Effect of long-distance inter-basin water transfer on the bioavailability of Cu for the receiving water.

Long-distance inter-basin water transfer solves the problem of unbalanced water resources in different regions. However, it also changes the natural water chemistry characteristics as well as the bioavailability of heavy metals in the receiving water. In this study, taking the South-to-North Water Transfer Project in China as an example, the basic physicochemical characteristics of the source water (in the Danjiangkou (DJK) Reservoir) and receiving water (in the Beitang (BT) Reservoir) were studied. The BLM (biotic ligand model) was used to study the effect of long-distance inter-basin water transfer on the bioavailability of Cu in receiving waters. The results showed that the TOC (total organic carbon) and TDS (total dissolved solids) in the BT Reservoir water were 10 times and 4.6 times greater than those of the DJK Reservoir water, respectively. The ions in the BT Reservoir were mainly (K++Na+)-(SO42-+CI-), while the ions in the DJK Reservoir were mainly (Ca2++Mg2+)-HCO3-. The results from the BLM showed that the main species of Cu in the water was total organic Cu (Torg Cu), which accounted for 98.69% and 99.77% of the Cu in the DJK Reservoir and BT Reservoir, respectively. The LC50 of Cu for Daphnia magna was 1203.40 ± 57.70 µg/l in the BT Reservoir and only 101.93 ± 7.60 µg/l in the DJK Reservoir. The criteria maximum concentration value of the BT Reservoir was 13.75 times that of the DJK Reservoir, while the criteria continuous concentration value of the BT Reservoir was 13.76 times that of the DJK Reservoir. These results showed that the heavy metals content in water bodies should not be used as the only consideration for water ecological security in the inter-basin water transfer process, and that differences in water quality criteria values caused by differing water environmental qualities in the river basins must be taken into consideration.

Effect of chitosan film incorporated with tea polyphenol on quality and shelf life of pork meat patties.

The objective of this study was to investigate the effect of chitosan (CH) film incorporated with tea polyphenol (TP) on quality and shelf life of pork meat patties stored at 4±1 °C for 12 days. The microbiological, physicochemical (pH, thiobarbituric acid-reactive substances (TBARS) values, and metmyoglobin (MetMb)), and sensory qualities were measured on all the samples. A microbiological shelf-life extension of 6 days was achieved for CH and CH-TP treatment groups when compared to the control group. Wrapping with CH-TP composite film tended to retard the increases in TBARS values and MetMb content. CH-TP composite film maintained acceptable sensory quality of pork meat patties throughout the storage. The results indicated that CH-TP composite film could be a promising material as a packaging film for extending the shelf life of pork meat patties.