Gaseous treatment with allyl isothiocyanate to control established microbial infestation on wood

Applicability of gaseous treatment with allyl isothiocyanate (AIT) was evaluated for controlling the established microbial infestation of wood in the laboratory. Small sapwood specimens from five wood species measuring 20 mm (T)×20 mm (R)×10 mm (L) were first preincubated on 2% malt-agar medium with placing them on a fully grown monoculture of seven test fungi. After 7 weeks of preincubation they were transferred to fresh medium and exposed to AIT fumigant at concentrations of 2360 and 23600ppm AIT in the air of a petri dish to determine threshold values of exposure periods for each test fungus. The 2360 ppm concentration was not effective forPenicillium funiculosum, Gliocladium virens, orRhizopus stolonifer for any of the wood species-exposure period combinations. Those test fungi could grow even at 23600ppm after 48h exposure whenCryptomeria japonica andFagus crenata were used as wood substrate. Growth of other test fungi was inhibited at 2360ppm with a few exceptions in the case ofAspergillus niger. The required periods of exposure to suppress microbial regrowth were different with wood species-test fungi combinations. As two wood-decaying basidiomycetes,Trametes versicolor andFomitopsis palustris, were easily controlled at 2360ppm after 24h exposure regardless of wood species, AIT treatment proved applicable to the control of internal decay of utility poles and other relevant products in service.     

EM对生活污水的有机物降解能力的研究

研究了有效微生物群（EM）对生活污水中有物的去除效果，实验结果表明，（1）EM对有机污染物的去除应在好氧条件下进行,(2)当接种量在0．1／1000以下时，EM对有机物的去除有显著促进作用，去除率增幅达10％以上。     

Performance of a Variable Tillage System Based on Interactions with Landscape and Soil

Understanding tillage system interaction with landscape variability is important in prescribing appropriate tillage systems that are profitable and environmentally sound. A three-year (1997–1999) study was conducted on a gently sloping, poorly drained lacustrine landscape to evaluate tillage, landscape, and soil interactions on grain yield. Tillage systems investigated were a reduced tillage (RT) system [no-tillage after soybean (Glycine max (L.) Merr), fall chisel plowing after corn (Zea mays (L.) var. mays)], and a conventional tillage (CT) system (fall chisel plowing after soybean and fall moldboard plowing after corn). Fall primary tillage was followed with a pre-plant field cultivation in the spring. Runoff and pollutant losses from the two tillage systems were also measured under a 63 mm h^–1 simulated rainfall. Runoff and pollutant (total solids, chemical oxygen demand, total P, dissolved molybdate reactive P) losses were similar, or lower (6.6, 8.0, 7.7, 5.5, and 4.1 times, respectively) in the RT than the CT system. Tillage system, landscape elevation, and soil type interactions on crop yield varied depending upon whether it was a wet or dry growing season. Using the interactions, soybean yield differences among the modeled fixed-RT, fixed-CT, and variable tillage (VT) systems in a wet year were less than 0.1 Mg ha^–1. During a dry year, corn yield was higher in the RT and the VT systems than in the CT system. When no new purchase of tillage equipment(s) is necessary to implement the RT, VT, or CT system, the modest yield benefits during relatively dry years, plus the improved runoff water quality by using reduced tillage system in all or part of the landscape, would justify the use of RT and VT systems over the CT system in the lacustrine landscape.     

南北方河流沉积物中污染物含量的对比分析

以南方河流袁河为例,北方河流太子河为代表,通过对两河流沉积物中氨氮、总氮、总磷和COD的含量监测,分别分析它们的分布规律;当同一水体个别断面沉积物中污染物含量较高时,研究其污染来源;对比两条河流的监测结果发现,太子河沉积物中污染物的含量是袁河的2～5倍,通过分析得出造成南北方河流沉积物中污染物含量差异的主要因素有：温度、水文条件、废污水排放及河流含沙量等。     

水污染物对革胡子鲇味觉功能的影响

革胡子鲇鼻粘膜毁损后，对亚致死的水污染物ＤＤＴ，硫酸铜，苯酚，ＬＡＳ。等表现出回避行为。当鱼的上颌须被切除后，回避反应几乎消失。用水污染物灌流上颌须，亦无反应信号。水污染物子早期降低了上颌须味蕾对味觉刺激物的相对反应强度。但对味觉器官的组织结构无明显损伤。苯酚村求以应有先增强后减弱的现象。因此认为，水污染物的作用，与味觉感受器的突触有关。     

生物标志物及其在环境中的应用

对作为污染物暴露的早期响应的生物标志物进行了简要介绍,综述了近年来重金属、有机磷农药以及PAHs和PCBs等有机污染物的生物标志物的最新研究结果,并探讨了生物标志物在环境中的应用,指出了生物标志物今后的应用和研究方向。     

基于氮收支平衡的河套灌区春小麦农田灌溉和施氮策略

针对中国黄河中上游河套灌区不合理灌溉和施肥造成的土壤氮素流失严重及氮收支不平衡等问题,该研究于2019－2021年开展田间试验,探讨不同灌溉和施肥策略对土壤氮损失、作物氮吸收及氮收支的影响。试验设置了3个灌溉水平（高水I1：450 mm,中水I2：315 mm,低水I3：180 mm）和2个施氮水平（高氮N1：340 kg/hm2,低氮N3：170 kg/hm2）,此外,2020和2021年在中等灌溉水平I2下补充了中等施氮水平（250 kg/hm2,N2）,对不同处理的土壤氮损失、作物氮吸收及氮收支等指标进行了对比分析。结果表明,肥料氮是农田氮输入的主要来源,其次是灌溉水、大气沉降和非豆科作物固定。作物吸氮占土壤氮输出的比例最大,其次是NO3--N淋失、NH3挥发和N2O排放。对于氮输入而言,其值随着灌水量和施氮量的减少而降低。对于土壤氮输出而言,减少灌水量和施氮量可显著降低土壤总氮损失量,但过低的灌水量和施氮量将导致小麦吸氮量的降低。传统的N1施氮处理可导致土壤氮素盈余,而施氮量降低50%的N3处理则导致土壤氮素大量亏缺。对照处理（I1N1）的土壤氮损失量最高,该处理氮损失占土壤氮输出的比例高达25%～35%,其中NO3--N淋失和NH3挥发占总氮损失的95%以上。与对照处理相比,I2N2处理可减少21%～29%的氮损失,且作物吸氮几乎未受到影响。同时,该处理土壤氮素处于轻度亏缺状态,其亏缺量为28～50 kg/hm2,占总施氮量的11%～20%。若在收获后将4～8 t/hm2的小麦秸秆还田,则可保持麦田土壤的氮收支平衡。因此,通过改善灌溉和施肥策略并配合适当的秸秆还田可以有效缓解河套灌区春小麦农田的氮损失且实现土壤氮平衡,该研究可为干旱半干旱地区春小麦农田可持续生产和氮污染物减排提供科学依据。     

引黄前后汾河上游水质变化对比分析

根据汾河上游区域1985～1995年水质资料,采用单因子评价方法和水质指数法,对汾河上游沿途进行取样分析。结果表明：在2003年黄河水进入前后,汾河上游污染物浓度和种类有一定变化,主要表现在水质类别大多从Ⅱ、Ⅲ类上升为Ⅳ类以上;黄河向汾河输水期间沿程水质化学需氧量、氨氮及高锰酸盐指数从喇嘛湾—万家寨水库—汾河头马营口—宁化—东寨—河岔—汾河水库均呈明显下降趋势;东寨水质好于其他取样点。     

城市污泥中有机污染物的研究进展

综述了城市污泥中有机污染物的研究进展。文章指出,城市污泥含有丰富的 N、 P、 K和有机质,但它通常也含有氯酚 (CPs)、氯苯 (CBs)、硝基苯 (NBs)、多氯联苯 (PCBs)、多氯代二苯并二恶英 /呋喃 (PCDD/Fs)、邻苯二甲酸酯 (PEs)、多环芳烃 (PAHs)和有机农药等种类复杂的有机污染物而影响其农业利用。不同城市污泥中有机污染物的种类及其含量不同,与污水的来源、污泥类型及其处理方式等因素有关。堆肥处理可以在一定程度上降低城市污泥中有机污染物的含量,从而达到农业利用的目的。     

桂林市城区主要污染物入河量估算

[目的]估算桂林市城区主要污染物入河量。[方法]根据用水量对桂林市城区城镇污染源包括生活源、工业源、规模化畜禽养殖源和农业面源(COD和NH3-N)的入河量进行了估算。[结果]城镇生活源和工业源是桂林市城区主要污染物入河量的主要来源;城镇生活源和工业源贡献比例分别为27.6%~31.4%和58.7%~59.7%;桂林市区和其他区县贡献比例分别为35.6%~37.1%和62.9%~64.4%;桂江流域贡献比例最大,为66.8%~68.3%,其次是柳江下游,比例为25.7%~26.8%。[结论]经估算,桂林市城区污染源的COD和NH3-N入河量分别为24 952.57和3 276.31 t/a。