Mineralization of phenanthrene and fluoranthene in yardwaste compost

The purpose of the study was to evaluate the potential of phenanthrene and fluoranthene biodegradation in yardwaste compost materials. These polynuclear aromatic hydrocarbons were chosen for this work because they are relatively readily biodegradable and ubiquitous in the environment. Compost samples were incubated in biometers with 14C-labeled phenanthrene and the evolution of "4CO2 was assessed as a measure of mineralization. The '4CO2 evolution varied widely among replicate biometers, possibly as the result of (1) uneven and patchy colonization of phenanthrene-degrading microorganisms on compost particles, and (2) non-uniform dispersion of the labeled substrate spike into the yardwaste microenvironment. Mineralization of phenanthrene reached about 40%extent of 14CO2 evolution at best before leveling off, but the maximum varied from sample to sample and could be as low as 1%after three months. Active mineralization occurred at mesophilic and thermophilic temperatures. Methanol extraction was used to recover "4C from biometer samples that were spiked with "4C-labeled phenanthrene. Extraction for 24-48 h yielded 1-14% recovery of 14C, depending on the length of the preceding incubation. The low extraction yield and relatively low maximum mineralization(<40%) indicated that residual phenanthrene was sorbed and bound within the compost matrix in the biometer. Amendment ofbiometers with 0.05% Tween 80 or addition of water did not consistently enhance the mineralization. Variability in mineralization was greatly reduced in liquid samples taken from pre-enriched compost samples. Mineralization of 14C-labeled fluoranthene was negligible in biometers but could be stimulated by pre-enrichment with salicylate or naphthalene. Pre-enrichment also accelerated the mineralization of phenanthrene.     

Impact of climate change and seasonal trends on the fate of Arctic oil spills

We investigated the effects of a warmer climate, and seasonal trends, on the fate of oil spilled in the Arctic. Three well blowout scenarios, two shipping accidents and a pipeline rupture were considered. We used ensembles of numerical simulations, using the OSCAR oil spill model, with environmental data for the periods 2009–2012 and 2050–2053 (representing a warmer future) as inputs to the model. Future atmospheric forcing was based on the IPCC’s A1B scenario, with the ocean data generated by the hydrodynamic model SINMOD. We found differences in “typical” outcome of a spill in a warmer future compared to the present, mainly due to a longer season of open water. We have demonstrated that ice cover is extremely important for predicting the fate of an Arctic oil spill, and find that oil spills in a warming climate will in some cases result in greater areal coverage and shoreline exposure.     

Oil spill response capabilities and technologies for ice-covered Arctic marine waters: A review of recent developments and established practices

Renewed political and commercial interest in the resources of the Arctic, the reduction in the extent and thickness of sea ice, and the recent failings that led to the Deepwater Horizon oil spill, have prompted industry and its regulatory agencies, governments, local communities and NGOs to look at all aspects of Arctic oil spill countermeasures with fresh eyes. This paper provides an overview of present oil spill response capabilities and technologies for ice-covered waters, as well as under potential future conditions driven by a changing climate. Though not an exhaustive review, we provide the key research results for oil spill response from knowledge accumulated over many decades, including significant review papers that have been prepared as well as results from recent laboratory tests, field programmes and modelling work. The three main areas covered by the review are as follows: oil weathering and modelling; oil detection and monitoring; and oil spill response techniques.