Measurement of Radioactivity in Carbonated Soft Drinks and Annual Dose Assessment

A set of measurements have been conducted, using gamma spectrometry technique, in order to determine the activity-level in some carbonated soft drinks. The obtained activity is about 0.18 ± 0.07 Bq/l for 137Cs, whereas it is less than 0.13, 0.18 and 4.51 Bq/l respectively for 212Pb, 214Pb and 40K. The total average annual dose is about 3.49, 1.69 and 1.68 μSv/y respectively for 7 - 12, 12 - 17 and >17 years old person leading to a radiological risk about 0.142 for adolescent and adults. The obtained results show no significant radiation dose and radiation hazard on human health due to the consumption of these carbonated soft drinks.

Comparison of different combined treatment processes to address the source water with high concentration of natural organic matter during snowmelt period

The source water in one forest region of the Northeast China had very high natural organic matter（NOM） concentration and heavy color during snowmelt period. The efficiency of five combined treatment processes was compared to address the high concentration of NOM and the mechanisms were also analyzed. Conventional treatment can hardly remove dissolved organic carbon（DOC） in the source water. KMn O4pre-oxidization could improve the DOC removal to 22.0%. Post activated carbon adsorption improved the DOC removal of conventional treatment to 28.8%. The non-sufficient NOM removal could be attributed to the dominance of large molecular weight organic matters in raw water, which cannot be adsorbed by the micropore upon activated carbon. O3＋ activated carbon treatment are another available technology for eliminating the color and UV254 in water. However, its performance of DOC removal was only 36.4%, which could not satisfy the requirement for organic matter. The limited ozone dosage is not sufficient to mineralize the high concentration of NOM. Magnetic ion-exchange resin combined with conventional treatment could remove 96.2%of color, 96.0% of UV254 and 87.1% of DOC, enabling effluents to meet the drinking water quality standard. The high removal efficiency could be explained by the negative charge on the surface of NOM which benefits the static adsorption of NOM on the anion exchange resin. The results indicated that magnetic ion-exchange resin combined with conventional treatment is the best available technology to remove high concentration of NOM.

Simultaneous removal of dissolved organic matter and bromide from drinking water source by anion exchange resins for controlling disinfection by-products

Anion exchange resins （AERs） with different properties were evaluated for their ability to remove dissolved organic matter （DOM） and bromide, and to reduce disinfection by-product （DBP） formation potentials of water collected from a eutrophic surface water source in Japan. DOM and bromide were simultaneously removed by all selected AERs in batch adsorption experiments. A polyacrylic magnetic ion exchange resin （MIEX） showed faster dissolved organic carbon （DOC） removal than other AERs because it had the smallest resin bead size. Aromatic DOM fractions with molecular weight larger than 1600 Da and fluorescent organic fractions of fulvic acid- and humic acid-like compounds were efficiently removed by all AERs. Polystyrene AERs were more effective in bromide removal than polyacrylic AERs. This result implied that the properties of AERs, i.e. material and resin size, influenced not only DOM removal but also bromide removal efficiency, MIEX showed significant chlorinated DBP removal because it had the highest DOC removal within 30 rain, whereas polystyrene AERs efficiently removed brominated DBPs, especially brominated trihalomethane species. The results suggested that, depending on source water DOM and bromide concentration, selecting a suitable AER is a key factor in effective control of chlorinated and brominated DBPs in drinking water.