A multi-residue method for the analysis of organophosphorus residues in cooked and polished rice using accelerated solvent extraction and dispersive-solid phase extraction (D-SPE) technique and uncertainty measurement

Quick, simple and efficient multi-residue analytical methods were developed and validated for the determination of organophosphorous insecticides from polished and cooked rice. Polished rice was extracted using a simple, automated technique namely accelerated solvent extraction (ASE) using dichloromethane as the extraction solvent. Cooked rice was extracted with acetone and cleaned up using dispersive-solid phase extraction (D-SPE) technique. The single step extraction method adopted for polished rice using accelerated solvent extractor provided satisfactory recovery for eight organophosphorus pesticides (OPPs) which ranged from 85.5–116.7%; 90.0–110.3% and 93.5–118.8% at 1, 5 and 10 limit of quantification (LOQ) levels, respectively. The recovery of cooked rice was in the range of 74–124%; from 75–100% and from 73–87% for 1, 5 and 10 level of fortification, respectively. The total uncertainty was evaluated, taking four main independent sources viz., weighing, purity of the standard, GC calibration curve and repeatability under consideration. The expanded uncertainty was found to be in the range of 5–20%.     

稻秆负荷与pH对稻秆厌氧发酵产酸系统启动过程的影响

为探讨稻秆负荷（即稻秆VS/污泥VSS）与发酵pH对稻秆厌氧发酵产酸系统启动过程产挥发性脂肪酸（VFAs）效果的影响,利用厌氧搅拌罐反应系统考察在不同的稻秆负荷（0.556、0.945、1.334和1.724 g/g）和不同的发酵pH（8.0、9.0和10.0）启动运行条件下的产酸性能,并分析了系统启动过程产酸与稻秆主要成分降解之间的关系。实验结果表明,VFAs浓度随稻秆负荷提高而增大,随发酵pH的升高而降低;发酵18 d时,发酵pH为9.0时,稻秆负荷1.334 g/g的产酸效果最好,VFAs浓度与稻秆产酸量分别为4 385.10 mg/L和2.19 gVFAs/g稻秆,此时半纤维素、纤维素和酸性洗涤木质素降解率分别为32.69%、22.53%和6.40%;稻秆负荷为0.945 g/g条件下,VFAs浓度在pH为8.0时达到最高值4 409.51 mg/L,此时稻秆降解量也最多,半纤维素、纤维素和酸性洗涤木质素降解率分别为28.60%、47.32%和22.69%。研究表明,稻秆负荷与发酵pH通过影响稻秆半纤维素、纤维素和木质素的降解影响稻秆厌氧发酵产酸的进程和效果。     

稻壳活性炭制备及其对磷的吸附

利用农业废弃物稻壳经炭化、活化、酸洗、水洗和干燥等工艺制备出一种富含微孔和中孔结构的稻壳活性炭,其BET比表面积达886.3 m2/g。通过正交实验优化了稻壳活性炭对磷吸附条件,并在该条件下进行了吸附等温和吸附动力学实验研究。结果表明,稻壳活性炭对磷的吸附等温曲线能较好符合Langmuir模型(R2=0.9284)和Freundlich模型(R2=0.9208),由Langmuir线性拟合方程可得稻壳活性炭对磷饱和吸附量达6.93 mg/g;稻壳活性炭对磷的吸附过程可用准二级动力学方程描述(R2=0.9968),吸附速度较快,颗粒内扩散为该过程控速阶段。稻壳活性炭作为一种易得、廉价、高效的填料,在农村分散型污水生态处理技术中,具有良好的应用前景。     

Value of Ecosystem Services in Conventional and Organic Rice Paddies： A Case Study in Wannian, Jiangxi, China

In the current study,the ecosystem services(ES)of conventional and organic rice paddies in Wannian,Jiangxi Province,China are investigated.First,the ES at the field level under organic and conventional paddies were investigated.Total economic value of ES in organic rice paddies was 30093.08yuan RMB/ha per year and that of conventional rice paddies was22 793.31 yuan RMB/ha per year.The total indirect value of ES was 14 813.7 yuan RMB/ha per year in organic rice paddies and12 424.56 yuan RMB/ha per year in conventional ones.There were significant differences between organic and conventional rice paddies for the economic values.Then,this economic information was used to extrapolate and to calculate the total and indirect value of ES from rice paddies in Wangnian.The total and indirect economic values of ES from conventional rice paddies in Wannian were6791 million and 3702 million yuan RMB per year respectively,and the total and indirect economic values of ES from organic rice paddies in Wannian were 1311 million and 646 million yuan RMB per year.If half the area had being converted to organic farming in Wannian,the total and indirect economic values of ES from conventional rice paddies were 3397 million and 1851 million yuan RMB per year,and the total and indirect economic values of ES from organic rice paddies were 5794 million and 2852 million yuan RMB per year.Finally,the total economic value of ES in rice paddies in Wannian was demonstrated through geographic information system techniques.     

Effects of cultivation conditions on the diversity of microbes involved in the conversion of rice straw to fodder

To confirm the optimum cultivation conditions for analyzing lactic acid bacterial communities and to provide the cultivation foundation for lactic acid bacterial communities that were used to convert straw into fodder, fermented rice straw was inoculated into 13 different broths. After 48 h of cultivation, pH values, volatile products, and microbial diversity were analyzed. Except for LAB broth, the pH values of the other broths could decrease to approximately 4.5. GC/MS analysis showed that lactic acid in Tomato MRS broth, MRS broth, LAB broth, and Tomato juice broth was higher than that in the other broths. DNA concentration analysis showed that the counts of microbes in Tomato MRS broth were 2.5 times of those in other broths and that tomato juice favored the reproduction of the microbes. Denaturing gradient gel electrophoresis （DGGE） analysis showed that the number of lactic acid bacterial species in HYA broth, Tomato juice broth, and Tomato MRS broth were higher than those in the other broths.     

四环素与镉复合污染对水稻根系的影响

为阐明抗生素与重金属复合污染对水稻根系的影响机制,考察了四环素(TC)与镉(Cd)单一和复合污染条件下,水培分蘖期水稻根系生长、污染物积累和根系分泌物的变化特征.结果表明:TC与Cd单一处理时,根部生物量和叶绿素含量下降,表现出毒害作用,低剂量的TC与Cd共同作用能够缓解其毒性效应;TC与Cd单一/复合污染均使根的伸长...     

外加Cd对两水稻品种细胞超微结构的影响研究

为了研究Cd在不同水稻品种(Oryza sativa L.)细胞中的分布位点及其耐Cd的具体表征状况,以子粒Cd积累水平不同的两水稻品种(品种A:中浙优1号,子粒高Cd含量品种;品种C:J196,子粒低Cd含量品种)为材料,进行盆栽实验,设不加Cd处理(CK)和加Cd处理(25mg·kg-1),采用透射电镜技术研究了外加Cd对两水稻品种细胞超微结构的影响.结果表明:Cd处理下两水稻品种的部分根细胞有Cd沉积现象,但不同品种的沉积部位表现不同,品种A主要在液泡边缘而品种C则在细胞壁和细胞间隙,表明不同水稻品种根系的耐Cd机制不同,品种A主要表现为液泡区室化,而品种C主要表现为细胞壁上有特定沉积.水稻叶肉细胞器中的叶绿体和线粒体是对Cd胁迫较为敏感的细胞器,外加Cd对茎叶细胞超微结构造成的伤害主要表现在使叶绿体上淀粉粒消失,叶绿体空泡化,部分线粒体出现肿胀或解体现象,品种C的受害程度高于品种A。     

黑曲霉M1M15M19降解稻草秸秆的试验研究

分析黑曲霉M1M15M19在含不同浓度的C源、N源稻草秸秆基质上培养30 d过程中木质纤维素酶类和主要化学成分.结果表明,黑曲霉M1M15M19降解秸秆的最佳条件是低碳高氮LCHN,降解秸秆中木质素的最佳条件是高碳低氮HCLN,经过25 d降解率分别为48.2%和20.4%.秸秆降解过程中纤维素酶和半纤维素酶起到了决定性的作用,秸秆中木质素降解过程中木质素过氧化物和锰依赖过氧化物起了重要作用.     

三元复合调理剂对土壤镉砷赋存形态和糙米镉砷累积的调控效应

为研究三元复合调理剂(石灰石+硅藻土+硫酸铁,LDF)对稻田土壤Cd 和As 赋存形态及水稻糙米Cd 和As 累积的影响,开展水稻盆栽试验.LDF按质量比设置7个施用水平(0、0.5、1.0、2.0、4.0、8.0和16.0 g·kg-1),种植2种水稻(黄华占和T优272).结果表明:①施用LDF分别提高黄华占和T优...     

基施硅肥对土壤镉生物有效性及水稻镉累积效应的影响

为研究硅肥对土壤Cd生物有效性以及水稻累积重金属Cd的影响,模拟土壤低Cd污染水平(Cd总量为0.72mg·kg~(-1))和土壤高Cd污染水平下(Cd总量为5.08 mg·kg~(-1)),土壤基施0、15、30、60 mg·kg~(-1)的硅肥,进行水稻盆栽种植实验.结果表明,施用15~60 mg·kg~(-1)硅肥能提升水稻各生育期土壤的pH值,降低土壤交换态Cd含量和TCLP提取态Cd含量24.2%~43.7%,12.7%~46.8%,土壤中Si能与Cd形成Si-Cd复合物,降低土壤Cd的生物有效性,且降低效果在土壤低Cd污染水平时优于高Cd污染水平.硅肥提升水稻地上部的生物量尤其是产量.土壤低Cd污染水平下,Si对土壤Cd向水稻地上部的转运有促进和阻碍两种作用,施用量过低(Si 15 mg·kg~(-1))或过高(Si 60 mg·kg~(-1))时均促进土壤Cd向水稻地上部转运,施用量为30 mg·kg~(-1)时则阻碍Cd向上转运.随着Si施用量的增大,糙米Cd含量先上升后下降,范围为0.07~0.15 mg·kg~(-1),均低于0.2 mg·kg~(-1).土壤高Cd污染水平下,Si阻碍Cd向水稻地上部的转运,糙米、谷壳、茎叶的Cd含量分别降低38.7%~48.5%、35.7%~70.7%、30.9%~40.7%,糙米Cd含量范围0.23~0.28 mg·kg~(-1).综合考虑产量和糙米Cd含量,土壤低Cd污染水平下,建议施用30 mg·kg~(-1)的Si;高Cd污染水平下,建议施用Si 15~60 mg·kg~(-1).