Performance evaluation of the UV activated chlorite process on trimethoprim: Degradation efficiency, energy consumption and disinfection by-products formation.

As the primary inorganic by-product species of ClO2, chlorite is believed to have negative toxicological effects on human health and therefrom greatly limits the wide application of ClO2 in water treatment. The synergistic trimethoprim (TMP) removal concerning degradation efficiency, energy consumption and disinfection by-products (DBPs) formation in the UV activated chlorite process accompanied by the simultaneously elimination of chlorite was comprehensively evaluated. UV/chlorite integrated process removed TMP far more rapidly than UV (1.52%) or chlorite (3.20%) alone due to the endogenous radicals (Cl•, ClO• and •OH), the contributing proportions of which were 31.96%, 19.20% and 44.12%. The second-order rate constants of TMP reaction with Cl•, ClO• and •OH were determined to be 1.75 × 1010, 1.30 × 109 and 8.66 × 109 M-1 s-1. The effects of main water parameters including chlorite dosage, UV intensity, pH as well as water matrixes (nature organic matter, Cl- and HCO3-) were examined. kobs obeyed the order as UV/Cl2>UV/H2O2≈UV/chlorite>UV, and the cost ranking via electrical energy per order (EE/O, kWh m-3 order-1) parameter was UV/chlorite (3.7034) > UV/H2O2 (1.1625) >UV/Cl2 (0.1631). The operational scenarios can be optimized to achieve the maximum removal efficiencies and the minimum energy costs. The destruction mechanisms of TMP were proposed by LC-ESI-MS analysis. The overall weighted toxicity in subsequent disinfection was assessed as UV/Cl2>UV/chlorite > UV, the values of which in post-chlorination were 6.2947, 2.5806 and 1.6267, respectively. Owing to the vital roles of reactive chlorine species (RCS), UV/chlorite displayed far higher TMP degradation efficiency than UV, and concurrently presented much less toxicity than UV/Cl2. In an effort to determine the viability of the promising combination technology, this study was devoted to reduce and reuse chlorite and synchronously realize the contaminants degradation efficiently.

[Distribution and Ecological Risk of Heavy Metals in the Soil of Redevelopment Industrial Sites].

Fifty typical redevelopment industrial sites in the Putuo, Baoshan, Minhang, and Jiangding districts of Shanghai were chosen to evaluate the ecological risk of heavy metals in the soil. The contents of heavy metal (Hg, Cd, Pb, Cr, and As) in 1847 soil samples, taken from vertical sections, were determined, and their risks were evaluated using the Nemero composite index and Hakanson potential ecological risk index. The average contents of Hg, Cd, Pb, Cr, and As in topsoil samples were 0.33, 0.37, 74.55, 69.23, and 9.05 mg·kg-1, respectively. The contents of Hg, Cd, and Pb exceeded the soil background values of Shanghai, which were 2.75, 2.85, and 2.93 times the background values, respectively. The contents of five heavy metals in soil decreased gradually with increased depth. The contents of heavy metals in deep and saturated soils were close to, or below, the background values, indicating that the anthropic activity disturbance was mainly confined to the topsoil. The accumulation of Hg, Cd, and Pb was the most obvious in Putuo topsoil, with the average contents being 4.25, 4.85, and 3.09 times the background values, respectively. The average contents of Hg and Pb in Baoshan were 4.92 and 6.43 times the background values, respectively. The Nemero Composite Index of Baoshan and Putuo districts were 3.70 and 3.20, respectively, representing heavy pollution level at these sites. The Hakanson potential ecological risk indexes of the Putuo and Baoshang districts were 398.59 and 303.08, respectively, with considerable ecological risk levels. The content and ecological risk of heavy metals at the Minhang and Jiading sites were relatively low. In summary, the pollution of heavy metal in the redeveloped industrial sites is influenced by the operating time, industry type, and past management level of the enterprises. The heavy metal accumulation in the Putuo and Baoshan districts, whose industries developed earlier, were higher than those in the Minhang and Jiading districts. The pollution of heavy metal Hg, Cd, and Pb in soil should be a focus of future work.

Inhibition of intestinal glucose uptake by aporphines and secoaporphines.

The effects of aporphines and secoaporphines on glucose uptake by isolated intestinal brush-border membrane vesicles (BBMV) or basolateral membrane vesicles (BLMV) and glucose absorption during in situ intestinal perfusion were studied. Of the tested compounds, N-allylsecoboldine was the most potent glucose uptake inhibitor, with IC50 values of 159 microM and 121 microM, respectively, for uptake by BBMV and BLMV. While thaliporphine competitively inhibited glucose uptake by both membrane preparations, inhibition by N-allylsecoboldine was competitive using BBMV and noncompetitive using BLMV. In addition, N-allylsecoboldine significantly reduced both glucose absorption during in situ intestinal perfusion and blood glucose levels in the oral glucose tolerance test. The results demonstrate that levels of both aporphines and secoaporphines achievable by oral administration have an inhibitory effect on intestinal glucose uptake and suggest that the hypoglycemic effects of these compounds merit attention.