Levels of Polychlorinated Dibenzo-p-Dioxins/Furans and Polychlorinated Biphenyls in Free-Range Hen Eggs in Central Italy and Estimated Human Dietary Exposure

Assessment of methomyl-induced adrenal gland disruption in rat fetuses and pups: Potential protective effects of propolis supplementation

The present study aimed to unravel the possible adverse effects of methomyl on the developing adrenal gland of rat fetuses and pups. Additionally, this study explored the potential improving effects of propolis against these possible hazards induced by methomyl exposure. To achieve that, pregnant rats were divided into four groups: control group, received 1 mL distilled water, propolis group, received 1 mL propolis at a dose of 300 mg/kg, methomyl group, received 1 mL methomyl at a dose of 2 mg/kg, and combined group, received 1 mL methomyl followed by 1 mL propolis, an hour later at the same previous doses. The results revealed that methomyl exposure, during pregnancy and lactation, induced many histological and ultrastructural changes, caused DNA damage and downregulated the expression of steroidogenic acute regulatory (StAR) and CYP11B2 genes in the adrenal glands of both rat fetuses and pups. Interestingly, propolis supplementation demonstrated a remarkable ability to mitigate these deleterious effects and restored the histology and ultrastructure architecture of the adrenal glands of both fetuses and pups, as well as decreased DNA damage and upregulated the expression of StAR and CYP11B2 genes in the adrenal gland of rat fetuses and pups. In conclusion, our study highlights the potential hazardous impact of methomyl exposure during pregnancy and lactation on the development of the adrenal gland in rat fetuses and pups, moreover, the study presents a new approach to alleviate these effects through propolis administration which could be used as a dietary supplement to mitigate the adverse effects of methomyl exposure.

Levels, enrichment characteristics and dietary intake risk of polychlorinated dibenzo-p-dioxin/furans in traditional smoked pork

The concentrations and TEQs of polychlorinated dibenzo-p-dioxin/furans (PCDD/Fs) in traditional smoked pork were significantly higher than those in raw pork, and mainly distributed in the surface layer. The main enriched congeners during traditional smoking were 2378-TCDF, 12378-PeCDF, 23478-PeCDF, 1234678-HpCDF, OCDF, 1234678-HpCDD and OCDD. The ability of each congener to transfer from the surface to the inner part was various. According to the dietary habits of local residents, PCDD/Fs in more than half of the traditional smoked pork samples posed a potential carcinogenic risk, and the risk in the surface samples were 1.02-10.2 times that of the corresponding inner samples. Some variables might be the important factors affecting the concentration of PCDD/Fs in smoked pork, such as the duration of smoking and the kind of fuel. It is recommended to achieve lower risk by reducing the consumption of smoked pork, especially the surface layer of smoked pork, and innovating traditional smoking technologies.

Occurrence and congener profiles of dioxins (PCDDs), furans (PCDFs) and polychlorinated biphenyls (PCBs) in ovine and caprine milk samples collected in a very polluted site in Central Italy

Concentrations of 7 polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs) and 18 polychlorinated biphenyls (PCBs), including 12 dioxin-like (DL-PCBs) and 6 non-dioxin-like PCBs (NDL-PCBs) were measured in 16 ovine and caprine milk samples collected in the territory of Bussi sul Tirino, central Italy, a Site of National Interest (SNI) due to its high and widespread environmental pollution. All the analyzed samples were compliant with the maximum levels fixed by Commission Regulation (EU) 1259/2011 for the content of PCDD/Fs and the sum of PCDD/Fs and DL-PCBs. In two cases, contamination levels of the sum of PCDD/Fs and DL-PCBs were higher than the action levels fixed by EU Recommendation 663/2014. The statistical analysis, performed by Principal Component Analysis (PCA), revealed that the differences in contamination profiles of the different milk samples were independent of the distance of the farms from the Bussi illegal landfill but likely related to local emission sources influencing the exposure to POPs of studied animals.

Update of Indicator PCB Levels in Food in Southern Italy: Assessment of the Dietary Exposure for Adult and Elderly Population

The levels of non-dioxin-like PCB indicators (iPCBs 28, 52, 101, 138, 153, and 180) were determined in food samples (seafood, meat and processed meat, milk and dairy products, hen eggs, olive oil, and other fats) to evaluate the exposure of adult and elderly population. iPCB levels in samples were in the following order: fishery products > meat and processed meat > milk and dairy products > olive oil and other fats. None of the samples had concentrations above the maximum permissible limits for human consumption established by the European Union legislation, except for salami samples. The dietary intake for the total population was 12.33 ng·kg−1 bw·d−1, while depending on the sex/age groups, exposure was estimated between 9.60 and 12.11 ng·kg−1 bw·d−1, with seafood being the major contributor. The exposure scenario indicates that further efforts must still be carried out to protect the consumer from these harmful chemicals.

Insights into the toxicokinetic, tissue distribution and maternal transfer of polychlorinated dibenzo-p-dioxins/dibenzofurans in laying hens fed with dioxin-associated dietary

A controlled feeding experiment was conducted to investigate the toxicokinetic of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) in laying hens. The laying hens were fed with fly ash contaminated diets to replicate the typical environment-feed-chicken transfer chain in China. Levels of PCDD/Fs rapidly increased in the pectoralis, adipose tissue, liver and blood of laying hens with daily ingestion of dioxin-associated diets during the 14-days exposure period, and then a gradual decrease was observed in the 28-days depletion period. The depletion rates (k_d) of the toxic equivalent of PCDD/Fs (TEQ_PCDD/Fs) were 0.043, 0.031 and 0.030 day^-1 for pectoralis, liver and adipose tissue in the high-exposure group, respectively. The k_d of individual PCDD/Fs in liver increased with the numbers of chlorine and n-octanol/water partition coefficient (logK_OW), indicating that lower chlorinated congeners had higher half-lives in liver. Decreasing ratios of liver to adipose tissue for PCDD/Fs (L/AT) throughout the experiment suggested a tendency of equilibrium partitioning between liver and adipose tissue. Congener-specific sequestration of PCDD/Fs in liver was revealed by the positive correlation between L/AT ratios and logK_OW. Physiological bioconcentration factors of PCDD/Fs were estimated at the end of exposure, indicating the preferential accumulation of hexachlorinated congeners in most tissues. Furthermore, maternal transfer of PCDD/Fs was positively correlated with logK_OW, implying that more lipophilic congeners were transferred to egg along with the lipid circulation.

The influence of different production systems on dioxin and PCB levels in chicken eggs from Emilia-Romagna and Lombardy regions (Italy) over 2017-2019 and consequent dietary exposure assessment

Hen eggs from farms with different production systems (organic, free range, barn, and in cage) sited in two regions of Italy (Emilia-Romagna and Lombardy) were collected from 2017 to 2019 to monitor the levels of 17 polychlorinated dibenzo-p-dioxin/dibenzofurans (PCDD/Fs), 12 dioxin-like polychlorinated biphenyls (dl-PCBs) and the 6 non-dioxin-like polychlorinated biphenyl indicators (ndl-PCBs). Average concentrations of PCDD/Fs (0.21 pg WHO₍₂₀₀₅₎-TEQ/g fat), PCDD/Fs + dl-PCBs (0.43 pg WHO₍₂₀₀₅₎-TEQ/g fat) and ndl-PCBs (6.41 ng/g fat) were below the maximum limits established at European level in eggs, but significantly higher amounts of PCDD/Fs and PCDD/Fs + dl-PCBs were found in eggs from free-range housing system compared to barn, cage, and organic ones. The potential dietary intake of the monitored contaminants by Italian population age groups through the consumption of locally produced eggs was also evaluated. Exposure levels to PCDD/Fs plus dl-PCBs were below the tolerable weekly intake (TWI) of 2 pg WHO₍₂₀₀₅₎-TEQ/kg bw/week recently set by the European Food Safety Authority (EFSA). However, the younger population was found to be more vulnerable than other age groups to exposure to these contaminants. Specifically, the preferential consumption of free-range eggs by infants, toddlers, and children contributed more than 30% to the TWI. The results confirm the need to continuously monitor the levels of chemical contaminants in the environment and provide a reminder of the importance of targeted intervention measures aimed to reduce their occurrence in food and feed, firstly by improving the management practices on egg-producing farms.

Dichlorodiphenyltrichloroethane and the Adrenal Gland: From Toxicity to Endocrine Disruption

Endocrine disruptors are exogenous compounds that pollute the environment and have effects similar to hormones when inside the body. One of the most widespread endocrine disruptors in the wild is the pesticide dichlorodiphenyltrichloroethane (DDT). Toxic doses of DDT are known to cause cell atrophy and degeneration in the adrenal zona fasciculata and zona reticularis. Daily exposure in a developing organism to supposedly non-toxic doses of DDT have been found to impair the morphogenesis of both the cortex and the medulla of the adrenal glands, as well as disturbing the secretion of hormones in cortical and chromaffin cells. Comparison of high and very low levels of DDT exposure revealed drastic differences in the morphological and functional changes in the adrenal cortex. Moreover, the three adrenocortical zones have different levels of sensitivity to the disruptive actions of DDT. The zona glomerulosa and zona reticularis demonstrate sensitivity to both high and very low levels of DDT in prenatal and postnatal periods. In contrast, the zona fasciculata is less damaged by low (supposedly non-toxic) exposure to DDT and its metabolites but is affected by toxic levels of exposure; thus, DDT exerts both toxic and disruptive effects on the adrenal glands, and sensitivity to these two types of action varies in adrenocortical zones. Disruptive low-dose exposure leads to more severe affection of the adrenal function.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in food and human dietary intake: An update of the scientific literature

It is well established that for non-occupationally exposed populations, dietary intake is, by far, the main way of human exposure to polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD/Fs), a family of environmental POPs with a well-known potential toxicity -including carcinogenicity-in humans. We here summarize the results of recent studies (2010-2021) (databases: Scopus and PubMed), focused on determining the levels of PCDD/Fs in food samples of different origins, as well as the dietary intake of these pollutants. We have revised studies conducted in various Asian, American and European countries. However, information is rather limited, with no recent data for most countries over the world. Due to the enormous differences in the methodologies of the studies, to conduct a detailed comparison of the results for the different regions and countries has not been possible. Notwithstanding, where data over time are available, important reductions have been observed. These reductions have been linked to the decreases in the environmental emissions of PCDD/Fs noted in recent years. Interestingly, reductions in the levels of PCDD/Fs in biological tissues are also occurring in parallel. In general, the tolerable daily/weekly/monthly dietary intakes of PCDD/Fs are not being currently exceeded where data are available.

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