) were evaluated in all participants. Additionally, the observance of personal health guidelines was assessed. Serum levels of OCPs in the FWs group were significantly higher than the controls. In addition, AChE activity in FWs was significantly lower than the controls. Moreover, it was found that higher levels of education lead to a better observation of most individual health guidelines, which results in reducing the biological adverse effects of pesticides. The results of this study indicated that the use of OCPs, as an illegal pesticide with known toxic and carcinogenic effects, has spread to southern Iran, which may have biological toxic effects. Also, observing the personal health points significantly reduced these complications and it is, therefore, recommended that more attention should be paid to this issue.

Synthesis and Characterization of Zero-Valent Iron Nanoparticles, and the Study of Their Effect against the Degradation of DDT in Soil and Assessment of Their Toxicity against Collembola and Ostracods

Of late, novel magnetic nanomaterials have drawn worldwide attention because of the uniqueness in their properties and uses. In our studies, we have prepared nearly monodisperse zero-valent iron nanoparticles (nZVIs) of diameter of less than 60 nm in aqueous medium by a reductive precipitation process and pectin as stabilizing agent. The characterization of these nanoparticles was done by dynamic light scattering and transmission electron microscopy (TEM) techniques. The TEM images confirmed that the average size of the nZVIs was about 25 nm. The resultant nZVIs were then employed to degrade DDT (dichlorodiphenyltrichloroethane) in spiked soil, and their toxicity toward Collembola (Folsomia candida) and Ostracods (Heterocypris incongruens) was measured. The fabricated nZVIs degraded DDT in soil quite effectively. Further, the effects of nZVIs on Collembola and Ostracods were found to be negative. This was due to the oxidation of nZVIs and creation of anoxic conditions thereupon, and the generation of excess Fe(II) in soil. In addition, the negative effects of DDT on ostracod development and Collembola reproduction were found to be quite weak.

Semi-volatile organic compounds in tap water from Hangzhou, China: Influence of pipe material and implication for human exposure

Investigations on environmental behaviors of SVOCs have recently received great attention. However, the SVOC occurrence and influence of pipe materials on SVOC levels in the tap water have received little attention. Herein, we collected tap water samples from 25 households constructed at different ages in Hangzhou, China. Concentrations of 61 SVOCs, including phthalate esters (PAEs), organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs), were simultaneously determined in these collected samples. The potential human exposure risks were evaluated via the hazard index calculation. Our results showed that the total concentration of detected SVOCs (∑SVOCs) ranged from 110 to 289 μg/L (mean, 179 μg/L), and the SVOCs were dominated by PAHs (mean, 116 ng/L) and PAEs (mean, 55 ng/L) in Hangzhou tap water. 12 PCB congeners were detected in Hangzhou tap water samples, with hepta-CBs (68% of samples) as the most frequently detected PCBs. Nearly all tap water samples contained measurable o, p'-DDE, p, p'-DDT, and p, p'-DDD, and ∑DDTs had significantly (p < 0.05) higher concentrations than ∑HCHs. All target PAHs had high detection frequencies (>72%) in tap water samples, with their mean concentrations in the range of 2.1-41 ng/L. Tap water from steel pipes had relatively lower SVOC concentrations than that from either reinforced concrete, gray cast iron, or ductile iron pipes. Although no carcinogenic risks originating from exposure to SVOCs through ingestion and bathing were observed, the tap water from steel pipes showed relatively low exposure risks than that from other materials. Data provided here, for the first, are helpful in understanding the influence of pipe materials on human SVOC exposure risks through tap water intake.

Comparative analysis of freshwater species sensitivity distributions and ecotoxicity for priority pesticides: Implications for water quality criteria

Organochlorine pesticides (OCPs) and organophosphate pesticides (OPPs) posed severe threats to the aquatic environment in China. The toxicity data of 18 priority OCPs and OPPs for Chinese and American species were collected, and their species sensitivity distributions (SSDs) and ecotoxicity were compared. Physicochemical characteristics and chemical structures were used to analyze the difference in the pesticide toxicity. Results suggested that there is no significant difference between the HC₅ values (hazardous concentration protecting 95% of species) of China and America as a whole. However, the HC₅ values of nearly half of these pesticides (8/18) differ dramatically between Chinese and American due to the different resident species distribution. It indicated that it is necessary to develop local water quality criteria in China. The regression analysis of pesticides toxicity differences indicated a decrease in LC₅₀/EC₅₀ values (for Oncorhynchus mykiss and Carassius auratu) with the increase in molecular weights of pesticides. Pesticides with larger MWs might be more toxic to aquatic species. Similar trend was also observed in the regression analysis of a decrease in both American and Chinese HC₅ values for with increase of the number of containing halogen atoms. It indicated the potency of these parameters to be used to predict the ecotoxicity of pesticide.

Determination of Occurrences, Distribution, Health Impacts of Organochlorine Pesticides in Soils of Central China

Organochlorine pesticides are groups of chemicals applied to prevent pest and insect infestation. This study was aimed at investigating the concentration, potential sources, cancer risk and ecological toxicity of organochlorine pesticides (OCPs) in Huangpi district, Wuhan, China. Eight OCPs in soil samples collected from four land-use types at depths of 0–10 and 10–20 cm were examined. Sample extraction was carried out by solid phase matrix extraction method and analyzed using Agilent gas chromatograph 7890B equipped with electron capture detectors (ECD). The total concentration of OCPs ranged from 0.00–32.7 ng g⁻¹ in the surface and 0.01–100.45 ng g⁻¹ in the subsurface soil layer. Beta hexachlorocyclohexanes (β-HCH) with 2.20 and 7.71 ng g⁻¹ in the surface and subsurface soil layers, respectively, was the dominant compound. The mean concentrations of OCPs in all samples were less than the threshold values for hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethane (DDTs) in China soil. Concentration of OCPs in the four land-use types were in the order of: paddy field > barren land > farmland > plastic greenhouse. Results of composition analysis revealed recent application of lindane as a major and historical use of new technical HCHs as a minor source of HCHs. On the other hand, application of new technical p,p’-DDT is the main source of DDTs in the study area. The estimated lifetime average daily dose, incremental lifetime cancer risks and hazard quotient values revealed that there is less likelihood of carcinogenic and noncarcinogenic health risks on the local residents.

Differences in the uptake and bioconcentration of dichlorodiphenyltrichloroethane by eight vegetable cultivars and their health risk assessments

Dichlorodiphenyltrichloroethane (DDT) is not easily degraded in soils, which will pose a threat to human health. We investigated the differences of eight vegetables' capacity to take up DDT, removing DDT from soil, and tolerating DDT (monitoring the responses of growth, root morphology and photosynthesis of vegetables to DDT). These vegetables included Chinese mustard (two genotypes, B.jf and B,jm), napa cabbage (two genotypes, B.coz and B.coc) and Bok choy (four genotypes, B.cz, B.cq, B.cs and B.chg). The results demonstrated that 5 mg kg^-1 DDT did not display significant effects on the growth of most vegetables in this study. As compared to the control, 5 mg kg^-1 DDT significantly increased the shoot and root biomass, the fine root numbers, and the fine root ratio for the genotype of B.chg. However, 5 mg kg^-1 DDT exposure showed a negative effect on the shoot growth of two genotypes of napa cabbage. In general, 5 mg kg^-1 DDT did not significantly affect the photosynthesis and root morphology of most vegetables in this study. Consuming these vegetables had a low non-cancer health risk, but showed a high cancer health risk. In addition, among the eight vegetables, B.chg accumulated less DDT in the edible parts and had low values of HR_non-cancer and HR_cancer for consuming these vegetables containing DDT. Planting these vegetables might promote the degradation of DDT reducing its residual amount in soil.

Chiral pharmaceuticals: Environment sources, potential human health impacts, remediation technologies and future perspective

Chiral pharmaceuticals (CPs), including non-steroid anti-inflammatory drugs (NSAIDs), β-blockers and some herbicide and pesticides, are widely used in aquaculture, clinical treatment and many other fields. However, people are increasingly concerned about such ubiquitous pollutants, which can frequently be detected in contaminated soil and water. In large part, the significant sources of chiral pharmaceuticals stem from industrial processes, such as the direct discharge of untreated or incompletely treated wastewaters containing chiral pharmaceuticals, incorrect storage and use, animal wastes and biosolids. The main ways for human exposure to chiral pharmaceuticals are the disease treatment process and chiral pharmaceuticals contaminants. According to the results of a series of toxic studies, some diseases, even cancers, may be associated with exposure to certain chiral pharmaceuticals. Therefore, the treatment of chiral pharmaceuticals has become an important issue. The current advanced remediation techniques for chiral pharmaceuticals include the conventional method (sorption and sonolysis), biotransformation (an aerobic granular sludge-sequencing batch reactor and constructed wetland system) and advanced oxidation processes (ozonation and photocatalysis). Herein, in this review, we summarize the current status and sources of chiral pharmaceuticals, potential effects on human health, as well as the superiority, disadvantages and prospects of current advanced remediation technologies. Moreover, we also anticipate the prospect of the future research needed for chiral pharmaceuticals pollutant remediation.

Concentrations of organochlorine pesticides in cord serum of newborns in Wuhan, China

Organochlorine pesticides (OCPs) had been widely used in China before they were banned decades ago due to the concern of the toxicology to human. Previous reports showed that OCPs were still often detectable in human bodies. However, there is limited study concerning the body burden of OCPs in infants and fetus in China. In this study, the prenatal exposure to OCPs was evaluated by measuring OCPs in cord serum. A total of 1046 cord serum samples were collected in Wuhan during 2014 and 2015, and analyzed for the concentrations of hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs), dichlorodiphenyldichloroethanes (DDDs) and dichlorodiphenyldichloroethylenes (DDEs) by using gas chromatography-tandem mass spectrometry (GC-MS/MS). The median levels of ∑HCHs and ∑DDTs were 10.1 ng/g lipid (with the range from <LOD to 1910 ng/g lipid) and 35.5 ng/g lipid (with the range from 0.18 to 11,100 ng/g lipid), respectively. β-HCH and p,p'-DDE were found to be the major OCPs presenting in the cord serum samples. A minor positive association between the serum levels of α-HCH and β-HCH was observed, and the concentrations of o,p'- and p,p'-DDT isomers were found positively associated. The OCP exposure levels obtained in this study were comparable to those data from other areas in China and much lower than some of highly polluted countries. The prenatal exposure to OCPs would be of concern since fetuses were more vulnerable than adults and the cord serum is an accurate non-invasive matrix for monitoring of prenatal exposure.

Assessment of pesticide contamination in Akkar groundwater, northern Lebanon

According to its high production and value, Akkar is considered as the second agricultural region in Lebanon. Groundwater constitutes the principal source of water in Akkar including drinking water of local inhabitants in Akkar. As such, the contamination of groundwater by organic pollutants can impact directly the population health. In this study, we evaluated the contamination status of groundwater in this region. Three classes of pesticides including 19 organochlorine (OC) pesticides, 8 organophosphorus (OP) pesticides, and 6 organonitrogen (ON) pesticides were monitored in 15 groundwater samples collected from different villages on the Akkar plain. Samples were extracted by using solid phase extraction (SPE) and analyzed by gas chromatography coupled with mass spectrometry (GC-MS). The results showed high contamination of Akkar groundwater by OCs with levels that can reach 58.9 μg/L. They were detected in the majority of the sample and represent 95-100% of ∑pesticides. Our results showed the recent use of these molecules with an average level of 0.3 and 0.39 μg/L for ∑HCHs and DDTs, respectively. Their concentrations were higher than those observed in the same region in 2014 and other regions elsewhere. OPs were also detected at high levels and among them, methylparathion was the predominant OP detected (44.6 μg/L). For ONs, lower levels were measured in all samples with a mean value of 5.6 μg/L. As a conclusion of this work, groundwater on the plain of Akkar was remarkably contaminated by the studied pesticides; indefinitely, more efforts should be taken to manage the pesticide use in this region, assess, and reduce their effects on human health. In the future, the application of organic farming can be a great solution to the groundwater contamination problem.

Determination of endocrine-disrupting potencies of agricultural soils in China via a battery of steroid receptor bioassays

Pollution of agricultural soils by pesticides, such as organochlorine pesticides (OCPs), can be a significant issue since high detection rates of these compounds were reported in our previous studies. However, more uncertain kinds, quantities and density of pollutants remained in soil samples were unidentified. In this study, the total hormonal activities of complex mixtures of both known and unknown contaminants in agricultural soils in mainland China were measured by applying highly sensitive reporter gene assays for detecting agonists/antagonists for estrogen receptor (ER), androgen receptor (AR), progesterone receptor (PR), glucocorticoid receptor (GR) and mineralocorticoid receptor (MR). High detection rates of estrogenic activities and anti-progestogenic activities were observed among the 123 soil samples, reaching 79% and 73%, respectively. More than half of the soil samples showed obvious antagonistic effects against AR and GR. Approximately a third of tested samples exhibited androgenic, progestogenic and glucocorticoidic effects. A total of 72% and 78% soil extracts had mineralocorticoid-like and anti-mineralocorticoid activities, respectively. Significant positive correlations were observed between estrogenic activity and the concentrations of Σdichlorodiphenyltrichloroethanes (DDTs), Σendosulfans, Σchlordanes, heptachlor and Σdrins, respectively, but not other receptors. As a rapid and convenient pre-caution method, determination of endocrine-disrupting potencies of contaminated soils via bioassay could help to identify and define sites that required further attention for ecological risk assessments.

Pollution levels of DDTs and their spatiotemporal trend from sediment records in the Southern Yellow Sea, China

In order to study the pollution levels and spatiotemporal trend of Dichlorodiphenyltrichloroethanes (DDTs) in the Southern Yellow Sea (SYS), thirty-two surface sediment samples and a sediment core have been analyzed, and our results have been compared with previous reports. DDTs contents in our samples ranged from below detection limit to 5.1ng/gdry weight (d.w.), which presented lower ecological risks in the SYS. Surface sediment results show a seaward increasing trend with high values in the northern region of the central basin of the SYS. Our reconstructed core record and historical data from previous reports reveal an increasing trend from 1905 to 1955 but a decline trend since 1985 for DDTs, which is consistent of the production, usage and banning of DDTs in China. The source identification, based on (DDE+DDD)/DDTs, suggested that aged DDTs were the major contributor, though there were some inputs of fresh DDTs from the usage of 1,1-bis(p-Chlorophenyl)-2,2,2-trichloroethanol (dicofol).

Risk assessment of an organochlorine pesticide mixture in the surface waters of Qingshitan Reservoir in Southwest China

Risk assessment of single pollutants has been extensively studied. However, the co-exposure of pollutants in a real environment may pose a greater risk than single chemicals. In this study, concentration addition-based risk quotients were applied to the risk assessment of the 15 organochlorine pesticides (OCPs) mixtures (α-hexachlorocyclohexane (HCH), β-HCH, γ-HCH, δ-HCH, heptachlor, aldrin, heptachlor epoxide, chlordane, α-endosulfan, p,p′-dichloro-diphenyl-dichloroethylene, endrin, β-endosulfan, p,p′-dichloro-diphenyl-dichloroethane, p,p′-dichloro-diphenyl-trichloroethane, and methoxychlor) detected in the surface water (reservoirs, ponds, and streams) of Qingshitan Reservoir in Southwest China from 2014 to 2016 by summing up the toxic units (RQ_STU) of the toxicity data from the individual chemicals. The RQ_STU of the OCPs mixture exceeded 1 in 45.23% of the 283 surface water samples based on acute data and an assessment factor of 100, indicating a potential risk for the aquatic environment (fish). Methoxychlor and γ-HCH contributed the most toxicities in the pesticide mixtures toward Daphnia and fish and provided at least 50% of the mixture toxicity in all samples with RQ_STU larger than 1. The most sensitive organism to realistic OCPs mixtures in the surface waters of Qingshitan Reservoir was fish, followed by Daphnia and algae. The values of the maximum cumulative ratio for all samples indicated that the risk assessment based on single chemicals underestimated the pesticide mixture toxicities, which shows that special consideration should be made for the ecological risk of pesticide mixtures in the aquatic environment.

Risk assessment of single pollutants has been extensively studied.

Occurrence and air-soil exchange of organochlorine pesticides and polychlorinated biphenyls at a CAWNET background site in central China: Implications for influencing factors and fate

Ambient air and soil samples were collected between March 2012 and March 2013 at Jinsha, a regional background site in central China, to measure the concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). The average concentrations of total OCPs and total PCBs were 191 ± 107 and 39.4 ± 27.1 pg/m³ in air (gaseous and particulate phase) and 0.585 ± 0.437 and 0.083 ± 0.039 ng/g in soil, respectively. The higher concentrations of p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) and p,p'-DDT/p,p'-DDE ratios in the soil indicated recent p,p'-DDT input to the soil. A strong positive temperature dependence and average fugacity fraction value > 0.5 were observed for p,p'-DDT, suggesting that volatilization of residual DDT in the soil was the main influencing factor on atmospheric p,p'-DDT. Highly average fugacity fractions (>0.7) of trans-chlordane (TC) and cis-chlordane (CC) and high TC/CC ratios both in the soil and atmosphere suggested fresh inputs. Higher gaseous concentrations of hexachlorobenzene (HCB) were observed in winter and negative temperature dependence was directly attributed to the surrounding ongoing source (e.g. fuel consuming activities), especially in winter. Overall, most targeted OCPs and PCBs were influenced by long-range transport, and fugacity fraction values indicated highly volatile compounds (e.g. α-hexachlorocyclohexane (α-HCH) and lower chlorinated PCBs) were volatilized and low volatility compounds (e.g. p,p'-DDE and higher chlorinated PCBs) were deposited at the air-soil interface. Knowing the source and sink of OCPs and PCBs can help to control their pollution in this area and provide a reference for other studies.

Endocrine-disrupting chemicals and the regulation of energy balance

Energy balance involves the adjustment of food intake, energy expenditure and body fat reserves through homeostatic pathways. These pathways include a multitude of biochemical reactions, as well as hormonal cues. Dysfunction of this homeostatic control system results in common metabolism-related pathologies, which include obesity and type 2 diabetes mellitus. Metabolism-disrupting chemicals (MDCs) are a particular class of endocrine-disrupting chemicals that affect energy homeostasis. MDCs affect multiple endocrine mechanisms and thus different cell types that are implicated in metabolic control. MDCs affect gene expression and the biosynthesis of key enzymes, hormones and adipokines that are essential for controlling energy homeostasis. This multifaceted spectrum of actions precludes compensatory responses and favours metabolic disorders. Herein, we review the main mechanisms used by MDCs to alter energy balance. This work should help to identify new MDCs, as well as novel targets of their action.

Which persistent organic pollutants in the rivers of the Bohai Region of China represent the greatest risk to the local ecosystem?

Freshwater aquatic organisms can be exposed to hundreds of persistent organic pollutants (POPs) discharged by natural and anthropogenic activities. Given our limited resources it is necessary to identify, from the existing evidence, which is the greatest threat so that control measures can be targeted wisely. The focus of this study was to rank POPs according to the relative risk they represent for aquatic organisms in rivers in the Bohai Region, China. A list of 14 POPs was compiled based on the available data on their presence in these rivers and ecotoxicological data. Those that were widely detected were benzo[a]pyrene, p,p'-DDE, p,p'-DDT, endrin, fluoranthene, heptachlor, hexabromocyclododecane, hexachlorobenzene, α-hexachlorocyclohexane, γ-hexachlorocyclohexane, naphthalene, perfluorooctanoic acid, perfluorooctane sulfonate and phenanthrene. Effect concentrations were compiled for Chinese relevant and standard test species and compared with river aqueous concentrations. Only bed-sediment concentrations were available so water levels were calculated based on the known local sediment organic carbon concentration and the K_oc. The POPs were ranked on the ratio between the median river and median effect concentrations. Of the POPs studied, fluoranthene was ranked as the highest threat, followed by phenanthrene, naphthalene and p,p'-DDE. The risk from p,p'-DDE may be magnified due to being highly bioaccumulative. However, the greatest overlap between river concentrations and effect levels was for lindane. Overall, fish was the most sensitive species group to the risks from POPs. Hotspots with the highest concentrations and hence risk were mainly associated with watercourses draining in Tianjin, the biggest city in the Bohai Region.

Indicator polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in seafood from Xiamen (China): levels, distributions, and risk assessment

Indicator polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in 289 seafood samples including fishes, crustaceans, and shellfish collected from six administrative regions in Xiamen of China. The residual levels of PCBs, dichlorodiphenyltrichloroethane and its metabolites (DDTs), and hexachlorocyclohexanes (HCHs) ranged <LOD-64 (median 1.8) ng g^-1 wet weight (ww), 0.03-88 (median 1.4) ng g^-1 ww, and <LOD-5.5 (median <LOD) ng g^-1 ww, respectively. The most abundant compounds were PCB101, p,p'-DDT, and β-HCH. Significant differences in the amounts of PCBs and DDTs were recorded among the species, whereas no significant differences were observed among the species with regard to HCH concentrations. Within the regions investigated, the concentrations of PCBs were much lower in Haicang than in other regions and HCHs were detected with highest concentration in Siming, while no significant differences were observed in DDT concentrations. Principal component analysis (PCA) showed that PCB and OCP pollutions came from similar sources in Xiamen. But the pollution sources of Xiangan were diverse. The predominance of PCBs might be attributed to the past usage of domestically produced commercial PCB mixtures, and the profiles of OCPs might indicate their current use in agriculture. Results of carcinogenic risk assessment based on the 50th or 95th percentile exposure levels exceeded the threshold, suggesting that the PCBs should be of concern. On the other hand, the hazard quotients (HQs) of noncancer risks were all far below than 1.

Removal of DDE by exploiting the alcoho-phobic interactions

DDE (1,1-bis-(4-chlorophenyl)-2,2-dichloroethene), which is a commonly used pesticides in agriculture, has harmful effects on human health. Therefore, the removal of this substance from the drinking water and the soil is essential. Since DDT (1,1″-(2,2,2-Trichloroethane-1,1-diyl) bis(4-chlorobenzene)) is derivation of DDE, the presence of DDT can be monitored by the detection of DDE present in the environment. Herein, we report on the development of aspartic acid-incorporated poly(2-hydroxyethyl methacrylate-L-aspartic acid) [poly(HEMA-MAsp)] cryogel for the removal of DDE from aqueous solutions for the first time in the literature. The synthesized cryogels were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), an N₂ adsorption method, elemental analysis, and swelling test. The separation experiments were carried out via a batch system to get the optimum adsorption conditions including pH, interaction time, initial DDE concentration, and temperature. The desorption and the reusability results revealed that there was no significant decrease in the DDE adsorption capacity of the cryogels after five adsorption-desorption cycles. The maximum DDE adsorption capacity of poly(HEMA-MAsp) cryogels was found to be 31.51 mg DDE/g polymer for 50 mg DDE/L solution.

Persistent organic pollutants in China's surface water systems

Following recent rapid industrialization, China is now one of the largest producers and consumers of organic chemicals in the world. This is compounded by variable regulatory oversight with respect to storage, use and waste management of these chemicals and their byproducts. This review synthesizes the data on the distribution of selected persistent organic pollutants (POPs) in waters in China. Surface water heavily polluted with POPs is distributed in the Yangtze River Estuary, Pearl River Delta, Minjiang River Estuary, Jiulongjiang Estuary, Daya Bay, Taihu Lake, and the waterways of Zhejiang Province, where concentrations of Polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) frequently exceed both international and Chinese guideline values. These areas are mainly distributed along the southeast coast of China, within or downstream of major manufacturing districts, intensive agricultural basins, and other industrial centers. A comparison of the levels of OCPs in the aquatic environment of China with other indicative regions worldwide shows comparable levels of pollution (overall range from below detection limit (BDL) to 5104.8ng/L and regional means from 2.9-929.6ng/L). PAHs and PCBs pollution appear to be particularly serious in China (PAHs overall ranging from BDL to 474,000ng/L with regional means from 15.1-72,400ng/L; PCBs from BDL to 3161ng/L with regional means ranging from 0.2-985.2ng/L). There is as yet limited evidence of serious perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) pollution. We discuss major sources and processes responsible for high POP occurrence using a range of measures (including diagnostic ratios of different compounds), regulatory oversight and policy gaps in the control of POPs in China, and potential long-term health and ecological effects. We argue that water quality guidelines, pollution control measures and cleanup strategies for POPs in China should be urgently improved.