Polybrominated diphenyl ethers (PBDEs) in human milk from Australia

Polybrominated diphenyl ethers (PBDEs) are flame retardants added to a multitude of products to reduce flammability. PBDEs have been widely detected and quantified in biota and humans in many industrialised countries from the Northern Hemisphere. However data concerning the levels of these compounds in the Australian population and environment remain limited. The objectives of this study were to determine PBDE concentrations and congener profiles in Australian human milk and compare this to concentrations found in other countries. Pooled human milk samples obtained from mothers residing in 12 regions of Australia were analysed by HRGC/HRMS for 18 PBDE congeners. In total, 157 human milk samples collected in 2002 and 2003 were divided into 17 regional pools. PBDEs were detected in all pools of human milk from Australia. The mean+/-standard deviation and median summation operatorPBDE concentrations were 11.1+/-3.2 and 11.0 ng g(-1) lipid, respectively with a range of 6.1-18.7 ng g(-1) lipid. The congener profile was dominated by BDE-47 followed by BDE-99, -100, -153, -154 and -183. Regional differences were evaluated, but no trends were observed. The data suggest regional differences are likely to be small if they exist at all. The concentrations of PBDEs found in Australian human milk were lower than those reported from North America but higher than those reported from Europe and Asia. Our results suggest that the exposure pathways which contribute to the PBDE body burden in the Australian population require a better understanding in order to determine future policy regarding their use and disposal.     

Evaluation and Improvement of a Dry Deposition Model using SO2 and O3 Measurements over a Mixed Forest

A dry deposition model (RDM) for operational application has beenevaluated and modified in the present study. Field measurements of friction velocity and dry deposition velocity of SO₂ andO₃ over a mixed forest have been used to evaluate RDM. It was found that RDM predicts friction velocities very close to measurements and thus it can predict reasonable aerodynamic resistance. RDM overestimated O₃ deposition during dry nighttime conditions and underestimated both O₃ andSO₂deposition for early morning hours. It could not predict the mean diurnal variation in deposition velocity for either O₃ or SO₂ deposition under wet surface conditions. Modifications have been made for O₃ and SO₂ dry deposition based on the comparison of results and based upon additional published data. Compared to an earlier version of RDM, the modified versionpredicts better results for O₃ and SO₂ dry deposition,especially under rain and dew conditions.     

Key role for nuclear energy in global biodiversity conservation

Modern society uses massive amounts of energy. Usage rises as population and affluence increase, and energy production and use often have an impact on biodiversity or natural areas. To avoid a business‐as‐usual dependence on coal, oil, and gas over the coming decades, society must map out a future energy mix that incorporates alternative sources. This exercise can lead to radically different opinions on what a sustainable energy portfolio might entail, so an objective assessment of the relative costs and benefits of different energy sources is required. We evaluated the land use, emissions, climate, and cost implications of 3 published but divergent storylines for future energy production, none of which was optimal for all environmental and economic indicators. Using multicriteria decision‐making analysis, we ranked 7 major electricity‐generation sources (coal, gas, nuclear, biomass, hydro, wind, and solar) based on costs and benefits and tested the sensitivity of the rankings to biases stemming from contrasting philosophical ideals. Irrespective of weightings, nuclear and wind energy had the highest benefit‐to‐cost ratio. Although the environmental movement has historically rejected the nuclear energy option, new‐generation reactor technologies that fully recycle waste and incorporate passive safety systems might resolve their concerns and ought to be more widely understood. Because there is no perfect energy source however, conservation professionals ultimately need to take an evidence‐based approach to consider carefully the integrated effects of energy mixes on biodiversity conservation. Trade‐offs and compromises are inevitable and require advocating energy mixes that minimize net environmental damage. Society cannot afford to risk wholesale failure to address energy‐related biodiversity impacts because of preconceived notions and ideals.     

Perinatal outcomes and genomic characteristics of fetal copy number variants: An individual record linkage study of 713 pregnancies

Objective

To determine the perinatal outcomes of fetuses diagnosed with a pathogenic copy number variant (CNV) or variant of uncertain significance (VUS); and to characterize these variants in terms of testing indication, genomic location, size, and inheritance.

Methods

Retrospective study of singleton pregnancies with a pathogenic CNV or VUS from a single laboratory during 2012–2018. Probabilistic record linkage between the prenatal diagnosis dataset and perinatal outcome data for births from 20 weeks gestation was performed. If no birth record was found, this implied a pregnancy loss <20 weeks.

Results

We included 6945 prenatal microarray results; a pathogenic CNV was detected in 230 (3.3%, 95% CI: 2.9%–3.8%) and a VUS in 483 (7.0%, 95% CI: 6.4%–7.6%). Of pregnancies with a pathogenic CNV, 20.0% (95% CI: 15.3%–25.6%) had a live birth, 3.0% (95% CI: 1.5%–6.2%) had a perinatal death (stillbirth or neonatal death), and 77% (95% CI: 71.1%–81.9%) had no birth record. Of those with a VUS, 64.4% (95% CI: 60.0%–68.5%) had a live birth, 1.8% (95% CI: 1.0%–3.5%) had a perinatal death, and no birth record was found for 33.7% (95% CI: 29.7%–38.1%). Most pathogenic CNVs (61.1%) were <7 Mb in size. The most common microdeletion syndromes were DiGeorge, Wolf-Hirschhorn, and Cri-du-chat syndromes.

Conclusion

This study provides an overview of perinatal outcomes and frequency of recurrent CNVs observed in the prenatal microarray era.     

Synchronous aggregated pseudo-copulation of the sea star <Emphasis Type="Italic">Archaster angulatus</Emphasis> Müller &; Troschel, 1842 (Echinodermata: Asteroidea) and its reproductive cycle in south-western Australia

Mass individual pairing or pseudo-copulation of the sea star Archaster angulatus was observed in November and December 2009, suggesting a late-spring/summer spawning period for this species on the west coast of Australia. Detailed measurements were made on the second of these occasions. Density of sea stars was 1.11 per m² and 68.5% were in mating pairs. Copulating pairs were mostly male on female, occasionally male on male. There was no difference in size between males and females in mating pairs. No evidence was found to indicate mating and spawning is coincident with lunar or tidal cycles. Females outnumbered males by more than 20%, but the difference in sex ratio was not statistically significant. Analysis of the reproductive cycle revealed that gonad indices reached their peak in October and declined from then until January. Histological sections of gonads confirmed that sea stars are in peak reproductive condition in October and November and are fully spent by January. Males have a much lower (ca. 1/3rd) gonad index than females when each are in peak reproductive condition, the second lowest recorded for any sea star. Pyloric caecae indices showed little annual variation and monthly averages of just 3–4% are among the lowest ever recorded for an asteroid. It is suggested that these characteristics are associated with the copulatory behaviour of the deposit feeding A. angulatus, enabling the species to maintain a high level of fertilisation success while also minimising the allocation of energy to gonad development in habitats with low or variable food availability. However, it is still difficult to explain why a species which ensures a high level of fertilisation by pseudo-copulation also does this en masse and synchronously. One hypothesis is that competition for males and the benefits of having eggs fertilised by multiple males favours both synchrony and aggregation.     

Visualising the equilibrium distribution and mobility of organic contaminants in soil using the chemical partitioning space

Assessing the behaviour of organic chemicals in soil is a complex task as it is governed by the physical chemical properties of the chemicals, the characteristics of the soil as well as the ambient conditions of the environment. The chemical partitioning space, defined by the air-water partition coefficient (K(AW)) and the soil organic carbon-water partition coefficient (K(OC)), was employed to visualize the equilibrium distribution of organic contaminants between the air-filled pores, the pore water and the solid phases of the bulk soil and the relative importance of the three transport processes removing contaminants from soil (evaporation, leaching and particle erosion). The partitioning properties of twenty neutral organic chemicals (i.e. herbicides, pharmaceuticals, polychlorinated biphenyls and volatile chemicals) were estimated using poly-parameter linear free energy relationships and superimposed onto these maps. This allows instantaneous estimation of the equilibrium phase distribution and mobility of neutral organic chemicals in soil. Although there is a link between the major phase and the dominant transport process, such that chemicals found in air-filled pore space are subject to evaporation, those in water-filled pore space undergo leaching and those in the sorbed phase are associated with particle erosion, the partitioning coefficient thresholds for distribution and mobility can often deviate by many orders of magnitude. In particular, even a small fraction of chemical in pore water or pore air allows for evaporation and leaching to dominate over solid phase transport. Multiple maps that represent soils that differ in the amount and type of soil organic matter, water saturation, temperature, depth of surface soil horizon, and mineral matters were evaluated.     

Moving beyond “mitigation and adaptation”: examining climate change responses in New Zealand

Despite the apparent failure of international negotiations and renewed criticism of the accuracy of climate science, responses to climate change continue in households, cities, fields, and meeting rooms. Notions of “doing something about”, or “taking action on” or “mitigating and adapting” to climate change inform practices of carbon trading, restoring native forests, constructing wind turbines, insulating houses, using energy efficient light bulbs, and lobbying politicians for more or less of these actions. These expressions of agency in relation to climate change provide the focus of our enquiry. We found that relationships or social networks linked through local government are building capabilities to respond to climate change. However, the framework of “mitigation–adaptation” will need to be supplemented by a more diverse suite of mental models for making sense of climate change. Use of appropriate languages, cultural reference points, and metaphors embedded in diverse histories of climates and change will assist actors in their networked climate change responses.     

Phosphorus and nitrogen in soil, plants, and overland flow from sheep-grazed pastures fertilized with different rates of superphosphate

Eutrophication of waterways through delivery of phosphorus (P) and nitrogen (N) from farmland is a problem in many countries. Loss of nutrients from grazed grassland via overland flow is well demonstrated, but the sources of these nutrients and the processes controlling their mobilization into water are not well understood. Much of the nutrient loss in overland flow from grazed pastures may be due to generally increased fertility of the soil–plant system (i.e. background or ‘systematic’ nutrient loss) rather than to immediate loss after fertilizer application [Nash, D., Clemow, L., Hannah, M., Barlow, K., Gangaiya, P., 2005. Modelling phosphorus exports from rain-fed and irrigated pastures in southern Australia. Aust. J. Soil Res. 43, 745–755]. The main aim of this study was to measure the effects of long-term (25 years) superphosphate (Ca(H₂PO₄)₂ + 2CaSO₄) fertilizer application (0–23 kg/(ha year)) on P and N in soil, plants, and potential background P and N movement in overland flow (generated using a rainfall simulator) from sheep-grazed pastures in southern Australia. Measurements were taken in autumn, under dry soil conditions, and in winter, under wet soil conditions, 12 and 15 months after the last fertilizer applications, respectively. Superphosphate application caused a strong increase in plant P, soil total P, Olsen P, and Colwell P; and a weaker increase in plant N, soil total N, and inorganic N (ammonium and nitrate). Soil P and N were concentrated in the surface 25 mm of soil. Soil water-extractable P, calcium chloride-extractable P, and calcium chloride organic P were in general only poorly associated with fertilizer application. The concentration of P and, to a lesser extent, the concentration of N in overland flow increased with increasing fertilizer application and showed strong seasonal differences (0.06–0.77 mg P/L and 0.6–5.5 mg N/L in autumn; 0.04–0.20 mg P/L and 0.4–1.7 mg N/L in winter). The P in overland flow was predominantly dissolved reactive P in autumn and particulate P in winter. The N in overland flow contained significant proportions of dissolved organic N, dissolved inorganic N (ammonium and nitrate), and particulate N. The concentrations of P and N in overland flow usually exceeded State water quality targets (<0.04 mg P/L and <0.90 mg N/L), suggesting that background losses of nutrients from these pasture systems could contribute to the eutrophication of waterways.