Trichloroethene (TCE) degradation by Fe(III)-activated calcium peroxide (CP) in the presence of citric acid (CA) in aqueous solution was investigated. The results demonstrated that the presence of CA enhanced TCE degradation significantly by increasing the concentration of soluble Fe(III) and promoting H2O2 generation. The generation of HO? and O2-? in both the CP/Fe(III) and CP/Fe(III)/CA systems was confirmed with chemical probes. The results of radical scavenging tests showed that TCE degradation was due predominantly to direct oxidation by HO?, while O2-? strengthened the generation of HO? by promoting Fe(III) transformation in the CP/Fe(III)/CA system. Acidic pH conditions were favorable for TCE degradation, and the TCE degradation rate decreased with increasing pH. The presence of Cl-, HCO3-, and humic acid (HA) inhibited TCE degradation to different extents for the CP/Fe(III)/CA system. Analysis of Cl- production suggested that TCE degradation in the CP/Fe(III)/CA system occurred through a dechlorination process. In summary, this study provided detailed information for the application of CA-enhanced Fe(III)-activated calcium peroxide for treating TCE contaminated groundwater. 相似文献
Pharmaceuticals and personal care products (PPCPs) have been regarded as an emerging problem in the surface water environment in the past few decades. In China, although related studies were initiated several years ago, an increasing number of studies on this topic have been conducted in recent years. These studies have expanded knowledge of their occurrence, behavior and associated risk in the surface water environment in China. This review compiles the most recent literature related to the studies of PPCPs in the surface water environment in China. It includes PPCP occurrence in surface water and sediments, their geographical distribution, and outcomes of the associated risk assessment. It shows that antibiotics have received much more attention in both surface water and sediments than other PPCPs. Compared to other countries; most antibiotics in the collected sediments in China showed higher contamination levels. Many more study areas have been covered in recent years; however, attention has been given to only specific areas. Environmental risk assessment based on risk quotients indicated that sulfamethoxazole presents the most significant environmental risk to relevant aquatic organisms; followed by ofloxacin, ciprofloxacin, enrofloxacin, 17α-ethynylestradiol, ibuprofen and diclofenac. Despite limited research on the environmental risk assessment of PPCPs in sediments, higher risks posed by PPCPs in the sediments rather than surface water were identified highlighting the need for further risk assessment of PPCPs in sediment samples.
Optimizing the beneficial mineral elements in rice grains is of interest for rice breeders. To study the environmental effects on mineral accumulation in rice grains, we grew a double-haploid (DH) population derived from the cross between cultivars Chunjiang 06 (CJ06, a japonica rice) and TN1 (an indica rice) under two different ecological environments (Lingshui and Hangzhou, China) and determined the content of Ca, Fe, K, Mg, Mn, P, and Zn in brown rice. These contents show transgressive variation among the DH lines. Subsequently, the quantitative trait loci (QTLs) for mineral accumulation in rice grain were mapped on the chromosomes using CJ06/TN1 population. For the 7 mineral elements investigated, 23 and 9 QTLs were identified for Lingshui and Hangzhou, respectively. Of these, 24 QTLs were reported for the first time in this study and 8 QTLs are consistent with previous reports. Only 2 QTLs for Mg accumulation have been detected in both environments, indicating that mineral accumulation QTLs in rice grains are largely environment dependent. Additionally, co-localizations of QTLs for Mn and Zn, Mg and P, and Mg and Mn accumulation have been observed, implying that these loci might be involved in the accumulation of different elements. Furthermore, the QTLs for the accumulation of Fe, K, Mg, Mn, P, and Zn were mapped to a region close to each other on chromosomes 8 and 9, suggesting that clusters of genes exist on chromosomes 8 and 9. Further characterization of these QTLs will provide a better understanding of the molecular mechanism responsible for mineral accumulation in rice grains. 相似文献
The dairy industry is an important part of the global economy, and the rapidly developing dairy enterprises in China have become increasingly important to the rest of the world. Due to increasing demand for dairy products and support from the government, China's dairy industry has thrived in recent decades. But rapid growth has been accompanied by a suite of industry/structural problems associated with raw milk supply, processing enterprises, product retailing and profit allocation. Thus, a major dairy crisis took place in 2008, triggered by a notorious melamine-contaminated milk event. The dairy crisis has had devastating impacts on China's dairy industry, negatively affecting farmers, consumers, processing enterprises and even government agencies. The Chinese government has developed rigorous measures to prevent future incidents of this sort, including the enactment of the Food Safety Law and reinstatement of the no-exemption quality inspection of food products. In this paper, we analyse the wide-ranging impacts and root causes of the recent dairy crisis in China. We also examine how the crisis has been handled and what measures have been put in place in its aftermath. Then we discuss policy implications for promoting the sustainability of China's dairy industry. Lessons learned from this crisis, as well as implications for policy improvements, should be valuable for the development of a sustainable dairy industry in other regions of the world. 相似文献
