[Pollution Characteristics and Risk Assessment of Heavy Metals in Water and Sediment from Daye Lake].

The surface water and surface sediments were collected from Daye Lake in April 2014. The concentrations of heavy metals were determined by atomic absorption spectroscopy. The pollution potential health risk and ecological risk of heavy metals in water and sediment were assessed by the health risk assessment model and the potential ecological risk index method. The results showed that the concentrations of the heavy metals (Ni, Cd, Cu and Pb) was 49.27 µg·L-1, 2.19 µg·L-1, 12.18 µg·L-1, 12.13 µg·L-1(water) and 78.46 mg·kg-1, 77.13 mg·kg-1, 650.13 mg·kg-1 and 134.22 mg·kg-1 (sediment). Enrichment coefficient indicated that the enrichment of Cd, Cu and Pb was more serious, especially the accumulation of Cd was the most obvious. Compared to typical lakes in China, the contents of heavy metals in water and sediment were relatively high. The spatial pollutant distribution of the heavy metals in water and sediment all presented that the concentrations of the heavy metals were relatively higher in east and west of Daye Lake, relatively more uniform in the middle, and their origins were mainly from human activities. The results of environmental risk indicated that the carcinogens and chemical non-carcinogens health risk values of heavy metals by drinking water pathway were 9.77E-08~1.63E-05a-1. Therefore, the pollution of Ni and Cd should be the primary control target for environmental health risk management. The descending order of pollution degree of four metals in sediment was Cd> Cu> Pb> Ni, and Cd was the main contributor of the potential ecological risk elements.

Speciation analysis and the assessment of bioavailability of manganese in phytomedicines by extraction with octanol and determination by flame atomic absorption spectrometry.

Trace elements in phytomedicines are present in the form of metallic complexes. Since n-octanol, a long-chain alkanol, presents a configuration similar to that of carbohydrates and lipids, the lipophilicity and absorptivity of organic medicines may be assessed from their distribution coefficients between octanol and water. This strategy has been used in order to define the species of manganese in a number of phytomedicines and to study the distribution of manganese in decoctions of phytomedicines in the stomach and the intestine. The concentrations of manganese in the original herbal materials and in octanol- and water-soluble fractions were determined by flame atomic absorption spectrometry following mixed acid digestion. The acidities of gastric and intestinal juices, the phytomedical composition and the compatibility of phytomedicines, i.e. the combination of single phytomedicines, greatly affected the manganese complexing ligands and determined the species and bioavailability of manganese. It is concluded that a knowledge of the level of octanol-soluble manganese in a phytomedicine could form the basis of dosage design in order to avoid manganese overload.