Levels and determinants of urinary phthalate metabolites in New Zealand children and adults.

BACKGROUND: This first national biomonitoring survey of urinary phthalate metabolites in the New Zealand population aimed to provide baseline data, identify exposure determinants, and make comparisons with health-based exposure guidance values. METHODS: The survey conducted in 2014-2016 involved the collection of morning-void urine from 298 children (5-18 years) and 302 adults (20-65 years), 33% of Maori ethnicity. A questionnaire collected information on demographic factors and diet. Urine was analysed for creatinine, specific gravity, and 10 phthalate metabolites through liquid chromatography tandem-mass spectrometry (MMP; MEP; MBP iso+n; MBzP; MCHP; MEHP; MEOHP; MEHHP; MCPP; and MiNP). Determinants of exposure were assessed using multivariable linear regression. RESULTS: Detection frequencies exceeded 95% for metabolites of DEP, DEHP and DBP. The highest GM was observed for the DBP metabolite MBP iso+n (36.1 µg/L adults; 60.5 µg/L children), followed by the sum of three DEHP metabolites (MEHP+MEOHP+MEHHP: 19.0 µg/L adults; 37.0 µg/L children), and the DEP metabolite MEP (19.1 µg/L adults; 12.0 µg/L children). For most phthalate metabolites New Zealand levels were in the mid-range of internationally reported levels, while for DEP they were in the low range. Maori and non-Maori had similar levels. Children had higher GMs than adults for most metabolites, except for MEP. A proportion of children and adults exceeded the biomonitoring equivalents of health-based guidance values for DBP (0-16% and 0-3% respectively), and DEHP (0-0.7% and 0-0.3% respectively). Eating warm meals from plastic containers ≥2 times/week was associated with higher levels of DEHP metabolites, MBP iso+n, and MBzP. CONCLUSION: Phthalate exposure is omnipresent in both children and adults in New Zealand. Exceedances of the biomonitoring equivalents for DBP and DEHP indicate that potential health effects from exposure to these phthalates cannot be excluded with sufficient certainty.

Total blood mercury and its determinants in New Zealand children and adults.

BACKGROUND: Mercury is a widespread persistent environmental pollutant associated with adverse health effects. OBJECTIVE: This first national biomonitoring survey of blood total mercury (tHg) conducted in New Zealand aimed to provide baseline data and identify exposure determinants. METHODS: Blood was collected from 191 children (age 5-18 years) and 304 adults (20-65) in 2014-2016 and analysed for tHg using inductively coupled plasma mass spectrometry. Linear regression was used to assess associations with demographic and lifestyle factors. RESULTS: Blood mercury was detected in 93% of children and 99% of adults, with geometric means (GMs) of 0.86 and 1.65 µg/L, respectively. The 60-65-year olds had the highest GM (2.34 µg/L). Regression indicated that tHg was 40% higher in boys compared to girls. Eating fish ≥ 3 times/week (compared to ≤once/week) was associated with 2.7 and 1.7 times higher tHg in children and adults, respectively. Shellfish consumption was also associated with higher tHg. High daily tap water consumption (≥2 L for children, ≥3 L for adults) was associated with lower tHg. In adults, smoking and milk consumption were associated with higher tHg. SIGNIFICANCE: Fish and shellfish consumption is a strong determinant of New Zealanders blood tHg levels, with water and milk consumption possibly acting as modulating factors.

Where are we at with lead? Current levels, time trend, and determinants of blood lead in New Zealand children and adults.

AIMS: A national biomonitoring survey was conducted in 2014-2016, to determine current blood lead levels (BLL) in New Zealand children and adults and identify determinants of BLL. METHODS: Blood samples were provided by 191 children (age 5-18) and 304 adults (age 20-65) and analysed for BLL using inductively coupled mass spectroscopy. Linear regression on log-transformed BLL was used to assess associations between BLL and demographic and lifestyle factors collected via questionnaire. RESULTS: The geometric mean (GM) BLL was 0.86 µg/dl (95%CI 0.80-0.92) for children and 1.31 µg/dl (1.23-1.39) for adults, representing a 90% reduction in BLL over the past 36 years. For children, shellfish consumption was associated with 20% higher BLL. Adult BLLs were positively associated with age, beer consumption, spirits consumption, having roof water as the home's water supply, and having worked in glass manufacturing. Determinants of reduced BLL were tofu and canned food consumption. For women, menopause was associated with 34% higher BLL. CONCLUSIONS: Although significant reductions in New Zealanders' BLL have been achieved in the past decades, this study identified several additional opportunities to reduce further background exposure to lead. In particular, consideration needs to be given to reducing lead levels in New Zealand roof water supplies.

Estimated infant intake of persistent organic pollutants through breast milk in New Zealand.

AIM: To estimate average infant daily intake of chlorinated persistent organic pollutants (POPs) through the consumption of breast milk in New Zealand. METHOD: Breast milk of 39 first-time mothers aged 20-30 years was collected during 2007-2010 and analysed for persistent organic pollutants including dioxin-like compounds and organochlorine pesticides. The quantity of POPs consumed by infants assuming exclusive breast feeding was estimated by calculating the Estimated Daily Intake (EDI) expressed as amount consumed through breast milk per kilogram of body weight per day. RESULTS: Of all POPs quantified, the EDI of DDT (principally in the form of its metabolite p,p'-DDE) was the highest (1.6 mcg/kg/day), and above the tolerable daily intake (TDI) of 0.5 mcg/kg/day. The mean EDI for dioxin-like compounds (including PCDD/Fs and PCBs) was 19.7 pg TEQ(toxic equivalency)/kg/day, which is among the lowest reported worldwide, yet above the TDI of 1 pg TEQ/kg/day. The EDI of HCH, HCB, dieldrin, heptachlor and mirex were 32.9, 37.9, 39.4, 2.0, and 0.9 ng/kg/day respectively, all of which were below the current TDI. Age of the mother was positively associated with higher EDIs for the infant, particularly for total-TEQ and total-DDT. CONCLUISON: Infant daily intakes of chlorinated POPs through breast milk estimated for New Zealand are low or average by international comparison, and 5 times lower than 25 years ago. Future breast milk monitoring will determine whether this diminishing trend is continuing as well as providing monitoring information on other POPs.

Concentrations of polybrominated diphenyl ethers in matched samples of indoor dust and breast milk in New Zealand.

Polybrominated diphenyl ethers (PBDEs) are present in many consumer goods. There is evidence that PBDEs are toxic to humans, particular young children. The purpose of this study was to assess indoor dust as an exposure source for PBDEs. Concentrations of 16 PBDEs were determined in dust samples from 33 households in New Zealand, and in breast milk samples from 33 mothers living in these households. Associations between dust and breast milk PBDE concentrations were assessed, and children's PBDE intake from breast milk and dust estimated. Influences of household and demographic factors on PBDE concentrations in dust were investigated. Indoor dust concentrations ranged from 0.1ng/g for BDE17 to 2500ng/g for BDE209. Breast milk concentrations were positively correlated (p<0.05) with mattress dust concentrations for BDE47, BDE153, BDE154, and BDE209 and with floor dust for BDE47, BDE183, BDE206, and BDE209. The correlation for BDE209 between dust and breast milk is a novel finding. PBDE concentrations in floor dust were lower from households with new carpets. The estimated children's daily intake of PBDEs from dust and breast milk was below U.S. EPA Reference Dose values. The study shows that dust is an important human exposure source for common PBDE formulations in New Zealand.

Current concentrations, temporal trends and determinants of persistent organic pollutants in breast milk of New Zealand women.

Breast milk samples of 39 first time mothers aged 20-30 were collected in 2007-2010 from rural and urban areas of New Zealand, following the fourth World Health Organization coordinated survey protocol. Samples were individually analysed for persistent organic pollutants (POPs) including dioxins and furans (PCDD/Fs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs). The lipid adjusted concentrations of PCDD/Fs (mean toxic equivalent (TEQ): 3.54 pg/g) and PCBs (mean TEQ 1.29 pg/g) were low in comparison to those reported for other countries, and concentrations of dieldrin (10 ng/g) and p,p'-DDE (379 ng/g) and PBDEs were in the mid-range. Breast milk concentrations of PCDD/F-TEQ, PCB-TEQ, dieldrin and p,p'-DDE were significantly higher in rural compared to urban areas (+23%, 33%, 59%, and 44% respectively), while concentrations of several PBDEs and lindane were higher in urban areas. Concentrations of PCDD/Fs, PCBs and OCPs, but not PBDEs, increased with age, and higher body mass index was associated with lower concentrations of PCBs. Despite New Zealand's low body burdens of many chlorinated POPs in comparison to other countries, breast milk concentrations continued to decrease over time, with a decrease by half over the last 10 years for PCDD/F-TEQ (-40%), PCB-TEQ (-54%) and OCPs -34 to -90%), indicating that regulatory measures continue to have beneficial effects. Continued monitoring is needed particularly for the brominated POPs for which little New Zealand specific data is available.

Partitioning of persistent organic pollutants (POPs) between human serum and breast milk: a literature review.

The literature was reviewed to assess the relationship between the lipid adjusted concentration in human serum and breast milk (expressed as the serum/milk ratio) of a broad range of POPs in paired samples. Thirteen studies were identified, including seven studies that reported serum/milk ratios for polychlorinated dibenzo-dioxins and -furans (PCDD/Fs), ten for polychlorinated biphenyls (PCBs), five for polybrominated diphenyl ethers (PBDEs), and five for organochlorine pesticides (OCPs). Mean serum/milk ratios ranged between 0.7 and 25 depending on the compound and congener. For PCDD/Fs, PCBs and PBDEs, a clear trend of increasing mean serum/milk ratio by increasing molar volume, hydrophobicity and number of halogen substitutes was observed. The mean serum/milk ratios reported by the 13 studies summarized here will aid comparison between human POPs exposure studies using either serum or milk samples. More studies are needed to allow a valid comparison between data obtained from analysis of breast milk and serum samples for a broader range of POPs. Furthermore such studies may shed light on compound specific factors as well as other determinants that may affect the partitioning and partition kinetics of POPs between serum and breast milk.

Occurrence of alternative flame retardants in indoor dust from New Zealand: indoor sources and human exposure assessment.

Due to worldwide restrictions on polybrominated diphenyl ethers (PBDEs), the demand for alternative flame retardants (AFRs), such as organophosphate flame retardants (OPFRs), novel brominated FRs (NBFRs) and hexabromocyclododecanes (HBCDs), has recently increased. Little is known about human exposure to NBFRs and OPFRs and that their levels in dust have been scarcely evaluated worldwide. To increase the knowledge regarding these chemicals, we measured concentrations of five major NBFRs, ten OPFRs and three HBCD isomers in indoor dust from New Zealand homes. Dust samples were taken from living room floors (n=34) and from mattresses of the same houses (n=16). Concentrations (ngg(-1)) of NBFRs were: 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) (<2-175), decabromodiphenyl ethane (DBDPE) (<5-1430), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB) (<2-2285) and bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBPH) (<2-640). For OPFRs, concentrations (ngg(-1)) ranged between: tri-ethyl-phosphate (TEP) (<10-235), tri-n-butyl-phosphate (TnBP) (<20-7545), tris-(2-chloroethyl)-phosphate (TCEP) (<20-7605), tris-(1-chloro-2-propyl) phosphate (TCPP) (20-7615), tri-(2-butoxyethyl)-phosphate (TBEP) (50-27325), tris-(2,3-dichloropropyl)-phosphate (TDCPP) (20-16560), tri-phenyl-phosphate (TPhP) (20-35190), and tri-cresyl-phosphate (TCP) (<50-3760). HBCD concentrations fell in the range <2-4100ngg(-1). BTBPE, DBDPE, TBPH, TBEP, and TnBP showed significant positive correlation (p<0.05) between their concentrations in mattresses and the corresponding floor dust (n=16). These data were used to derive a range of plausible exposure scenarios. Although the estimated exposure is well below the corresponding reference doses (RfDs), caution is needed given the likely future increase in use of these FRs and the currently unknown contribution to human exposure by other pathways such as inhalation and diet.