铁改性生物炭促进土壤砷形态转化抑制植物砷吸收

通过盆栽试验研究了不同砷污染水平(10、20、40和80 mg/kg)下,添加不同量(10、20和40 g/kg)改性前后的生物炭对土壤砷形态及植物吸收砷规律的影响。该文以棉花秸秆生物炭及改性生物炭(棉花秸秆生物炭与Fe Cl3?6H2O按质量比为20∶1)为试材,小白菜为供试植物。结果表明:生物炭(10~40 g/kg)和改性生物炭(10 g/kg)能促进小白菜的生长,在添加量分别为20和10 g/kg时生物量最大,其最大值分别为8.26和6.68 g/盆,改性生物炭在添加量为10 g/kg时高于对照组和等量未改性生物炭处理组。在砷质量分数为10和20 mg/kg的基础上,添加生物炭(10~40 g/kg)后,土壤中砷主要以残渣态形式存在;水溶态砷分别增加了0.22%~3.36%和0.96%~3.70%;改性生物炭添加对土壤砷质量分数为10 mg/kg时水溶态砷无明显影响,土壤砷质量分数为20 mg/kg时,添加改性生物炭(10~40 g/kg)后水溶态砷减少了0.12%~0.58%。在高浓度(40和80 mg/kg)砷土壤中,水溶态砷含量随着土壤中砷含量的增加而增大;添加生物炭(10~40 g/kg)后,土壤中水溶态砷分别增加了0.21%~1.56%和2.11%~8.94%,但砷主要以铝形砷形式存在,残渣态砷次之。各处理组小白菜可食部分和根部砷质量分数在添加10~40 g/kg生物炭后的变化规律不尽相同,等量的改性生物炭添加后,可食部分由18.28 mg/kg显著降低至2.66 mg/kg(P0.05),根部从133.99 mg/kg显著降低至20.21 mg/kg(P0.05)。改性生物炭与未改性生物炭相比,改性生物炭能降低土壤中水溶态砷的含量及对小白菜吸收砷有显著的抑制作用。因此,该研究可为改性生物炭在含砷土壤的修复应用中提供数据支撑与理论基础。     

原子荧光光谱法测定农药中砷和汞的方法研究

农药中的砷、汞是使农产品产生毒性的重要原因,为探究农药中砷和汞同时检测的方法,通过原子荧光光谱对农药中砷和汞进行测定,讨论了不同前处理方法对测定结果的影响,最终确定了王水消解样品-原子荧光光谱法同时测定砷和汞的方法,该方法对砷和汞的回收率分别为90.1%~104.0%和89.5%~96.2%,检出限为0.14和0.003 1ng·mL-1,RSD为4.9%和5.2%,当砷的质量浓度处于0~100.0ng·mL-1,汞的质量浓度处于0~2.0ng·mL-1时,标准曲线均能呈良好的线性关系,相关系数分别为1.000和0.999 8,结果满意。     

砒砂岩区不同灌木根系构型及根系抗拉对比

对砒砂岩区各主要灌木树种根系形态进行定量研究,探究哪种水土保持植物可以有效地抵抗砒砂岩区的复合型侵蚀,以该区分布较广的灌木树种沙棘(Hippophae rhamnoides L.)、酸枣(Ziziphusjujuba M.)、连翘(Forsythia suspensa V.)、文冠果(Xanthoceras sorbifolium B.)、黄刺玫(Rosaxanthina L.)和蒙古扁桃(Amygdalus mongolica R.)单株个体为研究对象,对其根系分布范围、几何形态,拓扑指数、单根力学特性,降维进行综合分析,筛选出在砒砂岩地区固土效果较好的灌木植物。结果表明:(1)文冠果和连翘以倾斜根为主,沙棘、酸枣、黄刺玫和蒙古扁桃以水平根为主;细根长文冠果(2 368.54 cm)＞沙棘(1 746.12 cm)＞黄刺玫(1 463.15 cm)＞蒙古扁桃(1 162.81 cm)＞酸枣(928.69 cm)＞连翘(817.45 cm);文冠果拓扑指数0.54且根系呈叉状分支结构;连翘拓扑指数0.71且呈鱼尾型分支结构。(2)根系平均抗拉强度文冠果(30.45 MPa)＞黄刺玫(18.21 MPa)＞连翘(17.03 MPa)＞蒙古扁桃(16.62 MPa)＞酸枣(16.34 MPa)＞沙棘(15.35 MPa)。基于主成分分析法对不同灌木树种根系固土效应进行对比,其中,文冠果的综合主成分指标最高达到2.28,则综合固土效果最好。研究结果可为砂岩地区选出适宜的土保持灌木,同时为灌木林的可持续发展提供理论参考。     

持续污染下洛克沙胂在土柱中的迁移转化及其风险评估

由于禽畜粪便未做防渗的露天堆积,导致饲料添加剂洛克沙胂（ROX）进入环境从而诱发无机砷污染。本研究通过157 d的一维土柱模拟探究了ROX长期持续污染的前提下,垂向包气带上砷化合物形态和含量的时空变化,并通过高通量测序技术揭示了不同深度的微生物群落结构响应。结果显示,在157 d的ROX持续污染模拟过程中,ROX降解速率很高,显著高于迁移速率,ROX的降解与吸附均发生在土壤浅层（0~10 cm）。ROX降解产物主要为As（Ⅴ）和As（Ⅲ）,其中As（Ⅴ）含量明显高于As（Ⅲ）含量,砷化合物均主要聚集在0~40 cm深度,土壤中砷化合物含量显著高于土壤溶液中的含量,土壤对砷化合物的固定能力很强,砷化合物的迁移速度十分缓慢,157 d最大迁移深度为40 cm。由此可见,土壤一旦被砷污染,其长期危害难以消除。表层土壤中微生物群落结构与其他深度显著不同,结合RDA与PERMANOVA分析证明深度和ROX含量是控制不同深度土壤中微生物群落多样性的主要影响因素。通过健康风险评估得知,表层土壤中ROX持续污染会诱发较大的砷致癌风险。因此,建议全面执行我国禁止使用ROX的规定,在仍然允许使用ROX的国家和地区,要加强对禽畜废弃物的规范处理,避免长期在未防渗的地面上露天堆积。     

Magnesium slag for remediation of cadmium- and arsenic-contaminated paddy soil: A field study

The accumulation of heavy metals like cadmium (Cd) and metalloids like arsenic (As) in plants can do harm to human health through the food chain, especially through the rice (Oryza sativa L.). To solve this problem, this study researched the application of magnesium slag (MS) and polyaspartic acid (PASP), which could accelerate rice growth and improve yield, increase soil pH and activate rice enzyme activity as well as reduce the bioavailability of Cd and As in the soil. After these two different treatments, rice yield increased by 17.0% and 18.9%, respectively. Meanwhile, the bioavailable As decreased by 49.1% and 42.5%, while the bioavailable Cd reduced by 72.6% and 44.3%. Besides, the Cd content in rice grains reduced by 77.7% and 17.3%, respectively, after two different treatments. In the MS treatment, the As content in rice grains was reduced by 21.8%, but showed no significant response to the other treatment. The contents of bioavailable Cd and As (determined by one-step extraction) in soil were decreased by MS and PASP, which was favourable for the reduction of Cd and As accumulation in rice. The health risk assessment showed that the application of passivators can effectively reduce the risk of carcinogenesis, but it was still unacceptable. The application dose of MS and PASP still needs further exploration.     

氮肥形态及用量对土壤砷生物有效性的影响研究

通过盆栽试验,探讨了高砷红壤中施用碳酸氢铵、尿素和硝酸钙3种不同形态氮肥对土壤砷生物有效性及小白菜吸收砷的影响。结果表明:在175、350mg·kg-1两种施氮水平下,不同形态氮肥的施用均显著(P<0.05)促进了小白菜(Brassica chinensis)植株的生长,生物量的增加幅度为104.5%～224.3%;氮肥施用显著增加了土壤中有效态砷含量和植物对砷的吸收(P<0.05),与对照相比,不同形态氮肥处理下土壤有效态砷含量增加了30.5～49.4倍,其中,以施氮量为350mg·kg-1Ca(NO3)2处理增幅最大,NH4HCO3的350mg·kg-1施氮处理的增幅较小;在3种氮肥形态的2种施氮量处理下,植物地上部砷吸收量比对照增加0.75～4.32倍,且以175mg·kg-1NH4HCO3和350mg·kg-1Ca(NO3)2的施氮处理较高,而350mg·kg-1CO(NH2)2和175mg·kg-1Ca(NO3)2施氮处理的植物砷浓度及吸收量均相对较低。随着化学氮肥的施用,发生了土壤残渣态的砷向易溶态等其他形态砷的转化和释放,导致作物吸收砷及相应的环境风险增加。     

用于表征三七种植区土壤中可利用态砷的化学提取剂的筛选

为正确表征云南文山三七种植区土壤中植物可利用态砷,选取NaH2PO4（0.5mol·L-1）、H2O、H3PO4（0.2mol·L-1）、EDTA（0.0625mol·L-1,pH=7）、NH4C（l1.0mol·L-1）和（NH4）2SO（40.05mol·L-1）6种提取剂,比较了它们对土壤中砷的提取效果,及其所提取的砷与三七植株各部位砷含量之间的相关关系。结果表明,NaH2PO4、H3PO4和（NH4）2SO4这3种提取态砷与土壤总砷呈极显著正相关,相关系数分别为0.8359、0.8177和0.8810。NaH2PO4和H3PO4的提取效率较高,平均提取效率分别为6%和11%;而（NH4）2SO4提取效率较低,平均仅为0.084%。NaH2PO4和（NH4）2SO4提取态砷与三七主根、须根和茎部砷含量呈显著正相关,H3PO4提取态砷与三七主根和须根砷含量呈显著正相关。综合考虑认为NaH2PO（40.5mol·L-1）是最佳提取剂,H3PO（40.2mol·L-1）提取剂次之,这两种提取剂均可较好地表征土壤中砷的三七可利用性。     

利用HPLC-ICP-MS方法测定中华绒螯蟹不同形态砷的残留量

采用高效液相色谱串联电感耦合等离子体质谱仪(HPLC-ICP-MS)测定中华绒螯蟹可食部位6种砷形态的残留量。经过前处理、提取和脱脂后,通过色谱柱、流动相、pH和流速等参数调节,筛选得到最优化的分离和检测条件。结果表明,6种砷形态的混合标准溶液在质量浓度0~50 μg/L范围时,均呈现良好的线性关系,其R²达到0.999,检测限为0.0060~0.0912 μg/kg,定量限为0.020~0.304 μg/kg。在样品中添加0.5、5、50 μg/L浓度水平,回收率良好,范围是70%~120%,相对标准偏差(RSD)均<5%,方法精密度与重复性均良好。本方法为中华绒螯蟹可食部位砷形态残留量建立了有效检测方法,为水产品砷残留快速检测提供技术支撑。     

Differential tissue accumulation of arsenic and heavy metals from diets in three edible fish species

Three different commercial fish species Odontesthes bonariensis, Rhamdia quelen and Oreochromis niloticus and fish feed were collected from four aquaculture farms. Heavy metal (Cd, Cr, Cu, Fe, Mn, Pb and Zn) and arsenic concentration were determined by inductively coupled plasma–optical emission spectrometry (ICP‐OES) in muscle, liver, gonad, skin, scale and fat from fish and in feed diets. Arsenic concentration was found in different tissues differing between species and within O. bonariensis. Cd was differentially accumulated in liver in O. bonariensis and R. quelen; however, in O. niloticus Cd was found in muscle and scales. Higher concentrations of Cr were determined in skin and scales of O. bonariensis and O. niloticus. Cu, Fe, Mn and Zn were found in all tissues being Cu and Fe concentrations higher in liver. Mn was differentially accumulated in O. bonariensis scales, however in R. quelen no significant differences were found and in O. niloticus liver was the main accumulation tissue. Zn concentration was higher in gonad, skin and liver from R. quelen and O. bonariensis, and in O. niloticus the highest concentration was found in scales. All the results were below the international limits for food safety except for the concentration of Cd in muscle and scales of O. niloticus.     

Reserarch advance on mechanism of arsenic trioxide on tumor

The article demonstrates the relative concepts of apoptosis and summarizes the effect of arsenic trioxide to the carcinoma, its possible principle included. Recent development of the reports about arsenic trioxide-induced apoptosis is referred and reviewed. Apoptosis is a natural mechanism and a common physiological death of cell, and its abnormity has great effect on cancer. Arsenic trioxide can induce apoptosis in APL cell and other cancer cells, and has been used in treating the patient with other kinds of malignant cancers. The mechanisms of arsenic trioxide-induced apoptosis are gradually becoming a hotspot, but still not lucid. With intensive study of arsenic trioxide, it can be a useful ways in treating cancer patients in the future.