A comparison of infant hair, cord blood and meconium analysis to detect fetal exposure to environmental pesticides

Analytical methods and biomonitoring results in hair for the assessment of exposure to endocrine-disrupting chemicals: A literature review

Endocrine-disrupting chemicals (EDC) are compounds that alter functions of the endocrine system due to their ability to mimic or antagonize endogenous hormones, or that alter their synthesis and metabolism, causing adverse health effects. Human biomonitoring (HBM) is a reliable method to assess human exposure to chemicals through measurement in human body fluids and tissues. It identifies new sources of exposure and determines their distribution, thereby enabling detection of the most exposed populations. Blood and urine are commonly used for HBM of EDC, but their interest is limited for compounds presenting short half-lives. Hair appears as an interesting alternative insofar as it provides a large exposure window. For the present study, we evaluated the relevance of hair in determining EDC exposure. With this in mind, we undertook a literature review focusing on the bioanalytical aspects and performances of methods developed to determine EDC in hair. The literature review was performed through methodical bibliographical research. Relevant articles were identified using two scientific databases: PubMed and Web of Science, with search equations built from a combination of keywords, MeSH terms and Boolean operators. The search strategy identified 2949 articles. After duplicates were removed, and following title, abstract, and full-text screenings, only 31 were included for qualitative synthesis. Hair collection was mainly performed in the back of the head and preparation involved two processes: cutting into small pieces or grounding to powder. The off-line LC-MS/MS method remains the main technique used to assess EDC through hair. Differences regarding the validation of analytical methods and interpretation of HBM results were highlighted, suggesting a need for international harmonisation to obtain reliable and comparable results. External contamination of hair was identified as a main limitation in the interpretation of results, highlighting the need to better understand EDC transfers through hair and to develop relevant hair decontamination processes.

Non-invasive biomonitoring of infant exposure to environmental organic pollutants in north-western Spain based on hair analysis. Identification of potential sources

Recent years have seen growing interest in hair sample analysis to detect organic pollutants (OPs). This biological matrix can be analysed non-invasively for biomonitoring of OPs over a wide exposure window. Obtaining hair sample amounts that meet the needs of the analytical methodology required for the determination of the POs of interest can be challenging, especially in infants. As a result, studies assessing organic pollutants in infant hair have been very scarce. We quantified levels of about 60 OPs, including persistent organic pollutants (POPs), in 110 hair samples from a patient cohort (60 mothers and 50 infants) from Santiago de Compostela (north-western Spain). For each participant we examined relationship between OP levels and corresponding epidemiological parameters using correlations, principal component analysis (PCA), hierarchical cluster analysis, and Multivariate analysis of variance (MANOVA). For many OPs we observed significant correlations with place of residence, parity, and maternal age, as well as pet ownership. Evaluation of dietary habits showed significant associations between levels some OPs and the consumption of fish, molluscs, and cereal. There were significant associations between chlorpyrifos and deltamethrin levels and infant birth characteristics such as birthweight and head circumference. Relations between OP levels in the hair of mothers and their infants were also examined, revealing common sources of exposure for dioxin-like polychlorinated biphenyls (DLPCBs), non-dioxin-like polychlorinated biphenyls (NDLPCBs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs). Levels of fluoranthene (F), pyrene (P), endrin, and some PBDEs in maternal hair were significantly correlated with those in infant hair. Our findings identified common sources of exposure to OPs of distinct chemical classes.

JNK and Jag1/Notch2 co-regulate CXCL16 to facilitate cypermethrin-induced kidney damage

Cypermethrin (CYP), a widely-used composite pyrethroid pesticide, has underlying nephrotoxic effects. To elucidate potential roles of the MAPK pathway, the Jag/Notch pathway, and miRNAs in CYP-mediated kidney lesion, Sprague-Dawley rats and glomerular mesangial cells were used in this work. Results displayed that β-CYP abnormally altered renal histomorphology and ultrastructures, induced renal DNA damage, and impaired renal functions, as evidenced by the increase in plasma levels of Cys-C and β2-Mg. β-CYP activated the JNK/c-Jun pathway by inducing ROS and oxidative stress. Meanwhile, β-CYP changed the miRNA expression profile, miR-21-5p showing the most significant increase. Moreover, the Jag1/Notch2/Hes1 pathway was directly targeted by miR-21-5p, the mRNA and protein expression of Jag1, Notch2, and Hes1 being declined in vivo and in vitro. The chemokine CXCL16 was induced by β-CYP, accompanied by the inflammatory factor production and inflammatory cell infiltration in kidneys. The specific JNK inhibitor, Jag1 overexpression, Hes1 overexpression, bidirectional Co-IP, ChIP, and CXCL16 silencing demonstrated that CXCL16 co-regulated by the JNK/c-Jun and Jag1/Notch2/Hes1 pathways elicited renal inflammation. Collectively, our findings indicate that β-CYP is of nephrotoxicity and it not only directly changes renal histomorphology and ultrastructures, but induces CXCL16 to trigger renal inflammation via the JNK/c-Jun and Jag1/Notch2/Hes1 pathways, finally synergistically contributing to kidney damage.

A narrative review of converging evidence addressing developmental toxicity of pyrethroid insecticides

Pyrethroid insecticides are broadly used in agriculture and household products throughout the world. Exposure to this class of insecticides is widespread, and while generally believed to be safe for use, there is increasing concern regarding their effects on neurodevelopment. Due to the critical roles that molecular targets of pyrethroids play in the regulation of neurodevelopment, particular focus has been placed on evaluating the effects of in utero and childhood pyrethroid exposure on child cognition and behavior. As such, this narrative review synthesizes an assessment of converging study types; we review reports of neonatal pyrethroid levels together with current epidemiological literature that convergently address the risk for developmental toxicity linked to exposure to pyrethroid insecticides. We first address studies that assess the degree of direct fetal exposure to pyrethroids in utero through measurements in cord blood, meconium, and amniotic fluid. We then focus on the links between prenatal exposure to these insecticides and child neurodevelopment, fetal growth, and other adverse birth outcomes. Furthermore, we assess the effects of postnatal exposure on child neurodevelopment through a review of the data on pediatric exposures and child cognitive and behavioral outcomes. Study quality was evaluated individually, and the weight of evidence was assessed broadly to characterize these effects. Overall, while definitive conclusions cannot be reached from the currently available literature, the available data suggest that the potential links between pyrethroid exposure and child neurodevelopmental effects deserve further investigation.

Cypermethrin triggers YY1-mediated testosterone biosynthesis suppression

Cypermethrin (CYP), an extensively-used broad-spectrum pyrethroid pesticide, is regarded as a potential environmental endocrine disruptor with the anti-androgenic characteristic. To explore underlying roles of non-coding RNAs and the Jak/Stat pathway in CYP-mediated testosterone biosynthesis suppression, SD rats and Leydig cells were employed in this work. Results displayed that β-CYP decreased plasma testosterone levels and led to abnormal alterations of testicular histomorphology and ultrastructures. LncRNA XIST and miR-142-5p were co-localized in the cytoplasm of Leydig cells, but the expression of XIST was inhibited by β-CYP while that of miR-142-5p was induced. Then overexpressed miR-142-5p dampened the Jak1/Stat1 pathway by directly targeting Jak1. Transcription factors NFκB and YY1 impeded by β-CYP were positively regulated by the Jak1/Stat1 pathway. Bidirectional Co-IP and ChIP assays demonstrated that NFκB interacted with and modulated YY1 by directly binding to the promoter region of YY1. ChIP, qPCR, and YY1 knockdown/overexpression assays indicated that YY1 acted as a transcriptional activator to directly modulate steroidogenic StAR and 3β-HSD in Leydig cells. Taken together, miR-142-5p sponged by lncRNA XIST directly targets the Jak1/Stat1 pathway, which regulates steroidogenic StAR and 3β-HSD via NFκB and YY1, and ultimately dampens testosterone production in Leydig cells.

Liquid chromatography tandem mass spectrometry for the determination of nine insecticides and fungicides in human postmortem blood and urine

Pesticide poisoning is a common occurrence due to their widespread use, easy access and high toxicity even in small concentrations. The most common poisoning fatalities have been observed due to exposure to organophosphates, carbamates and neonicotinoids, thus development of a method for the rapid determination of these compounds in blood and urine is of great importance for clinical and toxicology laboratories. A simple, fast and reliable method was developed for the determination of 9 pesticides in blood and urine using HPLC-MS/MS instrumentation. In order to find the most suitable sample pretreatment technique, three different sample preparation procedures: SPE, protein precipitation and QuEChERS were compared. The final optimized analytical method was fully validated with the values of parameters such as calibration linearity, accuracy, precision, recovery, matrix effect and stability being acceptable. The method proved reliable, accurate, robust and sensitive and was successfully applied for the quantitation of pesticides in three postmortem cases of pesticides poisoning.

Diet: A Source of Endocrine Disruptors

BACKGROUND

Food is indispensable for human life and determines the health and wellbeing of the consumer. As food is the source of energy for humans, it also emerges as one of the most important sources of exposure to deleterious chemicals both natural and synthetic. The food exposed chemicals cause a number of detrimental health effects in humans, with endocrine disruption being of serious concern amongst these effects. Such chemicals disrupting the health of endocrine system are known as endocrine-disrupting chemicals (EDCs). The food exposed EDCs need to be identified and classified to effectuate a cautious consumption of food by all and especially by vulnerable groups.

AIM

The aim of the present review was to discuss food as a source of exposure to common endocrine disruptors in humans. This review presents the occurrence and levels of some of the critical endocrine disruptors exposed through frequently consumed diets.

METHODS

The major source of data was PubMed, besides other relevant publications. The focus was laid on data from the last five years, however significant earlier data was also considered.

CONCLUSION

The food as a source of endocrine disruptors to humans cannot be neglected. It is highly imperative for the consumer to recognize food as a source of EDCs and make informed choices in the consumption of food items.

Analysis of six pyrethroid insecticide metabolites in cord serum using a novel gas chromatography-ion trap mass spectrometry method

Pyrethroid insecticides are commonly used for residential and commercial pest control in the US. Pregnant women and their fetuses are vulnerable to pesticide exposures during critical windows of neurodevelopment. Biomonitoring for exposure requires accurate and sensitive methods to assess exposures during pregnancy. The objective of this study was to develop a sensitive analytical method to measure pyrethroid metabolite concentrations in cord serum. Six pyrethroid metabolites, cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropanecarboxylic acid (c/t-DCCA), trans-chrysanthemum dicarboxylic acid (t-CDCA), cis-3-(2,2-dibromovinyl)-2,2-dimethyl-cyclopropane carboxylic acid (c-DBCA), 4-fluoro-3-phenoxybenzoic acid (FPBA), and 3-phenoxybenzoic acid (3PBA) were extracted from cord serum by a dichloromethane liquid-liquid extraction, derivatized by 1,1,1,3,3,3-hexafluoro-2-propanol carboxylic acid esterification, and then measured by gas chromatography/ion trap mass spectrometry. Limits of detection ranged from 0.02 to 0.6 ng/mL. Sixty-three cord serum samples were collected from maternal-fetal dyads in central New Jersey to test for pyrethroid metabolites. Non-specific metabolites, 3PBA, t-DCCA, and t-CDCA, were detected most frequently, present in 29%, 6.3% and 6.3% of samples, respectively. Sensitivities were comparable or greater than other published studies assessing pyrethroid metabolites in cord blood. Comparisons with other literature-reported studies emphasize the importance of method sensitivity when assessing exposures at biologically relevant concentrations.

Environmental exposures related to parental habits in the perinatal period and the risk of Wilms' tumor in children

INTRODUCTION

Wilms' tumor is the most frequently diagnosed renal tumor in children. Little is known about its etiology. The aim of this study was to investigate the potential role of specific exposures related to parental habits such as parental smoking, maternal alcohol consumption and the use of household pesticides during pregnancy.

METHODS

The ESTELLE study was a nationwide case-control study that included 117 Wilms' tumor cases and 1100 control children from the general French population, frequency-matched by age and gender. Unconditional logistic regression was used to estimate odds ratios and 95 % confidence intervals.

RESULTS

After controlling for matching variables and potential confounders, the maternal use of any type of pesticide during pregnancy was associated with the risk of Wilms' tumor in children (OR 1.6 [95 % CI 1.1-2.3]). Insecticides were the most commonly reported type of pesticide and there was a positive association with their use (OR 1.7 [95 % CI 1.1-2.6]. The association was stronger when they were used more often than once a month (OR 1.9 [95 % CI 1.2-3.0]. Neither maternal smoking during pregnancy nor paternal smoking during preconception/pregnancy was associated with a risk of Wilms' tumor (ORs 1.1[95 % CI 0.7-1.8] and 1.1 [95 % CI 0.7-1.7], respectively). No association was observed with maternal alcohol intake during pregnancy (OR 1.2 [95 % CI 0.8-2.0]).

CONCLUSION

Our findings suggest an association between the maternal use of household pesticides during pregnancy and the risk of Wilms' tumor.

Meconium identifies high levels of metals in newborns from a mining community in the U.S

BACKGROUND

This pilot study was conducted to determine if we could identify intrauterine exposure to metals in meconium, as a measure of exposure for mother-child pairs living in proximity to a mining operation.

OBJECTIVES

We used meconium as a means to measure metal exposure in utero. We set out to quantify the exposure to selected metals that are currently being mined and also are found in the Superfund site in Butte, Montana, and to compare it to that of Columbia, South Carolina, US, where mining is not occurring.

METHODS

This cross-sectional study was conducted between May and November 2018. We received Institutional Review Board approval and we consented women following the birth of their newborns, and collected meconium within 24 h of birth, without any identifiers. Each laboratory used the same protocol for collection, transport, and storage; and the same laboratory protocol was used for the analysis of all samples. Samples were digested using standard acid/peroxide digestion methods and measured by inductively coupled plasma mass spectroscopy.

RESULTS

We collected meconium specimens from 17 infants in Columbia, South Carolina and 15 infants in Butte, Montana. The concentrations found in Columbia were in the low μg kg^-1 range (or less) and were similar to the low levels that have been identified in other studies of meconium. The magnitude of the differences in concentrations found in Butte compared to Columbia was 1792 times higher for Cu, 1650 times higher for Mn, and 1883 times higher for Zn.

CONCLUSION

Using meconium to measure exposure of newborns has implications for risk assessment in a mining-exposed population. This approach was inexpensive and thorough. The magnitude of the differences in the metal levels identified from the two study sites suggests there is an urgent need for further research to learn if there are health consequences to these highly exposed infants.

ORGANOPHOSPHATES IN MECONIUM OF NEWBORN BABIES WHOSE MOTHERS RESIDED IN AGRICULTURAL AREAS OF THAILAND

Organophosphates (OPs) are widely used for pest and weed control in many countries including Thailand. In addition to causing environmental pollution, OPs affect human health by overstimulating neurotoxicants, and OP exposure during pregnancy can lead to adverse health effects of mothers and their fetuses. Using gas chromatography-mass spectrometry with a dedicated extraction protocol to identify OPs in meconium of newborn babies (n = 68) from hospitals in Amnat Charoen, Kanchanaburi and Nakhon Sawan provinces, agricultural regions of Thailand, among ten OP types analyzed, eight were detected in 98% of meconium samples (chlorpyrifos (median ± interquartile range (IQR) 0.08 ± 0.03-0.16 μg/g) in 32% of samples, demeton-s-methyl (0.35 ± 0.26-0.49 μg/g) in 73%, dichlorvos (0.67 ± 0.58-0.71 μg/g) in 38%, dimethoate (0.43 ± 0.09-1.56 μg/g) in 50%, ethion (0.21 ± 0.19-0.26 μg/g) in 12%, malathion (0.28 ± 0.15-0.52 μg/g) in 50%, omethoate (5.63 ± 4.85-8.57 μg/g) in 34%, and tolclofos-methyl (0.08 ± 0.03-0.10 μg/g) in 41%). There are no significant differences in these parameters from babies whose mothers did and did not work in the agricultural or who lived near (within one km) and distant from farmland. The findings should be of benefit in developing programs to protect pregnant women and newborn babies from exposure to OP pesticides.

Exposure of Larval Zebrafish to the Insecticide Propoxur Induced Developmental Delays that Correlate with Behavioral Abnormalities and Altered Expression of hspb9 and hspb11

Recent studies suggest that organophosphates and carbamates affect human fetal development, resulting in neurological and growth impairment. However, these studies are conflicting and the extent of adverse effects due to pesticide exposure warrants further investigation. In the present study, we examined the impact of the carbamate insecticide propoxur on zebrafish development. We found that propoxur exposure delays embryonic development, resulting in three distinct developmental stages: no delay, mild delay, or severe delay. Interestingly, the delayed embryos all physically recovered 5 days after exposure, but behavioral analysis revealed persistent cognitive deficits at later stages. Microarray analysis identified 59 genes significantly changed by propoxur treatment, and Ingenuity Pathway Analysis revealed that these genes are involved in cancer, organismal abnormalities, neurological disease, and hematological system development. We further examined hspb9 and hspb11 due to their potential roles in zebrafish development and found that propoxur increases expression of these small heat shock proteins in all of the exposed animals. However, we discovered that less significant increases were associated with the more severely delayed phenotype. This raises the possibility that a decreased ability to upregulate these small heat shock proteins in response to propoxur exposure may cause embryos to be more severely delayed.

Metabolomics of Pregnancy Complications: Emerging Application of Maternal Hair

In recent years, the study of metabolomics has begun to receive increasing international attention, especially as it pertains to medical research. This is due in part to the potential for discovery of new biomarkers in the metabolome and to a new understanding of the "exposome", which refers to the endogenous and exogenous compounds that reflect external exposures. Consequently, metabolomics research into pregnancy-related issues has increased. Biomarkers discovered through metabolomics may shed some light on the etiology of certain pregnancy-related complications and their adverse effects on future maternal health and infant development and improve current clinical management. The discoveries and methods used in these studies will be compiled and summarized within the following paper. A further focus of this paper is the use of hair as a biological sample, which is gaining increasing attention across diverse fields due to its noninvasive sampling method and the metabolome stability. Its significance in exposome studies will be considered in this review, as well as the potential to associate exposures with adverse pregnancy outcomes. Currently, hair has been used in only two metabolomics studies relating to fetal growth restriction (FGR) and gestational diabetes mellitus (GDM).

Perceptions, Practices, and Mother’s Willingness to Provide Meconium for Use in the Assessment of Environmental Exposures among Children in Mukono and Pallisa Districts, Uganda

Presence of biomarkers or metabolites is assessed in various human biospecimens including meconium in the investigation of exposures to environmental contaminants. This study gathered data on the perceptions and practices of mothers in two rural districts of Uganda concerning meconium and their willingness to provide meconium from their babies for research purposes. The study reveals a wide range of perceptions and beliefs around meconium as well as a number of associated taboos and practices. Many participants noted that meconium could be used to detect ailments among newborns based on its appearance. Practices and beliefs included using it to prevent stomach discomfort and other ailments of newborns, as a means to confirm paternity and initiate the child into the clan as well as facilitating father-child bonding that included ingestion of meconium by the fathers. Most mothers indicated scepticism in accepting to provide meconium for research purposes and had fears of unscrupulous people disguising as researchers and using meconium to harm their children. However, some were willing to provide meconium, if it helped to detect ailments among their children. These perceptions and practices may negatively influence mothers’ willingness to participate in meconium study. However, through provision of educational and behaviour change interventions, mothers’ willingness to participate in a meconium study can be improved.

Paraquat Exposure of Pregnant Women and Neonates in Agricultural Areas in Thailand

This study aimed to assess paraquat concentrations in the urine of women at 28 weeks of pregnancy, delivery and 2 months postpartum and in the meconium of neonates. In all, 79 pregnant women were recruited from three hospitals located in agricultural areas in Thailand. The subjects were interviewed about personal characteristics, agricultural activities and pesticide use patterns. Paraquat was analyzed in urine and meconium using high performance liquid chromatography equipped with a fluorescence detector. The geometric mean (GSD) of urinary paraquat concentrations at 28 weeks of pregnancy, delivery and 2 months postpartum were 2.04 (4.22), 2.06 (5.04) and 2.42 (5.33) ng/mL, respectively. The urinary paraquat concentrations at 28 weeks of pregnancy, delivery and 2 months postpartum between agriculturist and non-agriculturist were not significantly different (p = 0.632, p = 0.915, p = 0.57, respectively). The geometric mean (GSD) of paraquat concentration in the meconium was 33.31 (4.59) ng/g. The factors predicting paraquat exposures among pregnant women and neonates included working outside, living near farmland, having family members who work on a farm, drinking well water and using herbicides or paraquat.

Assessment of Pesticide-Related Pollution and Occupational Health of Vegetable Farmers in Benguet Province, Philippines

BACKGROUND

Agriculture accounts for 20% of the national income in the Philippines. In order to boost agricultural activity and prevent crop damage, farmers rely on pesticides for vector control and management.

OBJECTIVES

The present study assessed the pesticide exposure and occupational health of agricultural farmers in the Philippines. The study site is one of the largest vegetable-producing provinces in the Philippines.

METHODS

This study employed both a survey questionnaire and physical health assessment, including a mental state examination. Pesticide exposure was estimated based on the duration of pesticide use, as well as the amount per spray application. The data results were segregated by gender, as women are also heavily engaged in agriculture in this part of the Philippines.

RESULTS

The results showed that pesticide exposure usually occurred during agricultural activities such as spray applications in the field (63.7%), mixing (38.4%), loading (34.1%) and field re-entry (9.7%). The most frequently used pesticides were Tamaron, Selecron, and Dithane. The mean duration of pesticide exposure was 14.23 years for males and 15.4 years for females. The longest used pesticide among males was Sumicidine (16.2 years), and Tamaron for females (18 years). In terms of amount used, the average was 147 ml per spray application for males and 65.5 ml for females. Exposure to pesticides was expressed in number of years and amount used per spray application, and the average exposure of males was 2,024.43 ml/years and 993.55 ml/years for females. Among farmers, 49% complained of being sick due to their work. Of those who became ill, a large percentage (69.8%) did not receive any medical attention. The most prevalent health symptoms were muscle pains (63.3%), muscle weakness (55%), and easy fatigability (52.4%). For the mini-mental state examination, abnormalities were found in 5.4% of males and 13.3% of females. The use of insecticides was associated with weakness, easy fatigability and weight loss.

DISCUSSION

The present study demonstrated frequent and significant duration of pesticide use among farmers in Benguet province, Philippines.

CONCLUSIONS

Pesticide exposure was considerable among the farmers in the present study. The occupational health conditions reported by the study subjects can be linked to their pesticide use. Although this study assessed risk factors associated with general health symptoms, further investigation is needed to determine specific pesticide exposure-health correlations.

PARTICIPANT CONSENT

Obtained.

ETHICS APPROVAL

The study was approved by the Research Ethics Board of the University of the Philippines, Manila, which is recognized and accredited by the Forum for Ethical Review Committees in Asia and the Western Pacific (FERCAP).

Gas chromatography/negative chemical ionization mass spectrometry of transfluthrin in rat plasma and brain

RATIONALE

Transfluthrin is a relatively non-toxic rapid-acting synthetic pyrethroid insecticide. It is widely used in household and hygiene products. A sensitive and accurate bioanalytical method is required for quantification of its concentration in plasma and its potential target organ, the brain for studies to assess its health effects and toxicokinetics in mammals.

METHODS

The samples were prepared by liquid-liquid extraction. Gas chromatography mass spectrometry (GC/MS) analysis was performed for the determination of transfluthrin in biological samples with an overall method run time of 15 min. Transfluthrin was quantified using selected-ion monitoring (SIM) in the negative chemical ionization (NCI) mode. Chromatographic separation was achieved using a Zebron® ZB5-MS GC column operating with 1 mL/min constant flow helium. Cis-Permethrin was used as the internal standard.

RESULTS

The method was validated to be precise and accurate within the linear range of 1.0-400.0 ng/mL in plasma and 4.0-400.0 ng/mL in brain homogenate, based on a 100 μL sample volume for both matrices. This method was applied to samples following administration of a 10 mg/kg oral dose to male adult rats. The plasma concentrations were observed to be 11.70 ± 5.69 ng/mL and brain concentrations 12.09 ± 3.15 ng/g when measured 2 h post-dose.

CONCLUSIONS

A rapid GC/NCI-MS method was demonstrated to be sensitive, specific, precise and accurate for the quantification of transfluthrin in rat plasma and brain. The optimized method was successfully used to quantify the rat plasma and brain concentrations of transfluthrin 2 h after the oral dosing of Sprague-Dawley rats.

Human exposure to endocrine disrupting chemicals: effects on the male and female reproductive systems

Endocrine disrupting chemicals (EDCs) comprise a group of chemical compounds that have been examined extensively due to the potential harmful effects in the health of human populations. During the past decades, particular focus has been given to the harmful effects of EDCs to the reproductive system. The estimation of human exposure to EDCs can be broadly categorized into occupational and environmental exposure, and has been a major challenge due to the structural diversity of the chemicals that are derived by many different sources at doses below the limit of detection used by conventional methodologies. Animal and in vitro studies have supported the conclusion that endocrine disrupting chemicals affect the hormone dependent pathways responsible for male and female gonadal development, either through direct interaction with hormone receptors or via epigenetic and cell-cycle regulatory modes of action. In human populations, the majority of the studies point towards an association between exposure to EDCs and male and/or female reproduction system disorders, such as infertility, endometriosis, breast cancer, testicular cancer, poor sperm quality and/or function. Despite promising discoveries, a causal relationship between the reproductive disorders and exposure to specific toxicants is yet to be established, due to the complexity of the clinical protocols used, the degree of occupational or environmental exposure, the determination of the variables measured and the sample size of the subjects examined. Future studies should focus on a uniform system of examining human populations with regard to the exposure to specific EDCs and the direct effect on the reproductive system.

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.

A global assessment of phthalates burden and related links to health effects

Phthalates are ubiquitous environmental contaminants which are used in industry as plasticizers and additives in cosmetics. They are classified as Endocrine Disrupting Chemicals (EDCs) which impair the human endocrine system inducing fertility problems, respiratory diseases, childhood obesity and neuropsychological disorders. The aim of this review is to summarize the current state of knowledge on the toxicity that phthalates pose in humans based on human biomonitoring studies conducted over the last decade. Except for conventional biological matrices (such as urine and serum), amniotic fluid, human milk, semen, saliva, sweat, meconium and human hair are also employed for the estimation of exposure and distribution of pollutants in the human body, although data are not enough yet. Children are highly exposed to phthalates relative to adults and in most studies children's daily intake surpasses the maximum reference dose (RfD) set from US Environmental Protection Agency (US EPA). However, the global trend is that human exposure to phthalates is decreasing annually as a result of the strict regulations applied to phthalates.

Obstetrical outcomes and biomarkers to assess exposure to phthalates: A review

Studies of the effects on pregnancy outcomes of in utero exposure to phthalates, contaminants that are widely present in the environment, have yielded conflicting results. In addition, the mode of assessment of exposure varies between studies. The aim of this review was therefore to establish a current state of knowledge of the phthalates and metabolites involved in unfavorable pregnancy outcomes. Extant data were analyzed to determine which biomarker is the best suited to assess the relation between in utero exposure to phthalates and pregnancy outcomes. This review of the literature was conducted using the database of PubMed. A search was made of studies investigating exposure to phthalates and the following birth outcomes: preterm birth (gestational age <37 weeks), change in gestational age, change in body size at birth (birth weight, length, head circumference), anti-androgenic function, decreased anogenital distance, cryptorchidism, hypospadias and congenital malformation. The methodological approach adopted in each study was examined, in particular the methods used for exposure assessment (biomarkers and/or questionnaire). Thirty-five studies were included. Premature birth and decreased anogenital distance were the most commonly reported outcomes resulting from a moderate level of exposure to phthalates. The principal metabolites detected and involved were primary metabolites of di-2(ethylhexyl)-phthalate (DEHP) and di-n-butyl-phthalate (DnBP). No clear conclusion could be drawn with regard to gestational age at birth, body size at birth and congenital malformations. In epidemiological studies, maternal urine is the most suitable matrix to assess the association between in utero exposure to phthalates and pregnancy outcomes: in contrast to other matrices (cord blood, amniotic fluid, meconium and milk), sampling is easy, non-invasive and, can be repeated to assess exposure throughout pregnancy. Oxidative metabolites are the most relevant biomarkers since they are not prone to external contamination. Further epidemiological studies are required during pregnancy to i) determine the role of phthalates other than DEHP [currently replaced by various substitution products, in particular diisononyl-phthalate (DiNP)]; ii) establish the effect of phthalates on other outcomes (body size adjusted for gestational age, and congenital malformations); iii) determine the pathophysiological pathways; and iv) identify the most suitable time for biomarker determination of in utero exposure to phthalates.

Paraoxonase 2 gene polymorphisms and prenatal phthalates' exposure in Chinese newborns

BACKGROUND

Phthalates were reported to be associated with increased risk of LBW in newborns, but the mechanism and potential influencing factor was still unclear. The objectives of this study were to investigate whether paraoxonase-2 (PON2) Ala148Gly (A148G) polymorphisms have impacts on fetal growth, and evaluate potential modifying effect on the association between phthalate exposures and LBW and short birth length.

METHODS

In the current case-control study, 185 mother-newborn pairs including 74 low birth weight (LBW) cases and 111 controls were enrolled. Newborns' meconium specimens were collected and detected for mono-n-butyl phthalate (MBP) and mono-2-ethyhexyl phthalate (MEHP) by the method of high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Umbilical vein blood samples were used to identify PON2 A148G polymorphisms by using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

Newborns prenatally exposed to higher level of phthalates had lower birth weight (β=-0.92. p=0.045 for MBP, β=-0.62, p=0.013 for MEHP) and short birth length (SBL) (β=-0.024. p=0.049 for MBP, β=-0.023, p=0.007 for MEHP). Comparing with low-phthalate-exposed subjects with PON2 148AA genotype, newborns with PON2 148AG/GG genotype exposed to high concentrations of MBP and MEHP had higher risks of LBW and short birth length (LBW: OR: 5.0, p=0.017 for MEHP; OR: 2.6, p=0.023 for MBP; SBL: OR: 6.6, p=0.005 for MEHP; OR: 6.4, p=0.017 for MBP). Effects of MBP and MEHP on LBW were significantly modified by PON2 A148G (p=0.044 and 0.034, respectively), while the modifying effect of PON2 A148G polymorphisms on the association of two phthalate metabolites with SBL was not significant.

CONCLUSION

Prenatal exposure to phthalates affected birth weight and length in newborns. PON2 A148G polymorphisms modified the effects of prenatal phthalates' exposure on fetal development. Newborns with PON2 148AG/GG genotype and exposed to high concentrations of MBP and MEHP had higher risks of LBW and SBL.

Development of a multi-residue method in a fetal matrix: analysis of meconium

Meconium is the earliest stool of newborns. It is a complex matrix that reflects the degree of fetal exposure to environmental pollutants. To investigate exposure to xenobiotics, an analytical method was developed to identify and quantify some pesticides and their metabolites and BTEX metabolites in meconium. Samples were prepared by two liquid-solid extractions and purified twice using SPE cartridges, followed by analysis with liquid chromatography coupled with tandem mass spectrometry. SPE cartridges (polymeric phase with hydrophilic and hydrophobic interactions, ion exchange, mixed mode) were tested and matrix effects were evaluated to determine purification performance. The quantification limits in meconium of this multi-residue method were in the range of 30 ng g(-1). The analytical method was applied to "real" meconium samples. Some target analytes were determined in most samples.

Development of an analytical strategy based on LC-MS/MS for the measurement of different classes of pesticides and theirs metabolites in meconium: application and characterisation of foetal exposure in France

It is important to evaluate the impact of pesticides on human health because exposure to these compounds has been linked to harmful effects in many research studies. This exposure may be particularly harmful during the early stages of development (e.g. the prenatal period). The aim of the present study was to develop an analytical strategy for quantifying a number of pesticides and their metabolites in meconium (the neonate's first faeces), in order to characterize the extent of foetal exposure. The meconium sample was dried and grinded in order to homogenize the sample, prior to solid-liquid extraction and a purification by solid-phase extraction using a weak anion mixed-mode polymeric sorbent. Analyte separation and quantification was performed by liquid chromatography coupled to electrospray-triple quadrupole mass spectrometry. Five pesticide families (carbamates, organophosphates, pyrethroids, phenylureas and phenoxy herbicides) and their metabolites could be quantified in meconium with limits of quantification ranging between 0.2 ng/g and 200 ng/g. This method was applied to a set of 171 meconium samples collected in the Picardie region of northern France. The highest prevalence was observed for metabolites of organophosphates and carbamates (57.9% and 22.8%, respectively). The parent pesticides were rarely present and were only found at very low concentrations, except for the pyrethroids cyfluthrin and cypermethrin, which were found in 7.6% of meconium samples at concentrations of between 43.8 and 480 ng/g. The most frequently detected contaminant was the organophosphate metabolite dimethyl thiophosphate detected in 49.1% of the samples and quantified with a median concentration of 344 ng/g. These data evidence significant foetal exposure to organophosphate pesticides, pyrethroids and carbamates.

Analysis of BTEX and chlorinated solvents in meconium by headspace-solid-phase microextraction gas chromatography coupled with mass spectrometry

Meconium is the earliest stool of newborns, and is a complex matrix that reflects the degree of exposure of the fetus to xenobiotics. To investigate fetal exposure to volatile organic compounds, an analytical method was developed to identify and quantify BTEX (benzene, toluene, ethylbenzene, and o,m,p-xylene) and two chlorinated solvents (trichloroethylene and tetrachloroethylene) in meconium. Headspace-solid-phase microextraction coupled with gas chromatography-mass spectrometry was selected because it is simple, sensitive, can be automated, and requires no extensive sample preparation. Several extraction variables were optimized (fiber type, incubation time, temperature of fiber, and use of salt). Because meconium is a complex matrix, quantification by SPME was considered carefully because of potential interference, for example competitive adsorption. Calibration in water was compared with calibration in meconium using external and internal methods (with isotope-labeled compounds). In meconium, limits of quantification were determined to be in the range 0.064-0.096 ng g(-1) for the investigated compounds. All target compounds were determined in "real-case" meconium samples.

Biomonitoring of human fetal exposure to environmental chemicals in early pregnancy

The first trimester of human fetal life, a period of extremely rapid development of physiological systems, represents the most rapid growth phase in human life. Interference in the establishment of organ systems may result in abnormal development that may be manifest immediately or programmed for later abnormal function. Exposure to environmental chemicals may be affecting development at these early stages, and yet there is limited knowledge of the quantities and identities of the chemicals to which the fetus is exposed during early pregnancy. Clearly, opportunities for assessing fetal chemical exposure directly are extremely limited. Hence, this review describes indirect means of assessing fetal exposure in early pregnancy to chemicals that are considered disrupters of development. Consideration is given to such matrices as maternal hair, fingernails, urine, saliva, sweat, breast milk, amniotic fluid and blood, and fetal matrices such as cord blood, cord tissue, meconium, placenta, and fetal liver. More than 150 articles that presented data from chemical analysis of human maternal and fetal tissues and fluids were reviewed. Priority was given to articles where chemical analysis was conducted in more than one matrix. Where correlations between maternal and fetal matrices were determined, these articles were included and are highlighted, as these may provide the basis for future investigations of early fetal exposure. The determination of fetal chemical exposure, at the time of rapid human growth and development, will greatly assist regulatory agencies in risk assessments and establishment of advisories for risk management concerning environmental chemicals.

Evaluation of changes in monoamine levels and apoptosis induced by cyfluthrin in rats

The aim of this study was to evaluate monoamine and mitochondrial cytochrome c levels and lipid peroxidation in adult male rats treated with cyfluthrin (14 mg kg⁻¹dose; approximately 1/10 of the LD₅₀value) for 14 days. This study also examined cyfluthrin induced-apoptosisviathe signaling proteins Bcl-2, caspase-9 and caspase-3, and possible anti-apoptotic effects of Alfa-basic crystallin.

Is meconium useful to predict fetal exposure to organochlorines and hydroxylated PCBs?

The objective of this study is to compare meconium and maternal serum as biomarkers of fetal exposure to organochlorines (OCs). A subset of 40 meconium samples and complementary maternal sera from the Northern Norway Mother-and-Child Contaminant Cohort Study (MISA) were selected. Meconium samples were collected at the earliest opportunity (median 9.0 hours postpartum, range 0-61) and maternal serum in the 2nd trimester (median 19.0 gestational weeks, range 13-34) and analysed for OC contaminants selected from the Arctic Monitoring and Assessment Programme's (AMAP) suite of OCs and selected hydroxylated metabolites. Eight compounds with detection frequencies ≥70% in both media (criterion for inclusion) were included in the statistical analyses. Median concentration ratios for p,p'-DDE, HCB, trans-nonachlor and cis-nonachlor favoured meconium, and PCB 138 and 153 and OH-PCB 146 and 172 were higher in maternal serum. All inter-media correlations were significant (Spearman's rho) for wet-weight concentrations and improved when concentrations in a small subset of 15 meconium and serum samples were both lipid-adjusted; only OH-PCB 146 slightly favoured maternal serum. Multivariable linear regression modelling confirmed that maternal serum was the most consistent predictor of meconium concentrations, with gestational age and time of meconium sampling improving the models. Although more challenging to analyse, the lipid-adjusted OC concentration in meconium is viewed as a sensitive and informative fetal exposure index when taking into account the gestational age and its postpartum sampling time.

Determination of farm workers' exposure to pesticides by hair analysis

In the present work, a highly sensitive method based on solid phase microextraction and gas chromatography tandem (triple quadrupole) mass spectrometry was used to test hair samples for 50 pesticides including 39 molecules from different chemical families currently used in agriculture and 11 organochlorines. The population investigated was composed of 18 farm workers who provided hair samples repeatedly collected during the entire treatment period (from March to November 2009). Among the 62 hair samples that were collected, 33 different target molecules were detected. The most frequently detected agricultural pesticides were Diflufenican and Pyrimethanil, two herbicides which were detected in 13 subjects. The concentration in volunteers' hair matched with agricultural activity and the highest concentration was observed for Cyprodinil (1161pg/mg), an anilinopyrimidine used as a fungicide. For organochlorines, p,p'-DDE and γ-HCH were the most frequently detected molecules as they were present in at least one of the hair samples provided by each of the 18 volunteers. The highest concentrations detected for these chemicals reached 21.0pg/mg for p,p'-DDE and 23.5pg/mg for γ-HCH, but the highest concentration of organochlorine was observed for β-endosulfan (105pg/mg). The results suggest that farm workers have a weak, though constant exposure to organochlorine pesticides, especially to p,p'-DDE and γ-HCH, while exposure to currently used pesticides is strongly associated with occupation. Observations also suggest that spraying work would not necessarily be the only source of exposure to agricultural pesticides and that worker not directly involved in spraying can also be submitted to significant level of exposure.

Collection of biological samples in forensic toxicology

Forensic toxicology is the study and practice of the application of toxicology to the purposes of the law. The relevance of any finding is determined, in the first instance, by the nature and integrity of the specimen(s) submitted for analysis. This means that there are several specific challenges to select and collect specimens for ante-mortem and post-mortem toxicology investigation. Post-mortem specimens may be numerous and can endow some special difficulties compared to clinical specimens, namely those resulting from autolytic and putrefactive changes. Storage stability is also an important issue to be considered during the pre-analytic phase, since its consideration should facilitate the assessment of sample quality and the analytical result obtained from that sample. The knowledge on degradation mechanisms and methods to increase storage stability may enable the forensic toxicologist to circumvent possible difficulties. Therefore, advantages and limitations of specimen preservation procedures are thoroughfully discussed in this review. Presently, harmonized protocols for sampling in suspected intoxications would have obvious utility. In the present article an overview is given on sampling procedures for routinely collected specimens as well as on alternative specimens that may provide additional information on the route and timing of exposure to a specific xenobiotic. Last, but not least, a discussion on possible bias that can influence the interpretation of toxicological results is provided. This comprehensive review article is intented as a significant help for forensic toxicologists to accomplish their frequently overwhelming mission.

A prospective cohort study of biomarkers of prenatal tobacco smoke exposure: the correlation between serum and meconium and their association with infant birth weight

BACKGROUND

The evaluation of infant meconium as a cumulative matrix of prenatal toxicant exposure requires comparison to established biomarkers of prenatal exposure.

METHODS

We calculated the frequency of detection and concentration of tobacco smoke metabolites measured in meconium (nicotine, cotinine, and trans-3'-hydroxycotinine concentrations) and three serial serum cotinine concentrations taken during the latter two-thirds of pregnancy among 337 mother-infant dyads. We estimated the duration and intensity of prenatal tobacco smoke exposure using serial serum cotinine concentrations and calculated geometric mean meconium tobacco smoke metabolite concentrations according to prenatal exposure. We also compared the estimated associations between these prenatal biomarkers and infant birth weight using linear regression.

RESULTS

We detected nicotine (80%), cotinine (69%), and trans-3'-hydroxycotinine (57%) in most meconium samples. Meconium tobacco smoke metabolite concentrations were positively associated with serum cotinine concentrations and increased with the number of serum cotinine measurements consistent with secondhand or active tobacco smoke exposure. Like serum cotinine, meconium tobacco smoke metabolites were inversely associated with birth weight.

CONCLUSIONS

Meconium is a useful biological matrix for measuring prenatal tobacco smoke exposure and could be used in epidemiological studies that enroll women and infants at birth. Meconium holds promise as a biological matrix for measuring the intensity and duration of environmental toxicant exposure and future studies should validate the utility of meconium using other environmental toxicants.

Neonatal outcome following exposure to organophosphorous pesticides

The aim of our study was to determine the neonatal outcome in mothers and children exposed to organophosphorous pesticides (OP). We found that 22.4% pregnant women were exposed to organophosphorous pesticides. OP pesticide concentration was higher in breast milk, newborn sera than maternal sera. Newborn parameters such as birth weight, birth length, head circumference, Apgar score and presence of meconium, as well as gestational age of delivery, showed no significant difference between the two groups. However, postpartum weight loss, hospitalization duration, levels of newborn bilirubin and glycaemia differed significantly between the two groups. Morbidity and presence of CNS disorders were six times and more than twelve times higher, respectively, in the OP-exposed than in the OP pesticide non-exposed group.

Total pesticide exposure calculation among vegetable farmers in Benguet, Philippines

This was a cross-sectional study that investigated pesticide exposure and its risk factors targeting vegetable farmers selected through cluster sampling. The sampling size calculated with P = .05 was 211 vegetable farmers and 37 farms. The mean usage of pesticide was 21.35 liters. Risk factors included damaged backpack sprayer (34.7%), spills on hands (31.8%), and spraying against the wind (58%). The top 3 pesticides used were pyrethroid (46.4%), organophosphates (24.2%), and carbamates (21.3%). Those who were exposed to fungicides and insecticides also had higher total pesticide exposure. Furthermore, a farmer who was a pesticide applicator, mixer, loader, and who had not been given instructions through training was at risk of having higher pesticide exposure. The most prevalent symptoms were headache (64.1%), muscle pain (61.1%), cough (45.5%), weakness (42.4%), eye pain (39.9%), chest pain (37.4%), and eye redness (33.8%). The data can be used for the formulation of an integrated program on safety and health in the vegetable industry.

Phthalate levels and low birth weight: a nested case-control study of Chinese newborns

OBJECTIVE

To assess maternal-fetal exposure to phthalates and investigate whether in utero phthalate exposure is associated with low birth weight (LBW).

STUDY DESIGN

A total of 201 newborn-mother pairs (88 LBW cases and 113 controls) residing in Shanghai were enrolled in this nested case-control study during 2005-2006. Maternal blood, cord blood, and meconium specimens were collected and analyzed for phthalates by high-performance liquid chromatography-mass spectrometry. Nonparametric tests were used to compare demographic characteristics in cases and controls. Conditional logistic regression and Spearman correlation were used to analyze the association between phthalate exposure and LBW.

RESULTS

No significant differences in gestational age, prepregnancy body mass index, prenatal care, vitamin supplementation, or socioeconomic levels were found between the LBW and control infants. More than 70% of the biosamples had quantifiable levels of phthalates, with higher levels in the LBW infants compared with the controls. Prenatal di-n-butyl phthalate (DBP) exposure was associated with LBW, and di-2-ethylhexyl phthalate (DEHP) was negatively associated with birth length. After adjusting for the potential confounders, DBP concentrations in the highest quartile were associated with an increased risk of LBW.

CONCLUSIONS

Newborns in China are ubiquitously exposed to phthalates; significantly higher phthalate levels were detected in LBW cases compared with controls. In utero DBP and DEHP exposures were associated with LBW in a dose-dependent manner. Prenatal phthalate exposure may be a risk factor for LBW.

Comparison of pesticide exposure and physical examination, neurological assessment, and laboratory findings between full-time and part-time vegetable farmers in the Philippines

OBJECTIVES

This study aimed to compare the work practices and health effects of pesticide exposure between full-time and part-time vegetable farmers.

METHODS

Data was gathered via structured personal interview using a 9-page questionnaire, physical examination, and blood extraction for complete blood count and serum creatinine.

RESULTS

Pyrethroid was the pesticide type most used by both groups. The risk for full-time farmers was related to both the amount of exposure and the type of pesticide. There were more full-time farmers who complained of falling ill because of work. This difference was statistically significant (P = 0.05). The level of those seeking medical attention was also significantly different between the two groups (P = 0.01). In assessing the individual components of the neurologic examination, 5.22% of full-time and 8.63% of part-time farmers had abnormal cranial nerve function, and 22 (5.7%) and 9 (6.47%) had abnormal motor strength. All farmers tested for reflexes, meningeals, and autonomics from both groups were normal. Based on hematologic examination, full-time farmers had higher mean values for creatinine, white blood cell, red blood cell, hemoglobin, and hematocrit. Activity of cholinesterase enzymes in blood can be utilized as a biomarker for the effect of organophosphates; of the 232 blood cholinesterase results, 94 (40%) were abnormal.

CONCLUSION

The study showed certain differences between full-time and part-time farmers in terms of farming practices and health-related problems. Education on safe pesticide use and handling and better health monitoring of the farmers are recommended.

A biomarker validation study of prenatal chlorpyrifos exposure within an inner-city cohort during pregnancy

BACKGROUND

We previously documented significant decreases in chlorpyrifos concentrations in maternal personal and indoor air samples among pregnant African-American and Dominican women from New York City after the 2000-2001 restrictions on its residential use.

OBJECTIVE

We undertook a biomarker validation study within the same cohort to evaluate trends over time in multiple biomarkers of prenatal chlorpyrifos exposure.

METHODS

Subjects were enrolled between February 2001 and May 2004 (n = 102). We measured 3,5,6-trichloro-2-pyridinol (TCPy) in postpartum meconium (n = 83), repeat prenatal maternal spot urine samples (n = 253), and postnatal urine from the mothers (n = 73) and newborns (n = 59). We measured chlorpyrifos in postnatal maternal (n = 92) and umbilical cord (n = 65) blood.

RESULTS

We did not detect TCPy in infant urine, but all other biomarkers showed a highly significant decrease in detection frequencies (chi2 = 7.8-34.0, p < or = 0.005) and mean ranks (p < or = 0.006, Kruskal-Wallis) among subjects enrolled in 2003-2004 compared with those enrolled in 2001-2002. Chlorpyrifos in maternal personal and indoor air declined 2- to 3-fold over the same period (p < 0.05). In 2001-2002 samples, TCPy levels in repeat prenatal urine were positively correlated (r = 0.23-0.56), but within-subject variability exceeded between-subject variability (intraclass correlation coefficient = 0.43); indoor air levels explained 19% of the variance in prenatal urine TCPy (p = 0.001). Meconium TCPy concentrations were positively correlated with chlorpyrifos in maternal and cord blood (r = 0.25-0.33, p < 0.05) and with TCPy in maternal urine (r = 0.31, p < 0.01).

CONCLUSIONS

Results suggest the biomarkers are reliable dosimeters to differentiate between groups with prenatal chlorpyrifos exposures varying by a factor of 2 or more and vividly illustrate the efficacy of residential restriction on chlorpyrifos to reduce the internal dose during pregnancy.

Applicability of non-invasively collected matrices for human biomonitoring

With its inclusion under Action 3 in the Environment and Health Action Plan 2004-2010 of the European Commission, human biomonitoring is currently receiving an increasing amount of attention from the scientific community as a tool to better quantify human exposure to, and health effects of, environmental stressors. Despite the policy support, however, there are still several issues that restrict the routine application of human biomonitoring data in environmental health impact assessment. One of the main issues is the obvious need to routinely collect human samples for large-scale surveys. Particularly the collection of invasive samples from susceptible populations may suffer from ethical and practical limitations. Children, pregnant women, elderly, or chronically-ill people are among those that would benefit the most from non-invasive, repeated or routine sampling. Therefore, the use of non-invasively collected matrices for human biomonitoring should be promoted as an ethically appropriate, cost-efficient and toxicologically relevant alternative for many biomarkers that are currently determined in invasively collected matrices. This review illustrates that several non-invasively collected matrices are widely used that can be an valuable addition to, or alternative for, invasively collected matrices such as peripheral blood sampling. Moreover, a well-informed choice of matrix can provide an added value for human biomonitoring, as different non-invasively collected matrices can offer opportunities to study additional aspects of exposure to and effects from environmental contaminants, such as repeated sampling, historical overview of exposure, mother-child transfer of substances, or monitoring of substances with short biological half-lives.

Non-invasive matrices in human biomonitoring: a review

Humans and other living organisms are exposed to a variety of chemical pollutants that are released into the environment as a consequence of anthropogenic activities. Environmental pollutants are incorporated into the organism by different routes and can then be stored and distributed in different tissues, which leads to an internal concentration that can induce different alterations, adverse effects and/or diseases. Control measures should be taken to avoid these effects and human biomonitoring is a very useful tool that can contribute to this aim. Human biomonitoring uses different matrices to measure the target chemicals depending on the chemical, the amount of matrix necessary for the analysis and the detection limit (LOD) of the analytical technique. Blood is the ideal matrix for most chemicals due to its contact with the whole organism and its equilibrium with organs and tissues where chemicals are stored. However, it has an important disadvantage of being an invasive matrix. The development of new methodology and modern analytical techniques has allowed the use of other matrices that are less or non-invasive, such as saliva, urine, meconium, nails, hair, and semen or breast milk. The presence of a chemical in these matrices reflects an exposure, but correlations between levels in non-invasive matrices and blood must be established to ensure that these levels are related to the total body burden. The development of new biomarkers that are measurable in these matrices will improve non-invasive biomonitoring. This paper reviews studies that measure Cd, Pb, Hg, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), organochlorine pesticides and phthalates in non-invasive matrices, the most used techniques for measurements and what alternative techniques are available.

Combined analysis of prenatal (maternal hair and blood) and neonatal (infant hair, cord blood and meconium) matrices to detect fetal exposure to environmental pesticides

OBJECTIVE

The aim of this study was to determine optimum biomarkers to detect fetal exposure to environmental pesticides by the simultaneous analysis of maternal (hair and blood) and infant (cord blood, infant hair or meconium) matrices and to determine if a combination of these biomarkers will further increase the detection rate.

PATIENTS AND METHODS

Pregnant women were prospectively recruited from an agricultural site in the Philippines with substantial use at home and in the farm of the following pesticides: propoxur, cyfluthrin, chlorpyrifos, cypermethrin, pretilachlor, bioallethrin, malathion, diazinon and transfluthrin. Maternal hair and blood were obtained at midgestation and at delivery and infant hair, cord blood and meconium were obtained after birth. All samples were analyzed by gas chromatography/mass spectrometry (GC/MS) for the above pesticides and some of their metabolites.

RESULTS

A total of 598 mother/infant dyads were included in this report. The highest rates of pesticide exposure were detected in meconium (23.2% to propoxur, 2.0% to pretilachlor, 1.7% to cypermethrin, 0.8% to cyfluthrin, 0.7% to 1,1,1-trichloro-2,2-bis, p-chlorophenylethane (DDT) and 0.3% to malathion and bioallethrin) and in maternal hair (21.6% to propoxur, 14.5% to bioallethrin, 1.3% to malathion, 0.8% to DDT, 0.3% to chlorpyrifos and 0.2% to pretilachlor). Combined analysis of maternal hair and meconium increased detection rate further to 38.5% for propoxur and to 16.7% for pyrethroids. Pesticide metabolites were rarely found in any of the analyzed matrices.

CONCLUSIONS

There is significant exposure of the pregnant woman and her fetus to pesticides, particularly to the home pesticides, propoxur and pyrethroids. Analysis of meconium for pesticides was the single most sensitive measure of exposure. However, combined analysis of maternal hair and meconium significantly increased the detection rate. A major advantage of analyzing maternal hair is that prenatal pesticide exposure in the mother can be detected and intervention measures can be initiated to minimize further exposure of the fetus to pesticides.

Human carboxylesterases HCE1 and HCE2: ontogenic expression, inter-individual variability and differential hydrolysis of oseltamivir, aspirin, deltamethrin and permethrin

Carboxylesterases hydrolyze chemicals containing such functional groups as a carboxylic acid ester, amide and thioester. The liver contains the highest carboxylesterase activity and expresses two major carboxylesterases: HCE1 and HCE2. In this study, we analyzed 104 individual liver samples for the expression patterns of both carboxylesterases. These samples were divided into three age groups: adults (>or= 18 years of age), children (0 days-10 years) and fetuses (82-224 gestation days). In general, the adult group expressed significantly higher HCE1 and HCE2 than the child group, which expressed significantly higher than the fetal group. The age-related expression was confirmed by RT-qPCR and Western immunoblotting. To determine whether the expression patterns reflected the hydrolytic activity, liver microsomes were pooled from each group and tested for the hydrolysis of drugs such as oseltamivir and insecticides such as deltamethrin. Consistent with the expression patterns, adult microsomes were approximately 4 times as active as child microsomes and 10 times as active as fetal microsomes in hydrolyzing these chemicals. Within the same age group, particularly in the fetal and child groups, a large inter-individual variability was detected in mRNA (430-fold), protein (100-fold) and hydrolytic activity (127-fold). Carboxylesterases are recognized to play critical roles in drug metabolism and insecticide detoxication. The findings on the large variability among different age groups or even within the same age group have important pharmacological and toxicological implications, particularly in relation to pharmacokinetic alterations of ester drugs in children and vulnerability of fetuses and children to pyrethroid insecticides.