Combined inverse modeling approach and load duration curve method for variable nitrogen total maximum daily load development in an agricultural watershed

Purpose  

Nonpoint sources (NPS) pollution has been an important cause for water quality impairment worldwide. To take the temporal variations of both NPS pollution and in-stream attenuation into consideration, an inverse modeling approach and the load duration curve (LDC) method were combined for variable nutrient total maximum daily load (TMDL) development.     

Mn-CeOx/钛基层柱粘土(Ti-PILCs)低温选择性催化还原催化剂的钙中毒研究

以钛基层柱粘土(Ti-PILCs)为载体,制备了Mn-Ceox/Ti-PILCs低温选择性催化还原(SCR)催化剂,采用浸溃法模拟了催化剂钙中毒,研究了不同含钙量对催化剂活性的影响,并运用NH3-程序升温脱附(TPD)、H2-程序升温还原(TPR)及X射线光电子能谱(XPS)表征,分析了钙对催化剂的失活作用.结果表明:...     

Analyzing coastal wetland change in the Yancheng National Nature Reserve,China

Coastal zones provide habitat cores and corridors that maintain the diversity of entire landscapes, and they can form the cornerstone elements of regional conservation strategies. Natural environmental driving factors and excessive anthropogenic activities play important roles in coastal wetland change. Many studies have used remote sensing images to map and assess coastal wetland change on local or regional scales. This paper aims to provide insight into coastal wetland change in the Yancheng National Nature Reserve (YNNR) using remote sensing technology and landscape metrics analysis. The results reveal that grass flat and reed areas have significantly decreased, whereas agriculture fields, aquaculture ponds and built-up areas have continuously increased from 1988 to 2006. The spatial pattern of the coastal landscape has become fragmented and heterogeneous under great pressure from rapid economic development and population growth. The wetland changes have important impacts on natural habitat of the red-crowned cranes. The results of this study provide basic information that is required for developing measures toward a sustainable management and conservation of the YNNR.     

Acute toxicity, biochemical and gene expression responses of the earthworm Eisenia fetida exposed to polycyclic musks

Phytoremediation is a novel and promising approach for the treatment of pollutants. This study did explore the potential of Aster amellus Linn. to decolorize a sulfonated azo dye Remazol Red (RR), a mixture of dyes and a textile effluent. Induction in the activities of lignin peroxidase, tyrosinase, veratryl alcohol oxidase and riboflavin reductase was observed during RR decolorization, suggesting their involvement in the metabolism of RR. UV-Visible absorption spectrum, HPLC and FTIR analysis confirmed the degradation of RR. Four metabolites after the degradation of the dye were identified as 2-[(3-diazenylphenyl) sulfonyl] ethanesulfonate, 4-amino-5-hydroxynaphthalene-2,7-disulfonate, naphthalene-2-sulfonate and 3-(1,3,5-triazin-2-ylamino)benzenesulfonate by using GC/MS. Textile effluent and mixture of dyes showed 47% and 62% decrease respectively in American Dye Manufacturers Institute value. BOD of textile effluent and mixture of dyes were reduced by 75% and 48% respectively, COD of industrial effluent and mixture of dyes was reduced by 60% and 75% and TOC was reduced by 54% and 69% respectively after the treatment by A. amellus for 60 h; this indicated that the plant can be used for cleaning textile effluents. Toxicity study revealed the phytotransformation of RR into non-toxic products.     

Reversed association between levels of prostate specific antigen and levels of blood cadmium and urinary cadmium

Prostate cancer associated with cadmium exposure may indicate a link between prostate specific antigen (PSA) and levels of blood cadmium (BCd) and urinary cadmium (UCd). Thus, these associations were investigated. We recruited 295 men, 50 years of age and above from a health check-up program at a health center as subjects of the study. They completed a self-reported questionnaire and provided fasting samples of blood and urine for cadmium assay. The assay was performed using atomic absorption spectrophotometry. Blood samples were also collected for the assays of total cholesterol and high-density lipoprotein measures. The means of BCd and UCd increased with age and the means of all subjects were 1.19 ± 1.04 μg L⁻¹ and 1.37 ± 1.76 μg g⁻¹ creatinine, respectively. The PSA levels were positively associated with the lipid levels, but reversely associated with BCd and UCd levels. The multivariate logistic regression analysis showed that men with PSA ? 4.0 ng mL⁻¹ had an odds ratio (OR) of 0.4 (95% CI = 0.1-0.9) to have BCd > 0.49 μg L⁻¹, and an OR of 0.4 (95% CI = 0.2-1.0) to have UCd > 0.45 μg g⁻¹ creatinine. In conclusion, the PSA levels are reversely associated with BCd and UCd levels.     

粗MnSO4溶液中MnS2O6的去除条件研究

用软锰矿吸收SO2生成MnSO4时会伴随有副产物MnS2O6生成。产品中MnS2O6的存在会降低硫酸锰产品质量,同时会缓慢释放出SO2气体污染环境。本文用单因素实验方法研究了粗MnSO4溶液中MnS2O6的最优去除条件。研究结果显示,软锰矿用量为12.2 g,硫酸加入量为20 mL、反应温度100℃、反应时间3 h、搅拌速度500 r/min,MnS2O6的去除率可达91%以上。其最终产品能达到GB1622-1986一级品标准。     

竹炭对废水中Cu2+的吸附

探讨了竹炭粒径、加入量、溶液 pH、吸附时间、Cu2+初始质量浓度等因素对竹炭吸附 Cu2+效果的影响.实验结果表明:竹炭对废水中Cu2+有很好的吸附效果,当竹炭粒径小于0.15 mm、加入量为 16 g/L、溶液 pH 为 6.0、Cu2+初始质量浓度 25 mg/L、吸附时间为 1.5 h 时,竹炭对 Cu2+的去...     

氯氧化锆生产中废碱液的回收利用

建立了以 CaO 为沉淀剂去除废碱液中 SiO2回收 NaOH 的工艺,研究了各工艺因素对siO2去除效果的影响,实验结果表明,CaO 沉淀除去废碱液中 SiO2的最佳工艺条件为:CaO 与废碱液中 SiO2摩尔比 3.0,反应温度80～95℃,反应时间 40～60 min,搅拌转速 200 r/min.在此条件下,S...     

三苯类废气处理进展

综述了近年来三苯类废气处理所采用的方法,如吸收法、吸附法、催化氧化法、生物法、光催化法和低温等离子体法等,对各种方法的处理机理、处理效果以及优缺点进行了概括和分析,并指出联用技术将是未来的发展方向.