Pesticides and Essential Minerals Modify Endogenous Antioxidants and Cytochrome P450 in Tissues of Rats

Two experiments were conducted in male Sprague Dawley (SD) rats (175–200 g) to determine changes in the activities of endogenous antioxidants superoxide dismutase (SOD), glutathione peroxidase (GPX), cytochrome P450 (ethoxyresorufin deethylase; EROD) and concentrations of glutathione (GSH) in the blood, liver, and small intestinal mucosa (IM). In both experiments, six rats/group were fed diets based on the AIN-93M diet (Control) or the same modified to contain either 500 mg calcium (Low Ca), 7 mg Zn (Low Zn): 2 mg copper (Low Cu), 60 mg zinc (High Zn) or 12 mg copper (High Cu) in the following combination: Control, LCa/LZn, LCa/LZn/LCu, or HZn/HCu, with and without a pesticide mixture containing acephate, endosulfan, and thiram at 25% LD₅₀ for four or two weeks. Pesticides decreased feed intake and weight gain in all groups by 28%. Erythrocyte SOD was higher than control in the HZn/HCu group and in the LCa/LZn/LCu and HZn/HCu groups with pesticide (P# 0.05). Plasma GPX declined by more than 55% in all the groups with and without pesticides compared to the control. The LCa/LZn/LCu and HZn/HCu diets with and without pesticides reduced GPX in the IM by up to 88%, 40%, and 74%, respectively, than the control. Plasma GSH was about 20% higher than the control in most groups with and without pesticides in the diet. Liver and IM GSH were higher than the control in the HZn/HCu group, whereas IM GSH concentrations were lower than the control in the LCa/LZn and LCa/LZn/LCu groups (P#0.05). All three experimental diets with and without pesticides had a significant effect on liver EROD activity (P#0.05). The results indicate that endogenous antioxidants and EROD were independently modified by dietary zinc and copper levels and pesticides.     

Biomonitoring spatial and temporal impact of atmospheric dust from a cement industry

The objective of this work was to evaluate the spatial and temporal impact of dust-pollution in the vicinity of a cement industry, located in an area with dry climate. The spatial impact integrated over time was evaluated from the concentrations of Ca, Fe and Mg in in-situ Xanthoria parietina. The temporal pattern was assessed through one-month transplants of the lichen Ramalina canariensis. Four potential sources of atmospheric dust were evaluated: the limestone-quarry; the unpaved roads, the deposit area and the cement mill. Calcium concentration in lichens was considered the best cement-dust indicator. Different types of dust (clinker and grinded-limestone-dust) resulted in different time-patterns of Ca accumulation, which was also related with the different influence that wet and dry periods have in the lichen accumulation process. The dust pollution was found to be deposited locally and dependent on: the nature of dust particles and the volume and frequency of precipitation.     

碱浸-电解锌工艺中含锌废渣的除氯研究

含锌废渣及粉尘是危险废物,因含有较高含量的锌,可作酸法和碱法冶金的原料,但其中若存在氯,则锌产品质量就严重下降,对电极板也有严重腐蚀作用,因此,从含锌废渣及粉尘中高效去除氯有重要意义.系统地研究了碳酸钠溶液洗涤去除含锌粉尘中氯的工艺条件.结果表明,碳酸钠的除氯效果好且不会引起较大的锌损失,其除氯的优化工艺参数为: 碳酸钠质量浓度4 g/L,液固比8:1,温度90 ℃,反应时间90 min,氯的去除率可达到90%以上.对同一种锌粉尘进行了除氯与不除氯的碱浸-电解锌中试对比实验,分析表明: 经碳酸钠除氯后所得的锌粉质量明显提高,全锌和金属锌可分别提高2%～3%.     

Magnesium and the regulation of lead in three populations of the garden snail Cantareus aspersus

Helicid snails appear to regulate Pb more closely than other toxic metals, though it is reported as the least toxic. No regulatory mechanism has been described in animals, and the possible role of Mg in limiting Pb assimilation is examined here for the first time. Three populations of Cantareus aspersus were fed Pb and Ca with three levels of Mg for up to 64 days. Metal assimilation and production efficiency was calculated for each of 108 snails. Populations differed in their pattern of uptake but soft tissue Pb was unaffected by dietary Mg. The proportion of Pb assimilated did not change as soft tissue concentrations increased, indicating no specific regulatory mechanism. The daily addition of Pb to the soft tissues increases with growth rate suggesting uptake is instead some function of growth or cell turnover. Bioconcentration factors varied with time and are unreliable indicators of an evolved regulatory mechanism for Pb.     

Cs uptake by four plant species and Cs-K relations in the soil-plant system as affected by Ca(OH)2 application to an acid soil

Three rates of Ca(OH)₂ were applied to an acid soil and the ¹³⁴Cs uptake by radish, cucumber, soybean and sunflower plants was studied. The ¹³⁴Cs concentration in all plant species was reduced from 1.6-fold in the sunflower seeds to 6-fold in the soybean vegetative parts at the higher Ca(OH)₂ rate. Potassium (K) concentration in plants was also reduced, but less effectively. The significantly decreased ¹³⁴Cs-K soil to plant distribution factors (D.F.) clearly suggest a stronger effect of soil liming on ¹³⁴Cs than on K plant uptake. This observation was discussed in terms of ionic interactions in the soil matrix and within the plants. The results also indicated that the increased Ca²⁺ concentration in the exchange phase and in the soil solution along with the improved root activity, due to the soil liming, enhanced the immobilization of ¹³⁴Cs in the soil matrix and consequently lowered the ¹³⁴Cs availability for plant uptake.     

碳酸根对磷酸钙沉淀反应回收磷的影响

以模拟的厌氧消化液为处理对象,通过小试实验,考察不同初始磷浓度Cp、Ca／P物质的量比、pH和温度下,碳酸根（CO3 2-）对磷酸钙沉淀反应回收磷的影响;利用扫描电镜（SEM）、x射线衍射仪（XRD）和傅里叶变换红外光谱（FT．IR）对沉淀产物进行表征。结果表明,高浓度的CO3 2-对以磷酸钙沉淀反应去除和回收磷的效率影响较大;Cp相同时,CO3 2-浓度（CCO3^2-）越大,P的去除率越低,低C,（20mg／L）时尤为显著;当CCO3^2-相同时,随着Cp的增大,反应速率加快,P的去除率逐渐升高,但升高幅度越来越小;增大Ca／P比和pH能提高P的去除率,降低CO3 2-对磷酸钙沉淀反应的抑制作用,综合考虑实际效果,应选择Ca／P比为3．33,pH为9．0作为适宜的反应条件;升高温度对降低CO3 2-对磷酸钙沉淀反应的抑制作用贡献不大。在Cp为60ITIg／L,Ca／P比为1．67,pH为9．0,温度为20℃的条件下,当CCO3^2-为0时,得到的沉淀产物主要为羟基磷灰石HAP;当CCO3^2-为30mmol／L时,得到的沉淀产物为磷酸钙和碳酸合磷灰石的混合物。     

碳酸盐岩抑制煤中有害元素释放和迁移能力的研究

为了揭示碳酸盐岩地质背景下碳酸盐岩对煤中有害元素的抑制作用,以煤和碳酸盐岩为实验材料设计了3个不同组合的淋溶柱,采用淋溶实验方法,探讨了碳酸盐岩对煤中Fe、Mn、Cu、As等元素释放和迁移的抑制能力.结果表明:碳酸盐岩能有效中和煤中黄铁矿等硫化矿物氧化产生的酸,淋溶液pH值显著升高;碳酸盐岩对煤中硫的释放和迁移能力的抑制作用不明显,对煤中Fe、Cu和As元素的释放和迁移的抑制能力较强,但对煤中Mn、Pb和Cd元素的释放和迁移的抑制能力相对较弱.碳酸盐岩能有效抑制酸性矿山废水的形成和演化,可作为碳酸盐岩地区酸性矿山废水防治的理想材料.     

广西典型碳酸盐岩区农田土壤-作物系统重金属生物有效性及迁移富集特征

为揭示碳酸盐岩地质高背景区土壤重金属生态风险,选择广西典型的成土母岩为碳酸盐岩的土壤重金属高背景区,采集水稻籽实及对应根系土样品68套,在分析测试土壤、农作物籽实样品中砷(As)、镉(Cd)、铬(Cr)、铜(Cu)、汞(Hg)、镍(Ni)、铅(Pb)和锌(Zn)这8种重金属含量及土壤中重金属赋存形态的基础上,采用统计学、地累积指数、生物富集系数及相关性分析等方法开展土壤重金属生态风险研究.结果表明,研究区土壤中8种重金属平均含量明显高于全国和广西表层土壤的平均水平,其中Cd、As和Cr超过农用地土壤污染筛选值的比例分别达95. 6%、86. 8%和69. 1%,超过土壤污染管控值的比例分别为27. 9%、17. 6%和5. 9%.区内土壤中As、Cr、Cu、Ni、Pb和Zn主要以残渣态为主(残渣态占比 80%),显示出较低的生物活性; Cd的生物活性相对较高,生物有效态组分占20. 99%,但仍明显低于全国其它非碳酸盐岩地区的土壤; Hg的潜在生物有效态组分占44. 04%,然而土壤中Hg全量较低,因此其潜在生物有效态的绝对含量较低.与土壤相比,研究区水稻籽实中重金属超标率明显较低,仅部分样品中Cd、Cr、Pb超过国家食品限量标准,超标率分别为8. 8%、2. 9%和23. 5%.相关性分析显示,研究区土壤重金属全量与对应的水稻籽实中重金属含量不存在显著正相关关系.水稻籽实重金属生物富集能力普遍较低,8种重金属生物富集系数(BCF)的均值均小于0. 1,其中As、Cr、Hg、Ni和Pb的BCF均值小于0. 05.上述结果表明,对于碳酸盐岩等地质高背景区,相关部门在制定污染土壤管控政策时不能仅以土壤重金属全量作为衡量标准,应综合考虑金属赋存形态、生物活性及农作物超标率等因素.     

不同活性炭活化过硫酸盐的效能及机理的规律研究

选取煤质活性炭(F400D)、木质活性炭(Norit)和椰壳活性炭(Youshi)作为过硫酸盐(PS)活化剂,通过动力学实验研究了不同活性炭对过硫酸盐的活化效能及机理,考察了氯化钠和碳酸钠对活性炭/过硫酸盐体系的影响.结果表明,3种活性炭/过硫酸盐体系均可实现橙黄G的高效去除,效能略有差异,依次为:F400D/PSNorit/PSYoushi/PS.活性炭对染料的去除包括吸附作用和活化过硫酸盐的氧化降解作用,吸附位点与活化位点在活性炭上具有不同的分布.活性炭/过硫酸盐体系对1~100 mmol·L~(-1)氯化钠有很强的耐受作用,适用于高盐废水中有机污染物的去除.1~10 mmol·L~(-1)的碳酸钠对体系有明显的抑制作用.     

磁场水处理技术中微观电磁感应行为分析

运用电磁学基础知识,引用分子电流模型,通过数学推导,分析得出水系统中微观粒子因受到电磁感应影响,可引发电子云分布改变。同时论证说明各磁场因素对该过程的影响,并通过试验进行了验证。分析表明:在磁场水处理技术中,微观电磁感应现象更具有普遍意义,进一步揭示磁场水处理技术的磁场作用机理,为磁场水处理装置的设计与应用提供了依据。