Multi-residue method for the determination of 57 persistent organic pollutants in human milk and colostrum using a QuEChERS-based extraction procedure

Comprehensive Characterization of Organic Light-Emitting Materials in Breast Milk by Target and Suspect Screening

Organic light-emitting materials (OLEMs) are emerging contaminants in the environment and have been detected in various environment samples. However, limited information is available regarding their contamination within the human body. Here, we developed a novel QuEChERS (quick, easy, cheap, effective, rugged, and safe) method coupled with triple quadrupole/high-resolution mass spectrometry to determine OLEMs in breast milk samples, employing both target and suspect screening strategies. Our analysis uncovered the presence of seven out of the 39 targeted OLEMs in breast milk samples, comprising five liquid crystal monomers and two OLEMs commonly used in organic light-emitting diode displays. The cumulative concentrations of the seven OLEMs in each breast milk sample ranged from ND to 1.67 × 103 ng/g lipid weight, with a mean and median concentration of 78.76 and 0.71 ng/g lipid weight, respectively, which were higher compared to that of typical organic pollutants such as polychlorinated biphenyls and polybrominated diphenyl ethers. We calculated the estimated daily intake (EDI) rates of OLEMs for infants aged 0-12 months, and the mean EDI rates during lactation were estimated to range from 30.37 to 54.89 ng/kg bw/day. Employing a suspect screening approach, we additionally identified 66 potential OLEMs, and two of them, cholesteryl hydrogen phthalate and cholesteryl benzoate, were further confirmed using pure reference standards. These two substances belong to cholesteric liquid crystal materials and raise concerns about potential endocrine-disrupting effects, as indicated by in silico predictive models. Overall, our present study established a robust method for the identification of OLEMs in breast milk samples, shedding light on their presence in the human body. These findings indicate human exposure to OLEMs that should be further investigated, including their health risks.

Analysis of polyhalogenated carbazoles and two related compounds in earthworms using a modified QuEChERS method with GC/MS and GC/MS/MS

A precise analytical method based on QuEChERS has been proposed for the concurrent determination of 11 polyhalogenated carbazoles (PHCZs), benzocarbazole (BZCZ), and 9H-carbazoles (CZ). The quantification was confirmed by gas chromatography using triple quadrupole tandem mass spectrometry (Shimadzu GC-MS/MS-TQ8040) and gas chromatography coupled mass spectrometry (Agilent 7890A-5973 GC-MS). The developed method was validated by testing the following parameters: linearity, instrument limit of detection (LOD), instrument limit of quantification (LOQ), method limit of detection (MLD), method limit of quantification (MLQ), matrix effect (ME), accuracy, and precision. All compounds showed good linearity in the range of 0.005-0.2 μg/mL with correlation coefficients higher than 0.992. The method demonstrated satisfactory recoveries (ranging from 71.21 to 105.04%) for most of the compounds with relative standard deviation precision (RSD) < 10.46%, except 3-BCZ (Recovery = 67.53%, RSD = 2.83%). The values of LOD and LOQ varied from 0.05 to 0.24 ng and 0.14 to 0.92 ng, respectively, while those of MLD and MLQ ranged from 0.02 to 0.12 ng/g wet weight (ww) and 0.07 to 0.45 ng/g ww, respectively. The developed method represents a reliable tool for the routine analysis of PHCZ congeners in invertebrate animals.

Development of QuEChERS coupled with UHPLC-MS/MS for simultaneous determination of eight neonicotinoid pesticides in breast milk

A speedy and hypersensitive method was built to detect eight neonicotinoid insecticides (neonics) in breast milk by ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The breast milk was extracted with a mixture of acetonitrile and water and purified with primary secondary amine (PSA) and C18. The recovery of the method ranged from 74.3 to 105.9% with relative standard deviations (RSDs) of less than 10%, and the limit of detection ranged from 0.05 to 0.18 ng/mL. Among 32 samples obtained from women 1 month postpartum, thiamethoxam and imidacloprid were the most frequently detected neonics. Moreover, thiacloprid and imidaclothiz were not detected in any samples. The concentrations of neonics in breast milk ranged from 1.90 to 149.95 ng/mL. Considering the toxic effects on mammals and even humans, infants who are exposed to neonics through ingestion of breast milk should receive extensive attention in future studies.

Postnatal exposure to organic pollutants in maternal milk in north-western Spain

Evaluation of postnatal exposure to organic pollutants is especially important for suckling infants during breastfeeding, a crucial perinatal growth period when organs and hormonal systems develop. We determined levels of 60 pollutants, including organochlorine pesticides (OCPs), organophosphorus pesticides (OPPs), pyrethroids (PYRs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and polybrominated diphenyl ethers (PBDEs), in 81 breast milk samples from breastfeeding mothers from Santiago de Compostela (north-western Spain). For most detected organic pollutants, levels were correlated with the season of milk sampling, maternal age at delivery, and place of residence. Dietary consumption habits (eggs, molluscs, and vegetable oils) were also correlated with OCP, OPP, PCB, PBDE and PYR levels. We also assessed the risk to infant health of exposure to organic pollutants in breast milk. PAHs, OCPs, OPPs, and PYRs accounted for almost 95% of the targeted organic pollutants in the samples analysed.

Urinary metabolites of diazinon and chlorpyrifos in sprayer operators and farm workers of a potato farm

In order to investigate the effect of diazinon and chlorpyrifos on agricultural workers exposed to pesticides, urinary metabolites 2-Isopropyl-6-methyl-4-pyrimidinol (IMPy) and 3,5,6-Trichloro-2-pyridinol (TPCy) in farm workers, sprayer operators, and non-exposed people as a control group were measured. The modified QuEChERS method was applied to extract samples and was measured using a gas chromatograph/nitrogen-phosphorus detector. The obtained results showed that the median concentrations of TCPy were 36.92-547.7 and 7.7-49.58 ng/mL for sprayer operators and farm workers, respectively. Moreover, the median concentrations of IMPy were 81.66-593.1 ng/mL for sprayer operators and 40.6-66.1 ng/mL for farm workers. The control group had no measurable metabolites. The IMPy level of 60% of sprayer operators was significantly higher (P ˂ 0.05) than the TCPy level. The analysis of variance highlighted the significant relationship (P ˂ 0.05) between the levels of each metabolite and the use of safety gloves, respiratory masks, safety goggles, working time per week, and type of insecticide exposure. Our findings revealed the need to measure the urinary metabolites of these insecticides in other exposed workers. Also, workers should be taught the impact of using personal protective equipment.

Determination of multi-class pesticides residues of cow and human milk samples from Iran using UHPLC-MS/MS and GC-ECD: A probabilistic health risk assessment

Raw, pasteurized, powdered cow milk and human milk samples from Tehran, Iran were investigated for the residual of fifty pesticides with the aid of gas chromatography coupled with electron capture detector (GC-ECD) and mass detector for confirmation; and ultra-high performance liquid chromatography-tandem mass spectroscopy (UHPLC-MS/MS). No pesticide residue was determined in more than 91% of examined samples. However, the dimethoate residue was detected in 3 raw milk samples in levels higher than EU recommended MRL. While in 3 human milk samples, organochlorine pesticides residue, p,p'-DDT, and p,p'-DDD was recognized below MRLs, only in 1 human sample residue of p,p'-DDE was more than CODEX recommended MRL. HI in adults and children were 0.72 and 3.55, respectively. However, the health risk assessment based on HI demonstrated that adult consumers are not at considerable risk. The HI, higher than 1 in children, confirms the risks raised due to ingestion of organochlorine (OCP) and organophosphorus (OPP) pesticides via milk consumption. In addition, no carcinogenic risk to milk consumers was calculated. Therefore, implementation of good farming practices on farms, improving the knowledge and consciousness of pesticide users, use other safe methods for pest control such as biotechnology-based, and use a rational program for application of pesticides, continuous monitoring of pesticides in crops, and strict government regulations on pesticide residues in food are recommended.

Sample preparation techniques for suspect and non-target screening of emerging contaminants

The progress in sensitivity and resolution in mass spectrometers in recent years provides the possibility to detect a broad range of organic compounds in a single procedure. For this reason, suspect and non-target screening techniques are gaining attention since they enable the detection of hundreds of known and unknown emerging contaminants in various matrices of environmental, food and human sources. Sample preparation is a critical step before analysis as it can significantly affect selectivity, sensitivity and reproducibility. The lack of generic sample preparation protocols is obvious in this fast-growing analytical field, and most studies use those of traditional targeted analysis methods. Among them, solvent extraction and solid phase extraction (SPE) are widely used to extract emerging contaminants from solid and liquid sample types, respectively. Sequential solvent extraction and a combination of different SPE sorbents can cover a broad range of chemicals in the samples. Gel permeation chromatography (GPC) and adsorption chromatography, including acidification, are typically used to remove matrix components such as lipids from complex matrices, but usually at the expense of compound losses. Ideally, the purification of samples intended for non-target analysis should be selective of matrix interferences. Recent studies have suggested quality assurance/quality control measures for suspect and non-target screening, based on expansion and extrapolation of target compound lists, but method validations remain challenging in the absence of analytical standards and harmonized sample preparation approaches.

Pesticides in human milk collected from Jinhua, China: Levels, influencing factors and health risk assessment

In China, many studies have been carried out on pesticide residues in human milk, yet all of them are on organochlorine pesticides (OCPs) and mostly focused on large, economically developed cities. In this study, 27 pesticides including OCPs, pyrethroid pesticides (PYRs) and organophosphate pesticides (OPPs) in human milk were investigated in Jinhua, an inland and medium sized city in China. Method based on QuEChERS extraction and gas chromatography-mass spectrometer (GC-MS) determination was adopted to analyze the above pesticide residues. The influencing factors as well as the health risks were also evaluated. Results show that PYRs and OPPs in human milk samples were both undetectable. Regarding OCPs, the detection rate of hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH) and p,p'-dichlorodiphenyl-dichloroethylene (p,p'-DDE) were 83.6%, 36.4% and 58.2%, respectively, and their mean value were 29.4, 32.0 and 85.2 ng/g lipid, respectively. p,p'-DDE levels in human milk was significantly (p < 0.05) related to maternal age, but no association was detected between OCPs residues and other factors (living environment, dietary habit, living style, etc.), suggesting that OCPs in human milk in Jinhua were originated from nonspecific source. All estimated daily intake of pesticides (EDI_pesticides) by infants were under the guideline suggested by Food and Agriculture Organization (FAO) and China Ministry of Health (CMH). Yet 9% of EDIs_HCB and 16% of EDIs_HCHs exceeded the guideline recommended by Health Canada. The associations between DDE residues and the delivery way as well as HCBs residues and the birth weight were seemly significant, yet the significance disappeared when consider age or gestational age as a cofounder, indicating that OCPs residue in mother's body in Jinhua has no obvious influence on fetus development and the delivery way.

Development of Artificial Urine Certified Reference Material for Quantification of Neonicotinoid Insecticides

BACKGROUND

Neonicotinoid insecticides (neonicotinoids) are widely used, however, they can negatively affect human health. Thus, neonicotinoids and their metabolites in human urine are analyzed globally to assess exposure levels and health risks. To properly assess the exposure levels and health risks, accurate analytical results are a necessity.

OBJECTIVE

This study aims to develop urine certified reference material (CRM), NMIJ CRM 7408-a, for the quantification of neonicotinoids.

METHOD

To develop NMIJ CRM 7408-a, commercially available artificial urine was used as the raw material to which the target neonicotinoids were added. Analyses of neonicotinoids in NMIJ CRM 7408-a were carried out by isotope dilution mass spectrometry (IDMS).

RESULTS

Sample homogeneity was assessed, with the results showing that acetamiprid, clothianidin, thiacloprid, and thiamethoxam exhibited sufficiently homogeneous distributions in the material. The relative uncertainties due to inhomogeneity were 1.2-7.0%. The results obtained from long-term stability assessment indicated that the target neonicotinoids were stable. The relative uncertainties due to instability were 9.4-17.2% (for an expiry date of 21 months). The characterization for providing concentration values was carried out using one (clothianidin and thiacloprid) or two (acetamiprid and thiamethoxam) analytical methods. The certified values of the target neonicotinoids (acetamiprid, clothianidin, thiacloprid, and thiamethoxam) were 0.19-1.38 µg/kg.

CONCLUSIONS

This is the first frozen artificial urine CRM in which neonicotinoids were quantified by IDMS and will be useful for evaluating the accuracy of analysis and validation of analytical methods for the determination of neonicotinoids in urine.

HIGHLIGHTS

NMIJ CRM 7408-a, which has been certified for four neonicotinoids, was developed by NMIJ.

Exposure of nursing mothers to polycyclic aromatic hydrocarbons: Levels of un-metabolized and metabolized compounds in breast milk, major sources of exposure and infants' health risks

In this study, biomonitoring of nursing Portuguese mothers to polycyclic aromatic hydrocarbons (PAHs) exposure and assessment of potential health risks of their infants were performed through determination of 18 PAHs and 6 major metabolites (OH-PAHs) in breast milk. Concentrations of total PAHs ranged between 55.2 and 1119 ng/g fat, being naphthalene, dibenz(a,h)anthracene, benzo(g,h,i)perylene, and phenanthrene the most abundant compounds (68.4% of ∑PAHs). Benzo(a)pyrene, known carcinogenic, was not detected. Total levels of OH-PAHs ranged from 6.66 to 455 ng/g fat with 1-hydroxyphenanthrene, 1-hydroxynaphthalene and 1-hydroxyacenaphthene as major compounds (96% of ∑OH-PAHs). Concentrations of ∑PAHs and ∑OH-PAHs were strongly correlated between each other (r = 0.692; p ≤ 0.001) and moderately-to-strongly associated with individual compounds (0.203 < r < 0.841; p ≤ 0.001). The attained data suggest increased levels of PAHs in older nursing mothers (>30 years) and in those whose child had lower weight (up to 3.0 kg). Breast-fed infant presented a median PAHs daily intake of 1.41 μg/kg body weight (total benzo(a)pyrene equivalents of 0.0679 μg/kg) and were exposed to 0.024 μg/kg body weight of ∑PAH4 [benz(a)anthracene, benzo(b)fluoranthene, benzo(j)fluoranthene, and chrysene]. Although breast milk is a secure food for newborns, un-metabolized and metabolized PAHs should be included in biomonitoring surveillance studies during breastfeeding to prevent potential health risks for infants.

Micro QuEChERS-based method for the simultaneous biomonitoring in whole blood of 360 toxicologically relevant pollutants for wildlife

This work presents the optimization, validation, and verification of a miniaturized method for the determination of 360 environmental pollutants that are of toxicological concern for wildlife. The method implies a one-step QuEChERS-based extraction of 250 μl whole blood using acidified acetonitrile, followed by two complementary analyses by LC-MS/MS and GC-MS/MS. The optimized conditions allow the simultaneous determination of the major persistent organic pollutants, a wide range of plant protection products, rodenticides, pharmaceuticals, and a suite of metabolites that can be used as biomarkers of exposure. The method is very sensitive, and 95% of the pollutants can be detected at concentrations below 1.5 ng/ml. The method was applied to a series of 148 samples of nocturnal and diurnal wild raptors collected during field ecological studies in 2018 and 2019. Fifty-one different contaminants were found in these samples, with a median value of 7 contaminants per sample. As expected, five of the six contaminants that were detected in >50% of the samples were persistent or semi-persistent organic pollutants. However, it is striking the high frequency of detection of some non-persistent pollutants, such as 2-phenylphenol, benalaxyl, metaflumizone, diphenylamine, brodifacoum or levamisole, indicating the penetration of these chemicals into the food chains. The toxicological significance of all these findings should be studied in depth in future research. However, the results clearly demonstrated that the approach developed provides reliable, simple, and rapid determination of a wide range of pollutants in wildlife and makes it very useful to obtain valuable data in biomonitoring studies with only small amounts of sample.

Multiresidue analysis of 85 persistent organic pollutants in small human serum samples by modified QuEChERS preparation with different ionization sources in mass spectrometry

In this study, a multiresidue analytical method was developed, validated, and applied for quantifying 85 persistent organic pollutants (POPs), including 38 polychlorinated biphenyls (PCBs), 23 polybrominated diphenyl ethers (PBDEs), and 24 organochlorine pesticides (OCPs) from 200 μL of human serum. A modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method was applied to minimize the required sample amount and optimize various conditions including the extraction solvent and the number of extractions. The extraction efficiency was optimized using double extraction with an ethyl acetate/hexane/acetone mixture. Gas chromatography coupled with triple-quadrupole mass spectrometry was used for analysis, and two different ionization sources, electron impact ionization (EI) and atmospheric pressure chemical ionization (APCI), were used to compare their sensitivity. The APCI source employed soft ionization at atmospheric pressure, producing abundant molecular ion formation with minimal fragmentation, in contrast to extensive fragmentation caused by EI. Of the 85 POPs analyzed, 59 target compounds (69.4%) showed lower limits of detection that were two- to fifty-fold lower in APCI than those determined using EI. The developed method was validated for its detection limit (0.5-10 pg/mL for PCBs, 2-20 pg/mL for PBDEs, and 2-40 pg/mL for OCPs), precision (0.8%-34.3% of coefficient of variation), recovery (49.6%-77.1%), matrix effect (46.7%-156.9%), and accuracy (81.2%-113.1% for PCBs, 85.8%-112.2% for PBDEs, and 55.2%-113.9% for OCPs). Its linearity was R² > 0.99 for 84 compounds, and 96% average accuracy (for APCI) was obtained using the National Institute of Standards and Technology (NIST) standard reference materials (NIST 1957 and 1958). These ionization methods were compared by analyzing 25 real human serum samples. The observed species were 1.1-24.6 pg/mL of 28 PCBs, 2.5 pg/mL of BDE-47, and 6.5-195.1 pg/mL of 6 organochlorine pesticides (median concentration for each species), and only 11 compounds were detected with APCI owing to its enhanced sensitivity.

Supporting dataset on the validation and verification of the analytical method for the biomonitoring of 360 toxicologically relevant pollutants in whole blood

The dataset presented in this article supports "Micro QuEChERS-based method for the simultaneous biomonitoring in whole blood of 360 toxicologically relevant pollutants for wildlife" (Rial-Berriel et al., 2020). The supplementary data are: (1) Detailed validation data of the LC-MS/MS and GC-MS/MS methods for the quantification of 360 chemicals covering bias and precision (intra- and inter-day variability) for retention times, linearity, and limits of quantification. (2) Graphical data of the matrix effects on the quantification of all of the analytes. (3) Individual data of the 51 chemicals detected in real whole blood samples from two raptor species: 36 barn owls (Tyto alba) and 112 common kestrels (Falco tinnunculus).

Determination of polychlorinated biphenyls and organochlorine pesticides in Chinese mitten crabs (Eriocheir sinensis) using modified QuEChERS followed by GC-MS

Chinese mitten crabs (Eriocheir sinensis) are one of the most popular food items with a high nutritional value. The use of pesticides and environmental pollutants directly influenced improvements in productivity of mitten crabs. However, there is an increasing number of food safety issues raising consumer concerns. It is necessary to determine whether the pollutants that crabs contain are below the maximum residue limits to guarantee food safety. Moreover, there has been very little research on detecting pesticide residues and other pollutants in Chinese mitten crabs due to their complicated matrix effects. In the current study, a Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method has been modified and validated for the simultaneous analysis of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in mitten crabs. By using acetonitrile extraction, low temperature (freezing) precipitation and clean-up by mixed sorbents of C18, PSA and Florisil (magnesium silicate), the method was proved to be valid with linearity, precision, recovery, limit of quantification (LOQ), and limit of detection (LOD) with recoveries ranging from 85.9-119.8% and LOQ within 0.1-3.6 μg kg-1. The method was also applied to detect PCBs and OCPs in 48 crab samples from Jiangxi Province, China. The results showed that most of the crab samples contained PCB 118, beta-HCH and p,p'-DDT, and the content of p,p'-DDD in mitten crabs of Jiangxi Province showed sex-specific differences, which might be connected with sex-differential regulation.

QuEChERS extraction coupled to GC-MS for a fast determination of polychlorinated biphenyls in breast milk from Polish women

Polychlorinated biphenyls (PCBs) in breast milk has been determined. Therefore, it was necessary to develop and adapt an analytical method to analyze PCB compounds. The whole procedure was applied to 31 breast milk samples, which were collected from Polish mothers. The QuEChERS method was optimized as a fast and cheap sample preparation method. The procedure allowed us to obtain recovery values between 96.46% and 119.98% with acceptable relative standard deviations (3.36-12.71%). Gas chromatography with mass spectrometry (GC-MS) was used for final determination. The method was validated using parameters such as linearity, limit of detection and quantification, intra-day precision, and reproducibility. The mean concentration of ∑iPCBs in this study was 30.94 ng/g of lipid. Assigned daily intake of PCBs was lower than the tolerable daily intake, which shows that the analyzed milk is safe to the infants. However, the monitoring of PCBs in milk is still important, and the QuEChERS method with GC-MS can be an effective tool for tracking organic impurities in breast milk.

Polycyclic aromatic hydrocarbons in breast milk of obese vs normal women: Infant exposure and risk assessment

Biomonitoring of human breast milk is one of the best ways to identify body burdens of contaminants and associated risk estimation. The objectives of the current study were to evaluate milk concentrations of persistent organic pollutants (POPs), mainly polycyclic aromatic hydrocarbons (PAHs), associated exposure estimation, and the role of body mass index (BMI) in their bioaccumulation. A total of 45 breast milk samples were collected from 24 women with BMI > 30 (obese) and 21 women with BMI < 25 (18.5-24.9, normal) from 14 different counties surrounding Lubbock in west Texas/New Mexico (age range: 18-34 years). Samples were analyzed using high resolution gas chromatography coupled with mass spectrometry. A total of 31/45 (69%) of samples tested positive for PAHs. Phenanthrene was the most frequently detected PAH followed by pyrene and fluoranthene. The mean of individual PAH concentration for all samples ranged from 0 to 25.1 ng/g milk fat; the sum of all means of individual PAHs was 146.9 ng/g milk fat. The mean concentration of total PAHs in the BMI > 30 group was 224.8 ng/g milk fat, which was approximately 4 times the mean concentration of total PAHs in the BMI 18.5-24.9 group (57.9 ng/g milk fat). None of the samples from the BMI 18.5-24.9 group contained higher molecular weight (5-6 rings) PAHs, while in the BMI >30 group, a total of 11 PAHs including listed EPA priority pollutants were observed. In this study, benzo(b)fluoranthene was found to contribute the highest percentage of carcinogenic PAHs (32.08%), yet it was not detected in any samples from the BMI 18.5-24.9 group. The estimated total PAHs intakes by infants via obese and normal mothers' milk were 1.26 and 0.32 (μg/kg/day), which are 0.049 and 0.003 (μg/kg/day) B[a]P equivalent, respectively. These findings suggest that breastfed babies from obese mothers are potentially at higher risk of exposure to carcinogenic PAHs.

PAHs contamination levels in the breast milk of Ghanaian women from an e-waste recycling site and a residential area

Breast milk samples from 128 primipararae and multiparae Ghanaian women were screened for Polycyclic Aromatic Hydrocarbons (PAHs) from 2014 and 2016. These were breast milk from women residing or working around an electronic waste recycling site and a reference area (a residential area). This research is aimed at assessing PAHs levels in human milk samples from some Ghanaian mothers, prediction of the sources of these PAHs and the probable carcinogenic and mutagenic risks to infants. PAHs in the breast milk were analyzed using a gas chromatography coupled with a mass spectrometer (GC-MS/MS). A total of 18 PAH congeners were identified in the human milk samples with a total range between <LOD and 15,936.57 ng/g lipid wt and an overall mean of 1105.63 ng/g lipid wt. In general, the mean concentrations of low molecular weight PAHs were appreciably greater than the high molecular weight PAHs in the breast milk samples. Naphthalene recorded the highest mean concentrations of 1026.52 ng/g lipid wt and 78.73 ng/g lipid wt for both e-waste and residential areas, respectively. Naphthalene contributed 77.4% of the total PAHs in the milk samples. Most of the high molecular weight PAHs were below the limit of detection in milk samples from Kwabenya (a residential area) but were detected in the milk samples from Agbogbloshie (e-waste recycling site). The diagnostic ratio tests in this study suggest that most of the PAHs in the milk samples are originating from pyrogenic sources. Risk assessment for carcinogenicity and mutagenicity on infants based on this study were 1.1 × 10^-5 and 1.9 × 10^-5, respectively.

The impact of environmental pollution on the quality of mother's milk

Breastfeeding is a gold standard of neonate nutrition because human milk contains a lot of essential compounds crucial for proper development of a child. However, milk is also a biofluid which can contain environmental pollution, which can have effects on immune system and consequently on the various body organs. Polychlorinated biphenyls are organic pollutants which have been detected in human milk. They have lipophilic properties, so they can penetrate to fatty milk and ultimately to neonate digestive track. Another problem of interest is the presence in milk of heavy metals-arsenic, lead, cadmium, and mercury-as these compounds can lead to disorders in production of cytokines, which are important immunomodulators. The toxicants cause stimulation or suppression of this compounds. This can lead to health problems in children as allergy, disorders in the endocrine system, end even neurodevelopment delay and disorder. Consequently, correlations between pollutants and bioactive components in milk should be investigated. This article provides an overview of environmental pollutants found in human milk as well as of the consequences of cytokine disorder correlated with presence of heavy metals. Graphical abstract.

Persistent Organic Pollutants Residues in Human Breast Milk from Bathinda and Ludhiana Districts of Punjab, India

In the present study, persistent organic pollutants (POPs), including six congeners of polychlorinated biphenyls (PCBs) and organochlorine pesticides, were estimated in human breast milk samples collected from two districts of Punjab (India). The mean concentrations of POP residues were recorded higher in Bathinda district (PCBs: 33.7; DDTs: 519.2; HCHs: 46.6 ng g^-1 lipid wt.) than Ludhiana (PCBs: 24.2; DDTs; 415.3; HCHs; 35.5 ng g^-1 lipid wt.). Levels of PCBs and DDTs were observed higher in primiparas, whereas HCHs residues were seen more in multiparas. Risk analysis to POPs exposure through breast milk reflected that the daily intake for some infants was close to or above the tolerable daily intake limit for detrimental effects, which may raise a health concern. Comparative evaluation of present data indicated that DDT and HCHs residue levels in human breast milk from Punjab, India were among the lowest values reported for developing countries. The first-order kinetic reaction at a steady-state condition used to estimate the half-life of DDT and HCH suggested that DDT levels have declined from 18,211 to 490 ng g^-1 lipid wt. with a half-life (Tdec_1/2) of 3.25 years over a span of 15 years. Similarly, HCH levels have decreased from 8609 to 46.6 ng g^-1 in this duration with Tdec_1/2 of 2.25 years. Because some infants are still at risk, continuous monitoring of POPs in human milk is needed for surveillance and interpretation of time trends and for linkage to strict enforcement of agricultural regulations.

Pattern of blood concentrations of 47 elements in two populations from the same geographical area but with different geological origin and lifestyles: Canary Islands (Spain) vs. Morocco

The Canary Islands are one of the outermost regions of the European Union (EU), which are located barely 100 km from the coasts of Morocco. Although these islands are located in Africa, the degree of socioeconomic development and lifestyle in this archipelago is comparable to that of any other region of Europe. It is well established that the main determinants of human exposure to elements have to do both, with their place of residence and with habits related to their lifestyle. For this reason, we wanted to study the pattern of contamination by elements of these two populations so geographically close, but so different both in their lifestyle, and the geological origin of the territory where they live. Thus, we have determined the blood concentrations of 47 elements (including 25 rare earth elements (REE) and other minority elements (ME) widely employed in the hi-tech industry) in a paired sample of Moroccans (n = 124) and Canary Islands inhabitants (n = 120). We found that the levels of iron, selenium, zinc, arsenic, cadmium, strontium, and specially lead, were significantly higher in Moroccans than in Canarians, probably due to the intensive mining activity in this country. We also found significantly higher levels of the sum of REE and ME in Moroccans than in Canarians, possibly related to the inappropriate management of e-waste in this country. On the other hand, in the inhabitants of the Canary Islands we found higher levels of manganese, probably related to a higher degree of exposure to heavy traffic and exposure to Saharan dust of the people living in this region, and niobium and bismuth, probably related to the higher economic development in these islands. Our results indicate that the vicinity of both territories is not a major determinant of each other's contamination.

Distribution and Health Hazards of Polycyclic Aromatic Hydrocarbons in Egyptian Milk and Dairy-Based Products

In a market-basket study conducted in Cairo, Egypt, the most commonly consumed milk products were sampled and the contents of 13 polycyclic aromatic hydrocarbons were analyzed using gas chromatography with a mass spectrometer detector. The obtained data showed that the total amount of 13 PAHs was within the range of 1.3–8.2 µg/g. The results proved that the, highest mean levels of polycyclic aromatic hydrocarbons were detected in powdered milk (8.2 μg/g) followed by ultra-heat treatment milk and milk beverages (6.07 μg/g). The lowest level was detected in unsmoked cheese and yogurt (1.3 μg/g). Estimated daily intake (EDI) was used to estimate the carcinogenic risk. The total mean estimated daily intake for children in different age categories (1–10 years) was calculated with respect to benzo[a]pyrene, which ranged from 0.058 to 0.31 mg/day. The total mean value of EDI for the sum of seven carcinogenic PAHs in terms of benzo[a]pyrene ranged from 0.61 to 1.22 mg/day in all age categories. These results were higher than the critical limit set by the European Food Safety Authority. Therefore, there should be concerns regarding the effects of the consumption of different milk products on the local population.

Multi-residue pesticides analysis in water samples using reverse phase high performance liquid chromatography (RP-HPLC)

India is one of the leading suppliers of agrochemicals and has the largest pesticide industry in Asia. Among various Indian states, Punjab is the primary user of pesticides. Presence of pesticide residue in water and food products of Punjab is well documented. The present study was designed to envisage the level of pesticide contamination in pond water of eleven villages of Amritsar district of Punjab, India. A rapid and concurrent method for the identification and quantification of pesticides in water samples was developed and validated. The method validation parameters exhibited high sensitivity of the developed method and the proficiency for the identification and quantification of pesticide residues in water samples. The RP-HPLC method described here

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is a novel method which is applicable for simple, rapid and precise detection of pesticides.

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40.02% of water samples were found contaminated with multi-residue pesticides.

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carbofuran was the most abundant pesticide which was present in 18.18% samples.

Non-persistent pesticides in breast milk in an agricultural area in Turkey

BACKGROUND

Organophosphates, pythyreoids, carbamate pesticides and fungicides are heavily used in agriculture. They may have dangerous effects on newborn health especially on immune system and growth via prenatal transmission by placenta or postnatal transmission by breastfeeding.

METHODS

In 2015, 144 non-persistent pesticides in 64 milk samples of 32 mothers were studied by OuEChERS method in liquid chromatography/tandem mass spectrometer in neonatal Intensive Care Unit in Adana, a city in Cukurova region which is an important agricultural area in Turkey.

RESULTS

Pesticides were detected in milk samples of 11 mothers (34.3%) and 21 (32.8%) of milk samples. In five mothers, fungicides (in 5/10 samples propicanozole-PP, in 4/10 samples bromucanozole-BM), in five mothers, organophosphates (in 10/10 samples primyphosphomethyl-PPM), in one mother, both organophosphates and fungicide (in 1/2 samples PPM and in 1/2 samples buprimate) were detected. However, the estimated daily intakes (EDI) were less than acceptable daily intakes (ADI) for PPM, PP and BM, respectively.

CONCLUSIONS

Although pesticides levels in human milk did not exceed the ADIs, we suggest monitoring pesticides in human breast milk especially for newborn health.

Assessment of PCBs and exposure risk to infants in breast milk of primiparae and multiparae mothers in an electronic waste hot spot and non-hot spot areas in Ghana

The aim of the study was to assess the levels of PCBs in the breast milk of some Ghanaian women at suspected hotspot and relatively non-hotspot areas and to find out if the levels of these PCBs pose any risk to the breastfed infants. A total of 128 individual human breast milk were sampled from both primiparae and multiparae mothers. The levels of PCBs in the milk samples were compared. Some of these mothers (105 individuals) work or reside in and around Agbogbloshie (hot-spot), the largest electric and electronic waste dump and recycling site in Accra, Ghana. Others (23 donor mothers) also reside in and around Kwabenya (non-hotspot) which is a mainly residential area without any industrial activities. Samples were analyzed using GC-MS/MS. The total mean levels and range of Σ₇PCBs were 3.64ng/glipidwt and ˂LOD-29.20ng/glipidwt, respectively. Mean concentrations from Agbogbloshie (hot-spot area) and Kwabenya (non-hotspot areas) were 4.43ng/glipidwt and 0.03ng/glipidwt, respectively. PCB-28 contributed the highest of 29.5% of the total PCBs in the milk samples, and PCB-101 contributed the lowest of 1.74%. The estimated daily intake of PCBs and total PCBs concentrations in this work were found to be lower as compared to similar studies across the world. The estimated hazard quotient using Health Canada's guidelines threshold limit of 1μg/kgbw/day showed no potential health risk to babies. However, considering minimum tolerable value of 0.03μg/kgbw/day defined by the Agency for Toxic Substances and Disease Registry (ATSDR), the values of some mothers were found to be at the threshold limit. This may indicate a potential health risk to their babies. Mothers with values at the threshold levels of the minimum tolerable limits are those who work or reside in and around the Agbogbloshie e-waste site.

Comparative study on the occurrence of polycyclic aromatic hydrocarbons in breast milk and infant formula and risk assessment

The study compared the polycyclic aromatic hydrocarbons (PAH) profile of human milk collected from Italian mothers and different brands of infant formula available on Italian market. Levels of 14 PAHs most frequently occurred in food, PAH markers listed by Commission Regulation (EC) No. 1881/2006, and carcinogenic PAHs classified by the International Agency for Research on Cancer, were determined by high-pressure liquid chromatography with fluorescence detector. The average concentrations of total PAHs were 114.93 in breast milk and 53.68 μg kg^-1 in infant formula. Furthermore, Benzo(a)pyrene (BaP) and the sum of ∑PAH4 markers (BaP, Chrysene, Benzo(a,h)anthracene and Benzo(b)fluoranthene) were higher than the permissible limit of 1 μg kg^-1 in 43% and 86% for breast milk and in 10% and 76% for infant formula samples, respectively. Breast milk showed higher levels (P < 0.05) of carcinogenic, and possible carcinogenic hydrocarbons than infant formula samples. Both in human and commercial milk, data showed the occurrence of low and high molecular weight PAHs, respectively from petrogenic and pyrolytic environmental sources, characterizing the infant and mother exposure. Particularly, waste incineration could have represented an important exposure source for infants during breastfeeding, through exposition of mothers resident in some areas of Southern Italy. High PAH levels detected in infant formula enriched with LC-PUFA might be related to the contamination of the vegetable oils added as ingredients. Results showed a high percentage of samples of both breast milk and infant formulas with margin of exposure (MOE) value indicating a potential concern for consumer health.

Perspective on pre- and post-natal agro-food exposure to persistent organic pollutants and their effects on quality of life

BACKGROUND

Adipose tissue constitutes a continual source of internal exposure to organic pollutants (OPs). When fats mobilize during pregnancy and breastfeeding, OPs could affect foetal and neonatal development, respectively.

SCOPE AND APPROACH

The main aim of this review is to deal with pre- and post-natal external exposure to organic pollutants and their effects on health, proposing prevention measures to reduce their risk. The goal is the development of a biomonitoring framework program to estimate their impact on human health, and prevent exposure by recommending some changes in personal lifestyle habits.

KEY FINDINGS AND CONCLUSIONS

It has been shown that new studies should be developed taking into account their cumulative effect and the factors affecting their body burden. In conclusion, several programs should continuously be developed by different health agencies to have a better understanding of the effect of these substances and to develop a unified public policy.

Consumption of organic meat does not diminish the carcinogenic potential associated with the intake of persistent organic pollutants (POPs)

Numerous studies have shown an epidemiological link between meat consumption and the incidence of cancer, and it has been suggested that this relationship may be motivated by the presence of carcinogenic contaminants on it. Among the most frequently detected contaminants in meat are several types of persistent organic pollutants (POPs), and it is well known that many of them are carcinogenic. On the other hand, an increasing number of consumers choose to feed on what are perceived as healthier foods. Thus, the number of consumers of organic food is growing. However, environmental contamination by POPs is ubiquitous, and it is therefore unlikely that the practices of organic food production are able to prevent this contamination. To test this hypothesis, we acquired 76 samples of meat (beef, chicken, and lamb) of two modes of production (organic and conventional) and quantified their levels of 33 carcinogenic POPs. On this basis, we determined the human meat-related daily dietary exposure to these carcinogens using as a model a population with a high consumption of meat, such as the Spanish population. The maximum allowable meat consumption for this population and the carcinogenic risk quotients associated with the current pattern of consumption were calculated. As expected, no sample was completely free of carcinogenic contaminants, and the differences between organically and conventionally produced meats were minimal. According to these results, the current pattern of meat consumption exceeded the maximum limits, which are set according to the levels of contaminations, and this is associated with a relevant carcinogenic risk. Strikingly, the consumption of organically produced meat does not diminish this carcinogenic risk, but on the contrary, it seems to be even higher, especially that associated with lamb consumption.

Relationship of polychlorinated biphenyls (PCBs) with parasitism, iron homeostasis, and other health outcomes: Results from a cross-sectional study on recently arrived African immigrants

Polychlorinated biphenyls (PCBs) are toxic and persistent chemicals produced between 1930s and 1980s, which accumulate in humans and wildlife. Although a decreasing trend of PCB levels in humans has been described in developed countries, mainly as a consequence of strict regulations and remediation plans, an inverse trend has been recently reported in people from developing countries. We had the opportunity of sampling a series of African immigrants recently arrived to the Spanish archipelago of the Canary Islands, in which high levels of PCBs have been described, and we studied the relationships between their level of contamination and health status. A total of 570 subjects who underwent a complete medical examination and a face-to-face interview were recruited for this study. Hematological and biochemical parameters (blood and urine) were determined in all participants. Serology for the diagnostic of infectious diseases was also performed, and direct identification of parasites was performed in feces, urine or blood samples when appropriate. It is remarkable that up to 26.0% of the population had intestinal parasites, and we found an inverse relationship between PCB levels and parasitism and parasitic diseases: median values of PCBs were lower in parasitized subjects than in subjects without parasites in stool (237.6ng/g fat vs. 154.4ng/g fat for marker PCBs, p=0.015) and median values of dioxin-like PCBs were lower in subjects carrying pathogen parasites than among subjects showing non-pathogen parasites in stool (0.0 ng/g fat vs. 13.1ng/g fat, respectively; p=0.001). Although this inverse association had been described in some vertebrates this is the first study reporting such an association in humans. Furthermore, it has been also recently described that PCBs may disrupt iron metabolism, and we found a direct relationship between serum iron and total PCBs burden (r=0.231, p=0.025), suggesting that PCBs, although at subclinical level, could play a role on iron homeostasis. Although the role of PCBs in parasitism and in the iron metabolism needs future research, our findings may help to understand the adverse health outcomes associated to environmental exposure to PCBs and they might be used in exposed populations as indicators of subtle effects due to environmental insult.

Relationship between atmospheric pollution in the residential area and concentrations of polycyclic aromatic hydrocarbons (PAHs) in human breast milk

Human milk is an important source of beneficial nutrients and antibodies for newborns and infants and, under certain circumstances, its analysis may provide information on mothers' and infants' exposure to various contaminants. In the presented study, we have introduced the new analytical approach for analysis of 24 highly occurring polycyclic aromatic hydrocarbons (PAHs) in this indicator matrix. The sample preparation procedure is based on an ethyl acetate extraction of milk; the transfer of analytes into an organic layer is enhanced by addition of inorganic salts, i.e. sodium chloride and magnesium sulphate. Following the clean-up of a crude extract on silica SPE columns, gas chromatography coupled to triple quadrupole mass spectrometry is used for PAH identification and quantitation. The average recoveries of targeted PAHs from spiked samples were in the range of 68-110% with repeatabilities below 30% and method quantitation limits ranging from 0.03 to 0.3ng/g lipid weight. This newly validated method was successfully applied for analyses of 324 human milk samples collected from nonsmoking women during two sampling periods (summer and winter) in two residential areas in the Czech Republic differing in atmospheric pollution by PAHs. From 24 targeted analytes 17 were detected at least in one sample. Phenantherene, fluoranthrene, pyrene and fluorene were the most abundant compounds found at average concentration of 13.81, 1.80, 0.86, and 2.01ng/g lipid weight respectively. Comparing the data from two sampling periods, in both areas higher concentrations were measured in samples collected during winter. Also in the highly industrialized locality with heavily contaminated air PAH amounts in milk were higher than in the control locality. These first data on PAH concentrations in human milk collected in the Czech Republic are comparable with measurements for nonsmoking women reported earlier in the United States but significantly lower than results from China, Turkey or Italy.

Demographic, Reproductive, and Dietary Determinants of Perfluorooctane Sulfonic (PFOS) and Perfluorooctanoic Acid (PFOA) Concentrations in Human Colostrum

To determine demographic, reproductive, and maternal dietary factors that predict perfluoroalkyl substance (PFAS) concentrations in breast milk, we measured perfluorooctane sulfonic (PFOS) and perfluorooctanoic acid (PFOA) concentrations, using liquid chromatography-mass spectrometry, in 184 colostrum samples collected from women participating in a cohort study in Eastern Slovakia between 2002 and 2004. During their hospital delivery stay, mothers completed a food frequency questionnaire, and demographic and reproductive data were also collected. PFOS and PFOA predictors were identified by optimizing multiple linear regression models using Akaike's information criterion (AIC). The geometric mean concentration in colostrum was 35.3 pg/mL for PFOS and 32.8 pg/mL for PFOA. In multivariable models, parous women had 40% lower PFOS (95% CI: -56 to -17%) and 40% lower PFOA (95% CI: -54 to -23%) concentrations compared with nulliparous women. Moreover, fresh/frozen fish consumption, longer birth intervals, and Slovak ethnicity were associated with higher PFOS and PFOA concentrations in colostrum. These results will help guide the design of future epidemiologic studies examining milk PFAS concentrations in relation to health end points in children.

Assessment of human health hazards associated with the dietary exposure to organic and inorganic contaminants through the consumption of fishery products in Spain

In this work we have evaluated the potential carcinogenic and acutely toxic risks associated to the exposure to highly prevalent organic and inorganic contaminants through the consumption of fishery products by the Spanish population. The concentrations of 8 organochlorine pesticides (OCPs), 18 polychlorinated biphenils (PCBs), 7 polycyclic aromatic hydrocarbons (expressed as benzo[a]pyrene toxic equivalents (B[a]Peq)), and three inorganic toxic elements [arsenic (As), cadmium (Cd), and mercury (Hg)] were determined in 93 samples of the most consumed species of white fish, blue fish, cephalopods and seafood species, which were acquired directly in markets and supermarkets in the Canary Islands, Spain. The chemical concentration data were combined with the pattern of consumption of these foodstuffs in order to calculate the daily intake of these contaminants, and on this basis the risk quotients for carcinogenicity and acute toxicity were determined for Spanish adults and children. Our results showed that the daily intake of OCPs, PCBs and B[a]Peq, which is associated to blue fish consumption was the highest within the fish group. The estimated intake of pollutants can be considered low or very low for the individual contaminants, when compared to reference values, except in the case of HCB and As. All the estimated intakes were below the reported Tolerable Daily Intakes. Considering the additive effects of multiple contaminants, the risk of acute toxic effects can also be considered as low or very low. However, our results reflect that the current consumption of white fish in adults and children, and also the blue fish in the case of adults, poses a moderate carcinogenic risk to Spanish consumers, mainly related to their concentrations of As. The conclusions of this research may be useful for the design of appropriate risk communication campaigns.

Cumulative Chemical Exposures During Pregnancy and Early Development

Industrial and consumer product chemicals are widely used, leading to ubiquitous human exposure to the most common classes. Because these chemicals may affect developmental milestones, exposures in pregnant women and developing fetuses are of particular interest. In this review, we discuss the prevalence of chemical exposures in pregnant women, the chemical class-specific relationships between maternal and fetal exposures, and the major sources of exposures for six chemical classes of concern: phthalates, phenols, perfluorinated compounds (PFCs), flame retardants, polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCs). Additionally, we describe the current efforts to characterize cumulative exposures to synthetic chemicals during pregnancy. We conclude by highlighting gaps in the literature and discussing possible applications of the findings to reduce the prevalence of cumulative exposures during pregnancy.

Different pattern of contamination by legacy POPs in two populations from the same geographical area but with completely different lifestyles: Canary Islands (Spain) vs. Morocco

The archipelago of the Canary Islands is one of the so-called ultra-peripheral territories of the European Union due to its geographical location away from the continent. Although the level of socioeconomic development and lifestyle of this region is comparable to that of any other of the European Union, it is just 100 km off the coast of Morocco, in the African continent. The population of the Canaries has been extensively studied with respect to their levels of POPs, and it has been described that their levels are relatively high compared to other European regions. It has been speculated with that the proximity to Africa may be associated with this level of contamination, but so far this theory has not been verified. This paper describes for the first time the levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in a sample of the population of Morocco (n = 131), which were compared with those of a similar sample of the population of permanent residents in the Canary Islands (n = 100) in order to check this hypothesis. Our results showed that Moroccans have higher median values of OCPs than the residents in the Canaries (∑ OCP = 150.2 ng/g lw vs. 83.4 ng/g lw, p = 0.0001). Regarding the PCBs, although recent studies have reported that new environmental sources of PCBs exist in several African countries (including Morocco), the plasma levels of most congeners were significantly higher in Canarians than in Moroccans, especially for the dioxin-like PCBs (median = 7.3 ng/g lw vs. 0.0 ng/g lw, p = 0.0001). The detailed analysis of our results suggests that the levels of these pollutants in the Canarian people are more influenced by their lifestyle and the previous use of these chemicals in the archipelago than by its geographical vicinity with Morocco.

Chronic exposure to hexachlorobenzene results in down-regulation of connexin43 in the breast

Decreased expression of connexins has been associated with cancer, but the underlying mechanisms are poorly understood. We have previously shown that a 5 day exposure to hexachlorobenzene (HCB) resulted in decreased connexins expression in hepatocytes 45 days later, and that this down-regulation was linked to activation of Akt through the ILK pathway. Because HCB promotes cancer in both the liver and breast, the present study aimed to determine if the mechanisms are similar in both tissues. MCF-12A breast cells were thus transfected with vectors coding for either Akt or a constitutively active form of Akt. In those cells, activation of Akt was correlated with decreased Cx43 levels. Female rats were then exposed to HCB by gavage either following the same protocol used previously for the liver or through a chronic exposure. While no changes were observed after the 5 days exposure protocol, chronic exposure to HCB resulted in increased Akt levels and decreased Cx43 levels in breast cells. In vitro, Akt was activated in MCF-12A cells exposed to HCB either for 7 days or chronically, but no changes were observed in junctional proteins. Together, these results suggested that, while activation of Akt can decrease Cx43 expression in breast cells in vitro, other mechanisms are involved during HCB exposure, leading to a decrease in Cx43 levels in a model- and duration-dependent manner. Finally, we showed that HCB effects are tissue specific, as we did not observe the same results in breast and liver tissues.

The assessment of daily dietary intake reveals the existence of a different pattern of bioaccumulation of chlorinated pollutants between domestic dogs and cats

Pet dogs and cats have been proposed as sentinel species to assess environmental contamination and human exposure to a variety of pollutants, including POPs. However, some authors have reported that dogs but not cats exhibit intriguingly low levels of some of the most commonly detected POPs, such as DDT and its metabolites. This research was designed to explore these differences between dogs and cats. Thus, we first determined the concentrations of 53 persistent and semi-persistent pollutants (16 polycyclic aromatic hydrocarbons (PAHs), 18 polychlorinated biphenyls (PCBs) and 19 organochlorine pesticides (OCPs)) in samples of the most consumed brands of commercial feed for dogs and cats, and we calculated the daily dietary intake of these pollutants in both species. Higher levels of pollutants were found in dog food and our results showed that the median values of intake were about twice higher in dogs than in cats for all the three groups of pollutants (ΣPAHs: 274.8 vs. 141.8; ΣOCPs: 233.1 vs. 83; ΣPCBs: 101.8 vs. 43.8 (ng/kg bw/day); respectively). Additionally, we determined the plasma levels of the same pollutants in 42 and 35 pet dogs and cats, respectively. All these animals lived indoors and were fed on the commercial brands of feed analyzed. As expected (considering the intake), the plasma levels of PAHs were higher in dogs than in cats. However, for organochlorines (OCPs and PCBs) the plasma levels were much higher in cats than in dogs (as much as 23 times higher for DDTs), in spite of the higher intake in dogs. This reveals a lower capacity of bioaccumulation of some pollutants in dogs, which is probably related with higher metabolizing capabilities in this species.