毒草胺在环境中的降解特性研究

毒草胺是一种被广泛应用的农药,其在环境中的降解特性备受关注。文章采用室内模拟试验方法,研究了毒草胺的光解、水解及土壤降解特性。研究结果表明,毒草胺在光强为2 370l x、紫外强度为13.5μW.cm-2的人工光源氙灯条件下,光解半衰期为2.5 h,较易光解。25℃时在pH值为5.0、7.0和9.0的缓冲水溶液中,降解半衰期分别为147.5、173.3和239.0 d;50℃时半衰期分别为15.2、27.0和42.3 d,结果显示温度对其降解速率影响较大,温度增加,水解速率明显加快,水解半衰期降低约6~10倍。该药在江西红壤中降解半衰期为46.5 d,在太湖水稻土、东北黑土中降解半衰期分别为6.4和7.9 d,比较容易降解,主要为微生物降解。结果表明毒草胺在水体中具有一定的稳定性,尤其在避光条件下难以降解。但在土壤中,比较容易被微生物降解。     

甲酰氨基嘧磺隆在模拟环境中的降解特性

甲酰氨基嘧磺隆是一种新型磺酰脲类除草剂,其在环境中的归趋备受关注.采用室内模拟试验方法,研究了甲酰氨基嘧磺隆在不同土壤中的降解性、水解和光解特性.结果表明,甲酰氨基嘧磺隆在光照强度4000 lx,紫外强度25μW·cm~(-2)的人工光源氙灯条件下,甲酰氨基嘧磺隆的光解半衰期为1.72 h,易光解.25℃时,pH4、pH7和pH9条件下水解半衰期分别为4.17、91.2、97.6 d,50℃时的水解半衰期分别为1 d、4.75 d和14.5 d,温度和p H值对水解速率具有较大影响.甲酰氨基嘧磺隆在江西红壤、太湖水稻土和东北黑土中的降解半衰期分别为10.8、16.6、31.5 d,该药在酸性土壤中降解较快,影响其在土壤中降解速率的主要因素为土壤pH值.     

吡虫啉的光解水解和土壤降

在实验室测定了吡虫啉的光解、不同ｐＨ条件下的水解与在东北黑土等３种不同土壤中的降解。试验结果表明，在３００Ｗ低压汞灯下，吡虫啉水相溶液的光解呈一级反应动力学反应，光解半衰期为６．８１ｈ；在ｐＨ５、ｐＨ７、ｐＨ９的缓冲溶液中的水解半衰期分别为３０．６、１３．６与８．０ｄ；在东北黑土、太湖水稻土和江西红壤中的降解半衰期分别为１０．７、１１．１和４．１ｄ。     

丁虫腈在环境中的降解特性

采用室内模拟试验研究丁虫腈在水体中的光解、水解及其在3种不同类型土壤中的降解特性。结果表明,丁虫腈在酸性和中性条件下比较稳定,不易水解,而在碱性条件下水解较快,在50℃、pH值为9．0的缓冲溶液中降解半衰期为26．7d。通过对水解产物的鉴定,推断丁虫腈的水解机理为碱催化水解。在[光]照度为2500lx、紫外强度为25I．LW·cm-2的人工光源氙灯条件下,丁虫腈的降解半衰期为1．5h,主要降解产物为氟虫腈。丁虫腈在太湖水稻土、江西红壤和陕西潮土中培养180d后均未发生明显降解,表明该农药在土壤中较难降解。     

3种三唑类杀菌剂的环境降解特性

为了掌握三唑类杀菌剂在环境中的行为归趋,评价其在环境中的风险,采用室内模拟试验,对氟环唑、戊唑醇和粉唑醇3种三唑类杀菌剂在不同温度和p H值水体、不同类型土壤以及氙灯光照条件下的降解特性展开研究。结果表明:在4 000 lx、紫外强度25μW·cm-2的人工光源氙灯条件下,氟环唑、戊唑醇和粉唑醇的光解半衰期分别为0.68、2.35和9.30 h,氟环唑和戊唑醇属于易光解农药,粉唑醇为中等光解农药;在25℃,p H值为4.0、7.0和9.0条件下,氟环唑的水解半衰期分别为120、131和151 d,戊唑醇的水解半衰期分别为257、198和187 d,粉唑醇的水解半衰期分别为204、182和182 d,3种杀菌剂水解特性差异与水体p H值和农药本身结构相关;氟环唑、戊唑醇和粉唑醇在江西红壤、太湖水稻土和东北黑土中的降解半衰期分别为58.2~72.9、182~365和102~161 d,3种土壤中降解速率从大到小依次为东北黑土、太湖水稻土和江西红壤。3种农药在水体和土壤中的滞留期较长,建议关注其在环境中的污染影响,对其使用和残留状况进行跟踪监测。     

溴氟菊酯的光解、水解与土壤降解

在实验室测定了溴氟菊酯的光解、不同ｐＨ条件下的水解以及在太湖水稻土、江西红壤与东北黑土等３种不同土壤中的降解。试验结果表明：在３００Ｗ低压汞灯下，溴氟菊酯的水相溶液与其石油醚相济液中的光解均呈二级反应动力学方程，光解半衰期分别为１３．７与９．４ｍｉｎ；在ｐＨ为５，７，９的缓冲溶液中其水解半衰期分别为１５．６，８．３与４．２ｄ；在３种不同土壤中的降解半衰期为４．８～８．８ｄ。     

溴氟菊酯的光解,水解与土壤降解

在实验室测定了溴氟菊酯的光解、不同ｐＨ条件下的水解以及在太湖水稻土、江西红壤与东北黑土等３种不同土壤中的降解。试验结果表明：在３００Ｗ低压汞灯下，溴氟菊酯的水相溶液与其石油醚相溶液中的光解均呈二级反应动力学方程，光解半衰期分别为１３．７与９．４ｍｉｎ；在ｐＨ为５，７，９的缓冲溶液中其水解半衰期分别为１５．６，８．３与４．２ｄ；在３种不同土壤中的降解半衰期为４．８￣８．８ｄ。     

芸苔素内酯的水解及其在土壤中的降解特性

测定了芸苔素内酯在不同pH值和温度条件下的水解及其在东北黑土、灭菌东北黑土、江西红壤和河南二合土4种土壤中的降解特性。结果表明:芸苔素内酯的水解和在土壤中的降解均符合一级动力学方程。在pH值为5、7和9的条件下,25℃时芸苔素内酯的水解半衰期分别为24.1、19.6和16.4d;50℃时水解半衰期分别为20.9、16.3和13.6d。25℃时芸苔素内酯在东北黑土、灭菌东北黑土、河南二合土和江西红壤中的降解半衰期分别为13.8、14.1、16.5和43.3d。     

4种非农用农药的降解和吸附特性及多介质环境行为模拟

采用室内模拟试验,系统研究生物烯丙菊酯、反式氯氰菊酯、多杀霉素和甲氨基阿维菌素苯甲酸盐4种非农用农药的水解、光解和吸附特性,并采用EQC模型模拟4种非农用农药在多介质环境中的归宿和迁移通量。结果表明,在25℃,pH值分别为4、7和9条件下,生物烯丙菊酯的水解半衰期分别为77.00、57.80和4.41 d,反式氯氰菊酯的水解半衰期分别为180、40.80和5.64 d,多杀霉素的水解半衰期分别为180、180和6.03 d,甲氨基阿维菌素苯甲酸盐的水解半衰期分别为180、180和46.20 d;温度越高,pH值越大,4种非农用农药水解速率就越快。氙灯照射下,反式氯氰菊酯、生物烯丙菊酯、甲氨基阿维菌素苯甲酸盐和多杀霉素的光解半衰期分别为0.100、0.738、1.720和6.130 h,其分子结构和理化性质是重要影响因素。4种非农用农药在江西红壤、太湖水稻土和东北黑土中的吸附规律均能较好地用Freundlich方程进行描述,土壤pH值、有机质含量、阳离子交换量和水溶解度是影响其在土壤中迁移的主要因素。根据EQC模型评估结果,稳态平衡非流动条件下土壤相是反式氯氰菊酯、多杀霉素和甲氨基阿维菌素苯甲酸盐最大的贮存库,残留量超过95.0%;生物烯丙菊酯在土壤相、水体相和大气相中的质量分数分别为70.1%、18.2%和10.8%。     

芸苔素内酯的水解及其在土壤中的降解特性

测定了芸苔素内酯在不同pH值和温度条件下的水解及其在东北黑土、灭菌东北黑土、江西红壤和河南二合土4种土壤中的降解特性。结果表明：芸苔素内酯的水解和在土壤中的降解均符合一级动力学方程。在pH值为5、7和9的条件下，25℃时芸苔素内酯的水解半衰期分别为24．1、19．6和16．4d；50℃时水解半衰期分别为20．9、16．3和13．6d。25℃时芸苔素内酯在东北黑土、灭菌东北黑土、河南二合土和江西红壤中的降解半衰期分别为13．8、14．1、16．5和43．3d。     

香芋高产、优质栽培技术与产品分级及加工

香芋是多年生宿根草本植物,属天南星科(Araceae)一年生栽培,是我省重要的特种蔬菜之一,随着农业结构调整步伐的加快,香芋的种植面积也在不断扩大,为了提高香芋的产量和品质,达到绿色蔬菜的标准,该文提出了香芋高产、优质栽培技术与产品分级及加工.表3,参5.     

Nanosensors and nanobiosensors in food and agriculture

The food and agriculture sector controls the economic growth of a developing country. The food industries have practices of growing crops, raising livestock and sea foods, food processing and packaging, regulating production and distribution with quality and safety. The process control and monitoring quality are crucial steps. Here we review nanosensors and nanobiosensors as alternative of classical quantification methods. Nanoscale dimensions of metal nanoparticles, metal nanoclusters, metal oxide nanoparticles, metal and carbon quantum dots, graphene, carbon nanotubes, and nanocomposites expand the sensitivity by signal amplification and integrate several novel transduction principles such as enhanced electrochemical, optical, Raman, enhanced catalytic activity, and superparamagnetic properties into the nanosensors. The electrochemical nanosensors, optical nanosensors, electronic nose and electronic tongue, nanobarcode technology, and wireless nanosensors have revolutionized the sensing in food and agriculture sectors with multiplex and real-time sensing capabilities. Despite previous success stories of the remunerative health sector, the approaches are transferred subsequently to food and agriculture sector; with potential application in detection of food contaminants such as preservatives, antibiotics, heavy metal ions, toxins, microbial load, and pathogens along with the rapid monitoring of temperature, traceability, humidity, gas, and aroma of the food stuff.     

市场经济与土肥科技

土肥的基础地位是不随社会性质或社会经济类型的变化而变化的，它既具重要性，又具长久性．市场经济是仍然需要土肥科技的．土肥科技的教学、科研和推广的力度必须加大，局面必须改观，且宜快不宜迟．土肥科技工作者一定要将培肥地力作为中心工作．根据广东的实际，增施有机肥是培肥地力的主要措施，因而抓秸秆还田和发展冬绿肥是我们工作的重点．     

基因污染与生态环境安全

论述了基因污染可能对生态环境安全造成的影响。转基因作物有可能污染天然物种的基因库；有可能破坏传统农作物品种的遗传多样性，加速作物种植品种的单一化及基因资源的流失；使抗除草剂作物的基因向野生或半野生植物漂移的可能性加大，有可能创造出“超级杂草”；带有病毒型转基因作物的基因重组，有可能创造出新的植物病毒，导致新的病害；BT转基因抗虫作物分泌的毒素，在食物链中传递，很难加以控制，对非目标生物造成危害，并最终破坏自然生态系统的平衡。文章还从不同角度分析了基因污染的严重性。     

1株贫营养好氧反硝化菌的分离鉴定及其脱氮特性

从水库底泥样品中,以硝酸盐为唯一氮源进行驯化、分离筛选出1株能在贫营养及好氧条件下进行高效反硝化的菌株PY8,经过电镜形态学观察、生理生化和16S rDNA序列分析,并基于16SrDNA序列结果,构建了该菌株的系统发育树,最终确定菌株PY8为根瘤菌Rhizobiumsp.。考察了初始pH值、温度、C/N、初始硝酸钠质量浓度、投菌量对菌株PY8硝酸盐还原活性的影响,以及该菌株的异养硝化性能。结果表明,在pH6.0～10.0,温度25～30℃,C/N1.0～9.0,初始硝酸钠质量浓度0.01～0.50g·L-1,投菌量1%～15%时,菌株PY8培养72h后的硝氮去除率可达到95%以上。另外,该菌株具有同时硝化-反硝化作用,在培养过程中氨氮去除率可达到58%左右。实验结果表明,菌株PY8在微污染水体生物脱氮领域中具有很大的应用潜力。     

Indoor and outdoor air pollution and lung cancer in New Hampshire and Vermont

Indoor and outdoor air pollution is known to contribute to increased lung cancer incidence. This study is the first to address the contribution of home heating fuel and geographical course particulate matter (PM₁₀) concentrations to lung cancer rates in New Hampshire, USA. First, Pearson correlation analysis and geographically weighted regression were used to investigate spatial relationships between outdoor PM₁₀ and lung cancer rates. While the aforementioned analyses did not indicate a significant contribution of PM₁₀ to lung cancer in the state, there was a trend towards a significant association in the northern and southwestern regions of the state. Second, case-control data were used to estimate the contributions of indoor pollution and secondhand smoke to the risk of lung cancer with adjustment for confounders. Increased risk was found among those who used wood or coal to heat their homes for more than 10 winters before the age of 18, with a significant increase in risk per winter. Resulting data suggest that further investigation of the relationship between heating-related air pollution levels and lung cancer risk is needed.     

Characteristics of dispersions and water-soluble extracts of crude and refined oils and their toxicity to estuarine crustaceans and fish

The quantitative hydrocarbon composition and behavior in seawater of water-soluble fractions (WSF) and oil-in-water dispersions (OWD) of 4 oils was investigated. Two crude oils, South Louisiana crude and Kuwait crude, and two refined oils, No. 2 fuel oil and bunker C residual oil, were used in these investigations. The WSFs of the crude oils had higher total oil-hydrocarbon concentrations and were richer in light aliphatics and single-ring aromatics than were the WSFs of the refined oils. The WSFs of the refined oils contained significantly higher concentrations of naphthalenes than did those of the crudes. The hydrocarbon composition of the aqueous phase of OWDs closely resembled that of the parent oils. Gentle aeration of the OWDs resulted in a loss of 80 to 90% of the aqueous hydrocarbons in 24 h. Alkanes disappeared from the dispersions more rapidly than aromatics. The WSFs and OWDs of the refined oils were considerably more toxic to the 6 test species than were those of the crude oils. The test species can be ranked according to increasing sensitivity to oil as follows: Cyprinodon variegatus, Menidia beryllina, Fundulus similus, Penaeus aztecus postlarvae, Palaemonetes pugio and Mysidopsis almyra. The results of this investigation are discussed in relation to the potential impacts of oil spills on the marine and estuarine environments.