养殖场周边土壤-蔬菜系统磺胺类药物残留及风险评价

采集了新乡市周边不同种类、规模的养殖场施用粪便的土壤以及蔬菜样品,并采用高效液相-荧光分析法测定了样品中磺胺嘧啶、磺胺间甲氧嘧啶和磺胺甲恶唑这3种主要磺胺类药物的残留情况.结果表明,3种磺胺类药物在土壤和蔬菜中的总含量范围分别为7.60~176.26μg·kg~(-1)和ND~32.70μg·kg~(-1),平均含量分别为70.73μg·kg~(-1)和7.08μg·kg-1.土壤中药物平均残留量均低于兽药国际协调委员会规定的生态毒害效应触发值(100μg·kg~(-1)).不同种类蔬菜中药物的残留量不同,青菜、油麦菜、白菜和大葱这4种蔬菜中3种磺胺类药物的平均残留量最高.所有蔬菜样品中3种药物的残留水平未超过磺胺类药物的日允许摄入量,但仍不能忽略人类长期食用所导致人体抗药细菌或基因的形成.     

广东典型海水养殖区沉积物及鱼体中磺胺类药物的残留及其对人体的健康风险评价

采用高效液相色谱-紫外检测器(HPLC-UV)分析了广东沿海大亚湾和阳江两个典型海水养殖区中沉积物以及7种养殖鱼类肌肉和肝脏组织中磺胺嘧啶(SDZ)、磺胺二甲嘧啶(SM2)和磺胺甲基异噁唑(SMX)的残留量,并依据药品最高残留量(MRL)值和每日允许摄入量(ADI)值对海水养殖鱼类中磺胺类抗生素污染进行人体健康风险评价.结果表明,在所有沉积物样品中都能检出磺胺类抗生素.含量(干重)范围为:2.1~35.2 ng·g-1,检出率大小顺序为SDZ(85.7%)>SM2(71.4%)>SMX(28.6%).大亚湾养殖区磺胺药物在沉积物和鱼类样品中的检出频率大于阳江养殖区.3种磺胺类药物在鱼肝脏组织中的含量显著高于在肌肉组织中的含量(P<0.05).SDZ、SM2和SMX在鱼体肌肉组织中的含量(湿重)范围分别为11.6~37.9、16.3~27.8和4.9~20.0 ng·g-1.3种磺胺类药物的平均日摄入量范围为3.37~36.72 ng·kg-1,仅占食用肉类ADI的最高限值(50μg·kg-1)的0.007%~0.073%(<1%ADI),健康风险为可以忽略,膳食安全性高.     

北京市场常见淡水食用鱼体内农药残留水平调查及健康风险评价

利用超声波提取-气质联用法调查了北京市不同水产品市场4种常见淡水食用鱼体内25种农药的残留水平,并利用商值法评价了农药的潜在健康风险.在采集的48个样品中,除七氯、o,p’-DDT、敌敌畏、对硫磷、毒死蜱、仲丁威和久效磷以外,其余18种农药均有不同程度检出.其中,检出率最高的为乙草胺(97.9%)和β-六六六(93.8%);检出农药含量最高的为百菌清(1 779.4μg·kg-1),其次为溴氰菊酯(620.3μg·kg-1).鱼体中有2～10种农药共存,其总浓度为2.7～1 932μg·kg-1.潜在健康风险评价结果表明,按照北京市民的平均水产品消费量,北京水产品市场上的4种主要食用鱼中的农药风险商值为0.043 43,处于较低水平.     

磺胺类抗生素在华南地区不同污水处理工艺中的去除及风险评估

采用固相萃取、高效液相色谱-质谱(SPE-HPLC-MS)法研究了磺胺类抗生素在华南地区(以珠三角地区为例)AB、UNITANK、AAO 3种不同典型污水处理工艺中的去除规律。采用风险商值法评估磺胺类抗生素的环境风险。结果表明:3种工艺的进出水中均检测出较高浓度的磺胺类抗生素,较2007年和2010年调查取样结果增长较大,进水中以磺胺甲恶唑和磺胺嘧啶浓度最高,出水中磺胺甲恶唑浓度较高;AAO工艺较AB及UNITANK工艺的去除效果更好,总去除率达到97%;磺胺类抗生素人均日质量负荷呈现逐年上升趋势,2016年广州污水处理厂人均日质量负荷高达102.81~129.31 mg/d;磺胺类抗生素在3种工艺的剩余污泥中含量极少,主要随出水排放至外界环境中。风险评估表明:除磺胺甲基嘧啶及磺胺对甲基嘧啶未检出不存在环境风险外,其他检出的5种磺胺类抗生素的环境风险为中低等级环境风险。     

典型设施菜地土壤抗生素污染特征与积累规律研究

利用超声波提取,固相萃取-高效液相色谱-串联质谱分析方法,分析了山东省某典型设施菜地的20个蔬菜大棚土壤中14种抗生素的含量与分布特征.结果表明,在所有的土样中均检测出抗生素,其中4种四环素类抗生素(如四环素、土霉素、金霉素和强力霉素)是该地区主要的抗生素种类,单个化合物的检出率均为100%,其含量范围分别在2.11～139.16、6.06～332.02、1.82～391.31、2.20～248.56μg.kg-1之间.4种四环素类抗生素总含量Σ(TCs)为26.79～1 010.11μg.kg-1,平均含量为274μg.kg-1.磺胺类、喹诺酮类和大环内酯类抗生素也均有检出,其中喹诺酮类抗生素总含量Σ(QNs)在0～1 017.06μg.kg-1,平均含量73.05μg.kg-1,检出率为85%,而磺胺类和大环内酯类抗生素单个化合物的检出浓度很低,未检出氯霉素类抗生素.分析结果还发现,该设施菜地种植不同蔬菜的土壤中抗生素种类和含量差异很大.值得注意的是,个别大棚土壤诺氟沙星(QNC)和氧氟沙星(OFC)含量分别高达373.73和643.34μg.kg-1,均远远地超过抗生素生态毒害效应触发值(100μg.kg-1).可见,设施菜地土壤抗生素污染问题应引起关注.     

典型磺胺类抗生素在土柱中的淋溶规律研究

通过室内土柱淋溶试验,对2种磺胺类抗生素——磺胺嘧啶和磺胺甲基异噁唑在土壤中的淋溶行为,及其受到淋溶流速、淋溶浓度和不同剖面土壤理化性质的影响进行了研究.结果表明,随着剖面土层深度增加磺胺类抗生素的淋出速率变快且在土柱中的残留量减少,磺胺甲基异噁唑在0~20 cm土层土柱中的残留含量是其在40~60 cm土层土柱中的2倍.淋溶流速越快,淋出液中磺胺类抗生素浓度越大且在土柱中的残留含量越低.用浓度为500μg·L-1淋溶液以2 mL·min-1的速度淋溶时,淋出液中磺胺类抗生素的浓度接近500μg·L-1,而以1 mL·min-1和1.5 mL·min-1速度淋溶时,其浓度仅为100~200μg·L-1.随淋溶液浓度升高,磺胺类抗生素淋溶性增强,其在土柱中的残留含量也明显增高.用浓度为250μg·L-1和125μg·L-1淋溶液以2 mL·min-1进行淋溶时,磺胺甲基异噁唑在淋出液中仅有少量检出,而用浓度为500μg·L-1淋溶液淋洗时,其在淋出液中的浓度接近500μg·L-1,其在土柱中的残留含量是低浓度淋溶液淋溶时的2~3倍.本研究结论可为管理含磺胺类抗生素的水源灌溉方式提供理论依据.     

赤水河流域水体抗生素污染特征及风险评价

为了初步探究贵州赤水河流域地表水的抗生素浓度分布特征及潜在生态风险,利用固相萃取-液相色谱串联质谱法(SPE-LC-MS)对地表水样品中21种抗生素进行检测分析.结果表明,赤水河地表水共检出12种抗生素,总浓度水平为ND～1 166.97 ng·L-1,氧氟沙星、甲氧苄啶和磺胺嘧啶的检出率均为100％.平均检出浓度最高...     

毫米级根际微域磺胺嘧啶的降解动态研究

采用特制根际箱,研究了玉米根际效应作用下磺胺嘧啶在土壤中的降解动态.在空间上将根-土界面(0~5 mm)细化到1 mm,箱内磺胺嘧啶剂量分别设为1 mg·kg-1和5 mg·kg-1,分别在出苗后第20、40和60 d取样,并将磺胺嘧啶降解率与根-土界面4种有机酸含量进行回归分析,从而得出影响磺胺嘧啶在根际土壤降解的关键因素.结果表明,种植作物可有效促进磺胺嘧啶的降解,且磺胺嘧啶的最大消减水平发生在距离根室3 mm的近根区,降解顺序依次为:近根际根室远根际.通过对不同剂量磺胺嘧啶胁迫下有机酸响应的相关分析发现,苹果酸和乙酸是影响磺胺嘧啶在根际土壤中降解的关键因素之一.     

大通湖表层水体中抗生素赋存特征与风险

为了评价大通湖表层水体中典型抗生素的赋存特征及生态风险等级,采用超高效液相色谱-串联质谱仪（UPLC-MS/MS）检测了4类12种（磺胺类,磺胺增效剂,喹诺酮类和四环素）抗生素的浓度水平.结果表明：除氧氟沙星外,其余11种抗生素均有检出,其总浓度为0.19~261.89ng/L;磺胺嘧啶的平均浓度最高（37.41ng/L）,其次为磺胺甲恶唑（12.34ng/L）>沙拉沙星（8.55ng/L）>恩诺沙星（8.04ng/L）>甲氧苄啶（7.56ng/L）>金霉素（3.92ng/L）,并且磺胺嘧啶、四环素、沙拉沙星、金霉素、磺胺甲恶唑和甲氧苄氨嘧啶的检出率均超出50%,处于较高水平.与部分河流、湖泊相比,大通湖抗生素的浓度除磺胺嘧啶和恩诺沙星外,基本处于较普通水平;在空间分布上表现为明显的差异性.环境和健康风险评价结果表明：磺胺甲恶唑、沙拉沙星和环丙沙星为大通湖主要的风险因子,RQ>1,对洞庭湖有较高的潜在风险;点位S2、S3、S6对大通湖周围环境具有较高的累积风险,主要的贡献因子分别为恩诺沙星和沙拉沙星、磺胺甲恶唑和环丙沙星;11种抗生素通过饮水途径对成人和儿童的健康风险指数R_QH处于8.74×10^-8~9.17×10^-3之间,且通过饮水途径摄入抗生素对儿童的健康风险高于成人.     

华东地区某水源水中13种磺胺类抗生素的分布特征及人体健康风险评价

饮用水源水中残留微量抗生素对人体健康的潜在威胁日益引起广泛关注.采用固相萃取、高效液相串联质谱方法分析了13种磺胺类抗生素在华东地区某水源水中的分布特征.结果表明,13种磺胺类抗生素在水源水中均有不同程度检出,总浓度为10.5~238.5 ng·L~(-1).其中磺胺甲唑(SMX)和磺胺(SAM)的检出频率为100%,检出浓度分别高达107.0 ng·L~(-1)和43.1 ng·L~(-1).水源地入水口磺胺类抗生素污染水平高于出水口,SMX在水源地不同位置浓度变化不明显.磺胺类抗生素呈现季节变化特征,冬季和春季浓度为110.8~117.9 ng·L~(-1),是夏、秋季浓度的3.6~3.8倍.基于风险熵的方法评价水源水中残留的磺胺类抗生素对不同年龄段人群的健康风险,结果显示磺胺类抗生素风险值均远小于1,甲氧苄啶(TMP)对0~3个月的婴儿健康风险最大(0.001).该水源水中磺胺类抗生素对人体健康尚不构成直接威胁,但长期和综合风险值得关注.     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Degradation of metabolites accumulated of benzo[a]pyrene by coupling Penicillium Chrysogenum with KMnO4

Several main metabolites of benzo[a]pyrene （BaP） formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone （BP 1,6- quinone）, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene （BP 7,8-diol）, 3-hydroxybenzo[a]pyrene （3-OHBP）, were identified by high-performance liquid chromatography （HPLC）. The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that （1） the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; （2） the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; （3） the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% （w/v）, concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.