Polychlorinated biphenyls (PCBs) residues in commercial pasteurized cows' milk in Tehran, Iran

Polychlorinated biphenyls in bovine milk from a typical informal electronic waste recycling and related source regions in southern India before and after the COVID-19 pandemic outbreak

For more than a decade, Chennai city in southern India has been evidenced with informal electronic waste (e-waste) recycling and open burning practices as the potential sources for polychlorinated biphenyls (PCBs). PCBs can bioaccumulate in livestock particularly cows grazing on the contaminated soil. The outbreak of the COVID-19 pandemic led to additional challenges associated with waste management practices. Hence this study aims to elucidate twenty-five PCB congeners in bovine milk from the previously reported PCB source regions in Chennai and the suburbs before and after about three years of the pandemic outbreak along electronic waste recycling (EWR), open burning dumps (OBD), and residential (RES) transects. The geomean concentration of Ʃ25PCBs in ng/g lipid weight (lw) followed a decreasing trend of EWR (13 ng/g lw) > OBD (8 ng/g lw) > RES (4 ng/g lw). Over 80 % of PCBs stemmed from EWR and OBD transects before and after the pandemic. However, a significant surge in the level of PCB-52 was observed in the OBD transect after the pandemic outbreak. Most toxic PCB congeners, PCB-126 and -169 were significant contributors to TEQs in EWR and OBD transects and can be reasoned with the burning of waste materials and mixed plastics in these transects. The highest average daily dose (ADD) exposure risk was for children from EWR and was significantly higher (p < 0.05) than other transects. Mean ADD-induced TEQ (6.6 pg TEQ/kg-bw/day) from the cows grazing around Kodungaiyur dumpsite slightly exceeded the EU guideline of 5.5 pg TEQ/kg-bw/day after the outbreak of the pandemic due to PCB-126. However, none of the samples exceeded the US FDA (1.5μg/g milk fat) recommendation limits for PCBs in milk fat. Prolonged exposure to such persistent organic pollutants interlinked with the burning of mixed waste in the open dumps can be a public health concern.

Single and combined toxicity of polystyrene nanoplastics and PCB-52 to the aquatic duckweed Spirodela polyrhiza

As nanoplastics and persistent organic pollutants are broadly distributed in aquatic ecosystems and pose a potential threat to ecosystem, most pertinent studies have focused on aquatic animals, while studies on freshwater plants have been rarely reported. Therefore, we analyzed the single and combined toxicological impacts of various concentrations of 80 nm polystyrene nanoplastics (PS-NPs) including 0.5, 5, 10, and 20 mg/L and polychlorinated biphenyl-52 (PCB-52, 2,2',5,5'- tetrachlorobiphenyl) at 0.1 mg/L on the aquatic plant Spirodela polyrhiza (S. polyrhiza) after a 10-day hydroponic experiment. Laser confocal scanning microscopy (LCSM) showed the accumulation of PS-NPs mainly in the root surface and the lower epidermis of leaves, and the enrichment of PS-NPs was aggravated by the presence of PCB-52. PS-NPs at 10 mg/L and 20 mg/L alone or in combination with PCB-52 notably inhibited the growth of S. polyrhiza, reduced the synthesis of chlorophylls a and b, and increased the activities of superoxide dismutase (SOD) and peroxidase (POD) as well as malondialdehyde (MDA) levels, and induced osmotic imbalance (soluble protein and soluble sugar contents) (p < 0.05). However, a single treatment with low levels of PS-NPs had positive effects on the growth (0.5 mg/L) and photosynthetic systems (0.5, 5 mg/L) of S. polyrhiza, while co-exposure exacerbated the damaging impacts of PS-NPs on the antioxidant defense system of S. polyrhiza, which was more pronounced in the roots. Furthermore, correlation analysis revealed that plant growth parameters were positively correlated with chlorophyll a and b content and negatively correlated with soluble sugars, antioxidant enzymes, lipid peroxidation, and carotenoid content (p < 0.05). These results provide data to improve the understanding of the single and combined ecotoxicological effects of nanoplastics and polychlorinated biphenyls (PCBs) in aquatic plants and their application in phytoremediation measures.

Analysis of polychlorinated biphenyls (PCBs) in dairy products by modified QuEChERS/GC-QqQ-MS/MS method: A risk assessment study

Polychlorinated biphenyls (PCBs) are harmful chemicals that are persistent in the environment and can accumulate in the food chain. The purpose of the present research was to assess non-dioxin-like polychlorinated biphenyls (NDL-PCBs) in some dairy products (yogurt, doogh, and kashk) using modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) technique and gas chromatography-triple-quadrupole mass spectrometry (GC-QqQ-MS/MS) method and risk assessment study. The LOQs (limit of quantifications), LODs (limit of detections), recovery, and RSD for the PCB analytes were 0.180-0.360, 0.06-0.12 ng/g fat, 97.45-102.63%, and 6.33-8.86%, respectively. The results revealed that the mean concentrations of Ʃ6-NDL-PCBs in samples were 15.17 ± 3.44 ng/g fat, which was lower than the standard level established by European Union (EU, 40 ng/g fat). The maximum mean level was PCB 180 (9.98 ± 2.04 ng/g fat) and the minimum mean level of PCBs in samples was PCB 28 (0.09 ± 0.06 ng/g fat). Also, results showed that kashk samples had a maximum mean level of 6-NDL-PCBs (18.66 ± 2.42 ng/g fat) and doogh samples had a minimum mean level of 6-NDL-PCBs (12.21 ± 2.22 ng/g fat). The mean level of 6-NDL-PCBs in yogurt samples was 14.65 ± 2.02 ng/g fat. The heat map results showed the correlation between the spectral indices of 6-NDL-PCBs in different dairy products. According to the Monte Carlo method, risk assessment was done using calculating the Estimated Daily Intake (EDI) and Incremental Life Cancer Risk (ILCR). The EDI values of 6 NDL-PCBs based on the 95th percentile in yogurt, doogh, and kashk were 14.3, 1.49, and 0.5 ng/kg.day, respectively. Considering that the contaminant level in the samples is lower than the EU limit, it can be concluded that dietary exposure to 6 NDL-PCBs may not pose a risk to the health of consumers.

Safety Evaluation and Probabilistic Health Risk Assessment of Cow Milk Produced in Northern Italy According to Dioxins and PCBs Contamination Levels

Contamination levels of dioxins and polychlorinated biphenyls (PCBs) were monitored over 2018-2021 in 214 bovine milk samples from farms located in two regions in northern Italy (Lombardy and Emilia-Romagna). The average concentrations of the sum of dioxins and dioxin-like PCBs (0.78 ± 0.55 pg TEQ/g fat) and six non-dioxin-like PCBs (6.55 ± 2.24 ng/g fat) were largely below the maximum, and action limits established at European level, confirming a decreasing trend observed both locally and across Europe in recent years. The impact of contamination levels on chronic dietary exposure of the Italian population to dioxins and PCBs was found to be highly variable based on the type of cow milk (skimmed, semi-skimmed, or whole-fat milk) and the population age group considered. Indeed, a first-tier screening of the potential exposure via determinist methods allowed for the identification of the youngest population as the group with the worst risk profile. The refinement of exposure assessment via Monte Carlo probabilistic methods suggested that, at the less pessimistic middle-bound simulation scenario, infants, toddlers, and children consuming whole cow milk may be exposed to dioxins and PCBs levels above the toxicological reference values with a probability of 76, 56, and 22%, respectively.

Human health risk surveillance of polychlorinated biphenyls in bovine milk from alluvial plain of Punjab, Pakistan

Punjab is the leading province of Pakistan in the production of bovine milk and its consumption. Rapid industrialization, high energy demand, and the production of waste have increased the risk of polychlorinated biphenyls (PCBs) toxicity in the environment. This research work was designed to assess human dietary exposure of ∑PCBs17 congeners through ingestion of buffalo and cow's milk from eight main districts of Punjab, Pakistan. The average concentrations of ∑DL-PCBs (8.74 ng g^-1 and 14.60 ng g^-1) and ∑I-PCBs (11.54 ng g^-1 and 18.68 ng g^-1) in buffalo and cow milk samples were analyzed, respectively. The PCB-156 was predominantly high congener found in both buffalo (2.84 ng g^-1) and cow milk (2.86 ng g^-1). It was found that the highest PCBs in bovine milk samples were observed in close vicinities of urban and industrial areas. The estimated daily consumptions of DL-PCBs and I-PCBs, from buffalo and cow milk, were below the acceptable daily intake for both adults and children. Moreover, hazard quotients (HQ) of the ∑PCBs17 congener value were less than 1.0 in adults and greater in the case of children reflecting the high chances of cancer. Furthermore, comprehensive monitoring for childhood cancer is recommended to establish the relationship in future studies.

Gestational PCB52 exposure induces hepatotoxicity and intestinal injury by activating inflammation in dam and offspring mice: A maternal and progeny study

Although Polychlorinated biphenyl (PCB) levels are decreased in the environment, the adverse effects of gestational exposure on the mother and offspring cannot be ignored due to the vulnerability of the fetus. In the present study, pregnant Balb/c mice were administered PCB52 (1 mg/kg BW/day) or corn oil vehicle by gavage until parturition. In the dams, PCB52 caused histopathological changes in the liver, higher serum levels of aminotransferase and alanine aminotransferase, and activated apoptosis and autophagy, suggesting hepatotoxicity. Overexpressed indicators of TLR4 pathway were observed in the liver of PCB52-exposed dams, indicated hepatic inflammation. Moreover, PCB52 exposure weakened the intestinal barrier and triggered inflammatory response, which might contribute to the hepatic inflammation by gut-liver axis. In the pups, prenatal PCB52 exposure affected the sex ratio at birth and reduced birth length and weights. Similar to the dams, prenatal PCB52 exposure induced hepatotoxicity in the pups without gender difference. Consistent with the alteration of gut microbiota, intestinal inflammation was confirmed, accompanying the disruption in the intestinal barrier and the activation of apoptosis and autophagy in the PCB52-exposed pups. Intestinal injury might be responsible for hepatotoxicity at least in part. Taken together, these findings suggested that gestational PCB52 exposure induced hepatic and intestinal injury in both maternal and offspring mice by arousing inflammation.

Exposure sources of polychlorinated biphenyls (PCBs) and health risk assessment: a systematic review in Iran

This systematic review aims to identify the sources of exposure to polychlorinated biphenyls (PCBs), portioning, and human health risk assessment in Iran. The literature was searched in the international databases of Web of Science, PubMed, Scopus, Google Scholar, and the national databases of SID and MagIran up to November 14, 2020. Among all 153 articles, 21 eligible papers were identified. Among them, only one article was related to drinking water, the rest was related to food and soil, and no article was found on ambient air. The corrected portion of each exposure source was determined to be 90% for food, 9% for water, and 1% for air. The total hazard quotient (HQ) was determined to be within an unsafe range, and the total excess lifetime cancer risk (ELCR) was determined to be at a high risk of oral carcinogenesis. It is suggested that a comprehensive study be conducted in a specific period for all sources of exposure in all counties of Iran. Moreover, it is recommended that the policymakers set national standards for this pollutant in near future in some sources of exposure (e.g., drinking water) which have no standards in Iran.

Protection and Active Decontamination of Dairy Cattle Heifers against Lipophilic Toxins (PCBs) from Diet

We studied the effects of a hydrophobized reversed-phase feed adsorbent in the form of a polyoctylated polysilicate hydrogel (POPSH) on productivity indicators, metabolic adaptation, and on the level of polychlorinated biphenyls (PCBs) in the blood of growing Holsteinized black-and-white heifers during the transition period. Two groups of two-month-old heifers of 20 head each were used. The experimental group received POPSH in addition to the main diet. The use of the adsorbent led to an increase in daily weight gain by 19.9% and to a decrease in the total concentration of PCB congeners found in whole blood by 40%. The greatest decrease in concentration (35-52%) was observed for tetra-, penta- and hexachlorobiphenyls. These results demonstrate the possibilities of effective protection of calves from lipophilic toxins of feed and their active decontamination.

Strong adsorption of Polychlorinated Biphenyls by processed montmorillonite clays: Potential applications as toxin enterosorbents during disasters and floods

Polychlorinated biphenyls (PCBs) have been detected as prevalent environmental contaminants in water, food and biota. Previous studies in vitro have shown that a variety of sorbent materials, including carbon, can sorb PCBs; however, PCB sorbents that can be added to food or drinking water to decrease toxin bioavailability in humans and animals have not been reported. To address this problem, we have developed broad-acting and highly effective sorbents for PCBs using montmorillonite clays reported to be safe for consumption in animals and humans. In this study, calcium montmorillonite clays were acid processed (APMs) and the interactions of six PCB congeners (PCB 77, 126, 153, 157, 154 and 155) on the surfaces of APMs were characterized. Computational models and isothermal analyses were used to derive surface capacities and affinities, delineate mechanisms and predict the thermodynamics of sorption. To confirm the safety and predict the efficacy of APMs against individual PCBs and common mixtures (Aroclors 1254 and 1260), we have also used a living organism (Hydra vulgaris) that is sensitive to toxins. APMs significantly protected hydra against the toxicity of PCBs and Aroclors. This finding was supported by studies showing tight binding; high capacity, affinity, and enthalpy; and a low therapeutic dose.

Effect of Dioxins in Milk on the 3D Cultured Primary Buffalo Hepatocyte Model System

Cow and human milk have been reported to contain dioxins ranging from 0.023 to 26.46 and 0.88 to 19 pg/g of fat, respectively. However, the toxic effects of the dioxins in the milk in this range of concentrations were not explored. Therefore, considering the outbred livestock tissues as better models than inbred laboratory animals, the present study targeted to study the effect of dioxins present in the milk on three-dimensionally (3D) cultured buffalo primary hepatocyte spheroids. The spheroids were treated with a model dioxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), directly and also through milk fat at different concentrations (i.e, 0.02-20 pg/mL) for 24 h. Among the liver-cell-specific (ALB, HNF4α, and AFP) genes, a similar ALB and upregulated HNF4α expression at all treatments indicated the functional and transcriptionally active hepatocyte spheroids. Supportingly, no significant difference in the antiapoptotic gene expression between the treatments of milk fat and milk fat containing dioxins indicated the survivability of the spheroids during dioxin treatments. Among the selected TCDD responsive (CYP1A1, CYP1A2, AHR, CYP1B1, and TIPARP) genes, a nonsignificant increasing trend of the CYP1A1 expression was observed from 0.2 to 10 pg/mL of TCDD concentration through milk fat. This pattern was similar to the reported insensitive response of human primary hepatocytes toward dioxins than that of rat primary hepatocytes. This may indicate that the buffalo hepatocyte spheroids could be better models than rats for TCDD hepatotoxic studies. Further, TCDD in the milk in the range of 0.02-20 pg/mL concentration may not be very hepatotoxic.

Hydrophobized Reversed-Phase Adsorbent for Protection of Dairy Cattle against Lipophilic Toxins from Diet. Efficiensy in Vitro and in Vivo

The steady growth of inflammatory diseases of the udder in dairy cattle forces us to look for the causes of this phenomenon in the context of growing chemical pollution of the environment and feeds. Within the framework of this concept, an analysis was made of the polarity level of the three toxic impurity groups, which are commonly present in dairy cattle feeds. These impurities are presented by mycotoxins, polyaromatic hydrocarbons (PAH) and persistent organic pollutants (POP). It has been determined that 46% of studied mycotoxins (n = 1500) and 100% of studied polyaromatic hydrocarbons (n = 45) and persistent organic pollutants (n = 55) are lipophilic compounds, prone to bioaccumulation. A comparative evaluation of the sorption capacity of four adsorbents of a different nature and polarity with respect to the simplest PAH, naphthalene and lipophilic estrogenic mycotoxin, zearalenone in vitro has been carried out. The highest efficiency in these experiments was demonstrated by the reversed-phase polyoctylated polysilicate hydrogel (POPSH). The use of POPSH in a herd of lactating cows significantly reduced the transfer of aldrin, dieldrin and heptachlor, typical POPs from the “dirty dozen”, to the milk. The relevance of protecting the main functional systems of animals from the damaging effects of lipophilic toxins from feeds using non-polar adsorbents, and the concept of evaluating the effectiveness of various feed adsorbents for dairy cattle by their influence on the somatic cell count in the collected milk are discussed.

PCB28 and PCB52 induce hepatotoxicity by impairing the autophagic flux and stimulating cell apoptosis in vitro

Hepatotoxicity is one of the adverse health effects induced by polychlorinated biphenyls (PCBs). Recently, autophagy was revealed to play an important role in PCBs-induced toxicology, however, its precise role in PCBs-induced hepatotoxicity is as yet unknown. In this study, treatment of PCB28/PCB52 for 48 h dose-dependently induced hepatotoxicity at doses of 10, 20, 40 and 80 μM in homo and rattus hepatocytes. Expressions of proteins of BECN1, LC3-II and ULK1 significantly increased in PCB28/PCB52-treated cells at a dose of 40 μM, implying initiation of autophagy. Over-expression of p62 suggested deficient clearance of autophagosome. Consistently, accumulation of autophagosome was observed by transmission-electron microscopy and confocal fluorescence microscopy using adenovirus expressing mRFP-GFP-LC3, which may initiate apoptosis. Furthermore, increased reactive oxygen species levels might also induce autophagy and apoptosis. Consistently, cell apoptosis was evoked by the treatment of PCB28/PCB52 compared to the respective controls, which coincided with obvious hepatotoxicity. Subsequently, an inhibitor (3-methlyadenine) and an initiator (rapamycin) of autophagy were used. Compared to PCB28/PCB52 alone-treated cells, initiation of autophagy, blocked autophagic flux, cell apoptosis and hepatotoxicity were alleviated by 3-methlyadenine and aggravated by rapamycin, respectively. Taken together, PCB28 and PCB52 induced hepatotoxicity by impairing autophagic flux and stimulating cell apoptosis in vitro.