The Spatial and Temporal Variability of Airborne Pollutants in Stormwater Runoff

Atmospheric deposition is increasingly being recognised as a significant source of total suspended solids (TSS) and heavy metals in urban runoff. However, many uncertainties and challenges remain with measuring and managing these pollutants in runoff. Impermeable concrete boards were deployed in a residential, industrial, and airside land-use area in Christchurch for almost one year in 2013 to determine the spatial and temporal variability of airborne pollutant loads (principally TSS, Cu, Pb, and Zn) in runoff. Results showed that each land-use area displayed similar trends of increasing/decreasing pollutant loads throughout the monitoring period, suggesting that the pollutants originated from a similar source. Consistently higher pollutant loads were found for the industrial area, which was attributed to local topographic conditions rather than land-use activity. All pollutants had a statistically significant relationship with antecedent dry days, illustrating its importance on pollutant build-up. Pollutants dominated by their particulate-phase were influenced by peak rainfall intensity, which was explained by the energy from an intense rainfall event dislodging more particulate pollutants; however, this relationship was weak. Dissolved-phased pollutants displayed a greater relationship to rain depth showing that the quantity of rain influences the dissolution of pollutants from a surface

The contribution of wet deposition and particulate matter to total copper, lead and zinc in stormwater runoff

Wet deposition is an important process in the removal of heavy metal particulates from the atmosphere. However, the contribution of wet deposition to the total heavy metal deposition flux can vary widely between different airsheds. Understanding the contribution of wet deposition to the total metal deposition flux is important for accurate knowledge of local atmospheric deposition processes, which will subsequently help in the selection of appropriate stormwater treatment and management options. This research monitored Cu, Zn and Pb loads in wet deposition samples and in bulk deposition samples from modular concrete paving slab systems. In conjunction, ambient particulate matter (PM) concentrations were monitored to determine their contribution to the wet deposition flux. All research was conducted in an industrial land-use area in Christchurch, New Zealand. Results showed that wet deposition efficiently removed PM from the atmosphere, but after 1–2.5 antecedent dry days, PM concentrations recovered. Subsequent antecedent dry days, i.e > 1–2.5 d, did not influence PM concentrations. Pb loads in wet deposition were dependent on coarse PM (size range between 2.5 μm and 10 μm) concentrations. This suggested that there was a local source emitting coarse Pb particles into the atmosphere. Wet deposition was an important contributor of dissolved Zn to bulk deposition. However, dry deposition was the greatest source of total Cu, Zn, and Pb loads in bulk deposition. This is principally due to the low annual rainfall in Christchurch, which limits pollutant removal via wet deposition unlike dry deposition, which is continually occurring

Projected WIMP sensitivity of the LUX-ZEPLIN dark matter experiment

LUX-ZEPLIN (LZ) is a next-generation dark matter direct detection experiment that will operate 4850 feet underground at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. Using a two-phase xenon detector with an active mass of 7 tonnes, LZ will search primarily for low-energy interactions with weakly interacting massive particles (WIMPs), which are hypothesized to make up the dark matter in our galactic halo. In this paper, the projected WIMP sensitivity of LZ is presented based on the latest background estimates and simulations of the detector. For a 1000 live day run using a 5.6-tonne fiducial mass, LZ is projected to exclude at 90% confidence level spin-independent WIMP-nucleon cross sections above 1.4 × 10-48cm2 for a 40 GeV/c2 mass WIMP. Additionally, a 5σ discovery potential is projected, reaching cross sections below the exclusion limits of recent experiments. For spin-dependent WIMP-neutron(-proton) scattering, a sensitivity of 2.3 × 10−43 cm2 (7.1 × 10−42 cm2) for a 40 GeV/c2 mass WIMP is expected. With underground installation well underway, LZ is on track for commissioning at SURF in 2020

The Galactic Faraday rotation sky 2020

Galaxie

Search for Neutrinos in Super-Kamiokande Associated with the GW170817 Neutron-star Merger

We report the results of a neutrino search in Super-Kamiokande (SK) for coincident signals with the first detected gravitational wave (GW) produced by a binary neutron-star merger, GW170817, which was followed by a short gamma-ray burst, GRB170817A, and a kilonova/macronova. We searched for coincident neutrino events in the range from 3.5 MeV to ~100 PeV, in a time window ±500 s around the gravitational wave detection time, as well as during a 14-day period after the detection. No significant neutrino signal was observed for either time window. We calculated 90% confidence level upper limits on the neutrino fluence for GW170817. From the upward-going-muon events in the energy region above 1.6 GeV, the neutrino fluence limit is ${16.0}_{-0.6}^{+0.7}$ (${21.3}_{-0.8}^{+1.1}$) cm−2 for muon neutrinos (muon antineutrinos), with an error range of ±5° around the zenith angle of NGC4993, and the energy spectrum is under the assumption of an index of −2. The fluence limit for neutrino energies less than 100 MeV, for which the emission mechanism would be different than for higher-energy neutrinos, is also calculated. It is 6.6 × 107 cm−2 for anti-electron neutrinos under the assumption of a Fermi–Dirac spectrum with average energy of 20 MeV

Scintillator ageing of the T2K near detectors from 2010 to 2021

The T2K experiment widely uses plastic scintillator as a target for neutrino interactions and an active medium for the measurement of charged particles produced in neutrino interactions at its near detector complex. Over 10 years of operation the measured light yield recorded by the scintillator based subsystems has been observed to degrade by 0.9–2.2% per year. Extrapolation of the degradation rate through to 2040 indicates the recorded light yield should remain above the lower threshold used by the current reconstruction algorithms for all subsystems. This will allow the near detectors to continue contributing to important physics measurements during the T2K-II and Hyper-Kamiokande eras. Additionally, work to disentangle the degradation of the plastic scintillator and wavelength shifting fibres shows that the reduction in light yield can be attributed to the ageing of the plastic scintillator. The long component of the attenuation length of the wavelength shifting fibres was observed to degrade by 1.3–5.4% per year, while the short component of the attenuation length did not show any conclusive degradation

Spatial and temporal modelling of heavy metal contaminant loadings to urban streams

Urban stormwater contains substantial amounts of heavy metals (Zn, Cu, Pb) and suspended solids (TSS). Untreated, these contaminants are recognized as the main detriment to urban waterways. To quantify the sources of these pollutants in urban catchments and resulting discharges to specific points along waterways, the MEDUSA (Modelled Estimates of Discharges for Urban Stormwater Assessments) modelling framework was developed

Quantifying the Spatial Variability of Airborne Pollutants to Stormwater Runoff in different Land-Use Catchments

An understanding of the effects of land-use activities on atmospherically-derived pollutant loadings in stormwater is helpful for determining appropriate treatment strategies for different catchments. Impervious concrete boards (≈1 m2) were deployed for eleven months in different land-use areas (industrial, residential and airside of an airport’s runway) throughout Christchurch, New Zealand, to determine the spatial variability of atmospherically-derived pollutants in stormwater runoff. Runoff was analysed for metals (principally Cu, Zn, and Pb) and total suspended solids (TSS). All three land-use areas exhibited similar temporal patterns of varying metal and TSS loads, indicating that atmospherically-deposited metals and TSS had a homogenous distribution within the Christchurch airshed. However, mean pollutant loadings for all total metals and TSS were significantly higher in the industrial area compared to the residential and airside areas, which had statistically similar mean metal loadings. The signature ratios of specific heavy metals (As, Cr, Mn, Ni, Pb, Sr, and Zn) to Cu were relatively homogeneous between the three land-use areas, indicating that the pollutants originate from a similar source and that surrounding land-use was not as an important factor in determining atmospheric pollutant loadings to stormwater runoff as previously though

Estimates of the current and future burden of lung cancer attributable to PM 2.5 in Canada

The International Agency for Research on Cancer has classified PM 2.

Corrigendum to “Estimates of the current and future burden of lung cancer attributable to residential radon in Canada” [Prev. Med. 122 (2019)100–108](S009174351930129X)(10.1016/j.ypmed.2019.04.005)

The authors regret to inform on three corrections to the relevant paper: 1. In Table 1, there is missing information for Tomasek, 2012. The “Exposure basis” column should have read “Dosimete