Thirty-year amendment of horse manure and chemical fertilizer on the availability of micronutrients at the aggregate scale in black soil

Purpose

This study evaluates manure and chemical fertilizer effects on micronutrient (Fe, Mn, Cu, and Zn) content and availability in crops.

Methods

Seven treatments were selected, including three conventional fertilization treatments (NP, horse manure (M), and NP plus M (NPM)), three corresponding double rate fertilization (N2P2, M2, and N2P2M2), and a CK. Soil samples were collected and separated into four aggregates by wet-sieving in September 2009. Corn samples were collected and analyzed simultaneously.

Results

Treatment N2P2 increased DTPA extractable Fe, Mn, and Cu in soil by 732%, 388%, and 42%, whereas M2 decreased the corresponding values by 26%, 22%, and 10%, respectively, compared to CK. DTPA extractable Zn in soil and Zn in corn grain were higher in the M and M2 treatments than in the other treatments, and DTPA Zn was significantly correlated with soil organic carbon (SOC) in large macroaggregate, microaggregate, and silt + clay fractions. The Mn concentrations in corn stalks and grain were significantly correlated with DTPA extractable Mn in bulk soil and microaggregates, and Zn in stalks were significantly correlated with DTPA Zn in bulk soil, microaggregates, and large macroaggregates.

Conclusions

Long-term application of horse manure could increase soil Zn availability and uptake by corn, possibly due to its activation by SOC. In contrast, chemical fertilizer application increased DTPA extractable Fe, Mn, and Cu in soil by reducing soil pH. Our results also suggest that Mn uptake by corn originated mainly in microaggregates, whereas Zn in crops was primarily sourced from large macroaggregates and microaggregates.     

Effect of triazophos,fipronil and their mixture on miRNA expression in adult zebrafish

MicroRNA (miRNA) plays a crucial role in gene expression regulation. However, no data are available on change of miRNA expression of zebrafish (Danio rerio) after treatment with pesticides. We evaluated the effect of fipronil (5-amino-1-[2, 6-dichloro-4-(trifluoromethyl) phenyl]-4-[(trifluoromethyl) sulfinyl]-1H-pyrazole-3-carbonitrile) and triazophos (3-(O, O-diethyl)-1-phenyl thiophosphoryl-1, 2, 4-triazol) and their mixture on miRNA expression in zebrafish. MiRNA expression profiles in zebrafish were altered after treatment with these chemicals. An association between these chemicals and the expression of 21 miRNAs was found 96 h after treatment. Among them, 14 miRNAs were differentially expressed due to the treatments with fipronil, triazophos and their mixture; 5 miRNAs showed altered expression level after treatment with formulations of these chemicals; miR-29b and miR-738 were differentially expressed after treatment with adjuvants. MiRNAs might present a novel toxicological response that could be used as a toxicological biomarker and have a different direction for future investigations of their association with miRNAs involved in chemical related diseases.     

铜、镉复合污染红壤对黑麦草生长和土壤酶活性的影响

采用石灰石调节红壤酸性后,利用对铜、镉具有一定耐性的高产牧草黑麦草修复铜、镉复合污染土壤。分析黑麦草的生长、生理生化指标以及土壤中酶活性的变化,探索在修复铜、镉复合污染红壤的同时又满足饲料作物安全种植的土地利用方式。结果表明,对于弱酸性红壤（pH 6.0左右）,土壤铜全量较低时（〈50 mg/kg）,黑麦草的生物量、叶...     

硝基苯对硫酸盐还原过程的影响

为了探明硝基苯(NB)对硫酸盐还原的影响,揭示相关过程机制,采用以丙酸盐为碳源和电子供体的序批式厌氧反应系统(水力停留时间为33 h),考察了碳硫比为0.63～5.0,NB浓度为2.5～50 mg/L条件下,系统的硫酸盐还原效能。研究结果表明,NB对硫酸盐还原过程存在抑制作用,当系统NB进水浓度低于30 mg/L时,NB对硫酸盐还原过程抑制并不显著,但当进水NB浓度达50 mg/L时,硫酸盐还原率由近100%迅速降至17%。对比实验结果进一步表明,NB初始浓度为16.5 mg/L条件下,硫酸盐的比还原速率和丙酸的比消耗速率分别为对照组的63%和52%。硫酸盐还原的抑制主要源自NB及其还原产物苯胺(AN)的生物毒性,但上述抑制作用可逆。     

Fe(Ⅲ)-酒石酸盐配合物体系的光解特性

以Fe(Ⅲ)-酒石酸配合物体系光化学过程中产生的Fe(Ⅱ)和.OH为主要检测对象,探讨了Fe(Ⅲ)-酒石酸配合物体系光化学反应的基本规律及影响因素。结果表明,体系的光化学过程能产生Fe(Ⅱ)和.OH;产生Fe(Ⅱ)的速率远高于产生.OH的速率;Fe(Ⅱ)生成浓度在pH 3.50时最大,.OH则在pH 3.00时最大;配合物的光化学过程中会伴随pH的升高;在照度为3.6×103Lux的日光灯照射下,Fe(Ⅲ)-酒石酸盐配合物初级光解的速率常数为2.1×10-3S-1;Fe(Ⅱ)是高价重金属的主要还原剂,.OH是有机物的主要氧化剂。     

Biodegradation of acetochlor by a newly isolated Achromobacter sp. strain D-12

A highly effective acetochlor-degrading bacterial strain (D-12) was isolated from the soil of a pesticide factory. The strain was identified as Achromobacter sp. based on its 16S rRNA gene sequence. The strain D-12 optimally degrades acetochlor at a pH of 7.0 and a temperature of 30°C in a mineral salts medium (MSM). Approximately 95% of acetochlor was degraded by the stain treated at a concentration of 10 mg L^?1 after 5 days of incubation. A chiral high performance liquid chromatography (HPLC) system was used to study the enantioselectivity during the process. However, no obvious enantioselective biodegradation was observed. The primary biodegradation acetochlor products were identified by high-performance liquid chromatography-mass spectroscopy (HPLC-MS) and gas chromatography-mass spectrometry (GC-MS). The results indicated that the strain D-12 could be applied in the bioremediation of an acetochlor-polluted environment.     

Field Testing and Computer Modeling of an Oxygen Combustion System at the EPA Mobile Incinerator

The LINDE® Oxygen Combustion System has been demonstrated successfully at the EPA Denney Farm site as part of the modified EPA mobile incinerator. This paper describes the field testing results and computer modeling of the LINDE system. The oxygen system enables the EPA unit to incinerate dioxin and PCB contaminated soil at a consistent rate of 4000 lb/h—200 percent of the original maximum capacity. The pure oxygen combustion system improved the thermal efficiency of the incinerator by over 60 percent and reduced the flue gas volume dramatically. Therefore, the dust carryover problem was mitigated. The destruction and removal efficiencies of hazardous wastes exceeded EPA requirements.

The design of the proprietary burner allows the use of up to 100 percent oxygen in place of air for incineration with improvements over conventional oxy-fuel burners. As a result, the temperature distributions in the rotary kiln are uniform and NO_x emissions are low.

The oxygen combustion system, controlled by a programmable controller, provided much better response and flexibility than conventional air based systems. The system generated a stable flame and responsed well to the transient conditions of the rotary kiln. Kiln puff occurrence was virtually eliminated in the operation of the mobile incinerator.

A computer model of the incinerator was developed and used for the process design of the LINDE system. The model predicted the test results reasonably well. This model can be a useful tool in the design and operation of rotary kiln incineration systems.     

电镀污泥回收重金属的新工艺

合理、经济地处理混合电镀污泥,回收其中有价值的金属具有重要意义。以不同的酸作为浸出剂对电镀污泥中的金属进行了浸出效果实验。结果表明,在相同条件下,各酸的浸出效果顺序为:硫酸>盐酸>王水>硝酸;液体水与固体电镀污泥比为3,干污泥为5 g,硫酸加入量为15 mL,时间1 h条件下,混合电镀污泥中金属铜锌的浸出率最大,达到97.38%。分别采用铁和铁锰合金还原剂常温还原低熔点重金属离子铜、锌,浸出液中99%以上含量的铜、锌沉淀,使低熔点重金属与黑色金属铁、锰、铬有效分离。低熔点混合重金属可以用来做铜合金添加剂使用,最后沉淀的混合黑色金属氢氧化物处理后可以用来做炼钢合金添加剂使用。     

流化床-固定床一体化反应器处理模拟生活污水的性能研究

为了达到高效、低能耗处理分散性生活污水的目的，研制了无污泥回流和无沉淀池的流化床固定床一体化反应器。使用该反应器对模拟生活污水的处理结果表明，在水力停留时间为12 h的条件下，当进水温度为25～28℃，污染物COD、NH₃-N、TN、TP和SS的浓度分别为350～450、26.4～36.9、27.0～38.5、1.7～2.6和267～345 mg/L时，相应的处理水中污染物去除率分别达到了95.7%、97.0%、51.4%、63.5%和93.9%。出水中各指标均满足《城镇污水处理厂污染物排放标准》(GB 18918-2002)中的一级排放标准。     

Time domain reflectometry measured moisture content of sewage sludge compost across temperatures

Time domain reflectometry (TDR) is a prospective measurement technology for moisture content of sewage sludge composting material; however, a significant dependence upon temperature has been observed. The objective of this study was to assess the impacts of temperature upon moisture content measurement and determine if TDR could be used to monitor moisture content in sewage sludge compost across a range of temperatures. We also investigated the combined effects of temperature and conductivity on moisture content measurement. The results revealed that the moisture content of composting material could be determined by TDR using coated probes, even when the measured material had a moisture content of 0.581 cm³ cm^?3, temperature of 70 °C and conductivity of 4.32 mS cm^?1. TDR probes were calibrated as a function of dielectric properties that included temperature effects. When the bulk temperature varied from 20 °C to 70 °C, composting material with 0.10–0.70 cm³ cm^?3 moisture content could be measured by TDR using coated probes, and calibrations based on different temperatures minimized the errors.