堆肥污泥重金属在黄土中的淋滤特征

堆肥污泥中所含重金属是污泥堆肥土地利用最大的障碍,实验选用北方贫瘠的黄土作为供试样品,通过室内土柱淋滤实验,对堆肥污泥重金属在黄土中的淋滤特征进行了研究。结果显示,在0～40 cm的浅层淋滤层,各种重金属在黄土中的纵向迁移能力为:Pb>Zn>Ni>Cu,而在50～55 cm的深层淋滤层,Cd在黄土中的迁移能力相对其他4种重金属是比较强的;各种重金属在50～60 cm深层淋滤层中会出现二次富集,出现明显富集层。研究揭示了堆肥污泥重金属在黄土中的迁移特征,为有效控制和消除堆肥污泥土地利用中重金属的污染研究提供了理论依据。     

SDS和PVP强化生物淋溶锰渣的性能

在生物淋溶锰渣的过程中,设置一系列浓度梯度(0～100 mg/L)的离子型表面活性剂SDS(十二烷基硫酸钠)和非离子型表面活性剂PVP(聚乙烯吡咯烷酮),研究两种活性剂对硫杆菌生长和对锰渣中锰的浸出率的影响.结果表明,两种表面活性剂均能有效强化硫杆菌对锰渣的淋溶性能,SDS和PVP的最佳浓度分别为35 mg/L和15 mg/L,在最佳浓度条件下,两者均能显著降低培养液的pH值,提高锰的浸出率,其浸出率分别达到88％和83％,均高于对照组的72％.进一步分析表明,SDS比PVP更能有效提高浸出体系的ORP电位,促进锰的浸出.电镜结果表明,在最佳浓度条件下,SDS比PVP更能有效促进硫杆菌对锰渣表面的侵蚀,降低锰渣的表面粒度,提高锰渣中锰的浸出率.     

Modeling the mobility of glyphosate from two contrasting agricultural soils in laboratory column experiments

The method of single-strand conformational polymorphism (SSCP) was modified in our laboratories for the characterization of baculoviruses, insect viruses with great potential for use as bioinsecticides in biological protection programs. A series of primers were synthesized after the comparison of the polyhedrin gene sequences of over 20 baculoviruses. Polyhedrin is a highly conserved protein which is responsible for the persistence of the virus in the environment. Universal primers were designed which could be used in polymerase chain reactions (PCR) containing genomic DNA from an array of nucleopolyhedrosis viruses (NPVs) including these which are used as biopesticides against important pests of forests and crops, such as Anticarsia gemmatalis, Spodoptera frugiperda, Lymantria dispar, Lymantria monacha and many others. PCR products were denatured and subjected to single-strand DNA electrophoresis at variable temperatures (MSSCP) where, after silver staining, they gave ssDNA band patterns characteristic for each baculovirus species. This technique can be potentially applied to detect baculoviruses in insects collected in the field, as well as to plant tissues and the excrements or bodies of predators without need for sequencing the PCR products. Sometimes MSSCP can be used not only for species determination but also as an indication of genomic variability which can be related to infectivity.     

Atrazine leaching through surface and subsurface of a tropical Oxisol

The fate of ¹⁴C atrazine was investigated using microcosms and an undisturbed Red-Yellow Latossol (Oxisol) under simulated rainfall conditions of 200 mm water month^?1. Experiments were carried out using microcosm cores, the first with an uncovered surface soil; the second set with uncovered subsurface soil; the third with subsurface soil covered with 3 cm of cow manure and the last with subsurface soil covered with 5 cm of grass straw. Average values for the amount of atrazine leached after 60 days were as follows: surface soil 1.6%; subsurface 47.3%; subsurface plus manure 17.3% and subsurface plus straw 24.8%. In the surface soil, 53% of the ¹⁴C atrazine remained within the upper 1 cm, while in the subsurface microcosms the atrazine was more evenly distributed. The authors report that surface soil was retained atrazine and its metabolites for 60 days. The addition of a straw or manure covering to exposed subsoil helped to retard atrazine leaching.     

Retention capacity of an organic bio-mixture against different mixtures of fungicides used in vineyards

A laboratory experiment was carried out to test the efficiency of a bio-mixture made up of pruning residues at two (PR2) and five (PR5) years of composting and wheat straw (STW) in the biological cleaning of water contaminated by different mixtures of fungicides usually employed in vineyards. The experiment was conducted and reproduced at a scale of 1:100 of operating field conditions. Commercial formulates of penconazole (PC), (RS)-1-[2-(2,4-dichlorophenyl)pentyl]-1H-1,2,4-triazole), dimetomorph (DM), (EZ)-4-[3-(4-chlorophenyl)-3-(3,4-dimethoxyphenyl)acryloyl]morpholine), azoxystrobin (AZ), (methyl (E)-2-{2-[6-(2-cyanophenoxy)pyrimidin-4-yloxy]phenyl}-3-methoxyacrylate), iprovalicarb (IP), (isopropyl 2-methyl-1-[(RS)-1-p-tolylethyl]carbamoyl-(S)-propylcarbamate), metalaxyl (MX), (methyl N-(methoxyacetyl)-N-(2,6-xylyl)-DL-alaninate), fludioxonil (FL), (4-(2,2-difluoro-1,3-benzodioxol-4-yl)-1H-pyrrole-3-carbonitrile) and cyprodinil (CY), (4-cyclopropyl-6-methyl-N-phenylpyrimidin-2-amine) were mixed in water and discharged into the bio-mixture following the time schedule of the treatments carried out in the grapevine in real field conditions. At each treatment, contaminated water with fungicides was circulated repeatedly through the bio-mixture to enhance the sorption of fungicides. In fact, it retained them between 98–100% with the exception of MX of which it was able to retain only 90.5%. The adsorption/desorption experiment showed that repeated circulation of water, instead of enhancing MX retention, can easily remove about 30% of MX already adsorbed by the bio-mixture. This finding suggests that water contaminated by very mobile pesticides should be discharged at the end of field treatments without re-circulating the water in order to avoid the release of pesticides weakly adsorbed on the bio-mixture.     

Assessment of metolachlor and diuron leaching in a tropical soil using undisturbed soil columns under laboratory conditions

In the present study, diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-metoxi-1-methylethyl)acetamide] leaching was studied in undisturbed soil columns collected in a cotton crop area in Mato Grosso State, Brazil. The pesticides were applied to the soil surface in dosages similar to those used in a cotton plantation. To assess the leaching process, soil columns were submitted to simulated rain under laboratory conditions at 25 ± 3°C, in the absence of wind and direct solar radiation. During the rain simulations, leachate solutions were collected and herbicide concentrations were determined. At the end of the experiment, the soil columns were cut into 10 cm sections to determine the remaining herbicide concentrations through the soil profile. Metolachlor was detected in all soil sections, and approximately 4% of the applied mass was leached. Diuron was detected only in the upper two soil sections and was not detected in the leachate. A linear correlation (r > 0.94) between the metolachlor soil concentrations and the organic contents of the soil sections was observed. Mass balance suggests that around 56% of diuron and 40% of metolachlor were degraded during the experiments. Measurements of the water table depth in the area where the samples were collected showed that it varied from 2 to 6 m and is therefore vulnerable to contamination by the studied herbicides, particularly metolachlor, which demonstrated a higher leaching potential.     

Leaching of S-metolachlor,terbuthylazine, desethyl-terbuthylazine,mesotrione, flufenacet,isoxaflutole, and diketonitrile in field lysimeters as affected by the time elapsed between spraying and first leaching event

The effect of elapsed time between spraying and first leaching event on the leaching behavior of five herbicides (terbuthylazine, S-metolachlor, mesotrione, flufenacet, and isoxaflutole) and two metabolites (desethyl-terbuthylazine and diketonitrile) was evaluated in a 2011–2012 study in northwest Italy. A battery of 12 lysimeters (8.4 m² long with a depth of 1.8 m) were used in the study, each filled with silty-loam soil and treated during pre-emergence with the selected herbicides by applying a mixture of commercial products Lumax (4 L ha^?1) and Merlin Gold (1 L ha^?1). During treatment periods, no gravity water was present in lysimeters. Irrigation events capable of producing leaching (40 mm) were conducted on independent groups of three lysimeters on 1 day after treatment (1 DAT), 7 DAT, 14 DAT, and 28 DAT. The series was then repeated 14 days later. Leachate samples were collected a few days after irrigation; compounds were extracted by solid phase extraction and analyzed by high-performance liquid chromatography and gas chromatography–mass spectrometry. Under study conditions, terbuthylazine and S-metolachlor showed the highest leaching potentials. Specifically, S-metolachlor concentrations were always found above 0.25 µg L^?1. Desethyl-terbuthylazine was often detected in leached waters, in most cases at concentrations above 0.1 µg L^?1. Flufenacet leached only when irrigation occurred close to the time of herbicide spraying. Isoxaflutole and mesotrione were not measured (<0.1 µg L^?1), while diketonitrile was detected in concentrations above 0.1 µg L^?1 on 1 DAT in 2011 only.     

Leaching of azoxystrobin and its degradation product R234886 from Danish agricultural field sites

The objective was to estimate leaching of the fungicide azoxystrobin (methyl (αE)-2-[[6-(2-cyanophenoxy)-4-pyrimidinyl]oxy]-α-(methoxymethylene)benzene-acetate) and one of its primary degradation products R234886 ([(E)-2-(2-[6-cyanophenoxy)-pyrimidin-4-yloxyl]-phenyl-3-methoxyacrylic acid], major fraction) at four agricultural research fields (one sandy and three loamy) in Denmark. Water was sampled from tile drains, suction cups and groundwater wells for a minimum period of two years after application of azoxystrobin. Neither azoxystrobin nor R234886 were detected at the sandy site, but did leach through loamy soils. While azoxystrobin was generally only detected during the first couple of months following application, R234886 leached for a longer period of time and at higher concentrations (up to 2.1 μg L⁻¹). Azoxystrobin is classified as very toxic to aquatic organisms and R234886 as very harmful. Our study shows that azoxystrobin and R234886 can leach through loamy soils for a long period of time following application of the pesticide and thereby pose a potential threat to vulnerable aquatic environments and drinking water resources. We thus recommend the inclusion of azoxystrobin and R234886 in pesticide monitoring programmes and further investigation of their long-term ecotoxicological effects.     

氟化物对酸浸取沸腾炉渣中铝的影响

采用酸浸取法、加入助溶剂浸取沸腾炉渣中的铝,考察了各种因素对铝浸出率的影响。实验结果表明：在球磨时间为30min、固液比（沸腾炉渣质量与酸体积之比）为1：7、硫酸浓度为4mol／L、浸取温度为107℃、浸取时间为120min的条件下,铝浸出率最高（为29．72％）;KF,NH4F,NaF,CaF2等作助溶剂可明显提高铝浸出率,且助溶剂为CaF：时的铝浸出率最高,CaF2与沸腾炉渣的质量比为0．08时的铝浸出率大于75％。     

镀锌钢板废料中锌的碱浸过程影响因素分析

以强碱(NaOH)溶液为浸取剂,采用碱浸法回收镀锌钢板废料中的锌,考察了不同因素(反应温度、反应时间、碱浓度、添加剂)对锌浸出效果的影响,并对添加剂的作用机理进行了分析。实验结果表明:在NaOH质量浓度为250 g/L、反应温度为90℃、反应时间为300 min的最佳工艺条件下,锌的浸出率高达97.89%;添加NaNO_3可提高锌在碱液中的腐蚀电位和腐蚀电流,从而加快镀锌钢板废料中锌的溶解,缩短反应时间;添加KMnO_4对反应速率基本无影响。