Bandala Erick R, Andres-Octaviano Juan, Pastrana Paulino, Torres Luis G
Instituto Mexicano de Tecnología del Agua México.
J Environ Sci Health B. 2006;41(5):553-69. doi: 10.1080/03601230600701700.
Degradation of aldrin (1,2,3,4,10,10-Hexachloro-1,4,4a,5,8,8a-hexahydro-1,4:5-8-dimethanonaphthalene), heptachlor (1H-1,4,5,6,7,8,8-heptachloro-3a,4,7,7a-tetrahydro-4,7-methano indene), dieldrin (1aalpha,2beta,2aalpha,3beta,6beta,6aalpha,7beta,7aalpha)-3,4,5,6,9,9-Hexachloro-1a,2,2a,3,6,6a,7,7a-octahydro-2,7:3,6-d-methanonaphtha[2,3-b]oxirene, and heptachlor epoxide (1aalpha, 1bbeta,2alpha,5alpha,5alphabeta,6beta,6aalpha-2,3,4,5,6,7,7-Heptachloro-1a,1b,5,5a,6,6a-hexahydro-2,5-methano-2H-inden[1,2-b]-oxirene) was tested using free cultures of Pseudomonas fluorescens under controlled conditions. Pesticide concentrations were monitored by gas chromatography during 120 h. Percentages of degradation and biodegradation rates (BDR) were calculated. Data showed a trend suggesting a relation between chemical structure and degradability. Degradation kinetics for each pesticide tested showed that the highest degradation rates were found in the first 24 h. Kinetics data were adjusted to an empirical equation in order to predict their behavior, and the correlation coefficients obtained were satisfactory. Gas chromatography/mass spectrometry (GC/MS) analysis of the final extracts allowed the identification of chlordene and monodechlorodieldrin, which have been reported as final metabolite produced in the biodegradation of this kind of compounds. Regarding adsorption of pesticides on activated vegetal carbon, we concluded that removal efficiencies between 95.45 and 97.18% can be reached, depending on the pesticide and the carbon dose applied. The values for K from the Freundlich equation were quite similar for the four pesticides (between 1.0001 and 1.04), whereas the n values were quite different for each pesticide in the following order of affinity: dieldrin > aldrin > heptachlor epoxide > heptachlor. Equilibrium times, very important for scaling up the process, were between 43 min and 1 h, for the heptachlor epoxide and the heptachlor, respectively.
在可控条件下，使用荧光假单胞菌的纯培养物对艾氏剂（1,2,3,4,10,10 - 六氯 - 1,4,4a,5,8,8a - 六氢 - 1,4:5 - 8 - 二亚甲基萘）、七氯（1H - 1,4,5,6,7,8,8 - 七氯 - 3a,4,7,7a - 四氢 - 4,7 - 亚甲基茚）、狄氏剂（(1aα,2β,2aα,3β,6β,6aα,7β,7aα) - 3,4,5,6,9,9 - 六氯 - 1a,2,2a,3,6,6a,7,7a - 八氢 - 2,7:3,6 - d - 亚甲基萘并[2,3 - b]环氧乙烷）和七氯环氧化物（(1aα, 1bβ,2α,5α,5αβ,6β,6aα - 2,3,4,5,6,7,7 - 七氯 - 1a,1b,5,5a,6,6a - 六氢 - 2,5 - 亚甲基 - 2H - 茚并[1,2 - b] - 环氧乙烷）的降解情况进行了测试。在120小时内通过气相色谱法监测农药浓度。计算了降解百分比和生物降解率（BDR）。数据显示出一种趋势，表明化学结构与可降解性之间存在关联。对每种测试农药的降解动力学研究表明，最高降解率出现在最初的24小时内。为了预测其行为，将动力学数据拟合到一个经验方程，所得相关系数令人满意。对最终提取物进行气相色谱/质谱（GC/MS）分析，鉴定出了氯丹和单脱氯狄氏剂，据报道它们是这类化合物生物降解产生的最终代谢产物。关于农药在活性植物碳上的吸附，我们得出结论，根据所使用的农药和碳剂量，去除效率可达95.45%至97.18%。四种农药的弗伦德利希方程中的K值非常相似（在1.0001至1.04之间），而n值因每种农药的亲和力顺序不同而有很大差异：狄氏剂＞艾氏剂＞七氯环氧化物＞七氯。对于扩大该过程非常重要的平衡时间，七氯环氧化物和七氯分别为43分钟至1小时。
