灰分对挺水植物生物炭吸附硫丹的影响

将美人蕉、菖蒲和芦苇等挺水植物通过限氧高温热解（500℃）制备生物炭,探究灰分对生物炭吸附硫丹的影响.研究表明：挺水植物生物炭表面孔隙发育成熟,以介孔为主,灰分含量较高（15.86%~27.29%）,主要成分可能为碳酸钙.生物炭对硫丹的非线性吸附常数介于0.63~0.80之间,较去灰生物炭大（0.61~0.72）.去灰后,生物炭对β-硫丹和α-硫丹的吸附能力降低（logK_F在6744~11111mg/kg之间）.但各生物炭比表面积增大（20.55~58.13m²/g）,（O+N）/C值变小,炭表面极性降低,疏水性增强;且表层碳元素与主体碳占比增加,炭表面暴露出更多的有机质,增强对硫丹的疏水作用.加入上清液后,去灰后美人蕉、菖蒲和芦苇生物炭对硫丹的吸附变化显著,其上清液中的溶解性物质增强了去灰生物炭对硫丹的吸附作用.     

硫丹对草鱼Ⅰ相、Ⅱ相酶活性及DNA损伤的影响

研究了硫丹对草鱼肝脏Ⅰ相酶氨基比林-N-脱甲基酶（APND）和红霉素-N-脱甲基酶（ERND）、Ⅱ相酶谷胱甘肽-S-转移酶（GST）活性及DNA受损细胞彗星尾长（TL）和尾部DNA含量（%TDNA）的影响。试验共设置0.18、0.36和0.71μg.L-1 3个暴露浓度组和1个空白对照组,分别在试验24、72、120和168 h时取样测定各指标。结果表明,24 h时,0.36和0.71μg.L-1暴露组草鱼肝脏APND活性与对照组相比显著升高（P〈0.05或P〈0.01）,72 h时受到显著抑制（P〈0.01）;120 h后各暴露组APND活性与对照组相比均表现为受到显著抑制（P〈0.05或P〈0.01）。ERND活性总体表现为受诱导。GST活性总体呈先受诱导后受抑制的变化趋势;0.36和0.71μg.L-1暴露组GST活性均在72 h时达到最高值,之后随暴露时间的延长缓慢降低,并在168 h时表现为受抑制;0.18μg.L-1暴露组在120 h时达到最大值,之后降低,168 h时GST活性与对照组水平相当。经硫丹暴露后,草鱼肝脏细胞DNA明显受损,TL与%TDNA均随硫丹浓度的升高或暴露时间的延长而增加,且相关显著。硫丹可影响草鱼肝脏Ⅰ相、Ⅱ相代谢酶活性,并对肝细胞DNA造成遗传损伤。     

2种杀虫剂对日本沼虾的急性毒性

研究了毒死蜱和硫丹对日本沼虾(Macrobrachium nipponense)的毒性作用.根据预试验确定2种杀虫剂对日本沼虾的急性毒性试验浓度,测定沼虾24和48 h的半致死浓度p(LC50),在0～48 h的ρ(LC50)值范围内设定6个浓度梯度,对日本沼虾进行24 h胁迫试验以测定耗氧量和排氨量.毒死蜱和硫丹对日本沼虾的24和48 hρ(LC50)分别为5.03、2.01和8.47、4.02 μg·L-1,其安全质量浓度分别为0.096和0.272 μg·L-1,表明日本沼虾对毒死蜱的敏感性明显高于硫丹.随着2种杀虫剂浓度的逐渐升高,日本沼虾的耗氧量和排氨量均呈现下降趋势,表明日本沼虾采用相同的适应方式来抵御2种杀虫剂对其基础代谢的胁迫,表现为被动的忍耐.     

有机氯农药硫丹的生殖毒性及其机制研究进展

硫丹作为一种广谱有机氯农药,在农业区域周边的土壤和水体中都存在较高残留,2011年被斯德哥尔摩公约列入持久性有机污染物(POPs)名单。硫丹已被证实对神经系统、心血管系统、肝、肾等具有毒性作用,关于其生殖毒性的研究很多,但潜在机制尚不完全清楚。本文总结了硫丹导致的不同动物的生殖毒性,并从生殖器官和生殖细胞损伤、氧化应激以及DNA损伤、生殖细胞周期阻滞及细胞凋亡等方面,对近年来硫丹生殖毒性及其作用机制研究进展进行综述,并对其中存在的问题进行讨论,以期有助于深入了解硫丹的毒性效应。     

Enrichment and isolation of endosulfan-degrading microorganism from tropical acid soil

Endosulfan (6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,3,4-benzo-dioxathiepin-3-oxide) is a cyclodiene organochlorine currently used as an insecticide all over the world and its residues are posing a serious environmental threat. This study reports the enrichment and isolation of a microbial culture capable of degrading endosulfan with minimal production of endosulfan sulfate, the toxic metabolite of endosulfan, from tropical acid soil. Enrichment was achieved by using the insecticide as sole sulfur source. The enriched microbial culture, SKL-1, later identified as Pseudomonas aeruginosa, degraded up to 50.25 and 69.77 % of α and β endosulfan, respectively in 20 days. Percentage of bioformation of endosulfan sulfate to total formation was 2.12% by the 20th day of incubation. Degradation of the insecticide was concomitant with bacterial growth reaching up to an optical density of 600 nm (OD600) 2.34 and aryl sulfatase activity of the broth reaching up to 23.93 μg pNP/mL/hr. The results of this study suggest that this novel strain is a valuable source of potent endosulfan–degrading enzymes for use in enzymatic bioremediation. Further, the increase in aryl sulfatase activity of the broth with the increase in degradation of endosulfan suggests the probable involvement of the enzyme in the transformation of endosulfan to its metabolites.     

硫丹对草鱼乙酰胆碱酯酶及抗氧化酶活性的影响

研究了硫丹暴露对草鱼肝脏、肌肉抗氧化酶及脑乙酰胆碱酯酶活性的影响。结果表明,硫丹24 h暴露可诱导草鱼脑AChE活性,当暴露时间延长或质量浓度升高时,AChE活性表现为受抑制,120 h较高质量浓度组抑制率为41.8%和56.2%,抑制率与暴露时间呈良好的线性相关。硫丹暴露24 h后,草鱼肝脏及肌肉SOD、GSH-Px活性受到显著影响,表现出先诱导后缓慢降低的趋势,120 h后SOD活性显著低于对照组水平,GSH-Px活性与对照组无显著差异。在抗氧化酶受到影响的同时,鱼体脂质过氧化LPO程度不断上升,组织MDA含量逐渐增大,96 h达到最高值。硫丹可影响草鱼AChE及抗氧化酶活性,其变化可作为生物标志物,来评价化学污染物对水生动物的生物学效应。     

挺水植物生物炭对硫丹的吸附及催化水解作用

以美人蕉、菖蒲、芦苇、茭白、再力花、芦竹等挺水植物为原料,在限氧升温（550℃）条件下制备6种不同性质的生物炭,研究其组成及结构对硫丹吸附和催化水解作用.结果表明：550℃下热解,湿地植物生物炭所含灰分高于一般农产品废弃物,介于10.88%~31.11%间.生物炭表面芳香类官能团较多,孔隙部分呈碎片化,以介孔为主.6种生物炭对硫丹都具良好吸附性能.吸附行为主要发生在含致密有机质的生物炭表面,包括疏水、扩散及分配作用等.中/碱性条件下,美人蕉生物炭、菖蒲生物炭及再力花生物炭能有效去除水溶液中的硫丹,去除率为96.77%~98.57%.中性条件下,因生物炭对硫丹的催化,对硫丹的去除率提高约16.57%~72.57%.     

Insecticide Contamination of Jamaican Environment. IV. Transport of the Residues Coffee Plantations in the Blue Mountains to Coastal Waters in Eastern Jamaica

A survey of 120 coffee farmers in the Portland watershed revealed that they lacked training in pesticide application, and had no concept of the transport of residues in the environment and their impact on non-target organisms.Residues of organochlorine (OC) and organophosphorous compounds (OP) were monitored monthly for over a year in plantation soil, and water, sediment and fauna of three rivers and coastal waters of Portland watershed by gas chromatography. OP residues were not detected in any sample while OC residues were below detection levels in Rio Grande. The mean concentration ± standard error of residues detected in water (g L^_1), sediment (ng g^_1) and fauna (ng g^_1 in wet weight) were: -endosulfan 2.7 ± 1.29, 3.8 ± 0.15 and 15.9 ± 1.61, respectively, in Spanish River, 1.56 ± 0.43, 24.3 ± 16.44 and 9.0 ± 1.86, respectively, in Swift River; 0.40 ± 0.02, 1.77 ± 0.68 ± 12.63, respectively, in sea coast; -endosulfan, 1.2 ± 0.48, 0 and 8.1 ± 1.99, respectively, in Spanish River, 1.9 ± 0.49, 0.75 ± 0.32 and 11. ± 4.32, respectively, in Swift River; 0, 5.1 ± 0.30 and 30.9 ± 15.96, respectively, in sea coast; endosulfan sulphate, 0.12 ± 0.12, 4.8 ± 1.62 and 10.0 ± 2.02, respectively, in Spanish River, 3.6 ± 0.95, 3.1 ± 0.56 and 7.9 ± 1.29, respectively, in Swift River and 0, 3.9 ± 2.17 and 24.0 ± 14.67, respectively, in sea coast.Dieldrin residues were detected only once in water (0.2 ± 0.03) and sediment (0.02 ± 0.003) of Spanish River, water (0.76 ± 0.09) of Swift River and sediment (0.1 ± 0.005) of sea coast; pp DDE was found twice in water (3.1 ± 1.53) and sediment (0.1 ± 0.007) of Swift River and water (0.8 ± 0.22) and sediment (6.14 ± 0.41) of sea coast. Arochlor was detected only twice (0.011 and 0.153) in water of Spanish River.     

The role of soil humic and fulvic acid in the sorption of endosulfan (alpha and beta)

The sorption behaviour of alpha- and beta-endosulfan in soil organic matter was investigated using standard soil humic acid (HA) and soil fulvic acid (FA) with a modified solubility enhancement method and a dialysis bag technique. For HA, all the experiments were conducted at an ionic strength of 0.001 mol/L, in both the presence and absence of calcium and at an ionic strength of 0.01 mol/L. For FA, the experiments were conducted at two ionic strengths: 0.001 mol/L (with calcium) and 0.01 mol/L. This study is the first to describe the striking differences in the sorption behaviours of the two stereoisomers of endosulfan in HA and in FA. The sorption coefficients of alpha-endosulfan in HA and FA were significantly higher than those of beta-endosulfan. Beta-endosulfan has comparable sorption coefficients (1.5–5.4 L/g) in HA and in FA. Ionic strength and the presence of calcium have no significant effect on the sorption of beta-endosulfan in HA. However, calcium can significantly (p=0.01) enhance the solubility of alpha-endosulfan in HA. Changes in ionic strength by one order of magnitude also affect the solubility of alpha-endosulfan in HA. The sorption coefficients of alpha-endosulfan in HA (10–36 L/g) were greater than those in FA (9–14 L/g). The chirality of the alpha-isomer was hypothesised to be the primary reason behind its higher sorption in soil organic matter relative to the beta-isomer. In the presence of dissolved HA and FA found in natural soil environments, solubility of endosulfan can be increased by five times than the aqueous solubility of endosulfan without HA and FA.     

低分子量有机酸对红壤中硫丹释放动力学的影响

采用自行设计的动力学试验装置及平衡振荡试验,系统研究了3种低分子量有机酸(草酸、酒石酸和柠檬酸)和水对红壤中α-硫丹(-αendosulfan,αES)的动力学释放行为.结果表明,10 mmol/L的酒石酸和柠檬酸可使αES的释放百分率相对于水和草酸提高7~18个百分点,其中尤以酒石酸的效果最为明显,但水和草酸对αES的释放能力却不存在显著差异(p>0.05),αES的释放存在明显的快速和慢速释放期,特别在前200 mL释放较快;水和草酸对αES的释放动力学数据可由双常数方程和抛物线扩散方程较好描述,并不是代表简单表面扩散的表观一级动力学方程,而酒石酸和柠檬酸则更倾向于Elovich方程(R2>0.99,p<0.000 1),说明对这类立体结构较复杂的有机氯农药来说,影响其在水相中释放的主导因素已不是简单的颗粒表面扩散机制,还可能涉及到土壤颗粒内部的向外扩散机制、颗粒表面的活化与去活化作用、土壤颗粒表面的溶解及对包被在土壤矿物表面的固有有机质结构干扰造成的表面点位能量分布的不均匀等多种机制,使释放动力学的机制更进一步复杂化.