An assessment of persistent organic pollutants (POPs) in wild and rope grown blue mussels (Mytilius edulis) from Scottish coastal waters.

Farmed, rope grown mussels (Loch Etive and Loch Ewe, both on the west coast of Scotland) and wild mussels (Straad on the west coast and Shell Bay and Aberdeen Breakwater, both on the east coast of Scotland) were collected on a monthly basis and analysed for persistent organic pollutants (POPs) with the aim of assessing the status of Scottish mussels, with respect to concentrations of POPs, and investigating site-specific and seasonal differences. Samples were analysed for polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs) and chlorobiphenyls (CBs). Total PAH (2- to 6-ring parent and alkylated) concentrations in mussels from three pristine sites (ref. 1: ICES Marine Chemistry Working Group Report 2008, http://www.ices.dk/reports/MHC/2007/MCWG07.pdf) (Loch Etive, Loch Ewe and Straad) were significantly lower than in mussels from sites with greater coastal influences (Aberdeen Breakwater and Shell Bay). Seasonal trends in the PAH concentrations were evident at the pristine sites, with concentrations being significantly higher for samples collected between November and March compared to those collected between April and October. The PAH data was assessed using a recently proposed traffic light system, based on the assessment criteria adopted by OSPAR for use in the 2008 Coordinated Environmental Monitoring Programme (CEMP) assessment. Concentrations were compared to Background Assessment Concentrations (BAC; blue/green transition) and Environmental Assessment Concentrations (EACs; green/red transition). All sites were classed as 'green' for the PAHs analysed, being below EACs, where available. The pristine sites were also below BACs for some PAHs and therefore would be classed as 'blue' for these PAHs. CBs and PBDEs were measured in mussels collected between 2006 and 2008 inclusive. Concentrations for CB and PBDEs were significantly higher in the Aberdeen Breakwater mussels than for all other sites. Concentrations at all sites were low with many congeners being below the detection limits for both contaminant groups. No seasonal trends were observed in the CBs or PBDE concentrations or composition at any of the five sites. The green-red transition (described by the EACpassive) was exceeded for CB118 in mussels from Aberdeen Breakwater and surprisingly at the pristine site of Loch Etive. As such both sites were classed as 'red'. All other ICES7 CBs were below EACs and therefore classed as 'blue' or 'green'.

Continuous fermentative hydrogen production from a wheat starch co-product by mixed microflora.

For the transition to the hydrogen economy, hydrogen must be produced sustainably, e.g., by the fermentation of agricultural material. Continuous fermentative production of hydrogen from an insoluble substrate in nonsterile conditions is yet to be reported. In this study hydrogen production using mixed microflora from heat-treated digested sewage sludge in nonsterile conditions from a particulate co-product of the wheat flour industry (7.5 g L(-1) total hexose) at 18- and 12-hour hydraulic retention times, pH 4.5 and 5.2, 30 degrees C and 35 degrees C was examined. In continuous operation, hydrogen yields of approximately 1.3 moles hydrogen/mole hexose consumed were obtained, but decreased if acetate or propionate levels rose, indicating metabolism shifted towards hydrogen consumption by homoacetogenesis or propionate producers. These shifts occurred both at pH 4.5 and 5.2. Sparging the reactor with nitrogen to reduce hydrogen in the off-gas from 50% to 7% gave stable operation with a hydrogen yield of 1.9 moles hydrogen /mole hexose consumed over an 18-day period.