农户经济行为的分析与土地可持续利用

本文以农户这一微观主体的土地利用模型为起点,通过分析我国现阶段工农业关系及采取的政策对农户利用土地进行农业生产的影响,提出了转换农业政策、促进土地可持续利用的对策。     

用通用浸提剂Mehlich 3研究城市污泥重金属生物有效性

采用Mehlich3(M3)通用浸提剂对经稳定化处理的城市污泥中重金属元素Cd、Cr、Pb、Ni、Zn、Cu的有效态进行提取,同时进行了小麦盆栽试验,将M3通用浸提剂浸提所得的重金属元素有效态含量与该元素在小麦幼苗茎叶和根系中的元素的富集量进行相关分析.结果表明,城市污泥中不同元素的有效态含量明显不同.M3提取的有效态Cd、Cr、Cu与幼苗茎叶富集Cd、Cr、Cu极显著相关,但Pb、Ni、Zn的有效态含量与植物茎叶富集量相关性不明显,主要原因可能与元素从植物根系向茎叶迁移能力有关.M3提取的污泥中重金属的有效态含量与小麦幼苗根系富集的重金属元素的含量呈现显著的相关性.因而M3可用于污泥中重金属元素潜在的生物有效性评价.     

锅炉大气污染物测试

为贯彻国家新标准“锅炉大气污染物排放标准”（ＧＢ５４６８－９１），本文探讨了准确测算烟气流速，干烟气平均分子量等关于锅炉烟尘和ＳＯ２排放浓度测试的技术问题，对不易测试的参数提供经验估算法。     

大同市空气中多环芳烃与人尿中1-羟基芘的分析

用GC~2/MS和HPLC鉴定出大同市空气中的多环芳烃化合物35种.对大同市不同功能区空气中苯并(a)芘(BaP)和人尿中1-羟基芘同步采样分析.结果表明,不同功能区BaP浓度有显著差别:采暖期浓度急剧增加,城区浓度为对照点的17倍,日均值达330ng/m~3.人尿中1-羟基芘的浓度与空气中BaP的浓度显著相关.采暖期城区尿中1-羟基芘的几何均值为1.86μmol/mol肌酐,非采暖期为1.14μmol/mol肌酐,均较北京市的均值高出五倍多.证明大同市由于直接燃煤,造成空气中多环芳烃的严重污染.     

芳香族醛酮化合物溶解度和分配系数的测定与估算

本文测定了１５种芳香族醛酮化合物的溶解度和正辛醇－水分配系数,研究了水溶解度及分配系数与分子连接性能指数的相关性。结果表明,溶解度和分配系数之间以及与分子连接性指数呈较好的线性关系。     

大气颗粒物中微生物分析方法及分布特征的研究进展

大气颗粒物(particulate matter, PM)可能携带病原微生物,会对人体健康产生影响,因此,对大气颗粒物中微生物的采集和分析已成为当今的研究热点。本文对大气颗粒物中微生物的采集方法和分析方法(培养法、菌群多样性组成谱测序和宏基因组学技术)的研究进展进行简要概括,着重介绍不同条件下(区域、时间、粒径、天气条件和气象因素)大气颗粒物中微生物的分布状况差异,并对引起相关差异的原因进行了探讨,旨在为深入认识大气颗粒物中微生物的分布特征提供参考。     

Long-term tillage effects on soil metolachlor sorption and desorption behavior

Sorption and desorption are two important processes that influence the amount of pesticides retained by soils. However, the detailed sorption mechanisms as influenced by soil tillage management are unclear. This study examined the sorption and desorption characteristics of metolachlor [2-chloro-N-(2-ethyl-6-methyphenyl)-N-(2-methoxy-1-methylethyl)-acetamide] using the soil samples collected from the long-term conservation tillage (CnT) and conventional tillage (CT) research plots established in 1979 in Darlinton, SC. Humic acid (HA) and humin were extracted from the soils and used in the sorption experiments along with the whole soil samples. The sorption experiments were conducted using a batch-equilibration method. Three sequential desorption rinses were carried out following the sorption experiments. By comparing metolachlor sorption and desorption results we observed hysteresis for all soil samples and their organic matter fractions. Sorption nonlinearity (N) and hysteresis were dependent on the structure and composition of soil organic matter (SOM), e.g., Freundlich isotherm exponents (N) of HA and humin from CnT were higher than those of CT treatment, which may be related to high aromaticity of SOM fractions in CT treatment. Sorption capacity (K'f) was positively correlated with soil organic carbon (SOC) content. These results show that long-term tillage management can greatly affect metolachlor sorption and desorption behavior probably by qualitative differences in the structural characteristics of the humic substances.     

Changes in soil microbial biomass and Zn extractability over time following zn addition to a paddy soil

A laboratory incubation study was conducted using a paddy soil spiked with two quantities of Zn as soluble Zn(NO3)2 and unamended controls. Three single extractants (1 M ammonium acetate (pH 7.0), 0.43 M acetic acid and 0.05 M EDTA) were used to assess the bioavailability of Zn. Biological community assessments were made microbial biomass (chloroform fumigation), soil basal respiration and dehydrogenase activity. During the 84-day period of the experiment, addition of Zn at both 500 and 1,000 mg kg(-1) had little detectable effect on soil pH. The concentration of NH4OAc-extractable Zn decreased rapidly within the initial six weeks. The concentration of HOAc-extractable Zn showed no decrease during 84 days incubation. EDTA-extractable Zn was greater than NH4OAc- and HOAc-extractable fractions, and showed a similar trend to NH4OAc-extractable after incubation. Microbial biomass, soil basal respiration and dehydrogenase activity all decreased over time during 84 days incubation. Addition of Zn resulted in a significant increase in specific respiration (qCO2). Microbial biomass and dehydrogenase activity did not appear to be influenced by added Zn, probably due to the strong buffering capacity of the soil. The Zn extracted by EDTA, HOAc and NH4OAc showed close relationships with each other (p < 0.001). Zinc extracted by 0.05 M EDTA and NH4OAc were highly correlated with soil basal respiration and specific respiration rate (p < 0.01). The results suggest that NH4OAc-extractable Zn combined with soil specific respiration could be used as parameters for risk assessment.     

松花江中游(哨口-松花江村段)水中有毒有机物污染研究

1983—1990年,在松花江中游(哨口—松花江村)138公里江段中,进行七次五断面追踪水团采样,采用高分子微球GDX—502吸附富集,GC定性定量,GC/MS定性验证。依据有机物检出率、毒性持久性、有点源排放、分析方法适用等因素,筛选出65种主要有毒有机物。化合物总浓度逐年降低,石油烷烃、芳烃浓度增加;属致癌致变性化合物21种,EPA优测物21种,建议的优先控制黑名单20种;有点源排入的占90％以上,污染源来自吉化主要入江污水口;封冰期比其它水文期污染增强;该江段污染特征为氯代链烃、氯代苯类、硝基芳烃种类多、浓度高,应为重点控制对象。     

蓝宝石热处理的现状及前景

本文根据蓝宝石的致色机理 ,总结了蓝宝石热处理的模式及影响因素 ,给出了现行蓝宝石热处理的实例 ,结合国内经济发展状况对蓝宝石热处理的发展前景作了展望 ,并根据相关学科的发展提出了一些建议及设想。