Organochlorine pesticides and polychlorinated biphenyl congeners in wild terrestrial mammals from Croatia: Interspecies comparison of residue levels and compositions

Multi-cascade physiologically based kinetic (PBK) matrix model: Simulating chemical bioaccumulation across food webs

In modern ecosystems, many substances that biomagnify within food webs adversely affect organisms and ecological systems. To facilitate high-throughput screening of contemporary chemicals, we developed a multi-cascade physiologically-based kinetic (PBK) matrix model to simulate bioaccumulation and biomagnification along food chains. The model's validity is supported by the mean model bias (MB) values, which fall within the acceptable range when compared with measured biomagnification factors (BMFs) reported in the literature. Analyzing 3,074 organic chemicals, we estimated their biotransfer factors (BTFs)-the steady-state ratio of chemical concentrations in primary consumer tissues to those in their feed-and their BMFs-the steady-state ratio of chemical concentrations in predators to their prey. Our results reveal consistent BTF trends across different tissues within the same species for a given chemical. Chemicals with moderate lipophilicity and low diffusivity tend to be retained longer in organisms, leading to higher BMFs. Notably, mammals appear particularly sensitive to persistent organic pollutants, while birds and ectothermic species do not exhibit clear patterns. Overall, the study highlights that animal physiological parameters and chemical physicochemical properties are more critical in determining bioaccumulation and potential toxicity than an organism's trophic position. Future research should refine key physiological parameters, such as hepatic metabolic rate constants, account for life-stage variations, and evaluate multiple exposure pathways to further enhance model accuracy and real-world applicability.

First data on polybrominated diphenyl ethers and temporal trend of polychlorinated biphenyls in European brown bear as a bioindicator species

The contamination status on persistent organic pollutants (POPs) in the Croatian terrestrial ecosystem was investigated by analyzing two classes of contaminants in adipose tissue of male European brown bear (Ursus arctos, N = 27) collected in 2021 and 2022. In addition to seven indicator polychlorinated biphenyls (PCBs), for the first time seven polybrominated diphenyl ethers (PBDEs) were analyzed in terrestrial species from this region. Sum of mass fractions detected in adipose tissue ranged from 0.011 to 0.463 ng g-1 lipid weight (lw) for the PBDEs, and from 0.652 to 30.17 ng g-1 lw for PCBs, with two orders of magnitude difference in the median value for these two groups of POPs (PBDEs: 0.022 ng g-1 lw; PCBs: 2.307 ng g-1 lw). PCBs dominated over PBDEs with a share of over 94 % of the total mass fractions of both groups of analyzed POPs. Results of the comparison of the PCB levels in the adipose tissue of brown bears reported here and in previous investigation from this region showed decrease in PCB-28, but increase of PCB-118 and PCB-180, while other congeners seemed to have reached a steady-state level in the environment over a ten-year period. Among the compounds analyzed in this study, BDE-47, PCB-153 and PCB-180 were the dominant congeners. Somewhat higher sum of PCBs was measured in April compared to October, although not statistically significant, indicating possible impact of winter hibernation causing concentration of lipophilic compounds due to body fat loss. Revealed POP levels in brown bears are consistent with the data on the low contamination of the Croatian terrestrial ecosystem in general.

Legacy persistent organic pollutants (POPs) in eggs of night herons and poultries from the upper Yangtze Basin, Southwest China

Black-crowned night heron (Nycticorax nycticorax) eggs have been identified as useful indicators for biomonitoring the environmental pollution in China. In this study, we investigated thirty eggs of black-crowned night heron collected from the upper Yangtze River (Changjiang) Basin, Southwest China, for the occurrence of legacy persistent organic pollutants (POPs), including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). Our results showed a general presence of POPs in night heron eggs with OCPs being the dominant contaminants, having a geometric mean concentration of 22.2 ng g-1 wet weight (ww), followed by PCBs (1.36 ng g-1 ww), PBDEs (0.215 ng g-1 ww), and PCDD/Fs (23.0 pg g-1 ww). The concentration levels were found to be significantly higher in night heron eggs than in poultry eggs by one or two magnitude orders. Among OCP congeners, p,p'-DDE was found to be predominant in night heron eggs, with a geometric mean concentration of 15.1 ng g-1 ww. Furthermore, species-specific congener patterns in eggs suggested similar or different sources for different POPs, possibly associated with contaminated soil and parental dietary sources. Additionally, estimated daily intakes (EDIs) were used to evaluate non-carcinogenic and carcinogenic risk associated with consumption of bird eggs. Our results revealed non-negligible non-cancer and cancer risk for humans who consume wild bird eggs as a regular diet instead of poultry eggs.

Lead and Other Trace Element Levels in Brains of Croatian Large Terrestrial Carnivores: Influence of Biological and Ecological Factors

Trace element pollution can adversely affect the brains of individuals and thus impact the entire population of apex predators, such as large European carnivores. We assessed exposure to prominent neurotoxicants As, Cd, Hg and Pb by measuring their brain stem levels in brown bears (n = 114), grey wolves (n = 8), Eurasian lynx (n = 3), and golden jackals (n = 2) sampled in 2015-2022 in Croatia. The highest of the non-essential elements was the Pb level in the bears' brains (median, Q1-Q3; 11.1, 7.13-24.1 μg/kg wet mass), with 4% of animals, all subadults, exceeding the established normal bovine levels (100 μg/kg wet mass). Species-specific differences were noted for Ca, Cd, Cu, Fe, Pb and Se brain levels. Female brown bears had higher As brain levels than males. Cubs and yearlings had lower brain Cd, but higher Zn, while subadults had higher Cu than adult bears. Hepatic As, Cd, Cu and Hg levels were shown to be a moderate proxy for estimating brain levels in bears (r_S = 0.30-0.69). Multiple associations of As, Cd, Hg and Pb with essential elements pointed to a possible interaction and disturbance of brain Ca, Cu, Fe, Se and Zn homeostasis. Non-essential element levels in the brains of four studied species were lower than reported earlier for terrestrial meso-carnivores and humans. The age and sex of animals were highlighted as essential factors in interpreting brain element levels in ecotoxicological studies of large carnivores.

Estimation of the Effects of Neonicotinoid Insecticides on Wild Raccoon, Procyon lotor, in Hokkaido, Japan: Urinary Concentrations and Hepatic Metabolic Capability of Neonicotinoids

Toxicological effects of neonicotinoid insecticides (NNIs) have been reported for mammals, such as humans, rats, and mice. However, there are limited reports on their toxic effects on wild mammals. To predict NNI-induced toxic effects on wild mammals, it is necessary to determine the exposure levels and metabolic ability of these species. We considered that raccoons could be an animal model for evaluating NNI-induced toxicities on wildlife because they live near agricultural fields and eat crops treated with NNIs. The objective of the present study was to estimate the effects of NNI exposure on wild raccoons. Urinary concentrations of NNI compounds (n = 59) and cytochrome P450-dependent metabolism of NNIs (n = 3) were evaluated in wild raccoons captured in Hokkaido, Japan, in 2020. We detected either one of the six NNIs or one metabolite, including acetamiprid, imidacloprid, clothianidin, dinotefuran, thiacloprid, thiamethoxam, and desmethyl-acetamiprid in 90% of raccoons (53/59); the average cumulative concentration of the seven NNI compounds was 3.1 ng/ml. The urinary concentrations were not much different from those reported previously for humans. Furthermore, we performed an in vitro assessment of the ability of raccoons to metabolize NNIs using hepatic microsomes. The amounts of NNI metabolites were measured using liquid chromatography-electrospray ionization-tandem mass spectrometry and compared with those in rats. Raccoons showed much lower metabolic ability; the maximum velocity/Michaelis-Menten constant (V_max /K_m ) values for raccoons were one-tenth to one-third of those for rats. For the first time, we show that wild raccoons could be frequently exposed to NNIs in the environment, and that the cytochrome P450-dependent metabolism of NNIs in the livers of raccoons might be low. Our results contribute to a better understanding of the effects of NNIs on raccoons, leading to better conservation efforts for wild mammals. Environ Toxicol Chem 2022;41:1865-1874. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Poisoned chalice: Use of transformed landscapes associated with increased persistent organic pollutant concentrations and potential immune effects for an adaptable carnivore

Wildlife around cities bioaccumulate multiple harmful environmental pollutants associated with human activities. Exposure severity can vary based on foraging behaviour and habitat use, which can be examined to elucidate exposure pathways. Carnivores can play vital roles in ecosystem stability but are particularly vulnerable to bioaccumulation of pollutants. Understanding the spatial and dietary predictors of these contaminants can inform pollutant control, and carnivores, at the top of food webs, can act as useful indicator species. We test for exposure to toxic organochlorines (OCs), including dichloro-diphenyl-trichloroethane (DDT) and polychlorinated biphenyls (PCBs), in a medium-sized felid, the caracal (Caracal caracal), across the peri-urban and agricultural landscapes of the city of Cape Town, South Africa. Concentrations in both blood (n = 69) and adipose tissue (n = 25) were analysed along with detailed spatial, dietary, demographic, and physiological data to assess OC sources and exposure risk. The analysis revealed widespread exposure of Cape Town's caracals to organochlorines: detection rate was 100% for PCBs and 83% for DDTs in blood, and 100% for both compounds in adipose. Caracals using human-transformed areas, such as vineyards and areas with higher human population and electrical transformer density, as well as wetland areas, had higher organochlorine burdens. These landscapes were also highly selected foraging areas, suggesting caracals are drawn into areas that co-incidentally increase their risk of exposure to these pollutants. Further, biomagnification potential was higher in individuals feeding on higher trophic level prey and on exotic prey. These findings point to bioaccumulation of OC toxicants and widespread exposure across local food webs. Additionally, we report possible physiological effects of exposure, including elevated white blood cell and platelet count, suggesting a degree of immunological response that may increase disease susceptibility. Cape Town's urban fringes likely represent a source of toxic chemicals for wildlife and require focused attention and action to ensure persistence of this adaptable mesocarnivore.

Organochlorine pesticides and NDL-PCBs in wild boars from flatland region with intensive agricultural activities

The objective of this study was to analyse the content of OHCs and NDL-PCBs in wild boar population living in densely populated flatland region with intensive agricultural production. A total of 82 liver samples were analysed by GC-MS method, revealing the presence of minimum one residue in the liver of the majority of animals (92.7%). Most commonly detected residues included ∑ HCH (64.6%), ∑endrin (56.1%) and ∑dieldrin (32.3%). Mean concentrations were in the range ∑endrin > ∑dieldrin > ∑HCH > ∑NDL-PCB > ∑DDT > ∑CHL > ∑endosulfan > methoxychlor. The dominant compound within the total content of NDL-PCBs was PCB 153 (76%). The assessment of daily intake and determination of Health Index indicated that in 6.1% of the samples the consumption of one single portion of wild boar liver would be harmful to human health due to the presence of ∑endrin or NDL-PCBs.

Impact of broad-spectrum pesticides used in the agricultural and forestry sector on the pesticide profile in wild boar, roe deer and deer and risk assessment for venison consumers

The present work is the first extensive study of large-scale pesticides research in wild animals. The investigation covered three game species: wild boar (n = 42), roe deer (n = 79) and deer (n = 15) collected from north-eastern Poland. To characterize the 480 pesticides in muscle samples, LC-GC-MS/MS techniques were used. A total of 28 compounds were detected: 5 neonicotinoids, 6 organochlorine and 5 other insecticides, 9 fungicides and 4 herbicides, in the range of 0.1-85.3 ng g^-1. Over four hundred detections were done. The highest mean concentrations were as follows: anthraquinone (85.3 ng g^-1) > DDT-p,p' (4.6 ng g^-1) > imidacloprid (4.3 ng g^-1) > permethrin (3.6 ng g^-1) > thiacloprid (2.8 ng g^-1). DDT and metabolites were the most frequently detected, followed by acetamiprid, tebuconazole, clothianidin and imidacloprid. Overall, 92% samples with residues were recorded, including 100% of wild boar, 88% of roe deer and 86% of deer. More than one pesticide (up to 9) was found in over 73% of the tested samples. The estimated chronic and acute risk to consumers of venison were very low (below 1% ADI and ARfD). This interdisciplinary study may be helpful for estimating ecological risk to wild animals and risk to consumers of wild animal products, and also as a source of biomonitoring data.

PCB levels in adipose tissue of dogs from illegal dumping sites in Campania region (Italy)

The aim of the study is to investigate the potential relationship between exposure to PCBs and cancer. In doing so we relied on a sample of dogs coming from a peculiar area of the Campania region (Italy), that has been suffering for illegal waste dumping and open air burning of plastic waste for many years. The latter determined the release of organic and inorganic pollutants, such as the PCBs. By comparing dogs with cancer and healthy dogs, we found much higher PCB concentrations in the former, with a significant difference (p < 0.05) for the non-indicator ∑10NDL-PCB and the DL-PCBs. A regression analysis, controlling for three potentially confounding factors, that are sex, age and weight, confirmed the higher ∑10NDL-PCB concentration in dogs with cancer. Hence, our evidence suggests a potential health hazard for animals and likewise people living in a risky area due to the presence of environmental organic pollutants.

Assessment of persistent organic pollutants in hair samples collected from several Iranian wild cat species

Persistent organic pollutants (POPs), including the organochlorine pesticides (OCPs), such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, hexachlorobenzene (HCB), α, β and γ-hexachlorocyclohexane (HCH) isomers, and the polychlorinated biphenyl (PCB) congeners (IUPAC Nos. 28, 52, 101, 138, 153, and 180), were determined in hair samples collected from 41 Iranian wild cats belonging to 8 different species. This is the first report on the presence of selected POPs in feline hair from museum collections and it is an indication of the concentrations of OCPs and PCBs in Iran from 2000 to 2010. Median concentrations of HCHs, DDTs, PCBs, and HCB were 108, 99, 70 and 38 ng/g hair, respectively. p,p'-DDE and β-HCH were the most abundant OCPs (detected in 91% and 74%, respectively, of the analyzed samples), while CB 180 and CB 138 were the predominant PCB congeners, found respectively in 49% and 61% of the samples. Significant differences (p < 0.05) in the median concentrations of DDTs were found among species grouped according to both their feeding habits and territory range. Levels of DDTs and PCBs were generally higher in the omnivorous species compared with the carnivorous ones, likely due to both their dietary habits and habitat in the proximity of human settlements.

Metal(loid) exposure assessment and biomarker responses in captive and free-ranging European brown bear (Ursus arctos)

We investigated the level of five non-essential metal(loid)s (As, Cd, Hg, Tl, Pb) and nine essential metals (Mg, Ca, Mn, Fe, Co, Cu, Zn, Se, Mo) in hair and blood components of captive and free-ranging European brown bear populations in Croatia and Poland. Metal(loid) associations with biomarkers of oxidative stress (superoxide dismutase, SOD; glutathione-peroxidase, GSH-Px; malondialdehyde, MDA) and metal exposure (metallothionein, MT) were estimated in this top predatory mammal. Lead was the most abundant non-essential metal(loid) in both blood and hair, with 4 of 35 individuals having blood levels over 100 μg/L. A positive association was found between Pb level and SOD activity in blood. Free-ranging bears had higher blood SOD activity, Mn, Zn and Cd levels, hair Co, Cd, Tl and Pb compared to captive individuals, while the opposite was true for Mg and hair Ca thereby reflecting habitat and diet differences. With increasing age, animals showed lower levels of SOD activity and certain essential metals. Females had higher SOD activity and blood levels of some essential metals than males. Hair showed a higher Fe and Co level when sampled during the growth phase and was not predictive of non-essential metal(loid) blood levels. The established metal(loid) baseline values will enable future risk assessment in both captive and wild European brown bear populations.

Presence of organic halogenated compounds, organophosphorus insecticides and polycyclic aromatic hydrocarbons in meat of different game animal species from an Italian subalpine area

The exposure to several compounds such as polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), organophosphorus pesticides (OPs), polycyclic aromatic hydrocarbon (PAHs), perfluoroalkyl substances (PFASs) and polybrominated diphenyl ethers (PBDEs) is a public health issue. The European Union (EU) recommended that its member states monitor the presence of emerging contaminants, like PBDEs and PFASs, in food and in the environment to obtain an accurate estimation of exposure. The tissues of wild animals exposed to these compounds can represent a suitable indicator of environmental pollution. The aim of this work is to evaluate: (i) the occurrence of PCBs, PBDEs, PFASs, PAHs, OCPs and OPs in four game animals' meat (chamois, red deer, wild boar and roe deer); (ii) interspecies differences and (iii) human exposure. Muscle samples from seventy-nine animals were collected during the hunting season in a Northern Italy mountain area at altitudes ranging from 300 to 2500 meters above sea level. The analyses were performed with gas chromatography-mass spectrometry (GC-MS/MS) and ultra-performance liquid chromatography - tandem mass spectrometry (UHPLC-MS/MS). No PBDEs were found in the samples. OCPs, OPs and PCBs were detected in almost all samples at different concentration ranges, showing higher frequency in ungulate species than in wild boar. PFAs were found only in wild boar. Anthracene and benzopyrene, among PAHs, were found only in chamois, at low concentrations. The lack of an accurate pattern of exposure as well as variable consumption by hunters does not allow accurate risk characterisation. However, a low risk for consumers can be indicated due to the frequent detection of contaminants only at trace levels, the scarce prevalence of high concentrations of some contaminants and the low consumption of game animal meat. In conclusion, the organisation of a control plan on residues in game animals would be advisable.

Monitoring of environmental persistent organic pollutants in hair samples collected from wild terrestrial mammals of Primorsky Krai, Russia

Persistent organic pollutants (POPs) constitute a wide range of chemicals. Their release into the environment has raised great concern due to their potentially harmful impact in humans and wildlife species. The aim of this current study was to detect selected POPs in hair samples of wild terrestrial mammals from Primorsky Krai, Russia, so as to assess potential environmental exposure. The tested wild species were leopard cat, musk deer, wolf, amur hedgehog, and raccoon dog. The targeted organochlorines were hexachlorobenzene (HCB) and DDTs (opDDE, ppDDE, and opDDD), polychlorinated biphenyl (PCB) congeners (28, 52, 101, 118, 138, 153, and 180), and polycyclic aromatic hydrocarbons (PAHs) (acenaphylene (ACEN), fluorene (FLU), anthracene (ANTH) phenathrene (PHEN), and pyrene (PYR)). The detection of POPs was conducted in hair samples by a one-step hair extraction method, by using a headspace solid-phase microextraction technique (HS-SPME) and analyzed then by GC-MS. The majority of the wild animal hair samples were found positive in all tested pollutants. More specifically, the percentage of positive hair samples for HCB was 93.3% and for DDTs, PCBs, and PAHs, 20.0 to 100.0%, 6.7 to 100.0%, and 75.0 to 100.0%, respectively. DDT, PCB, and PAH detection ranged from 1.26 to 52.06 pg mg^-1, 0.73 to 31.34 pg mg^-1, and 2.59 to 35.00 pg mg^-1, respectively. The highest mean concentration levels of all tested pollutants were found for musk deer (PCBs 12.41 pg mg^-1, DDTs 21.87 pg mg^-1, PAHs 22.12 pg mg^-1) compared to the other wild species. To the best of our knowledge, this is the first study that provides results regarding contamination in different terrestrial mammals by POP exposure. The use of hair as a matrix is proven to be an effective tool for nondestructive biological monitoring of POP contamination in terrestrial ecosystems.

Assessment of multiple anthropogenic contaminants and their potential genotoxicity in the aquatic environment of Plitvice Lakes National Park, Croatia

In this study, the influence of anthropogenic pollution on the aquatic environment of Plitvice Lakes National Park (PLNP) was investigated during 2011-2012 using a combination of chemical and cytogenetic analyses. Four groups of major contaminants [(volatile organic compounds: benzene, toluene, ethylbenzene, and xylenes (BTEX); persistent organochlorine pollutants: organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs); major and trace elements; anthropogenic radionuclides (⁹⁰Sr, ¹³⁴Cs, and ¹³⁷Cs)] were determined in three aquatic compartments (water, sediment, fish). Mass fractions of inorganic constituents in different compartments reflected the geological background of the area, indicating their origin from predominantly natural sources. Levels of volatile and persistent organic compounds in water and fish, respectively, were very low, at levels typical for remote pristine areas. Analysis of anthropogenic radionuclides in water and sediment revealed elevated activity concentrations of ¹³⁷Cs in water, and measurable ¹³⁴Cs in the upper sediment layers from April 2011, possibly as a consequence of the Fukushima nuclear accident in March 2011. The potential genotoxicity of river and lake water and lake sediment was assessed under laboratory conditions using the alkaline comet assay on human peripheral blood lymphocytes, and measured levels of primary DNA damage were within acceptable boundaries. The results showed that despite the protected status of the park, anthropogenic impact exists in both its terrestrial and aquatic components. Although contaminant levels were low, further monitoring is recommended to make sure that they will not rise and cause potentially hazardous anthropogenic impacts.

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in Cyprinidae fish: Towards hints of their arrangements using advanced classification methods

To tackle the ever-present global concern regarding human exposure to persistent organic pollutants (POPs) via food products, this study strived to indicate associations between organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in lake-fish tissue depending on the species and sampling season. Apart from the monitoring initiatives recommended in the Global Monitoring Plan for POPs, the study discussed 7 OCPs and 18 PCB congeners determined in three Cyprinidae species (rudd, carp, and Prussian carp) from Vransko Lake (Croatia), which are widely domesticated and reared as food fish across Europe and Asia. We exploit advanced classification algorithms, the Kohonen self-organizing maps (SOM) and Decision Trees (DT), to search for POP patterns typical for the investigated species. As indicated by SOM, some of the dioxin-like and non-dioxin-like PCBs (PCB-28, PCB-74, PCB-52, PCB-101, PCB-105, PCB-114, PCB-118, PCB-156 and PCB-157), α-HCH and β-HCH caused dissimilarities among fish species, but regardless of their weight and length. To support these suggestions, DT analysis sequenced the fish species and seasons based on the concentration of heavier congeners. The presented assumptions indicated that the supplemental application of SOM and DT offers advantageous features over the usually rough interpretation of POPs pattern and over the single use of the methods.

Apex predatory mammals as bioindicator species in environmental monitoring of elements in Dinaric Alps (Croatia)

Tissue element investigations of apex terrestrial mammals are very scarce in Europe. We quantified 16 essential and nonessential elements in the kidney cortex, liver, and muscle tissue of 467 brown bears (Ursus arctos), 125 gray wolves (Canis lupus), one Eurasian lynx (Lynx lynx), and three golden jackals (Canis aureus) from Croatia by inductively coupled plasma mass spectrometry (ICP-MS). Renal cadmium (0.6% of animals) and lead (1%) and hepatic lead (5%) were found in toxicologically relevant levels for mammals only in bears, while the other elements were within normal range. The association of age, sex, season, and region with measured tissue elements in bear and wolf was estimated by multiple regression analyses. Age-related accumulation of cadmium was observed in bears and wolves. Lead tissue content increased with the age of bears but declined in wolves. Female bears and wolves had higher arsenic, iron, and thallium than males in some tissues. Also, cadmium, mercury, copper, zinc, selenium, molybdenum, and uranium were more abundant only in female bears. Male bears had higher potassium, zinc, and magnesium, while male wolves had higher calcium in some tissues compared to female wolves. Seasonal differences were mainly observed for bears' tissues and region-specific differences only in wolves. The bear kidneys had the highest levels of cobalt, copper, molybdenum, cadmium, and lead among the four studied species. The element levels reported for bears and wolves represent baseline values for the Dinaric population.

Bioaccumulation of PCBs in a Wild North American Felid

Organohalogenated compounds (OHCs) such as polychlorinated biphenyls (PCBs) are of global concern due to their environmental persistence, bioaccumulative potential, and adverse effects on humans and wildlife. We investigated the concentrations of PCBs in the liver tissues of bobcats (Lynx rufus) sampled in Illinois during 2013. Concentrations of ∑PCBs ranged from 76.4 to 3782 ng/g lw (median 562.97 ng/g lw). Male bobcats had significantly greater concentrations of PCBs than females (p = 0.04). Ours is one of the first studies to report PCBs in a wild North American felid. We suggest that bobcats can be used as a suitable bioindicator species to monitor organohalogen contamination in terrestrial ecosystems.

Organochlorine pesticides and PCBs (including dl-PCBs) in human milk samples collected from multiparae from Croatia and comparison with primiparae

This study investigated the levels of 20 congeners of polychlorinated biphenyls (PCBs), including toxic dioxin-like PCBs and 7 organochlorine pesticides (OCPs) in 33 human milk samples collected in 2011 from multiparae living in Zadar, Croatia. Concentrations of ∑PCBs, ∑DDTs, ∑HCHs and HCB in samples ranged from 11.7 to 146.3, 8.7 to 89.2, 0.9 to 28.4, and <LOD to 8.0ngg(-1) milk fat, respectively. PCB congeners -153, -138, -180 and -170 dominated in the PCB profiles, while p,ṕ-DDE was the most abundant OCP. PCB-126 was the most abundant non-ortho PCB, while among mono-ortho PCBs, the congeners -118, -105 and -156 equally contributed to the mono-ortho PCB fraction. TEQs for dl-PCBs ranged between 0 and 13.3pgg(-1) milk fat. The calculated estimated daily intakes for all compound groups were below the tolerable daily intake indicating no risk for breastfed infants. A comparison of our results with our previous study on primiparae revealed that the concentrations of the main contaminant groups are lower in the milk of multiparae, with the exception of toxic mono-ortho PCBs whose concentrations and TEQ remained similar among the groups, and HCB whose concentrations were found to be higher in multiparae. Concentrations of PCBs and OCPs found in the samples from this study did not exceed those from other parts of the world. This study revealed that there are differences in contaminant concentrations depending on the mothers' parity and that this fact should be taken into account when risk assessment studies are conducted.

Enantioselective Characteristics and Montmorillonite-Mediated Removal Effects of α-Hexachlorocyclohexane in Laying Hens

α-Hexachlorocyclohexane (α-HCH) is a chiral organochlorine pesticide that is often ubiquitously detected in various environmental matrices and may be absorbed by the human body via food consumption, with serious detriments to human health. In this study, enantioselective degradation kinetics and residues of α-HCH in laying hens were investigated after a single dose of exposure to the pesticide, whereas enantioselectivity and residues of α-HCH in eggs, droppings, and various tissues were investigated after long-term exposure. Meanwhile, montmorillonite (MMT), a feed additive with high capacity of adsorption, was investigated for its ability to remove α-HCH from laying hens. Most non-brain tissues enantioselectively accumulated (-)-α-HCH, while (+)-α-HCH was preferentially accumulated in the brain. The enantiomer fractions (EFs) in most tissues gradually decreased, implying continuous depletion of (+)-α-HCH in laying hens. After 30 days of exposure and 31 days of elimination, the concentration of α-HCH in eggs and tissues of laying hens with MMT-containing feed was lower than that with MMT-free feed, indicating the removal effects of MMT for α-HCH in laying hens. The findings presented herein suggest that modified MMT may potentially be useful in reducing the enrichment of α-HCH in laying hens and eggs, thus lowering the risk of human intake of α-HCH.