No abstract

Heavy metal pollution is hazardous for the environment and human health. However, there are few studies of heavy metal pollution caused by historic metallurgical activity. The Laoniupo site in the Bahe River valley, Guanzhong Basin, China, was an important settlement of the Shang Culture (1600-1046 BCE). We studied two stratigraphic profiles at the Laoniupo site, which were used for measurements of magnetic susceptibility, heavy metal concentrations, and AMS 14 C ages to provide evidence of copper smelting activity at the site during the Shang Dynasty. The Nemerow Pollution Index and Geoaccumulation Index were calculated to assess the heavy metals record (Cu, Zn, Ni, Pb, Cr, and As) in the topsoil on the loess tableland. According to the Single Pollution Index, the topsoil was slightly polluted by As and unpolluted by Cu, Zn, Ni, Pb and Cr; according to the Nemerow Composite Pollution Index the topsoil was mildly polluted; and according to the Geoaccumulation Index, the topsoil was moderately polluted by As, slightly polluted by Cu, and unpolluted by Zn, Ni, Pb and Cr. The main cause of the heavy metal pollution in the topsoil is the presence of copper slag in the cultural layers that was disturbed by modern farming activity.

M-dichlorobenzene can be degraded through biotrickling filter (BTF). However, its degradation needs to be enhanced, and the mechanism of enhancement is unclear. In this study, Zn(II) was taken as the biological growth promoter; the polysaccharides and proteins, zeta potential, Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, and the enzyme activity of the strains were analyzed. The results indicated that Zn(II) at 5mg/L promoted the growth of the strain. When the inlet concentration was 505.74 mg/m 3 and the empty bed resistance time (EBRT) was 90 s, the removal efficiency of BTF2 was 86.15%. In BTF2, the enzyme activity, polysaccharide, and protein content increased, while the zeta potential decreased. The changes of zeta potential indicated that there existed an electrostatic interaction between extracellular polymeric substance (EPS) and Zn(II). The results of Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy confirmed that there was a bond between the EPS surface functional groups and Zn(II).

A stable Au metal organic frameworks (AuMOF) nanosol was prepared. It was characterized by electron microscopy and molecular spectral techniques. In pH 6.8 PBS buffer solution, AuMOF nanoprobes exhibit a strong resonance Rayleigh scattering (RRS) peak at 330 nm. After basic fuchsin (BF) adsorbing on the surface of AuMOF, the RRS energy of the nanoprobe donor can be transferred to BF receptor, resulting in a decrease in the RRS intensity at 330 nm. Both sulfite and BF taken place an addition reaction to form a colorless product (SBF) that exhibit weak RRS energy transfer (RRS-ET) between AuMOF and SBF, resulting in the enhancement of the RRS peak. As the concentration of SO32–increases, the RRS peak is linearly enhanced. Thus, a new and sensitive RRS-ET method for the detection of SO32– (0.160–5.00 μmol/L) was developed accordingly using AuMOF as nanoprobes, with a detection limit of 0.0800 μmol/L. This new RRS method was applied to determination of SO32– in food and SO2 in air samples. The recoveries of food and air samples were 97.1–106% and 92.9–106%, and the relative standard deviation (RSD) was 2.10–4.80% and 2.10–4.50%, respectively.