Trace element concentrations, including Cd and Hg, in long-finned pilot whales (Globicephala melas edwardii) mass stranded on the New Zealand coast.

The Southern Hemisphere long-finned pilot whale (Globicephala melas edwardii) is a top predator in the New Zealand pelagic food web, feeding predominantly on arrow squids. This study quantified trace element concentrations (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Ni, Mn, Pb, Se, V, Zn) in four tissues (blubber, kidney, liver, muscle) from 21 individuals from stranding sites in New Zealand. Maximum Cd and Hg concentrations were measured in liver and kidney, respectively. Selenium had a positive correlation with Cd and Hg, suggesting the involvement of Se in Cd and Hg detoxification. Arrow squids from the whales' stomach contents were DNA barcoded and identified as Nototodarus sloanii. Trace element concentrations were measured in squid samples from the whale stomach contents. The significant correlation for Hg between the squid tissue and the whale tissue suggests that arrow squids play a major role in trace element uptake by G. m. edwardii.

Assessment of dispersion of airborne particles of oral/nasal fluid by high flow nasal cannula therapy.

BACKGROUND: Nasal High Flow (NHF) therapy delivers flows of heated humidified gases up to 60 LPM (litres per minute) via a nasal cannula. Particles of oral/nasal fluid released by patients undergoing NHF therapy may pose a cross-infection risk, which is a potential concern for treating COVID-19 patients. METHODS: Liquid particles within the exhaled breath of healthy participants were measured with two protocols: (1) high speed camera imaging and counting exhaled particles under high magnification (6 participants) and (2) measuring the deposition of a chemical marker (riboflavin-5-monophosphate) at a distance of 100 and 500 mm on filter papers through which air was drawn (10 participants). The filter papers were assayed with HPLC. Breathing conditions tested included quiet (resting) breathing and vigorous breathing (which here means nasal snorting, voluntary coughing and voluntary sneezing). Unsupported (natural) breathing and NHF at 30 and 60 LPM were compared. RESULTS: Imaging: During quiet breathing, no particles were recorded with unsupported breathing or 30 LPM NHF (detection limit for single particles 33 µm). Particles were detected from 2 of 6 participants at 60 LPM quiet breathing at approximately 10% of the rate caused by unsupported vigorous breathing. Unsupported vigorous breathing released the greatest numbers of particles. Vigorous breathing with NHF at 60 LPM, released half the number of particles compared to vigorous breathing without NHF.Chemical marker tests: No oral/nasal fluid was detected in quiet breathing without NHF (detection limit 0.28 µL/m3). In quiet breathing with NHF at 60 LPM, small quantities were detected in 4 out of 29 quiet breathing tests, not exceeding 17 µL/m3. Vigorous breathing released 200-1000 times more fluid than the quiet breathing with NHF. The quantities detected in vigorous breathing were similar whether using NHF or not. CONCLUSION: During quiet breathing, 60 LPM NHF therapy may cause oral/nasal fluid to be released as particles, at levels of tens of µL per cubic metre of air. Vigorous breathing (snort, cough or sneeze) releases 200 to 1000 times more oral/nasal fluid than quiet breathing (p < 0.001 with both imaging and chemical marker methods). During vigorous breathing, 60 LPM NHF therapy caused no statistically significant difference in the quantity of oral/nasal fluid released compared to unsupported breathing. NHF use does not increase the risk of dispersing infectious aerosols above the risk of unsupported vigorous breathing. Standard infection prevention and control measures should apply when dealing with a patient who has an acute respiratory infection, independent of which, if any, respiratory support is being used. CLINICAL TRIAL REGISTRATION: ACTRN12614000924651.

Biomarker responses in New Zealand green-lipped mussels Perna canaliculus exposed to microplastics and triclosan.

Microplastics (MPs) are of increasing concern for filter feeding marine and freshwater species. Additionally MPs can sorb hydrophobic contaminants from the water, potentially providing an additional pathway of exposure of aquatic species to contaminants. An acute 48 h laboratory study was conducted to investigate the effects of microplastics and triclosan, both individually and combined, on New Zealand's green-lipped mussel, Perna canaliculus. Biomarkers included clearance rate, oxygen uptake, byssus production; and superoxide dismutase (SOD) activity, glutathione-S-transferase (GST) activity and lipid peroxidation in the gill tissue. Microplastics and triclosan, both individually and combined significantly decreased oxygen uptake and byssus production. These physiological responses were not observed when the microplastics were spiked with triclosan. Triclosan, both alone and spiked to microplastics, increased mussel oxidative stress markers including SOD activity and lipid peroxidation. An enhanced effect was observed on the SOD enzyme activity when mussels were exposed to microplastics spiked with triclosan. No effects on the biochemical biomarkers were observed for mussels exposed to microplastic only. Microplastics enhanced the uptake of triclosan in mussel tissue compared with triclosan only treatments indicating that microplastics potentially provide an additional pathway of exposure to hydrophobic contaminants.

Regional assessment of trace element concentrations in arrow squids (Nototodarus gouldi, N. sloanii) from New Zealand waters: Bioaccessibility and impact on food web and human consumers.

The New Zealand arrow squids, Nototodarus gouldi and N. sloanii, play an important role in the marine food web, and are both economically important fishery species. This study compares trace element concentrations (As, Cd, Co, Cr, Cu, Fe, Hg, Ni, Mn, Pb, U, and Zn) in these animals from different fishing locations within New Zealand's Exclusive Economic Zone (Auckland Islands, Chatham Rise, Dunedin, Golden Bay, Taranaki, and West Coast of the South Island). Muscular mantle (the tissue usually consumed by humans) and digestive gland tissue (the primary organ for trace element accumulation) concentrations were compared among regions, revealing size, species, and sampling location effects. Overall, N. gouldi had higher concentrations of As and Zn. The Taranaki region had the highest concentrations for Cd, Co, Cu, and Zn in both tissues analysed. To assess the bioaccessibility of these trace elements to humans, an in-vitro digestion simulation experiment was conducted, revealing bioavailable concentrations overall below the maximum levels presently considered tolerable for human consumption. However, the in-vitro digestion had no observable effect upon Cd concentrations in arrow squid mantle tissue (implying that the measured concentrations are bioaccessible to humans), and revealed that Cd had the highest potential impact on marine food webs and human health. Digestive gland concentrations in particular indicate that arrow squids can be considered important vectors for trace element transfer to top predators (mean concentration for Cd: 123 ± 148 µg g-1 dw), with region-specific differences.

Elevated mercury concentrations in the feathers of grey-faced petrels (Pterodroma gouldi) in New Zealand.

Our objective was to measure the concentrations of Hg, As, Cd, Co, Cr, Cu, Pb, Sb, V and Zn in the body feathers of grey-faced petrel (Pterodroma gouldi), fluttering shearwater (Puffinus gavia), little shearwater (Puffinus assimilis) and common diving petrel (Pelecanoides urinatrix) from breeding colonies in New Zealand between 2006 and 2013. The mean Hg concentration (36.48ppm; SD=9.59) in grey-faced petrel feathers was approximately 8.5 to 14 times that detected in the other three species sampled. We detected no trend or differences in Hg concentrations in grey-faced petrels over the 8years of this study, but Hg concentrations varied between breeding colonies although there was no strong relationship with latitude. The elevated Hg concentrations detected in grey-faced petrels could pose a risk to the breeding performance of grey-faced petrels and the customary harvest of chicks by Maori (New Zealand's indigenous peoples).

High-temperature electromagnons in the magnetically induced multiferroic cupric oxide driven by intersublattice exchange.

Magnetically induced ferroelectric multiferroics present an exciting new paradigm in the design of multifunctional materials, by intimately coupling magnetic and polar order. Magnetoelectricity creates a novel quasiparticle excitation--the electromagnon--at terahertz frequencies, with spectral signatures that unveil important spin interactions. To date, electromagnons have been discovered at low temperature (<70 K) and predominantly in rare-earth compounds such as RMnO3. Here we demonstrate using terahertz time-domain spectroscopy that intersublattice exchange in the improper multiferroic cupric oxide (CuO) creates electromagnons at substantially elevated temperatures (213-230 K). Dynamic magnetoelectric coupling can therefore be achieved in materials, such as CuO, that exhibit minimal static cross-coupling. The electromagnon strength and energy track the static polarization, highlighting the importance of the underlying cycloidal spin structure. Polarized neutron scattering and terahertz spectroscopy identify a magnon in the antiferromagnetic ground state, with a temperature dependence that suggests a significant role for biquadratic exchange.

Uptake of SigmaDDT, arsenic, cadmium, copper, and lead by lettuce and radish grown in contaminated horticultural soils.

Horticultural soils can contain elevated concentrations of selected trace elements and organochlorine pesticides as a result of long-term use of agrichemicals and soil amendments. A glasshouse study was undertaken to assess the uptake of weathered SigmaDDT {sum of the p, p'- and o, p-isomers of DDT [1,1,1-trichloro-2,2- bis( p-chlorophenyl)ethane], DDE [1,1-dichloro-2,2- bis( p-chlorophenyl)ethylene] and DDD[1,1-dichloro-2,2- bis( p-chlorophenyl)ethane]}, arsenic (As), cadmium (Cd), copper (Cu), and lead (Pb) residues by lettuce ( Lactuca sativa) and radish ( Raphanus sativus) from field-aged New Zealand horticultural soils. Concentrations of SigmaDDT, DDT, DDE, Cd, Cu, and Pb in lettuce increased with increasing soil concentrations. In radish, similar relationships were observed for SigmaDDT, DDE, and Cu. The bioaccumulation factors were less than 1 with the exception of Cd and decreased with increasing soil concentrations. Lettuce Cd concentrations for plants grown on four out of 10 assayed soils were equivalent to or exceeded the New Zealand food standard for leafy vegetables of 0.1 mg kg (-1) fresh weight. Concentrations of As, Pb, and SigmaDDT did not exceed available food standards. Overall, these results demonstrate that aged residues of SigmaDDT, As, Cd, Cu, and Pb in horticultural soils have remained phytoavailable. To be protective of human health, site-specific risk assessments and soil guideline derivations for residential settings with vegetable gardens need to consider the produce consumption pathway.

Trace element and Sigma DDT concentrations in horticultural soils from the Tasman, Waikato and Auckland regions of New Zealand.

The long-term routine use of agrichemicals can result in elevated levels of trace elements and persistent organic pollutants in soils. Trace element concentrations and SigmaDDT levels were measured in soil (0-7.5 cm) samples collected from horticultural and grazing properties in 3 regions of New Zealand (Auckland, Tasman and Waikato). Elevated levels of arsenic (<2 to 58 mg kg(-1)), cadmium (<0.1 to 1.5 mg kg(-1)), copper (5 to 523 mg kg(-1)), lead (5 to 243 mg kg(-1)) and SigmaDDT (<0.03 to 34.5 mg kg(-1)) were detected in soils from all 3 regions. With the exception of cadmium and zinc, significantly higher levels of contaminants were generally detected in horticultural soils than in grazing soils. Our results have implications for the on-going use of agrichemicals as concentrations of cadmium, copper, tin and zinc in some samples exceeded ecotoxicity based soil criteria. The p,p'-DDE:DDT ratios indicate that the degradation of DDT in NZ horticultural soils may be inhibited by the co-contamination with trace elements.

Preliminary evidence that copper inhibits the degradation of DDT to DDE in pip and stonefruit orchard soils in the Auckland region, New Zealand.

Orchards (n=13) were sampled as part of a larger survey investigating agrichemical residues (pesticides and trace elements) in cropping soils in the Auckland region, New Zealand. SigmaDDT concentrations in orchard soils ranged from <0.03 to 24.41 mg kg(-1). DDT (o,p'- and p,p'-) comprised at least 40% of the SigmaDDT residues in 67% of orchards in which DDT residues were detected. There was a highly significant negative correlation (-0.924, P<0.001) between copper concentration (21-490 mg kg-1) and the ratio of DDE:DDT (0.4-5.2) in pip and stonefruit orchard soils. In further investigations involving five pip and stone fruit orchard sites and one grazing paddock it was found that soil respiration and the ratio of soil microbial carbon to soil carbon (%Cmic/Org-C) in orchard soils decreased with increasing copper concentration. These findings are consistent with the conclusion that elevated soil copper concentrations in pip and stone fruit orchard soils in the Auckland region may have reduced the ability of the indigenous soil microbial community to degrade DDT to DDE

ER aminopeptidases generate a unique pool of peptides for MHC class I molecules.

We define here the specificity and significance of proteases in the endoplasmic reticulum (ER) that generate peptides for presentation by major histocompatibility complex (MHC) class I molecules. We show that aminopeptidases efficiently trimmed all residues except proline that flank the NH2-termini of antigenic precursors in the ER and caused an accumulation of X-P-Xn peptides. An aminopeptidase inhibitor blocked peptide trimming in the ER and, consequently, the generation of peptide-loaded MHC molecules. Peptide trimming in the ER is therefore a key step in the MHC class I antigen-processing pathway and also explains the paradox of why many MHC class I molecules display peptides with the X-P-Xn motif despite the inability of the transporter associated with antigen processing to transport such peptides from the cytoplasm.