阿循拉津在土壤中的降解途径及其对持留性的影响

通过田间和实验室试验，研究了作草剂阿特拉津在土壤中的降解代谢规律及其与土壤特性的关系。试验表明，阿特拉津施用后，在作物生长期内可降解９０％以上，土壤酸碱度对阿特拉津在土壤中的代谢有显著影响。在碱性土 阿特拉津主要经过微生物代谢而被降解；在酸性土壤中化学水解占地位。     

阿特拉津在土壤中的生物降解研究

运用恒温培养法研究了阿特拉津在河北省白洋淀地区农田土壤中的生物降解动力学,并从中分离鉴定了土壤中降解阿特拉津的优势菌种.研究结果表明,该土壤对阿特拉津具有一定的降解能力,非生物+生物的降解、非生物降解和生物降解的速率分别为0.02626d-1,0.005548d-1和0.008194d-1,半衰期分别为26d,125d和85d.发现土壤中降解阿特拉津的优势菌种为蜡状芽孢杆菌(Bacillus cereus).     

皇竹草对土壤阿特拉津的降解特性

为了探明种植皇竹草(Pennisetum hydridum)对土壤阿特拉津降解的促进作用,通过盆栽试验研究了皇竹草对土壤阿特拉津的降解动态、转移特征以及土壤阿特拉津残留浓度与土壤相关酶活性的关系。结果表明:与未种植皇竹草相比,种植皇竹草土壤阿特拉津降解率明显提高,皇竹草对未灭菌和灭菌土壤阿特拉津的降解率分别提高52.84和42.38百分点;与未种植皇竹草处理相比,灭菌和未灭菌条件下种植皇竹草处理阿特拉津在土壤中的半衰期可分别缩短64.35和53.21 d;土壤中阿特拉津被皇竹草吸收后逐步由地下部分向地上部分转移,随着培养时间的延长,转移系数变大;土壤中阿特拉津残留浓度与土壤过氧化氢酶、过氧化物酶、转化酶和多酚氧化酶活性呈显著负相关(P0.05或P0.01)。认为种植皇竹草有助于阿特拉津的降解。     

微生物对地下水及土壤中阿特拉津降解的研究

从吉林市农药厂采集的污泥样品中筛选出降解阿特拉津（AT）能力较高的菌－JLNY01，JLNY02，通过条件实验表明，JLNY01在pH=6左右，此菌在10℃条件下，一定时间内驯化降解率可达83．6％，30℃时，6天内可达到对AT的完全降解，证明温度越高降解效果越好，JLNY02可直接在低温条件下进行降解，其降解率可达81．8％，而在高温条件下降解率仅达31．4％，证明此菌是一种嗜冷菌。     

地下水中阿特拉津降解菌种的筛选及其降解试验

从吉林市农药厂采集的污泥样品中筛选出JLNY01和JLNY02降解阿特拉津(AT)的菌种, 模拟地下水环境(pH=7,温度10℃)进行实验, 结果表明, JLNY01在一定时间内驯化, 降解率可达83.6%;JLNY02可直接在低温条件下进行降解, 其降解率可达81.8%.而在高温(30℃)条件下, JLNY01在6d内可达到对AT的完全降解, 而JLNY02的降解率仅为31.5%.证明JLNY01温度愈高降解效果愈好, 而JLNY02只适于在低温下降解, 可确定为一种嗜冷菌。     

生物炭对土壤中阿特拉津吸附特征的影响

为探究生物炭对土壤中阿特拉津的吸附特征及影响因素,采用批处理实验研究了灭菌（T1）、5%秸秆生物炭+灭菌（T2）、未灭菌（T3）和5%秸秆生物炭+未灭菌（T4）条件下对土壤中阿特拉津吸附特征及土壤理化性质的影响.结果表明,在最初0—12 h内,不同处理下阿特拉津吸附量均随时间的延长而快速增加,而在12—96 h内增加较为缓慢并逐渐趋于平衡.在96 h时,T2和T4处理下阿特拉津最大吸附量分别达到46.22 mg·kg^-1和46.43 mg·kg^-1,而未添加生物炭的T1和T3处理则有所降低,分别为44.20 mg·kg^-1和43.09 mg·kg^-1.准二级动力学模型更好地拟合不同处理下土壤对阿特拉津吸附特征,T2和T4处理下吸附速率常数K分别为0.257 kg·mg^-1·h^-1和0.339 kg·mg^-1·h^-1,显著高于未添加生物炭处理的T1和T3处理（K分别为-0.083 kg·mg^-1·h^-1和-0.261 kg·mg^-1·h^-1）.内扩散模型显示添加生物炭后,土壤对阿特拉津的吸附是一个由边界扩散、内部孔隙扩散等多因素控制的复杂化学过程.添加生物炭可显著提高土壤pH、有机碳、碱解氮、速效磷和速效钾含量,其中土壤有机碳含量与阿特拉津最大吸附量之间存在显著的正相关关系（P<0.05）.由此可见,添加生物炭可以提高土壤对阿特拉津的固持能力,减少其淋溶迁移风险,从而达到修复阿特拉津污染土壤的目的.     

皇竹草对土壤阿特拉津的修复作用

通过盆栽试验探讨了种植皇竹草（Pennisetum hydridum）对阿特拉津污染土壤的修复效果,阿特拉津对皇竹草生长的影响,以及皇竹草对土壤微生物数量的影响,以期为阿特拉津污染土壤的植物修复提供参考。结果表明：在≤200 mg.kg-1质量分数范围以内,种植皇竹草对土壤阿特拉津的初期降解效率比对照明显提高,最大提高了29.64%,达到显著或极显著差异;阿特拉津质量分数在≤200 mg.kg-1范围内对皇竹草株高没有影响,≤50 mg.kg-1质量分数范围内对生物量没有影响,根冠比变化不明显;随阿特拉津质量分数的增加皇竹草根际和非根际土壤中的细菌、真菌、放线菌数量均呈先增加后减少的趋势,在质量分数为100 mg.kg-1时达到最大,根际土壤中细菌和放线菌数量明显高于非根际土壤,真菌数量在根际与非根际土壤中变化不明显。说明种植皇竹草有助于阿特拉津降解效率的提高,且与种植皇竹草后改变了土壤微生物数量及皇竹草的生长状况有关。     

叶绿素光敏化降解水中阿特拉津

为考察阿特拉津在使用过程中的环境行为,实验在模拟太阳光照射下,以叶绿素铜钠盐作为光敏化剂,探讨了阿特拉津光降解的影响因素及降解动力学.结果表明,阿特拉津直接光解较慢,叶绿素铜钠加入可以促进阿特拉津的光降解,具有敏化作用,当阿特拉津初始浓度为2 mg·L-1,加入8 mg·L-1叶绿素铜钠时,阿特拉津的降解率最大,达52.4%.pH影响阿特拉津的光敏化降解,在pH=7时降解率较大,且随着光照时间的增加,阿特拉津的降解率也随之提高.阿特拉津的光降解反应符合一级反应动力学,半衰期为174 min.     

气相色谱质谱法测定土壤中的阿特拉津

建立了索氏提取、弗洛里硅土固相柱净化,质谱法测定土壤中的阿特拉津,考察了进样口分流模式、柱升温程序、索氏提取时间对测定的影响,确定了最佳测定条件:无分流进样;流速:1.0 mL·min-1;柱升温程序:100℃(1 min),10℃·min-1 到250℃ (3 min);离子源温度:250℃;索氏提取:4 h.方法的线性范围良好,相关系数为0.9997,线性范围:5.0-100.0 μg·kg-1,方法检出限(S/N=3)为0.38 μg·kg-1,相对标准偏差1.1%,平均回收率100.1%.     

Environmental degradation of atrazine,linuron and fenitrothion in soil samples

The persistence of atrazine, linuron and fenitrothion in soil samples from an estuarine area (Ebro delta, Tarragona, Spain) has been studied. Soil samples from the top surface (10 cm) were collected during 1989–91, freeze‐dried, sieved through 200 μm, Soxhlet extracted with methanol, cleaned‐up with Florisil and analysed either by gas chromatography‐nitrogen phosphorus detection (GC‐NPD), in the case of atrazine and fenitrothion, or by liquid chromatography with diode array detection (LC‐DAD), for linuron. Confirmation of the samples analysed by GC‐NPD was carried out using GC‐mass spectrometric detection (MS) in the electron impact mode. The soil half lives obtained under the real environmental conditions have been calculated and the values obtained have been correlated with the physicochemical properties of each pesticide and the soil type. Degradation was affected by volatilization since temperatures in the area of study are relatively high, ca. 30°C, in the summer period. In the case of atrazine it has been shown that deethylatrazine is formed in all the samples studied..     

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。     

阿特拉津对不同肥力土壤磷酸酶的影响

通过室内恒温培养法，研究除草剂阿特拉津对4种长期定位施肥处理下的土壤的磷酸酶活性的影响。试验结果表明，在阿特拉津质量分数不同和处理时间长短不同的情况下，阿特拉津对土壤磷酸酶的活性既有激活作用又有抑制作用。在试验过程中，4种不同肥力的土壤其磷酸酶活性随着处理时间的延续而呈现出“降低→升高→降低→升高”的消长趋势。不同阿特拉津质量分数对磷酸酶的影响没有规律，同一质量分数处理既有激活作用，也有抑制作用。在4种不同肥力的土壤中，磷酸酶活性最高的是以氮、磷、钾无机肥配合有机肥施用的土壤。     

Environmental fate of pesticides used in Australian viticulture V. Behaviour of atrazine in the soils of the south Australian Riverland

The transport of the s‐triazine herbicide, atrazine, through the red, calcareous earth soils of the South Australian Riverland was investigated. Small, undisturbed soil cores were extracted from the inter‐row topsoil of a vineyard adjacent to the River Murray, approximately 10 km south‐west of Overland Corner, South Australia. The vines were grown in a deep (1–4 m) reddish brown, strongly alkaline, sandy loam with a low organic carbon content (<2%). Atrazine concentrations in the leachate were dependent on application rate and soil type. High application rates on subsoil gave high rates of leaching for a longer time compared to the same application rate on topsoil and/or lower application rates on either topsoil or subsoil. Overall, 37–65% of the applied atrazine was detected in the leachate from subsoil cores, 14–25% in topsoil core leachates. Small amounts of atrazine (< 10% of applied dose) were found only in the top 2 cm of the core profiles. The results suggest that this herbicide is somewhat mobile in such strongly alkaline, sandy loam soils and that the irrigated soils of this region are likely to be prone to leaching of atrazine, and therefore that groundwater supplies in this area may be at risk of contamination through use of triazine herbicides.     

哒嗪硫磷水解与土壤降解研究

采用室内模拟方法,研究了哒嗪硫磷在东北黑土、江西红壤和南京黄棕壤3种不同类型土壤中的降解特性及pH、温度和表面活性剂（SDS）浓度对水解的影响。结果表明,哒嗪硫磷水解速率随pH值与温度的升高而显著加快,在15℃、pH 5缓冲溶液中水解半衰期为216.56 d,在35℃、pH 9缓冲溶液中半衰期为3.47 d,平均温度效应系数为2.98。SDS能显著抑制哒嗪硫磷水解,且随着浓度的增大抑制作用增强。哒嗪硫磷在3种土壤中的降解速率依次为南京黄棕壤〉东北黑土〉江西红壤,半衰期分别为10.27、78.75、105.00 d,降解速率随土壤pH值的增大而增大。灭菌处理下,哒嗪硫磷在3种土壤中半衰期显著延长,其中在南京黄棕壤中半衰期延长近10倍,哒嗪硫磷在土壤中降解主要为微生物降解。     

土壤中地乐酚降解的实验研究

利用一系列批实验来研究地乐酚在不同土壤样本中的非生物降解和生物降解，并对各土壤特性与降解参数的相关性作统计分析。结果表明地乐酚的降解主要是生物降解。地乐酚在土壤中降解缓慢，加上实验土壤对地乐酚的弱吸附，因此地乐酚对当地地下水资源存在较大的威胁。在本实验地区降解参数服从正态分布。在水平α=0．05下，地乐酚的降解与已知的几种土壤特性以及吸附的相关性不显著。     

菲在土壤中的微生物降解研究

研究了不同条件土壤中多环芳烃菲的降解动态。结果表明：温度和底物浓度对土壤中菲的降解有较大影响,未灭菌土壤中菲的降解半衰期为5.1d;从污染土壤中分离到一株高效降解菲的菌株,经16S rDNA鉴定为产碱杆菌属（Alcaligenes bacterium LBM.）,同源性高达99%;随着优势菌接种量增加,基础培养基中菲降解速率逐渐加快;Fe3＋、Co2＋和Cu2＋对优势菌降解菲能力均有不同程度影响,其中以Fe3＋影响最明显。     

绿麦隆、阿特拉津单一与复合污染对蚯蚓的毒性效应研究

以赤子爱胜蚓为研究对象,采用滤纸急性毒性实验研究了农药绿麦隆、阿特拉津对蚯蚓的单一和复合毒性效应。单一毒性实验表明,绿麦隆与阿特拉津单独存在时,均对赤子爱胜蚓产生毒性。阿特拉津对蚯蚓的毒性大于绿麦隆,绿麦隆和阿特拉津48h的半致死质量浓度分别为189.64和43.33mg·L-1。复合毒性实验表明,绿麦隆与30mg·L-1和40mg·L-1的阿特拉津复合,其48h的半致死量分别为116.03和48.14mg·L-1。绿麦隆和阿特拉津的复合污染对蚯蚓具有明显的协同作用,而这种协同作用与污染物的质量浓度有关。     

异丙隆在土壤和小麦中的降解与残留

在扬州和聊城两地进行了除草剂异丙隆在小麦上和麦田土壤中的残留动态和最终残留量试验，结果表明，异丙隆在小麦植株和土壤中消解较快，消解半衰期分别为３～４ｄ和８～１４ｄ；收获时小麦籽粒中异丙隆残留量小于０．０４ｍｇ／ｋｇ。推荐暂定异丙隆在小麦上ＭＲＩＬ值为０．５ｍｇ／ｋｇ。２５％异丙隆可湿性粉剂，按７．５ｋｇ／ｈｍ￣２用量，在次年早春（２月）使用，籽粒中异丙隆最终残留量不会超过ＭＲＬ值，对小麦是安全的。     

Extractable atrazine and its metabolites in agricultural soils from the temperate humid zone

Extractable atrazine and its metabolites (hydroxyatrazine, deethylatrazine and deisopropylatrazine) were evaluated in agricultural soils from the temperate humid zone (Galicia, NW Spain) under laboratory conditions. The experiment was performed with five soils with different properties (organic C, soil texture and atrazine application history), both unamended and treated with atrazine at field application rate. Measurements of the atrazine compounds were made at different time intervals (1, 3, 6, 9 and 12 weeks) during a 3-month incubation period. Results showed that only hydroxyatrazine was detected in the extractable fraction of the unamended soils, with values remaining relatively constant throughout the incubation period. Atrazine addition notably increased the concentration of the parent compound and its degradation products; deisopropylatrazine and hydroxyatrazine were the main metabolites detected in the extractable fraction of the treated soils, whereas deethylatrazine was not detected. After 7 days incubation, values of total extractable residues, expressed as percentage of initially added atrazine, ranged from 75 to 86% (25–68% of atrazine, 7–11% of hydroxyatrazine and 9–57% of deisopropylatrazine). The values decreased rapidly during the first 3 weeks of incubation, showing values of 2–8% in soils with higher atrazine application and from 28 to 30% in soils with lower application history. At the end of the incubation, 2–8% of total extractable residues were still detected (0–4% of atrazine, 2–3% of hydroxyatrazine and 0–2% of deisopropylatrazine), indicating a residual effect of atrazine addition. These variations in the extractable fraction indicated that most added atrazine was rapidly degraded, especially in soils with higher application history.