Enhancement of accelerated carbonation of alkaline waste residues by ultrasound.

The continuous growth of anthropogenic CO2 emissions into the atmosphere and the disposal of hazardous wastes into landfills present serious economic and environmental issues. Reaction of CO2 with alkaline residues or cementitius materials, known as accelerated carbonation, occurs rapidly under ambient temperature and pressure and is a proven and effective process of sequestering the gas. Moreover, further improvement of the reaction efficiency would increase the amount of CO2 that could be permanently sequestered into solid products. This paper examines the potential of enhancing the accelerated carbonation of air pollution control residues, cement bypass dust and ladle slag by applying ultrasound at various water-to-solid (w/s) ratios. Experimental results showed that application of ultrasound increased the CO2 uptake by up to four times at high w/s ratios, whereas the reactivity at low water content showed little change compared with controls. Upon sonication, the particle size of the waste residues decreased and the amount of calcite precipitates increased. Finally, the sonicated particles exhibited a rounded morphology when observed by scanning electron microscopy.

Elemental content of commercial 'ready to-feed' poultry and fish based infant foods in the UK.

The study reported herein was conducted in order to establish the concentration of 20 essential and non-essential elements in a representative range of commercial infant foods in the UK targeted for infants aged between 6-12 months. The primary objective of this study was to examine the nutritive values and safety of such complementary infant foods on the UK market in relation to dietary and safety guidelines. Quantitative analyses were conducted on eight different products representing four popular brands (poultry and fish based) of ready to-feed infant foods currently on sale in the UK. Six essential elements, namely: calcium, iron, magnesium, potassium, sodium and zinc were determined by ICP-OES. The concentrations of six essential trace elements (selenium, molybdenum, cobalt, copper, chromium, manganese) and eight non-essential, potentially toxic, elements (arsenic, barium, nickel, cadmium, antimony, lead, mercury, aluminium) were determined by ICP-MS due to the higher sensitivity required. The total daily intakes of essential and trace elements from the consumption of such products were then estimated, based on the results of this study, and were referenced to the Recommended Nutrient Intake (RNI) values and safety guidelines for 6-9 months old children. Based on these comparisons the concentration of essential, except for potassium, and trace elements were found to be inadequate in meeting the RNI. In terms of the risk of exposure to toxicity, the concentration of toxic elements in ready to feed products analysed in this study, were not considered to be of concern. These results suggest that commercial complementary infant foods on the UK market may not contain minimum levels of minerals required for labelling declaration of micronutrient content (Commission Directive 2006/125/EC). This provides opportunities and scope for product optimisation to improve their nutritive value.

Essential and trace elements content of commercial infant foods in the UK.

There is a paucity of data in respect of the nutritional quality of complementary foods for infants and young children aged between 6 and 12months. The primary objective of this study was to examine nutritive values of such complementary infant food on the UK market in order to ascertain their suitability relative to dietary guidelines for the 6-9months age group. Quantitative analyses were conducted on eight different products representing four popular brands (meat and vegetable based) currently on sale in the UK. Eight major mineral and trace elements, namely: calcium, copper, magnesium, iron, zinc, potassium, sodium and selenium were measured by ICP-OES and ICP-MS. The results of these studies were referenced to the Recommended Nutrient Intake (RNI) values for 6-9months old children, and a menu of entire daily intake of minerals and trace elements was composed taking into consideration the nutrient and energy intake from milk consumption. Based on these comparisons, all the food samples studied in this work contained less essential minerals than expected from the RNI values except for potassium in meat and vegetable based recipes. These results suggest that commercial complementary infant foods on the UK market may not contain the minimum levels of minerals required for the labelling declaration of micronutrient content (Commission Directive 2006/125/EC). This provides opportunities and scope for product optimisation to improve their nutritive value.

Elemental analysis of soil samples for forensic purposes by inductively coupled plasma spectrometry--precision considerations.

Major and trace elemental composition provides a powerful basis for forensic comparison of soils, sediments and rocks. However, it is important that the potential 'errors' associated with the procedures are fully understood and quantified, and that standard protocols are applied for sample preparation and analysis. This paper describes such a standard procedure and reports results both for instrumental measurement precision (repeatability) and overall 'method' precision (reproducibility). Results obtained both for certified reference materials and example soils show that the instrumental measurement precision (defined by the coefficient of variation, CV) for most elements is better than 2-3%. When different solutions were prepared from the same sample powder, and from different sub-sample powders prepared from the same parent sample, the CV increased to c. 5-6% for many elements. The largest variation was found in results for certified reference materials generated from 23 instrument runs over an 18 month period (mean CV=c. 11%). Some elements were more variable than others. W was found to be the most variable and the elements V, Cr, Co, Cu, Ni and Pb also showed higher than average variability. SiO2, CaO, Al2O3 and Fe2O3, Rb, Sr, La, Ce, Nd and Sm generally showed lower than average variability, and therefore provided the most reliable basis for inter-sample comparison. It is recommended that, whenever possible, samples relating to the same investigation should be analysed in the same sample run, or at least sequential runs.