Land use change increases contaminant sequestration in blue carbon sediments.

Coastal blue carbon habitats perform many important environmental functions, including long-term carbon and anthropogenic contaminant storage. Here, we analysed twenty-five Pb-dated mangrove, saltmarsh, and seagrass sediment cores from six estuaries across a land-use gradient to determine metal, metalloid, and phosphorous sedimentary fluxes. Cadmium, arsenic, iron, and manganese had linear to exponential positive correlations between concentrations, sediment flux, geoaccumulation index, and catchment development.

Anthropogenic nitrate attenuation versus nitrous oxide release from a woodchip bioreactor.

Nitrogen loss via overland flow from agricultural land use is a global threat to waterways. On-farm denitrifying woodchip bioreactors can mitigate NO exports by increasing denitrification capacity. However, denitrification in sub-optimal conditions releases the greenhouse gas nitrous oxide (NO), swapping the pollution from aquatic to atmospheric reservoirs.

Cryptic night-time trace metal and metalloid contamination in an intensively cultivated coastal catchment.

Detailed, high resolution time-series observations were performed to investigate sources, diel cycling, natural attenuation, and loadings of dissolved trace metals/metalloids in a subtropical headwater stream draining intensive horticulture in Australia. A transect of ∼3 km away from the source (farms) showed >75% reduction in concentration and loads of most trace elements. Mercury and arsenic had elevated loads downstream relative to other elements.

Assessing pesticide, trace metal, and arsenic contamination in soils and dam sediments in a rapidly expanding horticultural area in Australia.

Industrial horticulture can release pesticides and trace metals/metalloids to terrestrial and aquatic environments. To assess long-term and more recent land contamination from an expanding horticultural region, we sampled soils from chemical mixing, crop production, and drainage areas, as well as retention reservoirs (dam) sediments, from 3 blueberry farms with varying land-use history in subtropical Australia. Soils were analysed for 97 different pesticides and trace metal/metalloid contents.

Nitrate loads in sub-tropical headwater streams driven by intensive horticulture.

Nitrogen runoff from fertiliser intensive land uses has become an issue worldwide, contributing to algal blooms, hypoxic waters and aquatic biodiversity losses. This study assessed potential nutrient pollution from blueberry farms in subtropical Australia and examines whether nutrient loads were driven by groundwater discharge and/or surface water runoff. Streams downstream of eight blueberry farms were compared to eight nearby control sites without any blueberry activity.

A comparison of the relative biological effectiveness of low energy electronic brachytherapy sources in breast tissue: a Monte Carlo study.

Electronic brachytherapy sources use low energy photons to treat the tumor bed during or after breast-conserving surgery. The relative biological effectiveness of two electronic brachytherapy sources was explored to determine if spectral differences due to source design influenced radiation quality and if radiation quality decreased with distance in the breast. The RBE was calculated through the number of DNA double strand breaks (RBEDSB) using the Monte Carlo damage simulator (MCDS) in combination with other Monte Carlo electron/photon spectrum calculations.

Comparison of TG-43 and TG-186 in breast irradiation using a low energy electronic brachytherapy source.

Purpose: The recently updated guidelines for dosimetry in brachytherapy in TG-186 have recommended the use of model-based dosimetry calculations as a replacement for TG-43. TG-186 highlights shortcomings in the water-based approach in TG-43, particularly for low energy brachytherapy sources. The Xoft Axxent is a low energy (<50 kV) brachytherapy system used in accelerated partial breast irradiation (APBI).

Influence of trace elements in human tissue in low-energy photon brachytherapy dosimetry.

The aim of this paper is to determine the dosimetric impact of trace elements in human tissues for low-energy photon sources used in brachytherapy. Monte Carlo dose calculations were used to investigate the dosimetric effect of trace elements present in normal or cancerous human tissues. The effect of individual traces (atomic number Z = 11-30) was studied in soft tissue irradiated by low-energy brachytherapy sources.