Polychlorinated biphenyls and organochlorines pesticides in indoor dust: An exploration of sources and health exposure risk in a rural area (Kopawa) of Nepal

Review of scientific literature on available methods of assessing organochlorine pesticides in the environment

Organochlorine pesticides (OCPs) are persistent organic pollutants (POPs) widely used in agriculture and industry, causing serious health and ecological consequences upon exposure. This review offers a thorough overview of OCPs analysis emphasizing the necessity of ongoing work to enhance the identification and monitoring of these POPs in environmental and human samples. The benefits and drawbacks of the various OCPs analysis techniques including gas chromatography-mass spectrometry (GC-MS), gas chromatography-electron capture detector (GC-ECD), and liquid chromatography-mass spectrometry (LC-MS) are discussed. Challenges associated with validation and optimization criteria, including accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ), must be met for a method to be regarded as accurate and reliable. Suitable quality control measures, such as method blanks and procedural blanks, are emphasized. The LOD and LOQ are critical quality control measure for efficient quantification of these compounds, and researchers have explored various techniques for their calculation. Matrix interference, solubility, volatility, and partition coefficient influence OCPs occurrences and are discussed in this review. Validation experiments, as stated by European Commission in document SANTE/11813/2017, showed that the acceptance criteria for method validation of OCP analytes include ≤20 % for high precision, and 70-120 % for recovery. This may ultimately be vital for determining the human health risk effects of exposure to OCP and for formulating sensible environmental and public health regulations.

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.

Physical exercise and persistent organic pollutants

Exposure to the legacy and emerging persistent organic pollutants (POPs) incessantly has become an important threat to individual health, which is closely related to neurodevelopment, endocrine and cardiovascular homeostasis. Exercise, on the other hand, has been consistently shown to improve physical fitness. Whereas associations between traditional air pollutants, exercise and lung function have been thoroughly reviewed, reviews on associations between persistent organic pollutants and exercise are scarce. Hence, a literature review focused on exercise, exposure to POPs, and health risk assessment was performed for studies published from 2004 to 2022. The purpose of this review is to provide an overview of exposure pathways and levels of POPs during exercise, as well as the impact of exercise on health concerns attributable to the redistribution, metabolism, and excretion of POPs in vivo. Therein lies a broader array of exercise benefits, including insulin sensitizing, mitochondrial DNA repair, lipid metabolism and intestinal microecological balance. Physical exercise is conducive to reduce POPs body burden and resistant to health hazards of POPs generally. Besides, individual lipid metabolism condition is a critical factor in evaluating potential link in exercise, POPs and health effects.

Assessment of organochlorine contamination source and ecological risk in the Litani River: polychlorinated biphenyls and organochlorinated pesticides in surface sediments

In this paper, we investigate for the first time the contamination source and the ecological risk associated to organochlorinated compounds in the Litani system. For this purpose, the levels of 7 polychlorinated biphenyls (PCBs) and 13 organochlorinated pesticides (OCPs) were assessed, using a microwave-assisted extraction coupled to gas chromatography-electron capture detector (MAE/GC-ECD) method, in surficial sediments from 30 sites along the main course of the river, two major tributaries, and the Quaraoun Lake. ∑7PCBs exhibited total concentrations ranging from 0.11 to 8 ng g-1 of dry weight and are not able apparently to pose ecological risks since none of the samples showed concentration above the effects range low (ERL) guideline (22.7 ng g-1). The detected levels of OCPs in the river were significantly higher than those of PCBs; ∑13OCPs range from 0.5 to 46.5 ng g-1 of dry weight. Overall, the integrated eco-toxicological risk imposed by the organochlorine contamination in the Litani River, estimated as the mean effects range medium quotient (mERMq), is considered low with risk probability lower than 21% in all sites. The six dichlorodiphenyltrichloroethane-based pesticides (∑6DDT) contributed to more than 70% of the mERMq in 15 over the 29 included sites. Moreover, the approach of ∑6DDT/∑7PCB ratios was applied to investigate the contamination source. ∑6DDT/∑7PCB was higher than one in all samples suggesting that the organochlorine contamination result from agricultural activities set in the surrounding areas of the Litani River.

Spatial characteristics, sources and exposure risk of polychlorinated biphenyls in dusts and soils from an urban environment in the Niger Delta of Nigeria

Chlorinated organic compounds, such as polychlorinated biphenyls (PCBs), are a threat to both humans and the environment because of their toxicity, persistence, and capacity for long-range atmospheric transport. The concentrations of 28 PCB congeners, including 12 dioxin-like and seven indicator PCBs, were investigated in soils, and indoor and outdoor dusts from Port Harcourt city, Nigeria, in order to evaluate the characteristic distribution patterns in these media, their sources, and possible risk. The PCB concentrations varied from 4.59 to 116 ng g^-1 for soils, and from 1.80 to 23.0 ng g^-1 and 2.73 to 57.4 ng g^-1 for indoor and outdoor dusts respectively. The sequence of PCB concentrations in these matrices was soil > outdoor dust > indoor dust. The composition of PCBs in these matrices indicated the prevalence of lower chlorinated PCBs in indoor and outdoor dusts, while the higher chlorinated congeners were dominant in soils. Di-PCBs were the predominant homologues in indoor dusts, while deca-PCBs were the most prevalent homologues in outdoor dusts and soils. The TEQ values of dioxin-like PCBs in 60 % of the soils, 100 % of the indoor dust, and 30 % of the outdoor dust were above the indicative value of 4 pg TEQ g^-1 established by the Canadian authority. The hazard index (HI) values for exposure of adults and children to PCBs in these media were mostly greater than one, while the total cancer risk (TCR) values exceeded the acceptable risk value of 10^-6, which indicate probable non-carcinogenic and carcinogenic risks resulting from exposure to PCBs in these media. Source analysis for PCBs in these matrices shows that they originated from diverse sources.

Characterization of organic contaminants associated with road dust of Delhi NCR, India

Hydrophobic organic contaminated polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and CHNS (carbon, hydrogen, nitrogen and sulphur species) are explosively associated with road dust particles. A few organic contaminants are toxic in nature and have an unpleasant effect on human health. The International Agency for Research on Cancer (IARC), the US Department of Health and Human Services (HHS) and the United States-Environmental Protection Agency has considered several PAHs and PCBs as carcinogens for human beings. In the proposed study, the anthropogenic contaminants present in road dust were assessed in six representative diversified sites i.e. industrial, commercial, office, residential, construction and traffic intersection in Delhi NCR, India. Roadside dust samples were gathered in premonsoon, monsoon and postmonsoon seasons and characterized for PAHs, PCBs and CHNS. The concentration of total PAHs (16 Nos) and PCBs (6 Nos) of the selected sites ranged from 0.27 µg/kg to 605.80 µg/kg and 0.01 µg/kg to 41.26 µg/kg, respectively. The Fourier transform infrared spectroscopy-attenuated total reflectance study suggested that the presence of O = C = O, Si-O, carbonyl, acidic or aliphatic esters group were associated with road dust particles. Hydrogen and sulphur concentrations were not detected in the selected road dust samples. Carbon and nitrogen concentrations varied from 2.24% to 16.82% and 0.69% to 14.5%, respectively, seasonally. In the premonsoon season, road dust was distinguishably contaminated as compared to monsoon and postmonsoon season, which might be due to movement of contaminated road dust from adjacent locations. It was perceived that Delhi NCR organic contamination in road dust was much below as compared to other countries. It may be concluded that due to the presence of significant amounts of carbon and nitrogen concentrations in the road dust, to a greater extent, road dust can be fertile and might be advantageous for green belt development to mitigate air pollution. The utilization of road dust will further bring down the burden of landfill sites and may lead towards sustainability.

Outdoor Atmospheric Micro-/Nanomineral-Mediated Organochlorine Pesticides in Sichuan Basin, China: Adsorption, Occurrence, and Risk Assessment

Atmospheric micro-/nanominerals play an important role in the adsorption, enrichment, and migration of organochlorine pesticides (OCPs). In the present study, the correlations between OCPs and minerals in outdoor atmospheric dustfall were investigated, and the correlations were used to speculate the source of p,p'-(dicofol+dichlorobenzophenone [DBP]), which is the sum of p,p'-dicofol and p,p'-DBP. Atmospheric dustfall samples were collected from 53 sites in the Chengdu-Deyang-Mianyang economic region in the Sichuan basin. In this region, 24 OCPs were analyzed by gas chromatography-tandem mass spectrometry. The average concentration of 24 OCPs was 51.2 ± 27.4 ng/g. The results showed that the concentration of Σ₂₄ OCPs in urban areas was higher than that in suburban areas (p < 0.05). Minerals in atmospheric dustfall were semiquantitatively analyzed by X-ray diffraction. The primary minerals were quartz, calcite, and gypsum. A Spearman correlation analysis of OCPs and minerals showed that low-volatility OCPs could be adsorbed by minerals in atmospheric dustfall. A density functional theory simulation verified that p,p'-(dicofol+DBP) in atmospheric dustfall was primarily derived from the p,p'-dicofol adsorbed by gypsum. Isomeric ratio results suggested that the samples had weathered lindane and chlordane profiles and confirmed that residents in the Sichuan basin used technical dichlorodiphenyltrichloroethane. Finally, the OCPs were evaluated to determine the potential risk of cancer in adults and children from OCP exposure. Exposure to OCPs via atmospheric dustfall was safe for adults. The cancer risk for children exposed to OCPs was slightly lower than the threshold value (10^-6 ) under a high dust ingestion rate, which poses a concern. Environ Toxicol Chem 2023;42:594-604. © 2022 SETAC.

A new insight into the emission source of DDT in indoor environment from rural area of South China and comprehensive human health exposure assessment

Human exposure to dichlorodiphenyltrichloroethanes (DDTs) and the subsequent risk to human health remain an important concern due to the "new" input of DDTs in the environment, especially since exposure to DDTs in indoor microenvironments is often ignored. In this study, we identified a new source of DDT emission in indoor environments and evaluated the health risk from the exposure to DDTs by investigating DDTs in indoor and outdoor dust, air, and coatings of household items in rural areas of Qingyuan, South China. The concentrations of DDTs in house dust and air were < MQL (method quantification limit)-3450 ng/g (median 42.4 ng/g) and 22.7-965 pg/m³ (median 49.5 pg/m³), respectively, which were significantly higher than the outdoor DDT values. Dichlorodiphenyldichloroethylene (DDE) was the main isomer in air samples, while DDT was the dominant isomer in indoor dust. Significant correlations between different DDT isomers were observed in indoor samples but not in outdoor samples. Furniture coating was identified as a source of DDTs in the indoor dust. The total daily exposure dose of DDTs (1.75 × 10^-2 ng/kg bw/day for adults and 1.28 × 10^-1 ng/kg bw/day for toddlers) through inhalation, dust ingestion, and dermal contact was found unlikely to pose a health risk. Our findings provide new insights into the emission sources and health risks caused by DDT indoors, highlighting the need to further investigate the toxicity mechanisms of parent DDT compound.

Distribution and health risks of organic micropollutants from home dusts in Malaysia

Indoor dust is an important medium to evaluate human exposure to emerging organic contaminants. The principal aim of this study was to determine overall status of organic micropollutants (OMPs) of indoor dust in Kuala Lumpur, Malaysia and assess their corresponding health risks. One hundred thirty-three OMPs, ascribed to 13 chemical groups, were screened by Automated Identification and Quantification System with a GC-MS database. The concentrations of OMPs ranged between 460 and 4000 μg/g, with the median concentration of 719 μg/g. The dominant chemical groups were ascribed to n-alkanes (median: 274 μg/g), plasticizers (151 μg/g), sterols (120 μg/g), and pesticides (42.6 μg/g). Cholestrol was the most abundant compound (median: 115 μg/g). Different sources and usage patterns of OMPs in various houses were expected. Toxicity values of OMPs were obtained from existing databases or predicted by quantitative structure-activity relationship models. Cumulative hazard quotients for OMPs through ingestion route were lower than one for all the dust samples, demonstrating that there was no remarkable non-cancer risk. The cancer risks of these OMPs were greater than 10^-4, with cholestrol dominating 99.1% of the carcinogenic risks, which suggested that there was a significant cancer risk. This study might offer a benchmark to ensure the safety of chemical usages in future in Malaysia.

Pesticides in the Indoor Environment of Residential Houses: A Case Study in Strasbourg, France

Indoor environmental exposure to pesticides has become one of the major concerns that might adversely affect human health and development. People spend most of their lifetime in enclosed indoor environments where they might inhale harmful toxic chemicals, such as pesticides, dispersed either in particulate or in a gas phase. In this study, an assessment of pesticide contamination in indoor environments was conducted. The study covered nine houses during one year, starting from February 2016 and ending in February 2017, in which both air and dust samples were assessed for their potential contamination with 50 pesticides. The results showed that all the assessed houses were contaminated by several pesticides, especially with the allethrin pesticide (detection frequency (DF) = 100%). The highest pesticide contamination was detected in the spring/summer season when it reached an average of around 185 ng g^-1 and 186.4 ng sampler^-1 in the collected dust and air samples, respectively. The potential contamination of pyrethroid insecticides within all the targeted samples revealed by this study stresses the importance of minimizing the use of such indoor treatments as part of the efficient prevention and control of human exposure to pesticides.

A Review of Polychlorinated Biphenyls (PCBs) Pollution in the Air: Where and How Much Are We Exposed to?

Polychlorinated biphenyls (PCBs) were widely used in industrial and commercial applications, until they were banned in the late 1970s as a result of their significant environmental pollution. PCBs in the environment gained scientific interest because of their persistence and the potential threats they pose to humans. Traditionally, human exposure to PCBs was linked to dietary ingestion. Inhalational exposure to these contaminants is often overlooked. This review discusses the occurrence and distribution of PCBs in environmental matrices and their associated health impacts. Severe PCB contamination levels have been reported in e-waste recycling areas. The occurrence of high PCB levels, notably in urban and industrial areas, might result from extensive PCB use and intensive human activity. Furthermore, PCB contamination in the indoor environment is ten-fold higher than outdoors, which may present expose risk for humans through the inhalation of contaminated air or through the ingestion of dust. In such settings, the inhalation route may contribute significantly to PCB exposure. The data on human health effects due to PCB inhalation are scarce. More epidemiological studies should be performed to investigate the inhalation dose and response mechanism and to evaluate the health risks. Further studies should also evaluate the health impact of prolonged low-concentration PCB exposure.

Toxicity of polychlorinated biphenyls in aquatic environments - A review

The assessment of polychlorinated biphenyls (PCBs) and their congeners resulting from the pollution of all environmental media is inherently related to its persistence and ubiquitous nature. In principle, determination of this class of contaminants are limited to the determination of their concentrations in the various environmental matrices. For solving many problems in this context, knowledge of the emission sources of PCBs, transport pathways, and sites of contamination and biomagnification is of great benefit to scientists and researchers, as well as many regulatory organizations. By far the largest amounts of PCBs, regardless of their discharged points, end up in the soil, sediment and finally in different aquatic environments. By reviewing relevant published materials, the source of origin of PCBs in the environment particularly from different pollution point sources, it is possible to obtain useful information on the nature of different materials that are sources of PCBs, or their concentrations and their toxicity or health effects and how they can be removed from contaminated media. This review focuses on the sources of PCBs in aquatic environments and critically reviews the toxicity of PCBs in aquatic animals and plants. The review also assesses the toxicity equivalency factors (TEFs) of PCBs providing valuable knowledge to other scientists and researchers that enables regulatory laws to be formulated based on selective determination of concentrations regarding their maximum permissible limits (MPLs) allowed. This review also supplies a pool of valuable information useful for designing decontamination technologies for PCBs in media like soil, sediment, and wastewaters.

Pesticide screening and health risk assessment of residential dust in a rural region of the North China Plain

Pesticides that have accumulated in arable soil could be easily transported by wind erosion, thereby potentially threating air quality and human health in surrounding areas. The risks this poses to farmers exposed to pesticide-associated dust is still unknown, especially in rural areas of China. In this study, we screened pesticide residues in dust (indoor and outdoor) collected from the homes and yards of pesticide sprayers (21 participants) and farm workers (14 participants) living in Quzhou County located in the North China Plain to assess health risks by exposed to pesticide-contaminated dust. The results showed that multiple pesticide residues were detected in the dust samples and more than 90% of the samples contained over 10 pesticide residues. The maximum detected number of residues was 23, out of the 25 pesticides currently used in the farming area. There was a wide range of pesticide concentrations with the geometric mean values measuring between 0.03 and 0.86 mg kg^-1. More residues and higher concentrations of pesticides were detected in indoor dust compared to outdoor dust. Over the monitoring period, the pesticide application has not caused significant pesticide accumulation in dust. The measured concentrations of carbendazim, dimethomorph, dimethomorph and pendimethalin paired indoor-outdoor dust samples were significantly correlated (p < 0.05). The health risks were assessed using the hazard index (HI) and highest HI was found for children under indoor exposure (HI = 0.82). In addition, based on the survey and statistics, pesticide preparation in the home was significantly correlated with the pesticide indoor exposure level. Therefore, farmers should take measures, such as preparing pesticides outside of the house or in the open fields with protection, in order to avoid the exposure risk of pesticides associated with dust.

Epigenetic Regulation in Exposome-Induced Tumorigenesis: Emerging Roles of ncRNAs

Environmental factors, including pollutants and lifestyle, constitute a significant role in severe, chronic pathologies with an essential societal, economic burden. The measurement of all environmental exposures and assessing their correlation with effects on individual health is defined as the exposome, which interacts with our unique characteristics such as genetics, physiology, and epigenetics. Epigenetics investigates modifications in the expression of genes that do not depend on the underlying DNA sequence. Some studies have confirmed that environmental factors may promote disease in individuals or subsequent progeny through epigenetic alterations. Variations in the epigenetic machinery cause a spectrum of different disorders since these mechanisms are more sensitive to the environment than the genome, due to the inherent reversible nature of the epigenetic landscape. Several epigenetic mechanisms, including modifications in DNA (e.g., methylation), histones, and noncoding RNAs can change genome expression under the exogenous influence. Notably, the role of long noncoding RNAs in epigenetic processes has not been well explored in the context of exposome-induced tumorigenesis. In the present review, our scope is to provide relevant evidence indicating that epigenetic alterations mediate those detrimental effects caused by exposure to environmental toxicants, focusing mainly on a multi-step regulation by diverse noncoding RNAs subtypes.

Non-Occupational Exposure to Pesticides: Experimental Approaches and Analytical Techniques (from 2019)

BACKGROUND

Pesticide residues are a threat to the health of the global population, not only to farmers, applicators, and other pesticide professionals. Humans are exposed through various routes such as food, skin, and inhalation. This study summarizes the different methods to assess and/or estimate human exposure to pesticide residues of the global population.

METHODS

A systematic search was carried out on Scopus and web of science databases of studies on human exposure to pesticide residues since 2019.

RESULTS

The methods to estimate human health risk can be categorized as direct (determining the exposure through specific biomarkers in human matrices) or indirect (determining the levels in the environment and food and estimating the occurrence). The role that analytical techniques play was analyzed. In both cases, the application of generic solvent extraction and solid-phase extraction (SPE) clean-up, followed by liquid or gas chromatography coupled to mass spectrometry, is decisive. Advances within the analytical techniques have played an unquestionable role.

CONCLUSIONS

All these studies have contributed to an important advance in the knowledge of analytical techniques for the detection of pesticide levels and the subsequent assessment of nonoccupational human exposure.