双唑草腈对3种水生生物的急性毒性及初级生态风险评估

为研究双唑草腈对水生生物的毒性和水体环境风险,在实验室条件下,以斜生栅藻、大型溞和斑马鱼为研究对象,分别采用OECD推荐的生长抑制法、活动抑制法、静态法和TOP-RICE模型,开展了双唑草腈的急性毒性试验和初级生态风险评估。结果表明:双唑草腈对斜生栅藻细胞增殖的72 h半数抑制效应浓度 (72 h-EC₅₀) 为1.44 × 10?2 mg/L,对大型溞活动的48 h半数抑制效应浓度 (48 h-EC₅₀) 为15.09 mg/L,对斑马鱼的96 h半数致死效应浓度 (96 h-LC₅₀) 为23.05 mg/L,根据我国《化学农药环境安全评价实验准则》中的毒性等级划分标准,相应毒性等级分别为高毒、低毒和低毒;在水生生态系统中,双唑草腈对脊椎动物和无脊椎动物的急性毒性风险商(RQ) 值小于1的分组占所有模拟场景的60%以上,超过60% 的分组对初级生产者的RQ值大于1,说明双唑草腈对大型溞和斑马鱼较为安全,对水生生态系统中脊椎动物和无脊椎动物的风险在可接受范围,但其对斜生栅藻毒性高,且对初级生产者的风险为不可接受。因此,生产中在施用双唑草腈时应避免药剂进入稻田周边水体,可通过减少农药使用量、合理调整施药时期等方法来减少双唑草腈对水生生态环境的风险,建议在早稻分蘖前期和晚稻分蘖后期使用。     

茶皂素对几种水生生物的急性毒性研究

以淡水水生态系统常见的绿藻和大型溞为受试生物,测定了茶皂素对斜生栅藻、羊角月牙藻的急性毒性以及对大型溞的急性毒性。结果表明,茶皂素对斜生栅藻和羊角月牙藻均为低毒,96h-EC50分别为54.33mg/L和280.54mg/L;对大型溞表现高毒,48h-EC50为0.75mg/L。     

三种双酰胺类杀虫剂制剂对环境非靶标生物的急性毒性

采用"OECD化学品测试准则"和"化学农药环境安全评价试验准则"方法,以赤子爱胜蚓、非洲爪蟾、斜生栅藻、大型溞、斑马鱼,意大利蜜蜂以及家蚕为受试生物,测定了20%氟虫双酰胺水分散粒剂、200g/L氯虫苯甲酰胺悬浮剂和200g/L溴氰虫酰胺悬浮剂3种双酰胺类杀虫剂对环境非靶标生物的急性毒性。结果表明:氟虫双酰胺、氯虫苯甲酰胺、溴氰虫酰胺3种药剂对赤子爱胜蚓、非洲爪蟾、斜生栅藻和斑马鱼的急性毒性均为低毒,但对大型溞的48 h-EC_(50)值分别为1.51×10~(-2)、2.58×10~(-3)、7.63×10~(-2)mg/L,对家蚕的96h-LC_(50)值分别为6.11×10~(-2)、0.12和0.30 mg/L,均为剧毒;氟虫双酰胺和氯虫苯甲酰胺对意大利蜜蜂为低毒,但溴氰虫酰胺对其的48h经口LC_(50)值和接触LD_(50)值分别为2.90 mg/L和3.71×10~(-2)μg/bee,均为高毒。研究表明,虽然双酰胺类杀虫剂对多数非靶标生物毒性较低,但在水体环境和桑蚕区以及作物开花期仍需谨慎使用。     

甲氨基阿维菌素苯甲酸盐乳油对环境生物的急性毒性研究

室内测试甲氨基阿维茵素苯甲酸盐乳油对鹌鹑、蜜蜂、家蚕、鱼、蝌蚪5种环境生物的急性毒性.该药剂对鹌鹑7d的LD50为115(a.i.)mg/kg,对蜜蜂48h的LC50为0.0864(a.i.)mg/L,对家蚕96h的LC50为0.006 22(a.i.)mg/L,对斑马鱼96h的LC50为0.113(a.i.)mg/L,对蝌蚪48h的LC50为0.264(a.i.)mg/L.试验结果表明,甲氨基阿维菌素苯甲酸盐乳油对鹌鹑中毒,对蜜蜂剧毒,对家蚕剧毒,对鱼高毒,对蝌蚪高毒,对环境生物有较大风险,生产上使用该药剂时应注意环境生物的安全.     

新奥霉素母药对5种非靶标生物的急性毒性

测定了新奥霉素 (xinaomycin)母药对5种非靶标生物——斑马鱼Brachydanio rerio、大型溞Daphnia magna Straus、羊角月芽藻Pseudokirchneriella subcapitata、意大利工蜂Apis mellifera L.和家蚕Bombyx mori的急性毒性。结果显示:新奥霉素母药对斑马鱼96 h-LC₅₀值大于100 mg/L;对大型溞48 h-EC₅₀值为1.48 mg/L;对羊角月芽藻72 h-EyC₅₀值为8.74 mg/L,72 h-ErC₅₀值为29.2 mg/L;对意大利工蜂急性经口96 h-LD₅₀值为31.3 μg/蜂,急性接触96 h-LD₅₀值为39.9 μg/蜂;对家蚕96 h-LC₅₀值大于2.00×103 mg/L。研究表明,新奥霉素母药对斑马鱼、羊角月芽藻、蜜蜂、家蚕均为低毒,对大型溞是中等毒性。     

蜡状芽孢杆菌对烟嘧磺隆的降解及降解产物2-氨基-4,6-二甲氧基嘧啶的环境生物毒性

为明确蜡状芽孢杆菌对烟嘧磺隆的降解及母体和降解产物对环境生物的毒性,采用超高效液相色谱-质谱 (UPLC-TQD) 联用法分析了蜡状芽孢杆菌对烟嘧磺隆的降解产物,同时参照“化学农药环境安全评价试验准则”方法,分别测定了烟嘧磺隆和主要降解产物2-氨基-4,6-二甲氧基嘧啶对斑马鱼、大型溞和斜生栅列藻3种水生生物的急性毒性。结果表明:经蜡状芽孢杆菌降解后,共检测到4种烟嘧磺隆的降解产物,分别为2-氨基-4,6-二甲氧基嘧啶 ( Ⅰ )、2-[N-(氨基甲基) 氨磺酰基]-N,N-二甲基烟酰胺 ( Ⅱ )、2-[1-(4,6-二甲氧基嘧啶-2-基) 脲基]-N,N-二甲基烟酰胺 ( Ⅲ ) 和N-(4,6-二甲氧基嘧啶-2-氨基甲酰基)-1-(甲基亚氨基) 甲磺酰胺 ( Ⅳ ),其中2-氨基-4,6-二甲氧基嘧啶 ( Ⅰ ) 为主要降解产物,由此推测蜡状芽孢杆菌对烟嘧磺隆的降解主要是通过使其磺酰脲桥上C—N键、C—S键以及吡啶环断裂而实现的。毒性测定结果显示:烟嘧磺隆及主要降解产物 Ⅰ 对斑马鱼的96 h-LC₅₀值分别为16.95和 > 100.0 mg/L,其急性毒性等级均为“低毒”;两者对斜生栅列藻的72 h-ErC₅₀值分别为8.070和142.7 mg/L,均为“低毒”;对大型溞的48 h-EC₅₀值分别为9.190和51.95 mg/L,分别为“中毒”和“低毒”。研究表明,烟嘧磺隆经蜡状芽孢杆菌降解后,其主要降解产物对3种水生生物的毒性均明显降低。     

雷帕霉素的水解行为及对4种非靶标生物的急性毒性

雷帕霉素为大环内脂类抗生素药剂,对多种人类疾病有效,近年发现其对多种植物病原真菌也有较好的抑制活性,有望开发为微生物源农药用于植物病害的防治,而目前关于雷帕霉素的水解行为及其对非靶标生物的急性毒性还未见报道。为评价雷帕霉素的水解行为及其对非靶标生物的急性毒性,本研究通过室内模拟试验,测定了雷帕霉素在不同pH值、温度、初始浓度及光源中的水解特性,同时测定了其对家蚕、意大利工蜂、斑马鱼及赤子爱胜蚯蚓4种非靶标生物的急性毒性。水解试验结果表明:碱性环境、紫外光照及高温有利于雷帕霉素的水解。当其初始质量浓度为10 mg/L时,半衰期分别为66.63、38.93及77.00 h;初始质量浓度为50 mg/L时,半衰期分别为144.38、105.00及165.00 h。急性毒性试验结果表明:雷帕霉素对家蚕和斑马鱼的96 h-LC₅₀值分别为 386.46和3.50 mg/L (有效成分,下同);对意大利工蜂的急性经口毒性48 h-LD₅₀值为8.95 μg/bee,急性接触毒性48 h-LD₅₀值为16.79 μg/bee;对赤子爱胜蚯蚓的14 d-LC₅₀值为223. 81 mg/kg。按照 “化学农药环境安全评价准则” (GB/T 31270—2014) 的毒性等级划分标准,雷帕霉素对家蚕、斑马鱼、赤子爱胜蚯蚓的急性毒性分别为 “低毒”、“中毒” 和 “低毒”,对意大利工蜂的急性经口毒性为 “中毒”,急性接触毒性为 “低毒”。研究表明,雷帕霉素属于易降解性药剂,对家蚕、意大利工蜂、斑马鱼及赤子爱胜蚯蚓4种非靶标生物安全。     

手性乙虫腈对3种非靶标生物的急性毒性及初步风险评价

乙虫腈作为氟虫腈的替代药剂已在我国登记并推广使用,但其对环境有益生物的毒性研究鲜有报道。本研究分别采用点滴法、食下毒叶法和滤纸法测定了乙虫腈外消旋体及两个对映单体对意大利蜜蜂Apis mellifera L.、家蚕Bombyx mori和蚯蚓Eisenia foetida的急性毒性,并进行了初步风险评价。结果显示:乙虫腈外消旋体及其S-(+)-乙虫腈和R-(-)-乙虫腈单体对意大利蜜蜂的48 h-LD50值分别为0.0187、0.0181和0.0188 μg/bee,对家蚕的96 h-LC50值分别为66.9、63.7和70.3 mg/L,对蚯蚓的48 h-LR50值分别为511、488和547 μg/cm2。研究表明,乙虫腈对意大利蜜蜂具有高风险性,对家蚕为中等毒性,对蚯蚓毒性较低,田间施用时应防止药剂漂移至周围桑园对桑叶造成污染,并应避免在作物花期施药。此外,由于乙虫腈对供试3种非靶标生物的急性毒性均未表现出显著的对映体选择性差异,故无法通过对映单体的应用来降低其对蜜蜂、家蚕和蚯蚓的毒性及风险。     

4种苦参碱制品对非靶标生物的毒性评价

非靶标生物毒性评价是新农药开发应用的重要基础工作。为推进植物源农药苦参碱的科学合理使用,本研究评价并比较了苦参碱、苦参总生物碱、苦参乙醇浸膏和0.3%苦参碱水剂对生态环境中非靶标生物 (鹌鹑、家蚕、蜜蜂、蚯蚓、蝌蚪、斑马鱼) 的毒性及农作物 (豇豆) 对其的敏感性。结果表明:苦参碱、苦参总生物碱、苦参乙醇浸膏和0.3%苦参碱水剂对鹌鹑、家蚕、蜜蜂、蚯蚓、蝌蚪和斑马鱼的急性毒性均为低毒,对豇豆属于低风险性,且0.3%苦参碱水剂对家蚕无慢性毒性;但不同苦参碱制品对同种非靶标生物的毒性存在较大差异,苦参碱、苦参总生物碱、苦参乙醇浸膏和0.3%苦参碱水剂对鹌鹑的7 d-LD₅₀值 (均为有效成分,下同) 分别为512、504、>1 000和 >3 000 mg/kg_鹌鹑;对家蚕的96 h-LC₅₀值分别为 >3 000、1 300、>5 000和821 mg/L;对蜜蜂的48 h-LC₅₀值分别为1 145、1 361、>3 000和337 mg/L;对蚯蚓的14 d-LC₅₀值分别为549、428、564和 >1 000 mg/kg_土壤;对蝌蚪的48 h-LC₅₀值分别为 >100、>100、263和15 mg/L;对斑马鱼的96 h-LC₅₀分别为85、65、193和20 mg/L;其中苦参乙醇浸膏的毒性最低。可见,苦参碱制品对环境生物较为安全,具有良好的生态效益。     

一些常用农药对斑马鱼的毒性与安全评价

采用半静态法在室内测定了一些常用农药对斑马鱼的急性毒性,并根据<化学农药环境安全评价试验准则>中农药对鱼类的毒性等级划分,评价了这些农药对鱼类的安全性.结果表明:有1种药剂的96h LC50＜0.1mg/L,属于剧毒级;6种药剂的96h C50为0.1～1.0 mgCL,属于高毒级;8种药剂的96h C50为1.0～10 mg,L,属于中毒级;6种药剂的96h LC50＞10 mg/L,属于低毒级.     

Photolysis of the herbicide sulcotrione: formation of a major photoproduct and its toxicity evaluation

BACKGROUND: Sulcotrione is a selective herbicide marketed for use in maize since 1993, but its environmental fate is not yet fully elucidated. A major metabolite resulting from cleavage between the two ring moieties, leading to 2‐chloro‐4‐mesylbenzoic acid (CMBA), has been identified; it presents a rather low toxicity. In photochemical studies this compound has also been claimed to be formed in high proportions. The present authors recently found that, under irradiation, sulcotrione mainly yields a cyclization product (CP). Thus, Sulcotrione photochemistry is still a matter of debate. The aim of the present work was to give an unequivocal answer to this issue. The potential toxicity of CP, CMBA and sulcotrione towards three organisms considered as representative of aquatic ecosystems was also evaluated. RESULTS: The main transformation product of sulcotrione is the cyclization product (CP), and CMBA is formed in smaller amounts. For the toxicological approach, the tested organisms were a bacterium, Vibrio fischeri (Bejerinck) Lehmann & Neumann, an alga, Pseudokirchneriella subcapitata (Korshikov) Hindak, and a protozoan, Tetrahymena pyriformis (Ehrenberg) Lwoff. Sulcotrione is more harmful towards the alga, but CP is more toxic to the bacterium and the protozoan. It must be noted that the measured toxicities are nonetheless rather low. CONCLUSION: On irradiation, sulcotrione mainly gives the photocyclization product, which presents a higher toxicity than sulcotrione and CMBA. This cyclization product should thus be considered in sulcotrione environmental risk assessment. Copyright © 2008 Society of Chemical Industry     

Fumigant distribution in forest nursery soils under water seal and plastic film after application of dazomet, metam-sodium and chloropicrin

Adequate concentration, exposure time and distribution uniformity of activated fumigant gases are prerequisites for successful soil fumigation. Field experiments were conducted to evaluate gas phase distributions of methyl isothiocyanate (MITC) and chloropicrin (CP) in two forest-tree nurseries. Concentrations of MITC and CP in soil air were measured from replicated microplots that received dazomet, metam-sodium and CP. Half of the plots were covered with high-density polyethylene tarp immediately after fumigation; the other half were not covered but received daily sprinkler irrigation for 1 week to create and maintain a water seal. The magnitude of MITC concentrations was similar between nurseries for metam-sodium in both tarp and water seal treatments and for dazomet in the tarp treatment. Consistently greater MITC and CP concentrations were found in the upper 30 cm of soil in the tarped plots compared with the water-sealed plots. Despite potential environmental and economic benefits with the water seal method, tarp covers were more reliable for achieving and maintaining higher MITC and CP concentrations and less prone to variations due to irrigation/rain, soil bulk density and other environmental conditions.     

苯醚甲环唑在芹菜和土壤中的残留行为及风险评估

在湖南和山东开展了10%苯醚甲环唑水分散粒剂在芹菜上的残留田间试验,在室内进行了土壤生物的急性毒性试验。基于苯醚甲环唑的残留试验数据和毒性端点值,就苯醚甲环唑对中国不同人群的长期及短期膳食摄入风险和对土壤生物的环境风险进行了评估。结果表明：苯醚甲环唑在芹菜叶、茎和土壤中的消解半衰期分别为5.2～8.8 d、8.0～8.2 d和13.6～15.0 d。苯醚甲环唑按推荐剂量有效成分120 g/hm²喷雾施药3次,施药间隔期5 d,距最后一次施药5 d收获时苯醚甲环唑在芹菜叶片中的残留量高于MRL (3 mg/kg,中国),在茎和整株芹菜中的残留量均低于MRL。普通人群和1～6岁儿童的短期摄入风险商(RQ_a)值分别为0.09和0.10;对于不同人群,芹菜中苯醚甲环唑对长期膳食摄入风险商的贡献率(RQ_c%)为9.4%～19.8%。10%苯醚甲环唑水分散粒剂对环境中的土壤生物风险商(RQ_e)值为0.368～0.890,不会产生初级急性风险。     

大豆制品转基因成分检测和定量标识分析

分别以大豆凝集素(Lectin)和5-莽草酸-3磷酸合成酶(CP4-EPSPS)为内源和目标基因,对28种大豆制品进行实时荧光PCR检测.检测结果表明,4种大豆制品的CP4-EPSPS扩增结果为阳性,含有转基因大豆成分.转基因成分的定量检测在贸易和可操作性方面要优于定性检测.     

甲氰菊酯对斑马鱼的毒性效应

选用模式生物斑马鱼(Brachydanio rerio)作为毒性实验动物,探索甲氰菊酯(fenpropathrin)对鱼类的毒性效应,为农业生产和环境保护提供参考数据。结果显示甲氰菊酯对斑马鱼成鱼96h LC50为3.38×10-3mg/kg,属于剧毒级,安全浓度为0.34×10-3mg/kg;较低浓度下甲氰菊酯对斑马鱼早期发育影响不显著,在较高浓度1、10mg/kg下,斑马鱼96h畸形率分别达到84%和90%,心包囊肿率分别为25%和88%,而致死效应不明显。亚致死剂量下甲氰菊酯对斑马鱼肝胰脏GPT、GOT、SOD活性有明显诱导效应,在高浓度和长时间暴露下诱导效应降低;肝胰脏中AChE活性显著地受到甲氰菊酯的抑制,抑制效应对毒物的浓度和染毒时间有良好的依赖性,是一种良好的环境污染检测生物学指标。     

乙羧氟草醚对斑马鱼的急性毒性和生物富集性研究

采用半静态法测定了乙羧氟草醚对斑马鱼Brachydanio rerio的急性毒性和生物富集系数。以N,N-二甲基甲酰胺和吐温-80为助剂,配制不同浓度的乙羧氟草醚溶液,测得其对斑马鱼的 LC50值为 3.10 mg/L,属于中等毒性。生物富集性试验中设乙羧氟草醚浓度为0.03 和0.30 mg/L, 持续暴露时间为8 d,测得生物富集系数 (BCF8d)分别为1.16 和2.43,属于低富集性。     

Use of phages for identifying the citrus canker bacterium Xanthomonas campestris pv. citri in Taiwan

Phages CP115 and CP122, which were isolated from canker lesions on grapefruit and Liucheng sweet orange, respectively, showed a high degree of specificity with respect to lysis of test bacterial strains. When used jointly, they lysed 135 (97·8%) out of 138 Xanthomonas campestris pv. citri strains isolated from the canker lesions on leaves, twigs, and fruits of various citrus species, cultivars, and hybrids grown throughout Taiwan, but they did not lyse other X. campestris pathovars and other phytopathogenic bacteria, nor other bacteria isolated from soil, clinical or environmental samples. Of 252 CP115/CP122-sensitive and 78 CP115/CP122-resistant bacterial strains with colony characteristics typical of or similar to those of X. campestris pv. citri , isolated from canker lesions of various citrus plants in diverse growing regions in Taiwan, 250 (99·2%) and 76 (97·4%) strains were pathogenic and non-pathogenic, respectively, when inoculated into Liucheng sweet orange or Mexican lime. Thus, phages CP115 and CP122, when used jointly, appear to be applicable for identifying X. campestris pv. citri in Taiwan.     

丁氟螨酯在蚯蚓体内的富集及其急性毒性

丁氟螨酯 (CYF) 对土壤中非靶标动物蚯蚓的影响尚未明确。本研究建立了蚯蚓体内丁氟螨酯的检测方法。样品经乙腈提取，采用液-液萃取法去除样品中的油脂，利用正相液相色谱 (NP-HPLC) 进行检测。结果表明:在0.5、5和10 mg/kg 3个添加水平下，CYF在蚯蚓中的回收率在84%~88%之间，相对标准偏差在1.3%~3.1%之间，验证了该提取方法的可靠性。生物-土壤富集因子 (BSAF) 测定结果表明，蚯蚓富集CYF 7 d后两个对映体((+)/(?)? CYF)在蚯蚓体内的富集浓度达到最大值，且 (+)-CYF的富集能力显著高于 (?)-CYF的。蚯蚓在含0.5~10 mg/kg CYF的土壤中暴露28 d时会严重抑制其体重。通过滤纸法检测CYF对蚯蚓的急性毒性，测得CYF消旋体对蚯蚓的LC₅₀值为162.5 mg/L，(?)-CYF对蚯蚓的LC₅₀值为323.1 mg/L，(+)-CYF对蚯蚓的LC₅₀值为309.4 mg/L。根据联合毒性效应分析得到AI = ?0.03，表明同时使用CYF的两个对映体对蚯蚓造成毒性相加作用。     

The relationship between brain levels of cismethrin and bioresmethrin in female rats and neurotoxic effects

The oral toxicity of 5-benzyl-3-furylmethyl-(1R, cis)-chrysanthemate (cismethrin) to female rats decreased as their environmental temperature was raised. Acute oral LD₅₀ values increased from 157 mg/kg at 4°C to 197 mg/kg at 20°C and to > 1000 mg/kg at 30°C. Cismethrin was much more toxic given intravenously when the LD₅₀ was 4.5 mg/kg. This value did not change at different environmental temperatures. Irrespective of the environmental temperature, or route of adminstration, following the respective LD₅₀'s cismethrin caused tremors in rats when brain levels of 0.5–1.0 μg/g were reached and, at death, brain concentrations were 3.9–5.1 μg/g. These results suggested that the accumulation of cismethrin by the brain could be used as a model for the nervous system as a whole. The isomeric 5-benzyl-3-furylmethyl-(1R, trans)-chrysanthemate (bioresmethrin) was about 50 times less toxic to rats than cismethrin. After an intravenous LD₅₀, tremors started when brain concentrations were 4–5 μg/g. At death, brain levels were 25–35 μg/g. Plasma esterases were about equally active in hydrolysing cismethrin and bioresmethrin, whereas liver microsomal esterases hydrolyzed bioresmethrin over 10 times more rapidly than cismethrin. It is suggested that the lower toxicity of bioresmethrin is not only due to its faster metabolism but to an intrinsically lower toxicity at the critical site of action in the nervous system.