Assessing body burden of persistent organic pollutants (POPs) in infants/toddlers through analysis of faeces

Abstract

The fact that non-communicable diseases (NCDs) have become the leading causes of death and disability over the past two decades globally warrants dedicated research and the implementation of prevention strategies. Global restrictions/bans have been placed on persistent organic pollutants (POPs) due to the links between early-life exposure to them and NCD risks that have been observed in epidemiological studies. Certain POP groups (such as polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenylethers (PBDEs)) are present/persistent in human breast milk at considerable levels several decades/years despite restrictions/bans. Increased understanding of exposureresponse relationship is now needed to confirm the significant pollutants exposures and their exposure windows. Individual data from early childhood biomonitoring POPs is, therefore, vital.Direct measurements of body burdens in early childhood have been a challenge, due to the reduced availability of invasive-biomonitoring (such as blood sampling) under ethical and practical considerations. Early-childhood biomonitoring studies typically rely on measurements of breast milk concentrations and/or modelling the body burden of POPs in infants/toddlers using intake estimates and growth data. Previously, concentrations of selected POPs in faeces of adults were reported to be largely independent of the dietary intake of chemicals, but dependent on the body burden. Thus, this thesis aimed to investigate the viability of using faeces as a non-invasive matrix for estimating the body burden of POPs in infant/toddlers. Faeces, as a biomonitoring matrix, was not well-documented for both the convenience and the practical scope previously. An effective analytical method, including sampling faeces and POPs extraction/cleanup and quantification, was developed and had been modified throughout the study with recent advances in sample-preparation techniques. Based on the effective analytical method, the relationship between the POP concentrations in faeces and the body burden (assessed via breast milk and blood samples) in infants/toddlers was then investigated.The measured concentrations of POPs in the faeces of a group of 7 infants/toddlers were compared to existing pooled blood serum data from children (0-4 years) in Australia (Chapter 2). The similarity of POP profiles observed between the existing blood data and the collected faeces samples hold promise for the viability of faecal analysis as an early-exposure biomonitoring tool. Subsequently, matched breast milk and faecal samples from 10 mother-child pairs were obtained and analyzed with the distribution of individual exposure levels of infants/toddlers and the correlation between exposure and faecal concentrations being investigated for the first time (Chapter 3). 3The monthly variation of POP concentrations in faeces over the first year of life of one infant was investigated and compared to modelled blood concentrations (Chapter 4). The results showed the POP concentrations ...

Feasibility Study of Feces for Noninvasive Biomonitoring of Brominated Flame Retardants in Toddlers

“…Several established and emerging BFRs were detected, many for the first time, in feces from toddlers. The concentrations of BDE-47 and -153 in this study were 11–12 and 2–4 times lower, respectively, compared to the concentrations reported in an infant and a toddler and 10 and 8 times lower, respectively, in 10 nursing infants from Australia . This is in agreement with earlier studies reporting higher BDE levels in house dust and humans in Australia compared to Europe. ,, No other matching congeners were reported in the Australian studies, , and to our knowledge, no other studies have reported PBDEs in human feces.…”

“…44 This is in agreement with earlier studies reporting higher BDE levels in house dust and humans in Australia compared to Europe. 30,50,51 No other matching congeners were reported in the Australian studies, 44,45 and to our knowledge, no other studies have reported PBDEs in human feces.…”

“…Tri-heptaBDEs have been reported in feces from an infant and a toddler from Australia comparing BDE levels between the two feces samples and a pooled blood sample from Australian children 0−4 years of age. 45 No other BFRs have been reported in human feces. If BFR concentrations correlate between serum and feces in toddlers as has been seen for adults, feces could be feasible for use as a noninvasive sample matrix to estimate BFR concentrations in serum of toddlers for biomonitoring purposes.…”

“…Several studies of nursing infants have also compared PCDD/F, PCB, and HCB , and PCBs, tetra-hexaBDEs, and pesticide concentrations in feces to those in breast-milk to determine uptake and fecal excretion rates. Tri-heptaBDEs have been reported in feces from an infant and a toddler from Australia comparing BDE levels between the two feces samples and a pooled blood sample from Australian children 0–4 years of age . No other BFRs have been reported in human feces.…”

Determining Polychlorinated Biphenyls in Soil Using Accelerated Solvent Extraction (ASE)

“…the polycyclic aromatic hydrocarbons (PAH), pesticides, and PCBs from various environmental matrices. The method is often used due to the use of small amounts of solvents, small weighed amounts, short analysis time, and satisfactory repeatability [6][7][8][9][10].…”