Variation in chemical composition of MSWI fly ash and dry scrubber residues.

Our society generates extensive amounts of municipal solid waste (MSW), which are mainly incinerated for volume reduction and energy recovery. Though, MSW incineration generates hazardous air pollution control (APC) residues that must be treated and deposited in appropriate landfills. An alternative to landfilling is material recovery, leading to regeneration of valuable products and reducing hazardous waste amounts. The chemical composition of APC residues, stemming from MSW, makes the waste attractive for metal and salt recovery, but its variation makes the development of material recovery processes challenging. This study investigates results from 895 X-ray fluorescence analyses of fly ash and dry scrubber residue samples originating from Norway and Sweden between 2006 and 2020 to explore variation in chemical composition within and between different incineration plants. The average relative standard deviation of elemental concentration in APC residue was estimated to 30% within plants. The variation in elemental concentration between grate fired incineration plants is about half of the average variation within the plants. The study also clarifies compositional differences from APC residues originating from fluidized bed incinerators and grate incinerators. Also, reported concentrations of APC residues from other countries than Sweden and Norway showed significant differences in chemical composition. The presented variations clarifies the importance of holistic approaches for waste valorization processes which can substitute stabilization processes for landfilling.

Bioaccumulation and lack of oxidative stress response in the ragworm H. diversicolor following exposure to 226Ra in sediment.

The main effluent from oil and gas production, produced water, from some platforms in the North Sea contains elevated concentrations of (226)Ra. The aim of this study was to investigate whether (226)Ra in sediment would accumulate in and affect sediment-dwelling organisms. In addition, we wanted to determine if the bioavailability would be modulated by the presence of a scale inhibitor which is used during oil and gas production. Hediste diversicolor was therefore exposed to different levels of (226)Ra (30-6600 Bq kg(-1)) in combination with scale inhibitor in the sediments in a flow through system. The levels of radioactivity in the exposures were close to levels that can be measured in proximity to oil/gas production facilities. (226)Ra spiked to natural sediment partitioned into pore water and accumulated in the sediment-dwelling polychaete following a four-week exposure period. The results suggest that (226)Ra did not bind strongly to sediment (low sediment:water partitioning coefficient), but it was not shown to bioaccumulate in any great extent (bioaccumulation factors of 0.019-0.022). Exposure of H. diversicolor in sediments with up to 6600 Bq kg(-1)(226)Ra had no measurable effect on the total oxyradical scavenging capacity of the organisms compared to control. So although they accumulated the alpha-emitter, the treatments did not appear to cause oxidative stress in polychaete tissues.

Disposition of arsenobetaine in two marine fish species following administration of a single oral dose of [14C]arsenobetaine.

The distribution and excretion of arsenobetaine in fish were investigated using whole body autoradiography and liquid scintillation counting. A single dose of synthesised [(14)C]arsenobetaine was orally administered to Atlantic salmon, Salmo salar L., and Atlantic cod, Gadus morhua L. Arsenobetaine was distributed to most organs within both species. Nevertheless, there were species differences in tissue distribution and excretory pattern. The highest level of arsenobetaine in Atlantic salmon was present in muscle tissue, while high levels of arsenobetaine were found in both muscle and liver (including gall bladder) from Atlantic cod. The results suggest that the major route of excretion was via urine, which seemed to be more important in Atlantic cod than in Atlantic salmon. Elimination of arsenobetaine via bile appeared to be negligible in both species.