Polychlorodibenzodioxin and -furan and dioxin-like polychlorobiphenyl distribution in tissues and dairy products of dairy buffaloes

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.

Dioxins and dioxin-like PCBs in buffalo milk from the Campania region (Italy): Decreasing trend and baseline assessment over 10 years (2008-2018)

Polychlorodibenzo-p-dioxins, polychlorodibenzo-furans (PCDD/Fs) and dioxin-like polychlorobiphenyls (DL-PCBs) enter the food chain from the environment. In this study, we report the 2008-2018 time-trends in the PCDD/F and DL-PCB contamination of milk from buffaloes fed on local forage in rural areas of the Campania region. Validated according to QA/QC criteria, the dataset (N = 808 on a total of 2068 samples, after excluding follow-up results and outliers) was computed on the upper-bound value pg WHO-TEQ₂₀₀₅ g^-1fat. We assessed time-trends and assayed baseline contamination levels, which displayed log-normal distribution. A significant decreasing trend (p < 0.01) was observed from 2008 to 2009 and 2010; the P50-P95 range fell from 2.37-8.48 pg WHO-TEQ₂₀₀₅ g^-1fat (N = 393) in 2008 to 1.73-4.61 in 2009 (N = 86) and to 0.67-1.46 in 2010 (N = 42). From 2010 to 2018 (N = 329), no significant variation was found among years and the related dataset fitted a log-normal distribution (p < 0.05). Occurrence descriptors indicated that the baseline contamination of dairy products (mean = 0.54; P50-P95 = 0.47-1.24) in the Campania Region was well below the EU regulatory limit in force (5.5 pg WHO-TEQ₂₀₀₅ g^-1fat). Given the Tolerable Weekly Intake of 2 pg WHO-TEQ kg^-1 body weight (bw) proposed by the EFSA for PCDD/Fs and DL-PCBs, this level of baseline contamination is discussed with regard to the orientation of food safety and food security risk connected with buffalo mozzarella cheese production.

Polychlorinated dioxins, furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in food from Italy: Estimates of dietaryintake and assessment

Abstract

Dietary intake of polychlorinated dioxins and furans (PCDD/Fs) and dioxin‐like polychlorinated biphenyls (dl‐PCBs) from various foods (fish and seafood, meat and meat‐based products, milk and dairy products, hen eggs, olive oil and fats) was investigated for various sex/age groups of the Italian population. The concentrations of PCDD/Fs and dl‐PCBs and their contribution to total TEQ values varied depending on food matrix. Fish (0.50 pg WHO‐TEQ/g wet weight) and seafood (0.16 pg WHO‐TEQ/g wet weight) showed the highest mean concentrations of PCDD/Fs plus dl‐PCBs, followed by meat (1.70 pg WHO‐TEQ/g lipid weight), meat based products (1.03 pg WHO‐TEQ/g lipid weight), milk and dairy products (0.78 pg WHO‐TEQ/g lipid weight), hen eggs (0.71 pg WHO‐TEQ/g lipid weight), fats (0.27 pg WHO‐TEQ/g lipid weight) and olive oil (0.09 pg WHO‐TEQ/g lipid weight). In all samples WHO‐TEQ PCDD/F plus dl‐PCB concentrations fulfilled the European Union food law, except in pork loin samples (1.39 pg WHO‐TEQ/g lipid weight). Differences in exposure depending on the sex/age groups (children > teenagers > adults > elders) and hypotheses considered (lower bound and upper bound) were encountered. Non‐cancer risk values showed a low exposure. Carcinogenicity risk results revealed that highly exposed individuals were distributed over all sex/age groups, even though the proportion of individuals exceeding the safe limit was higher in children. These data once again underline the importance of trying to control the levels of these contaminants in fishery products, particularly in fish, who represents one of the main exposure sources for consumers.

Practical Application

This paper may help the consumer in making food choices to minimize the exposure risk to dioxins, furans and PCBs

Risk for animal and human health related to the presence of dioxins and dioxin-like PCBs in feed and food

The European Commission asked EFSA for a scientific opinion on the risks for animal and human health related to the presence of dioxins (PCDD/Fs) and DL-PCBs in feed and food. The data from experimental animal and epidemiological studies were reviewed and it was decided to base the human risk assessment on effects observed in humans and to use animal data as supportive evidence. The critical effect was on semen quality, following pre- and postnatal exposure. The critical study showed a NOAEL of 7.0 pg WHO2005-TEQ/g fat in blood sampled at age 9 years based on PCDD/F-TEQs. No association was observed when including DL-PCB-TEQs. Using toxicokinetic modelling and taking into account the exposure from breastfeeding and a twofold higher intake during childhood, it was estimated that daily exposure in adolescents and adults should be below 0.25 pg TEQ/kg bw/day. The CONTAM Panel established a TWI of 2 pg TEQ/kg bw/week. With occurrence and consumption data from European countries, the mean and P95 intake of total TEQ by Adolescents, Adults, Elderly and Very Elderly varied between, respectively, 2.1 to 10.5, and 5.3 to 30.4 pg TEQ/kg bw/week, implying a considerable exceedance of the TWI. Toddlers and Other Children showed a higher exposure than older age groups, but this was accounted for when deriving the TWI. Exposure to PCDD/F-TEQ only was on average 2.4- and 2.7-fold lower for mean and P95 exposure than for total TEQ. PCDD/Fs and DL-PCBs are transferred to milk and eggs, and accumulate in fatty tissues and liver. Transfer rates and bioconcentration factors were identified for various species. The CONTAM Panel was not able to identify reference values in most farm and companion animals with the exception of NOAELs for mink, chicken and some fish species. The estimated exposure from feed for these species does not imply a risk.

Intake estimates of dioxins and dioxin-like polychlorobiphenyls in the Italian general population from the 2013-2016 results of official monitoring plans in food

The implementation of the European Union strategy for polychlorodibenzo-dioxins and -furans (PCDD/Fs), and dioxin-like polychlorobiphenyls (DL-PCBs) is determining a general reduction of their presence in the environment and in the food chain. The most important route for human exposure to these substances is food consumption and, as a consequence, a progressive decrease of their dietary intake has been observed in the last decades. In this context, it seemed worth updating the PCDD/F and DL-PCB intake estimation for the Italian population. A total of 2659 samples of food of animal and vegetable origin analyzed for PCDD/Fs and DL-PCBs in the period 2013-2016 by accredited official laboratories and the national food consumption database were considered for the dietary intake assessment in different age groups of the Italian general population The median cumulative intake estimates expressed as pg WHO-TEQ/kg body weight per day and computed with a deterministic and a probabilistic approach were 1.40-1.52 for children, 0.82-0.85 for adolescents, and 0.64-0.61 for adults, respectively. Such results confirm the decreasing trend of PCDD/F and DL-PCB dietary intake even though the Tolerable Daily Intake (TDI) value of 2 WHO-TEQ/kg body weight per day is exceeded at the 95th percentile for all age groups, with children as sensitive group. Most contributing food categories to the intake resulted fish, food of vegetable origin, and cheese. A sensitivity analysis was also performed to calculate the target contamination levels able to keep the dietary exposure below the TDI. Computed target levels fall between P50 and P97 of the occurrence distribution of the main food groups, meaning that most of the Italian food production can be considered safe.

Automated milk fat extraction for the analyses of persistent organic pollutants

We have utilized an automated acid hydrolysis technology, followed by an abbreviated Soxhlet extraction technique to obtain fat from whole milk for the determination of persistent organic pollutants, namely polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls. The process simply involves (1) pouring the liquid milk into the hydrolysis beaker with reagents and standards, (2) drying the obtained fat on a filter paper and (3) obtaining pure fat via the modified Soxhlet extraction using 100mL of hexane per sample. This technique is in contrast to traditional manually intense liquid-liquid extractions and avoids the preparatory step of freeze-drying the samples for pressurized liquid extractions. Along with these extraction improvements, analytical results closely agree between the methods, thus no quality has been compromised. The native spike (n=12) and internal standard (n=24) precision and accuracy results are within EPA Methods 1613 and 1668 limits. While the median (n=6) Toxic Equivalency Quotient (TEQ) for polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans and the concentration of the marker polychlorinated biphenyls show a percent difference of 1% and 12%, respectively, compared to 315 previously analyzed milk samples at the same laboratory using liquid-liquid extraction. During our feasibility studies, both egg and fish tissue show substantial promise using this technique as well.