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    No place to hide: Marine habitat does not determine per- and polyfluoroalkyl substances (PFAS) in odontocetes
    (Elsevier B.V., 2025-12-10) Stockin KA; Peters KJ; Saltré F; Machovsky-Capuska GE; Betty EL; Tremblay LA; Yi S
    As meso- and apex predators in food webs, marine mammals can bioconcentrate persistent environmental contaminants like per- and polyfluoroalkyl substances (PFAS). Although the presence of PFAS is widely reported in the marine environment, there is a lack of data for cetaceans in Oceania. We investigated whether ecological habitat influences bioconcentration patterns across a range of odontocete (toothed whale, dolphin and porpoise) species. We measured PFAS in liver samples (n = 127) from 16 cetacean species representing four families inhabiting four marine habitats along the Aotearoa New Zealand coastline. We analysed six perfluoroalkyl carboxylic acids, ten perfluoroalkyl sulphonic acids and four precursor compounds in the context of sex, body index, habitat and species/family using generalized linear mixed models. Results showed that marine habitat remained a weak predictor of PFAS burden. Instead, biological factors including sex and age class best explained the levels of PFAS detected across all species and habitats. We offer first important insights on PFAS levels across several new taxa globally, including endemic endangered species and poorly described polar vagrants. Our findings further highlight how the ubiquitous nature of PFAS pose a higher risk to odontocetes across different seascapes than previously anticipated.
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    Biological monitoring of persistent organic pollutants (POPs) in New Zealand : a thesis by publications presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Public Health, Centre for Public Health Research, Massey University, Wellington, New Zealand
    (Massey University, 2018) Coakley, Jonathan Davis
    This thesis reports the results of a national research program investigating persistent organic pollutants (POPs) in New Zealanders. The research investigated human body burdens, and exposure sources, of the following POPs: • Polychlorinated dibenzo-p-dioxins (PCDDs) and furans (PCDFs) • Polychlorinated biphenyls (PCBs) • Organochlorine pesticides (OCPs) such as dichlorodiphenyltrichloroethane (DDT) • Brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) • Perfluoroalkyl substances (PFAS) such as perfluorooctanosulfonic acid (PFOS). Previous research has shown that POPs are toxic, and that they are found in the bodies of all humans and wildlife. This thesis builds on previous research by describing the results of recent studies of New Zealand human body burdens of POPs and comparing these results to previous New Zealand research and international studies. The research includes the second national survey of POPs in the serum of adult New Zealanders, and a related study of the importance of household dust as an exposure source for BFRs in breast-feeding infants. The POPs serum survey methodology was assessed, showing that younger adults, and those of Māori ethnicity, are less likely to participate in human biological monitoring surveys. The research found that the body burdens for the chlorinated POPs were higher for the older age groups. In contrast, the majority of BFRs showed higher serum concentrations in younger age groups. The observed positive association with age for the chlorinated POPs may be attributed primarily to a cohort effect (i.e. more recent cohorts having been exposed to lower levels of chlorinated POPs). The research also provides evidence that within the same cohort, chlorinated POPs body burdens have reduced over time, though some POPs appeared to have reached steady-state concentrations in individuals. In addition, burdens of BFRs and PFASs were found to be higher in men compared to women, possibly due to sex-related differences in human elimination of these POPs. In comparison to international results, New Zealand adults have (a) relatively low body burdens of PCDDs, PCDFs, and PCBs, and (b) similar body burdens of BFRs, PFASs, and OCPs (especially DDT compounds) to the rest of the world. Household dust is an important exposure source of BFRs in human milk. Over the past 15 years, human body burdens (measured in serum and breast milk) of chlorinated POPs have decreased in New Zealand and internationally, illustrating the effectiveness of measures to control POPs (e.g. the Stockholm Convention). The research provides the first reference point for human body burdens of BFRs and PFASs in the New Zealand adult population. In summary, the research outlined in this thesis provides insights into the distribution and dynamics of POPs in humans. The findings from the research, particularly the influence of age on the dynamics of POPs over time, and the exposure of children to POPs at a very early age, provide incentive for further research and public health initiatives. The research provides a resource to inform future biological monitoring programmes, and to aid in the assessment of human health risks from exposure to POPs.
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    Elevating phosphorus accumulation in waste stabilisation pond algae : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Environmental Engineering at Massey University, Palmerston North, New Zealand
    (Massey University, 2019) Sells, Matthew
    Facultative waste stabilisation ponds (WSP) are used globally for wastewater treatment due to their low cost and simple operation. While WSPs can be effective at removing organic pollutants and pathogens, phosphorus removal is typically poor. Algae that are common in WSPs are known to accumulate phosphorus and increase their phosphorus content in the biomass from 1% up to 3.8% (gP/gSS), which is believed to be from the production of intracellular polyphosphate granules. This phenomenon, known as luxury uptake, may be possible to manipulate to improve phosphorus removal in WSPs; however, its occurrence is sporadic and poorly understood. This PhD thesis was undertaken to investigate the conditions that influence phosphorus accumulation in WSP algae. Phosphorus accumulation was quantified using two methods: (1) the traditional phosphorus content in the biomass (gP/gSS), and (2) a new image analysis method developed in this thesis that quantifies stained polyphosphate granules within individual algal cells (μm2 granule/μm2 cell). Following a literature review and screening experiments that sought to identify variables that could affect the phosphorus content in the biomass (gP/gSS), six variables: temperature, phosphorus concentration, light intensity, mixing intensity, organic load, and pH were comprehensively examined using 40 batch factorial experiments (26-1) and a mixed genus culture from a full-scale WSP. Nine variables and interactions had a significant effect on the phosphorus content in the biomass and were incorporated into a regression equation. This ‘mixed genus’ regression equation was tested against literature data, where seven out of the eight batch experiments from the literature were successfully predicted. In order to identify if the batch findings could be applied to a continuous process, which is more typical of full-scale WSPs, a bench-scale novel ‘luxury uptake’ process was designed, built, and operated under five different scenarios. The regression equation successfully predicted the experimental results for three of the five conditions examined. It was theorised that differences in behaviour at the genus level might explain why all five conditions were not successfully predicted. In an attempt to improve the prediction capability, the ‘black-box’ of mixed genus analysis was ‘opened’ to allow the effects of variables on phosphorus accumulation at the genus level to be directly examined. To achieve this, a new image analysis method was developed that quantified stained polyphosphate granules in individual algal cells. To ensure the granules being measured were indeed polyphosphate, algal cells were analysed using transmission electron microscopy coupled with energy dispersive X-ray spectroscopy, which confirmed the granules contained higher levels of phosphorus compared to the remaining cell. The image analysis method was then used to quantify stained polyphosphate granules in individual cells from the 40 batch factorial experiments mentioned previously. The results using the image analysis method showed that, for the five most abundant algal genera, Micractinium/Microcystis had the highest average accumulation of polyphosphate granules (17% μm2 granule/μm2 cell), followed by Scenedesmus (12%), Pediastrum (11%), Monoraphidium (8%), and Actinastrum (4%). Although none of the genera studied had the same combination of significant variables, all five genera preferred a high phosphorus concentration to elevate polyphosphate granule accumulation. Furthermore, a high light intensity, high organic load, or high temperature was preferred by the algae if the variable was significant for that genus. The culture used in the bench-scale continuous flow ‘luxury uptake’ process originated from a mixed genus WSP culture; however, it had become dominated by the Scenedesmus genus. Therefore, the regression equation was refined to use the batch data for this genus alone. This new Scenedesmus regression equation was compared against the experimental data from the ‘luxury uptake’ process previously mentioned. Polyphosphate granule accumulation was now successfully predicted in all five experimental conditions at the 95% confidence level. This improved prediction capability indicates that an understanding of the algal genus present in a WSP system is required for accurate predictions of the phosphorus accumulation to be obtained, and the batch data can indeed be applied to a continuous process. An unexpected result of the research was that, contrary to what was believed in the literature, an increase in the phosphorus content in the biomass did not necessarily increase the polyphosphate granule accumulation. Further examination identified that individual cells from the same algal species had varying polyphosphate granule contents from 0% to over 20% (μm2 granule/μm2 cell) when exposed to the same conditions. This variation was hypothesised to be from cellular functions influencing the granules differently depending on the individual alga’s cell cycle. In addition, when the phosphorus content in the biomass was increased above 2.1% (gP/gSS), no significant effect on the average quantity of polyphosphate granules was observed. This finding indicates that other forms of phosphorus storage must be responsible for attaining a highly elevated phosphorus content in the biomass.