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Breastfeeding is one of the most effective ways to ensure child health and survival, with several benefits for both the infants and their mothers. However, breast milk can contain environmental pollutants with endocrine disruption capacity, neurotoxicity and/or potential to alter microbiota. Monitoring breast milk provides information on the current chemical exposure of breastfed infants and, in addition, on the current and historical exposure of nursing mothers. In this study, the levels of a wide range of pollutants were measured in breast milk of Spanish nursing mothers. Target chemicals were dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene (DDE), hexachlorobenzene (HCB), oxy-chlordane, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), per- and poly-fluoroalkyl substances (PFASs) (including perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA)), chlorpyrifos, bisphenol A (BPA), tetrabromobisphenol A (TBBPA), and a number of toxic and essential elements. Traces of most chemicals were found. A correlation between the levels of some persistent organic pollutants (POPs) and maternal characteristics (age and body mass index) was observed, while smoking was associated to higher concentrations of some toxic elements. Higher levels of PCBs were detected in samples from Spanish primiparous mothers compared to non-Spanish multiparous women. Breast milk from low-income mothers showed higher content of DDT and DDE than high-income mothers. Although breastfeeding is clearly beneficial for babies, the exposure to this mixture of hazardous substances, as well as their interaction and combined effects must not be disregarded.

Since 1999, a hazardous waste incinerator (HWI) is operating in Constantí (Tarragona County, Catalonia, Spain). In 1996–1998, when the facility was being built, we started a monitoring program aimed at evaluating the impact of the emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) by the HWI on the environment and the human health. This study aimed at determining the current concentrations of PCDD/Fs in breast milk samples of women living nearby the HWI and at comparing these levels and profiles with those obtained in the baseline (1996–1998) and previous surveys (2002, 2007 and 2012). Furthermore, the association between the dietary intake of PCDD/Fs and the congener profiles in breast milk was also explored. Twenty milk samples were collected from women living in Tarragona downtown and near the industrial area where the HWI is placed. The content of PCDD/Fs was analyzed by following a procedure derived from the US EPA methods 1613 and 8290A. The mean concentration of PCDD/Fs was 2.26 pg WHO-TEQ/g fat. No significant differences were found between women living in industrial and urban areas (1.67 pg vs. 2.48 pg WHO-TEQ/g fat). Interestingly, a notable significant reduction (81%) was observed with respect to the concentrations found in the baseline study. The profiles of PCDD/Fs in breast milk were similar independently on the area and period of collection, being mainly influenced by the intake of fish, meat, oils and fats. The decreasing trend of PCDD/Fs in human milk agrees with the reduction observed in the dietary intake of these pollutants. It was also concluded that the current levels of PCDD/Fs in human milk levels are not influenced by the HWI stack emissions. Keywords: PCDD/Fs, Profiles, Breast milk, Biomonitoring, Hazardous waste incinerator

For non-occupationally exposed adults, dietary intake is the main route of exposure to bisphenols (BPs), with canned foodstuffs playing a key role. This study was aimed at biomonitoring bisphenol A (BPA) and 5 more BP analogues (BPB, BPE, BPF, BPAF and BPZ) in spot urine and blood samples of a cohort of adults, who followed a diet based on a high consumption of canned food. To the best of our knowledge, this is the first study aimed at assessing the co-exposure of BP analogues in food and biological samples after a two-day duplicate diet study. The estimated total dietary exposure was 0.37 and 0.045 µg/kg body weight/day, for the canned-diet and control groups, respectively. BPA was the compound with the highest concentration in urine in comparison with the values of the remaining BP analogues. A high detection rate of BPA was noted in urine for both groups, 96% for the canned-diet group and 90% for the control group, while in blood it could be only quantified in 6% of the samples. The identification of other analogues was hardly related to diet, so it could be the result of other potential exposure sources, such as personal care products (PCPs) or air inhalation. After 2 days, the excretion of BPA was considerably higher in the canned-diet group subjects than those in the control group (7.02 vs. 1.89 µg/day), confirming that diet and canned foodstuffs are the main route of exposure to BPA. Anyhow, the temporary tolerable daily intake (t-TDI) established by the EFSA was not exceeded, even by those consumers with a diet rich in canned food. Moreover, spot urine samples provided accurate information about exposure and excretion of BPA, being the 4 h, instead of 24 h, the optimal sampling interval, when the collection of spot urine samples is not possible.

This study was aimed at determining the concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in 15 samples of adipose tissue from subjects who had been living in the vicinity of a hazardous waste incinerator (HWI). The results were compared with levels obtained in previous surveys carried out in 1998 (baseline study), 2002 and 2007. The current (2013) concentrations of PCDD/Fs in adipose tissue ranged from 2.8 to 46.3 pg WHO-TEQ/g fat (mean and median concentrations: 11.5 and 7.4 pg WHO-TEQ/g fat, respectively), being significantly lower (64%) than those observed in 1998. In contrast, no significant differences in the mean PCDD/F concentrations were noted in the period 2002–2013. The significant decrease of the PCDD/F content in fat, also noted in other biological monitors such as plasma and breast milk, is in agreement with the reduction in the dietary intake of PCDD/Fs found in the same area of study. Similarly to other investigations across Europe, an increase of PCDD/F levels in adipose tissue in relation to age was observed, while no significant differences were noted according to gender. A multicompartmental physiologically-based pharmacokinetic (PBPK) model was also applied to estimate the levels of PCDD/Fs in adipose tissue. When comparing the modeled and experimental concentrations of PCDD/Fs in that tissue, very similar values were obtained for the four surveys, which indicates this can be a reliable tool to predict the internal dose of PCDD/Fs. Keywords: PCDD/Fs, Adipose tissue, Temporal trend, Hazardous waste incinerator, PBPK model

Perfluoroalkyl substances (PFASs) are environmental pollutants with an important bioaccumulation potential. However, their metabolism and distribution in humans are not well studied. In this study, the concentrations of 21 PFASs were analyzed in 99 samples of autopsy tissues (brain, liver, lung, bone, and kidney) from subjects who had been living in Tarragona (Catalonia, Spain). The samples were analyzed by solvent extraction and online purification by turbulent flow and liquid chromatography coupled to tandem mass spectrometry. The occurrence of PFASs was confirmed in all human tissues. Although PFASs accumulation followed particular trends depending on the specific tissue, some similarities were found. In kidney and lung, perfluorobutanoic acid was the most frequent compound, and at highest concentrations (median values: 263 and 807 ng/g in kidney and lung, respectively). In liver and brain, perfluorohexanoic acid showed the maximum levels (median: 68.3 and 141 ng/g, respectively), while perfluorooctanoic acid was the most contributively in bone (median: 20.9 ng/g). Lung tissues accumulated the highest concentration of PFASs. However, perfluorooctane sulfonic acid and perfluorooctanoic acid were more prevalent in liver and bone, respectively. To the best of our knowledge, the accumulation of different PFASs in samples of various human tissues from the same subjects is here reported for the very first time. The current results may be of high importance for the validation of physiologically based pharmacokinetic models, which are being developed for humans. However, further studies on the distribution of the same compounds in the human body are still required. Keywords: Perfluoroalkyl substances (PFASs), Human distribution, Tissues, Turbulent flow chromatography coupled to tandem mass spectrometry (TFC-LC-MS/MS), Principal Component Analysis