Risks Of Persistent Organic Pollutants Research Articles

Accumulation of persistent organic pollutants in the kidneys of pet cats (Felis silvestris catus) and the potential implications for their health

Persistent organic pollutants (POPs), such as polychlorinated diphenyls (PCBs) and brominated diphenyl ethers (PBDEs), are ubiquitous in the pet cat's living environment and are ingested through dietary intake and environmental exposure such as house dust. Cats are known to be susceptible to chronic kidney disease (CKD) and exposure to POPs may be associated with CKD. However, no studies have been conducted on the renal accumulation and health effects of POPs in cats. The objective of this study was to elucidate the accumulation of PCBs, PBDEs, and organochlorine pesticides (OCPs) in the kidneys of domestic cats and discuss their potential impact on feline health.We report here that cats specifically accumulate POPs in their kidneys. Tissue samples were collected from the kidneys, livers, and muscles of cats and the concentrations of POPs in these tissues were analyzed in this study. The results showed that these compounds accumulated significantly higher in the kidney compared to other tissues. In addition, the ability to accumulate in the kidney was higher in cats than in other animals, suggesting that cats have a unique pattern of POPs accumulation in their kidneys, which is thought to occur because cats store a significant number of lipid droplets in the proximal tubules of the kidneys. This unique feature suggests that lipophilic POPs may accumulate in these lipid droplets during the excretory process. Accumulation of certain POPs in the kidneys causes necrosis and sloughing of renal tubular epithelial cells, which may be associated with CKD, a common disease in cats. This study provides valuable insight into understanding the renal accumulation and risk of POPs in cats and provides essential knowledge for developing strategies to protect the health and welfare of domestic cats.

Grain transportation and consumption reshapes the α-HCH exposure picture of China

Socio-economic activities like food trade can increase the uncertainty of human risk of persistent organic pollutants (POPs). We compared the change in model predicted α-hexachlorocyclohexane (α-HCH) cancer risk (CR) with and without grain trade in mainland China. In scenario without grain logistics, α-HCH moved fast away from southern and southeastern China via northward atmospheric transport. However, the grain logistics from northeastern China delivers the α-HCH previously accumulated in northeastern sink back to densely populated areas in recent years, which enhance CR by >50 % in the southern seaboard of China. The northward movement of grain production center and recent grain deficiency in southern provinces induced by dietary pattern changes is identified as the major driving factors of the reversed transport of α-HCH. The finding highlights the potential of socio-economic activities that can otherwise offset the risk reduction effect of the geochemical cycle of POPs.

Unexpectedly high levels and health risks of atmospheric polychlorinated biphenyls in modern mechanical dismantling of obsolete electrical equipment: investigations in a large integrated e-waste dismantling industrial estate

Large industrial estates for electrical and electronic waste (e-waste) mechanical dismantling and recycling are gradually replacing outmoded small factories and intensive domestic workshops for e-waste manual and chemical dismantling. However, the air pollution and health risks of persistent organic pollutants during the modern mechanical processing of e-waste, especially obsolete electrical equipment, still remain unclear. Here, unexpectedly high levels (409.3 ng/m3) and health risks of airborne polychlorinated biphenyls (PCBs) were found during the mechanical processing of obsolete electric equipment or parts in a large integrated dismantling industrial estate, which is comparable to or a dozen times higher than those reported during chemical processing. In contrast, the levels (936.0 pg/m3) and health risks of particulate polybrominated diphenyl ethers (PBDEs) were all lower than those of previous studies. PCB emissions (44.9–3300.5 ng/m3) varied significantly across six mechanical dismantling places specifically treating waste motors, electrical appliances, hardware, transformers, and metals, respectively. The high PCB content and mass processing number of obsolete electrical equipment probably result in the highest PCB emissions from the mechanical dismantling of obsolete motors, followed by waste electrical appliances and metals. The PCB non-cancer and cancer risks associated with inhalation and dermal exposure in different mechanical dismantling places were all above the given potential risk limits. In particular, the health risks of dismantling obsolete motor exceeded the definite risk levels. Little difference in PCB emissions and health risks between working and non-working time suggested the importance of PCB volatilization from most e-waste. Such high PCB emissions and health risks of PCBs undoubtedly posed a severe threat to frontline workers, but fortunately, they decreased significantly with the increasing distance from the industrial estate. We highlight that PCB emissions and associated health risks from obsolete electrical equipment with high PCB content during mechanical dismantling activities should be of great concern.

A comprehensive assessment framework for the risk and source of polycyclic aromatic hydrocarbons (PAHs) using two weight of evidence (WOE) approaches in bays of Shandong Province, China

Polycyclic aromatic hydrocarbons (PAHs) are one of the most widely distributed typical persistent organic pollutants (POPs) in the global environment, and the high PAHs pollution level worldwide calls for the establishment of environmental risk assessment and source analysis techniques for effective control. Here, we selected four bays of Shandong Province, one of the areas in China with the severest emissions of PAHs, as the research area, and chose clam Ruditapes philippinarum as the sentinel species, to systematically assess the ecological risk, bioeffects, and health risks of PAHs, identify their sources, and establish a comprehensive assessment framework for marine POPs using weight of evidence (WOE) approach. Taken together, ecological, bioeffect, and health risk assessments for marine POPs were integrated using Sediqualsoft model of WOE in seawater and sediment, and the overall risk level of PAHs in Shandong coastal area was ‘Moderate’. Meanwhile, the primary source of PAH was analyzed based on socio-economic parameters using a WOE framework, which was mainly derived from traffic and coal in seawater and sediment, respectively. Collectively, a comprehensive framework for assessing risk and source of marine POPs was built for the first time, and it may be applicable to other environments and pollutants.

α-Galactosidase interacts with persistent organic pollutants to induce oxidative stresses in rice (Oryza sativa L.)

Persistent organic pollutants (POPs) in agricultural soil often triggered metabolic alterations and phytotoxicity in plants, ultimately threatening crop quality. Unraveling the phytotoxic mechanisms of POPs in crops is critical for evaluating their environmental risks. Herein, the molecular mechanism of POP-induced phytotoxicity in rice (Oryza sativa L.) was analyzed using metabolic profile, enzyme activity, and gene expression as linkages, including polycyclic aromatic hydrocarbons, polybrominated diphenyl ethers, polychlorinated biphenyls, and phthalate esters. Despite no observable changes in phenotypic traits (e.g., biomass and length of aboveground), the levels of reactive oxygen species (ROS) were promoted under stresses of the tested POPs, particularly 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47), dibutyl phthalate (DBP), and di(2-ethylhexyl) phthalate (DEHP). Metabolomics analysis revealed that ROS contents positively correlated with metabolic perturbation levels (r = 0.83), among which the galactose metabolism was significantly inhibited when exposed to DBP, DEHP, or BDE-47. The α-Galactosidase (α-Gal) involved in galactose metabolism was targeted as the key enzyme for the phytotoxicity of DBP, DEHP, and BDE-47, which was revealed by the inhibition of saccharide levels (45.5−82.1%), the catalytic activity of α-Gal (18.5−24.3%), and the gene expression (28.5−34.5%). Molecular docking simulation suggested that the three POPs occupied the active sites of α-Gal and formed a stable protein-ligand complex, thus inhibiting the catalytic activity of α-Gal. Partial least-squares regression analysis indicated that α-Gal activity was negatively associated with hydrogen bond acceptor, rotatable bond, and topological polar surface area of POPs. The results offered novel insights into the molecular mechanisms of phytotoxicity of POPs and provided important information for evaluating the environmental risk of POPs.

Optimizing the physiological pharmacokinetic model to rank the risks of persistent organic pollutants towards fish on the Tibetan Plateau

Persistent organic pollutants (POPs) could pose adverse risks towards fish in aquatic environments. However, related risk assessments in remote regions are lacking. In this study we investigated three kinds of POPs in four common fish species (n = 62) from high-altitude rivers and lakes on the Tibetan Plateau. The results showed that the lipid weight concentrations of organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), and perfluoroalkyl substances (PFAS) in fish muscle followed the order Σ13PAHs (24.5–3354 ng/g) > Σ11PFAS (2.48–164 ng/g) > Σ7OCPs (1.61–82.2 ng/g), which is comparable to that found in other remote regions. The physiologically based pharmacokinetic (PBPK) model was optimized using physiological parameters specific to the sampled Tibetan fish to generate accurate effective concentration (EC) thresholds. Based on these measured concentrations and newly simulated EC thresholds, the ecological risk ratios for selected toxic POPs (dichlorodiphenyltrichloroethane (DDT), pyrene (Pyr), and perfluorooctane sulfonate (PFOS)) ranged from 8.53 × 10−8 to 2.03 × 10−5. Racoma tibetanus and Schizothorax macropogon were the most vulnerable Tibetan fish species. All the risk ratios were far below 1, indicating that there was no risk of POPs towards Tibetan fish. However, the risk ratios for emerging POPs (i.e., PFOS) were 2–3 orders of magnitude higher than for legacy POPs (i.e., DDT and Pyr), suggesting that monitoring of emerging POPs should be reinforced. Our study sheds light on the risk assessment of wildlife exposed to POPs in remote regions with limited toxicity data.

Research progress on bioaccessibility of persistent organic pollutants in oral exposure matrices

<p indent="0mm">Persistent organic pollutants (POPs) have been widely concerned due to their bioaccumulation, environmental persistence, and strong toxic effects on humans and organisms. Oral digestion via food, dust, and soil is the most important route for humans to uptake POPs. However, not all POPs that enter human body are bioavailable, thus exposure risk assessment based on the total amount of POPs in matrices would overestimate the resulting health risks. Measurement of bioaccessibility using <italic>in vitro</italic> gastrointestinal (GI) digestive simulation has been used to predict the bioavailability of POPs. In this paper, the impacts of <italic>in vitro</italic> experimental approaches, properties of oral matrices, compositions of digestive fluid, and properties of POPs on the bioaccessibility of POPs in oral exposure matrices are comprehensively reviewed and analyzed. The dynamic <italic>in vitro</italic> GI digestive simulation improved the accuracy of the results compared with traditional static GI digestive simulation. The digestion of nutrients in the GI tract and cooking methods affect the distribution of POPs between matrices and digestive fluids, thus affecting bioaccessibility. Lipids generally enhanced the bioaccessibility of most POPs because they promote the formation of stable fatty acid-bile salt micelles and increase the solubility of POPs in digestive fluid. However, this solubilization effect of mixed micelles does not apply to POPs with very high hydrophobicity because they prefer to distribute in the undigested food matrix. The bioaccessibility of POPs is mostly positively correlated with the carbohydrate content of food, whereas the effects of protein and dietary fiber were uncertain. Particle size and organic matter content of dust or soil are important factors affecting the bioaccessibility of POPs. The smaller the particle size of the dust or soil, the larger specific surface area, and the digestive fluid displayed strong capacity to dissolve POPs, thus increasing their bioaccessibility. Organic matter has a significant effect on the adsorption and desorption of POPs from dust or soil. The higher the organic matter content, the more POPs will be adsorbed, thus hindering the release of POPs from the matrices. Bile salts and various digestive enzymes such as pepsin and trypsin can also change the bioaccessibility of POPs by affecting the digestion process of matrices. There is generally a negative relationship between the bioaccessibility of POPs and their log<italic>K</italic>_OW values. The higher the hydrophobicity of POPs, the more difficult it is to dissolve in the digestive fluid. Different migration routes of POPs will also lead to different bioaccessibility, and the bioaccessibility of POPs adsorbed into the matrices is higher than that of POPs existing as a component of matrices. When considering bioaccessibility, the estimated daily intake of POPs from a matrix will decrease and the estimated exposure risk will therefore be reduced. Thus the contribution of POPs via different matrices to total human exposure should be re-examined. Collectively, bioaccessibility should be fully considered in the assessment of oral exposure and health risk to ensure accurate results. There are still some limitations in the current research. Firstly, results obtained using different <italic>in vitro</italic> methods varied widely and validation with <italic>in vivo</italic> data is lacking. Secondly, current studies mostly focused on only one oral matrix which cannot represent rich daily diets and different exposure scenarios among different populations. Thirdly, there is still a big gap in the research on the bioaccessibility of emerging POPs and the mixed exposure to multiple POPs. This paper provides an important theoretical basis for the accurate assessment of the human exposure risk of POPs, and for formulating measures to reduce the oral exposure risk of POPs in different populations.

Estimating the dietary exposure and risk of persistent organic pollutants in China: A national analysis

Substantial heterogeneities have been found in previous estimations of the risk from dietary exposures to persistent organic pollutants (POPs) in China, mainly due to spatiotemporal variations. To comprehensively evaluate the dietary risks of POPs listed in the Stockholm Convention, more than 27,580 data records from 753 reports published over the last three decades were examined. Respectively, for various food categories, the results obtained for the range of mean concentrations of POPs are as follows: total dichlorodiphenyltrichloroethanes (DDTs: 1.4–27.1 μg/kg), hexachlorocyclohexanes (HCHs: 1.8–29.3 μg/kg), polybrominated diphenyl ethers (PBDEs: 0.046–2.82 μg/kg), polychorinated biphenyls (PCBs: 0.05–7.57 μg/kg), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD&Fs: 2.9–210 pg toxic equivalent (TEQ)/kg), perfluorooctanoic acid (PFOA: 0.02–0.97 μg/kg), perfluoroctane sulfonate (PFOS: 0.00082–2.76 μg/kg) and short-chain chlorinated paraffins (SCCPs: 64–348.92 μg/kg). Temporal decreasing trends were observed for DDTs, HCHs, PBDEs, PCDD&Fs, and PFOA, with no significant change for other POPs. Meanwhile, the estimated daily intake for adults were 75.2 ± 43.6 ng/kg/day for DDTs, 123 ± 87 ng/kg/day for HCHs, 0.37 ± 0.17 pg TEQ/kg/day for PCDD&Fs, 17.8 ± 9.5 ng/kg/day for PCBs, 3.3 ± 1.8 ng/kg/day for PBDEs, 3.6 ± 1.9 ng/kg/day for PFOA, 3.3 ± 2.0 ng/kg/day for PFOS, and 2.5 ± 1.6 μg/kg/day for SCCPs. Furthermore, non-carcinogenic risks were the highest for PCBs (0.89) and PCDD&Fs (0.53), followed by PFOA (0.18), PFOS (0.17), HCHs (0.062), SCCPs (0.025), DDTs (0.0075), and PBDEs (0.00047). These findings illustrated that exposure to POPs declined due to the control policies implemented in China, while the cumulative risk of POPs was still higher than 1, indicating continuous efforts are required to mitigate associated contamination.

High spatial resolution measurements of passive-sampler derived air concentrations of persistent organic pollutants in the Campania region, Italy: Implications for source identification and risk analysis

Because most relevant studies have used small sample sizes, to date, representative atmospheric monitoring of persistent organic pollutants (POPs) on a regional scale has been very limited, which makes it difficult to precisely identify “hotspots” and possible pollution sources. In this study, an ultrahigh resolution monitoring technique was used to measure the atmospheric spatial variations in POP concentrations on a regional scale, throughout Campania, Italy. The occurrence of specific POPs—including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs) and phthalate esters (PAEs)—were investigated using polyurethane foam-based passive air samplers (PUF-PAS), which were deployed at 129 sites across the Campania Territory between April and July 2016. The results show that the highest POP levels occurred in the Naples metropolitan area (NMA), although there were other problematic spots throughout the Territory. More specifically, hotspot areas in the NMA that depict serious POP pollution were found in the Bagnoli brownfield site, Sarno River Basin, and parts of the northeastern NMA sector. The atmospheric POP contamination in Campania is jointly controlled by the contributions of local emissions and long-range atmospheric transport. Diffusion model was employed to identify the potential sources of various POPs. The simulation showed that all the POP sources are located in the NMA and are closely related to industrial sites. This study demonstrates the advantage of using large sample sizes to identify POP source locations and achieve geospatial visualization of POP concentration and risk assessment levels.

Characteristics, distribution, sources, and ecological risk of persistent organic pollutants (PAHs, PCBs) in the bottom sediments of a potamic ecosystem, in conditions of urban-industrial anthropopressure

Characteristics, distribution, sources, and ecological risk of persistent organic pollutants (PAHs, PCBs) in the bottom sediments of a potamic ecosystem, in conditions of urban-industrial anthropopressure

Mechanism study on organic pollutant accumulation by iron-based particles in drinking water conditions

Discoloration events in drinking water distribution systems (DWDSs) caused by iron oxide particles have occurred worldwide, but the mechanism of organic pollutant accumulation by iron-based particles in DWDSs has not yet been fully recognized. Here, iron particle-dominated loose deposits were collected from a real DWDS through pipe flushing. Also, FeOOH-based particles, as an important component of deposits, were grown with various coexisting substances to further simulate the influence of structure on accumulation effects. Here, we found that the presence of cations, including Al3+ and Mn2+; phosphate anion; and organic pollutants, such as the disinfection byproducts (DBPs) and persistent organic pollutants (POPs) with trichloroacetic acid (TCA) and perfluorosulfonic acid (PFOA) as representatives, could influence the accumulation effects of FeOOH particles in DWDSs due to the structural transformation. The FeOOH particles grown with coexisting organic matter (FeOOH-TCA and FeOOH-PFOA) had a higher specific area and more OH groups than other samples. With abundant contact sites due to their hairy urchin-like structures and rich surface oxygen-containing functional groups, the FeOOH-based particles had higher accumulation abilities for antibiotics, with FeOOH-TCA presenting the highest ability. The formation of Fe-O-C confirmed that the OH groups in organics could bind with iron ions and guide hydrolysis to induce obvious structural transformation into a material with a higher specific area and more contact sites. Moreover, molecular dynamics (MD) simulations suggested that hydrogen bonding played an important role in this accumulation process. The results not only revealed the importance of focusing on the complex iron-based particles in DWDSs, but also showed previously unknown risks of DBPs and POPs, as such compounds may promote the accumulation effect of deposits.

Chemical fate of persistent organic pollutants in the arctic: Evaluation of simplebox

Persistent organic pollutants (POPs) are of great concern for decades due to their persistence, bioaccumulation and long-range transport potential. Multimedia fate models are useful scientific and decision-support tools for predicting the chemical fate in the environment. The SimpleBox multimedia fate model (v4.0) was used in this study to estimate the impact of POP emissions from the European and North American mainland on POP contamination in the Arctic. The purpose of the study was to evaluate the performance of SimpleBox by comparing estimations to measurements. Model performance for the air compartment was reasonable as estimated concentrations were generally within a factor of five of measured concentrations. SimpleBox suggested higher POP concentrations in Arctic oceans than in temperate oceans, contrary to the few measured data. Discrepancies between estimations and measurements may be attributed to the variability in emission estimates and degradation rates of POPs, representativeness of monitoring data, and a missing snow and ice environmental compartment in SimpleBox. Emission rates and degradation rate constants were the most influential input parameters in SimpleBox based on sensitivity analysis. Suggestions for improvements of SimpleBox refining POP risk assessment are provided.

Annual changes in concentrations and health risks of PCDD/Fs, DL-PCBs and organochlorine pesticides in ambient air based on the Global Monitoring Plan in São Paulo

Ambient air contains a number of persistent organic pollutants (POPs), to which inhalation exposure has drawn worldwide concern. However, information regarding annual changes in the concentrations and health risks of POPs in the ambient air of São Paulo, Brazil, are limited. This study provides comprehensive information on annual changes in polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (DL-PCBs), and 10 groups of organochlorine pesticides (OCPs) in the ambient air of São Paulo between 2010 and 2015 based on the Global Monitoring Plan. The mass concentrations of the studied POPs (PCDD/Fs, DL-PCBs, and OCPs) showed declining trends from 2010 to 2015 (from 2.65 × 10−2 to 1.33 × 10−2 pg m−3, from 9.89 × 10−2 to 3.12 × 10−2 pg m−3, and from 0.313 to 0.100 ng m−3, respectively), which might be due to the decrease of non-intentional emissions. The carcinogenic risk (CR) and non-carcinogenic risk (Non-CR) of the studied POPs were 1.48 × 10−11 to 6.08 × 10−7 and 3.44 × 10−8 to 3.34 × 10−3, respectively, which are lower than the generally accepted threshold values (10−6/10−5 and 1 for CR and Non-CR, respectively), suggesting that the health risks posed by the studied POPs were acceptable. PCDD/Fs had the highest CR (6.08 × 10−8-4.81 × 10−7), whereas the 95th percentile CR of DL-PCBs and nine of the OCPs were lower than 10−7, suggesting that among the studied POPs, PCDD/Fs in the ambient air warrant special attention. The 95th percentile CRs of dichlorodiphenyltrichloroethane (2.30 × 10−8), dieldrin (1.30 × 10−8), hexachlorocyclohexanes (1.05 × 10−8), heptachlor (8.97 × 10−9), hexachlorobenzene (6.47 × 10−9), chlordane (5.89 × 10−9), heptachlor epoxide (1.42 × 10−9), aldrin (1.33 × 10−9), and mirex (2.71 × 10−10) in ambient air were relatively low, suggesting that their threats to human health were negligible. In general, PCDD/Fs, DL-PCBs, and OCPs in the ambient air of São Paulo did not pose serious threats to human health during 2010–2015.

Persistent organic pollutants in typical lake ecosystems

Persistent organic pollutants (POPs) are highly toxic organic chemicals. Lakes are one of the main sinks of POPs. POPs can be accumulated in multiple matrices in lake ecosystems and biomagnified through the food web, and thus pose a potential threat not only to lake ecosystems, but also to human health. Given their potential persistent risks, they have received much attention over the past decades. This review comprehensively summarizes the data on the levels and distributions of POPs in selected typical lake ecosystems in China and worldwide, involving water, sediments, organisms, and surrounding soils and atmosphere. It was found that current publications on POPs in Chinese lakes are mainly related to lakes in the developed eastern plain area, with only a few studies concerning the less-developed Qinghai-Tibet Plateau area. Similarly, around the world, there are more research on POPs in developed countries and less in relatively less-developed areas. Moreover, there are significant differences in the levels of POPs in different matrices in different lake ecosystems. Legacy POPs, such as polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polybrominated diphenyl ethers (PBDEs), were commonly detected and reported in different lakes, while emerging POPs like perfluorinated compounds (PFCs), polychlorinated naphthalenes (PCNs), Tetrabromobisphenol A (TBBPA), and hexabromocyclododecane (HCBD) were relatively less detected or reported. A comprehensive summarization on the levels and distributions of traditional and emerging POPs in lake ecosystems could be significant for further understanding the behaviors and risks of POPs in lake ecosystems.

Learning from Dioxin & PCBs in meat – problems ahead?

Persistent organic pollutants (POPs) including polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs; “Dioxins”), or polychlorinated biphenyls (PCBs) are widely recognized environmental and food contaminants. More than 90% of PCDD/Fs and PCB exposure of the average population stem from animal based food including meat. While average PCDD/F and PCB levels have decreased compared to levels 1980s, still contamination above regulatory limits are observed and a share of the population is above the tolerable daily intake recommended by the WHO. For PCBs the contamination of feed and food along the life cycle from production, use, recycling, end of life and related contaminated sites has been documented and can be seen as a model. Furthermore, it has been recently discovered that levels of PCBs in feed and soil below regulatory limits can result in meat contamination above EU regulatory limits. In particular, beef meat and chicken meat/eggs have been found very sensitive towards PCB contamination in the environment (soil and feed) but also in stables (paints and sealants). For PCDD/Fs, the major exposure pathways are feed, feed additives and contaminated sites.Chlorinated paraffins have substituted PCBs the last 40 years in open application and short chain chlorinated paraffins (SCCPs) were recently (05/2017) listed in the Stockholm Convention. Furthermore, brominated and fluorinated POPs have been listed in the Convention. All these POPs groups can accumulate in meat animals. For these new listed POPs no regulatory limits in food including meat has been established yet. Initial information on presence and risk of new listed POPs to food animals is compiled. A more systematic assessment of exposure and risks of POPs to food animals/meat is needed.

Pollutant and Soil Types Influence Effectiveness of Soil-Applied Absorbents in Reducing Rice Plant Uptake of Persistent Organic Pollutants

Persistent organic pollutants (POPs) in soils are an environmental concern due to their long-term bioavailability, which could be reduced by adding adsorbents. However, testing of these adsorbents is necessary prior to widespread field application. The effects of three adsorbents, nano-organic montmorillonite, nano-organic silicon dioxide (SiO2), and activated carbon, on hexachlorobenzene (HCB) and pentachlorobenzene (PeCB) accumulation in rice (Oryza sativa L.) plants were tested in a greenhouse experiment using two soils, a Hydragric Acrisol (Ac) and a Gleyi-Stagnic Anthrosol (An). The bioconcentration factors (BCFs) of HCB and PeCB to rice roots were 2.3–3.7 and 2.0–3.0 times those to rice shoots, respectively. The applications of the three adsorbents decreased HCB and PeCB extractability in Ac, while only the application of activated carbon decreased their extractability in An. The bioavailability of HCB and PeCB to rice plants in Ac was higher than that in An. In Ac, the applications of nano-organic SiO2 and activated carbon decreased the BCF of HCB to rice roots by 16.1% and 26.8%, respectively, whereas only the application of activated carbon decreased the BCF of PeCB to rice roots by 31.4%, compared to the control. In An, only the application of activated carbon decreased the BCFs of HCB and PeCB to rice roots by 22.9% and 18.2%, respectively, compared to the control. However, the application of nano-organic montmorillonite inhibited rice growth in both soils. The results of this study suggested that the effectiveness of adsorbents would vary with pollutant and soil types, providing a reference point for developing efficient adsorbents to reduce the ecological risk of POPs.

Body burden of persistent organic pollutants on hypertension: a meta-analysis.

Except the known risk factors for hypertension, several studies have suggested that exposure to persistent organic pollutants (POPs), endocrine disrupting chemicals, could be associated with an increased risk of hypertension. In this study, we performed a meta-analysis to summarize the existing epidemiological studies to investigate the association between POPs concentration and risk of hypertension. Based on comprehensive literature search results (PubMed, EMBASE, and KoreaMed), a meta-analysis of 11 articles was performed using a random-effects model. While we observed no significant association between the sum of non-dioxin-like PCBs and the risk of hypertension (OR = 1.00; 95% CI 0.89, 1.12), the sum of dioxin-like PCBs was associated with a significantly increased risk of hypertension (OR = 1.45; 95% CI 1.00, 2.12). High p,p'-DDE level was also significantly associated with the increased risk of hypertension. When subgroup analyses were carried out for studies which analyzed POPs concentrations using high-resolution gas chromatography/high-resolution mass spectrometry, the overall pooled estimate ORs increased with decreased heterogeneity, providing it as a possible heterogeneity source (OR = 1.36; 95% CI 1.21, 1.52; I (2) = 42.8%; p = 0.045). This study suggested that the concentration of certain POPs, especially dioxin-related compounds, was associated with the risk of hypertension.

Source identification, spatio-temporal distribution and ecological risk of persistent organic pollutants in sediments from the upper Danube catchment

Riverine sediments, collected on a monthly basis during a period of one year, from five sites in a mixed land use region of the Czech Republic were analysed for chlorinated and brominated persistent organic pollutants (POPs). The region is located in the upper catchment of the Danube River. The POPs concentrations were as follows: 11–930pgg−1 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/Fs), 170–980pgg−1 dioxin-like polychlorinated biphenyls (dl-PCBs), 34–13,700pgg−1 polychlorinated naphthalenes (PCNs), 5.7–29,200pgg−1 polybrominated diphenylethers (PBDEs) and 0.21–351ngg−1 hexabromocyclododecanes (HBCDs). Concentrations expressed as toxic equivalents (TEQs), for PCDD/F+dl-PCB+PCN (TEQPCDD/F+dl-PCB+PCN) ranged from 0.37 to 19pgg−1. The results revealed a clear spatial separation between sites based on concentration and congener profile. There were also some obvious temporal patterns of selected POPs, which were related to river flow (seasonality) and organic carbon (TOC) of the sediment. Potential sources of POPs include local municipalities (flame retardants), some diffuse sources (PCNs and PCDDs/Fs) and potential point sources (PBDEs). Risk assessment based on risk quotients (RQ) revealed limited to medium ecological risk from PBDEs. TEQPCDD/F+dl-PCB+PCN were low relative to other European rivers, hence the risk to aquatic organisms was considered to be low. PCNs contributed significantly to overall TEQ in several cases.

Geographic variation of persistent organic pollutants in Hawaiian monk seals Monachus schauinslandi in the main Hawaiian Islands

Geographic variation in the levels of persistent organic pollutants (POPs) was as - sessed in the serum of Hawaiian monk seals Monachus schauinslandi from the main Hawaiian Islands. Twenty seals were outfitted with tracking devices to map their home ranges, which were then compared with the POP levels in their serum. Seals with similar ranges were shown to have similar POP levels, and seals with home ranges around the island of O'ahu had significantly higher summed polychlorinated biphenyls and polybrominated diphenyl ethers than seals around the islands of Kaua'i and Moloka'i. This difference was not seen for summed diphenyl-dichlorot- riphenylethanes or chlordanes. Non-metric multi-dimensional scaling (NMS) was used to deter- mine if this geographic variation in serum POP levels was associated with specific POPs, water- sheds, or state land use districts. The NMS ordination revealed patterns at the island scale, rather than the finer watershed scale. Additionally, there were differences in the land use characteristics adjacent to seals' home ranges between 2 islands: seals with home ranges around O'ahu had a high percentage of area adjacent to urban land use districts, and seals with home ranges around Moloka'i had a high percentage of area adjacent to rural and agricultural land use districts. Inte- gration of serum POP levels and seal home ranges revealed geographic patterns that will help assess the risk of POPs to individual seals. The integrated approach highlighted in this study is applicable to other marine wildlife exposed to local and non-point pollutants.

Persistent organic pollutants (POPs) in the topsoil of typical urban renewal area in Beijing, China: Status, sources and potential risk

In order to assess the health risk of persistent organic pollutants (POPs) in the topsoil of a typical urban renewal area, a comprehensive study was conducted to determine their spatial distribution, possible sources and potential carcinogenic risk. Topsoil samples were collected from former chemical industrial areas in south-east Beijing and tested for concentrations of POPs, including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). The concentration of PAHs ranged from 126.68 to 365926.17ng/g, OCPs ranged from 2.38 to 933.12ng/g, and PCBs ranged from 47.04 to 3883.77ng/g. The spatial distribution of POPs was mapped using a geographic information system (GIS) to identify hotspots. Although PAHs, OCPs and PCBs varied in terms of their concentration and spatial distribution, the sources of each type of POPs were identified using multivariate statistical analysis and the diagnostic ratios method. Total lifetime carcinogenic risk (TLCR) for PAHs, OCPs and PCBs exposure was evaluated quantitatively for each sampling site using the Risk Assessment Guidance for Superfund (RAGS) methodology, and a risk distribution map was created. The TLCR values of 76% sites for the PAHs were higher than the target level for individual excess lifetime cancer risk (10−6) and with 12% sites were higher than the acceptable levels (10−4) for residential cancer risk. There are 28% sites that have TLCR above 10−6 for recreational exposure to PAHs.