Influence of soil-applied coal combustion by-products on growth and elemental composition of annual ryegrass

The total annual production of coal combustion by-products in the USA is expected to exceed 150 million Mg by the year 2000. Agricultural utilisation may offer a partial solution to disposal problems, but the benefits and risks associated with using these materials must be assessed. Four coal combustion by-products, bed ash (BA) and fly ash (FA) from a fluidised-bed combustion furnace and stabilised scrubber sludge (SS) and a high gypsum content by-product (G) from flue gas desulphurisation processes were added to two soils at rates of 0, 20, 40 and 80 g kg-1. The growth and elemental composition of Gulf annual ryegrass (Lolium multiflorum L.) were evaluated in the treated soils. Adding FA, SS and G to both soils at application rates of up to 80 g kg-1 was not detrimental to the growth of ryegrass and resulted in higher yields than controls in some instances. Adding BA created a high alkalinity, high soluble-salt environment that initially inhibited seedling germination and significantly reduced (p<0.05) yields of dry matter, so it will probably need to be restricted to rates of lime requirement. Ryegrass concentrations of Cu, Zn, Ni, Pb, Cd and Cr were similar in control and treated soils, but levels of B, Se, As and Mo were raised in treatments. Based on low trace-element concentrations in ryegrass shoots and in soil solution, Se from FA application may be the only potential food-chain risk associated with application of the four coal combustion by-products used in this investigation.     

福建农业可持续发展的土地资源与环境分析

从农业用地和非农业用地两方面分析了福建省土地资源与环境的状况与潜力，提出了调整用地结构来促进农业可持续发展的思路。     

农业开发项目环境影响综合评价方法研究

对农业开发项目环境影响综合评价的难点进行了分析，提出了定性指标与定量指标模糊评价集的计算方法；并运用多级模糊综合评价方法，对所有指标进行综合评判，解决了定性指标与定量指标综合分析这一难题。     

南方天然水体DOM的化学分级、变化特征及三卤甲烷生成势(THMFP)特性研究

采用XAD树脂吸附法,在春季内(3～5月)连续对南方深圳水库中的水体溶解性有机物(DOM)进行化学分级表征.结果表明,天然水体DOM的总量和单个化学分级组分含量在一个季节会发生一定的波动,但总的分布特征在季节内未发生根本变化,即憎水酸(HoA)和亲水部分(HiM)浓度始终较高,而憎水碱(HoB)、憎水中性物(HoN)、弱憎水酸(WHoA)浓度则相对较低.同时,选取代表性时间点对DOM各化学分级组分进行了消毒副产物三卤甲烷生成势(THMFP)的研究,发现三卤甲烷(THMs)的主要前驱物为憎水和弱憎水有机部分,对THMFP的贡献共占约80%.进一步研究发现,憎水中性物、憎水酸、弱憎水酸的THMs生成能力较强,总体上与紫外吸收能力基本一致;但弱憎水酸表现略有不同,其SUVA(100×UV254/DOC)值并不十分突出,但三卤甲烷生成能力却明显较高,说明DOM的紫外吸收特性不能完全作为THMFP特性的替代指标.亲水物质(HiM)的SUVA值也不高,但其THMs生成能力接近憎水酸部分,值得水处理工艺研究重点关注.     

Trihalomethane formation in ozonated and chlorinated surface water

The relatively recent discovery of disinfection by-products has driven the main regulatory organisms to set maximum contaminant levels for certain substances in drinking water. Trihalomethanes can be deemed as the most important group of by-products in chlorinated surface waters. The present work has focused on trihalomethane formation in a full-scale water treatment plant. We studied the effect of several factors, including ozonation, on trihalomethane levels in chlorinated treated water. The treatment scheme also includes an ozonation step. Electronic Publication     

The effects of agricultural cooperatives on smallholder livelihoods and agricultural performance in Cambodia

Cooperatives are increasingly advocated as a means to improve incomes, livelihoods and the sustainability of smallholder farmers. This study analyzes the impact of commercial vegetable cooperative membership on smallholder agricultural performance in Cambodia. Institutional heterogeneities are considered across cooperatives and various econometric techniques are used to control for potential selection bias. The impacts of horticulture on agricultural outcomes are also analyzed. The results indicate that membership of commercial vegetable cooperatives has so far had no effect on agricultural incomes or the value or amounts of agricultural inputs. However, results indicate that membership has affected technology choice, access to credit services and information transmission through technological training. Additionally, there is evidence that horticulture, as a component of overall agricultural diversification, can augment farm income. The results suggest that much of the benefit of cooperative membership stems from the cooperative's provision of services, which might not be easily inferred from measures of member incomes.     

The impact of UV treatment on microbial control and DBPs formation in full-scale drinking water systems in northern China

To manage potential microbial risks and meet increasingly strict drinking water health standards, UV treatment has attracted increasing attention for use in drinking water systems in China. However, the effects of UV treatment on microbial control and disinfection by-products (DBPs) formation in real municipal drinking water systems are poorly understood. Here, we collected water samples from three real drinking water systems in Beijing and Tianjin to investigate the impacts of UV treatment on microbial control and DBP formation. We employed heterotrophic plate count (HPC), flow cytometry (FCM), quantitative PCR analysis, and high-throughput sequencing to measure microorganisms in the samples. Different trends were observed between HPC and total cell count (measured by FCM), indicating that a single indicator could not reflect the real degree of biological re-growth in drinking water distribution systems (DWDSs). A significant increase in the 16S rRNA gene concentration was observed when the UV system was stopped. Besides, the bacterial community composition was similar at the phylum level but differed markedly at the genera level among the three DWDSs. Some chlorine-resistant bacteria, including potential pathogens (e.g., Acinetobacter) showed a high relative abundance when the UV system was turned off. It can be concluded that UV treatment can mitigate microbial re-growth to some extent. Finally, UV treatment had a limited influence on the formation of DBPs, including trihalomethanes, haloacetic acids, and nitrogenated DBPs. The findings of this study may help to understand the performance of UV treatment in real drinking water systems.     

氯、氯胺消毒下钱江源水源水消毒副产物形成特征研究

以钱江源水源水为研究对象,以氯、氯胺为消毒方式,研究了不同消毒条件下,三卤甲烷(THMs)、卤乙腈(HANs)、氯代酮(CKs)、二卤乙酸(DHAAs)、三卤乙酸(THAAs)等消毒副产物(DBPs)的形成情况,以便为水务工作者监测钱江源建库前后水质、DBPs形成的变化提供基础数据.结果显示,氯消毒下DBPs的产量比氯胺消毒高出3~7倍甚至1个数量级,但不管是氯消毒还是氯胺消毒,THMs、HAAs形成量均在我国饮用水标准范围内.氯消毒下,大部分DBPs产量为中、碱性条件酸性条件(除了CKs),氯胺消毒则呈现不同的情况(所有DBPs的产量均为p H=6、p H=7p H=8).消毒剂量对所有DBPs形成具有明显的促进作用;溴离子对THMs、DHANs、DHAAs的形成有明显的促进作用.进一步研究表明,钱江源水源水的水质比钱塘江下游九溪水源水好,DBPs形成也较低,某些指标(如有机碳、有机氮、HANs形成量等)甚至比同省水质较好的金兰水库还要好;而且由于其较高的比紫外吸收值(SUVA),DBPs的溴嵌入能力均比九溪水源水、金兰水库低.此外,就目前的钱江源水源水来说,控制消毒剂量(氯、或氯胺)是控制DBPs形成的有效策略.     

Dynamics of major air pollutants from crop residue burning in mainland China, 2000–2014

Based on satellite image data and China's Statistical Yearbooks(2000 to 2014), we estimated the total mass of crop residue burned, and the proportion of residue burned in the field vs.indoors as domestic fuel. The total emissions of various pollutants from the burning of crop residue were estimated for 2000-2014 using the emission factor method. The results indicate that the total amount of crop residue and average burned mass were 8690.9 Tg and4914.6 Tg, respectively. The total amount of emitted pollutants including CO_2, CO, NOx,VOCs, PM_(2.5), OC(organic carbon), EC(element carbon) and TC(total carbon) were 4212.4–8440.9 Tg, 192.8–579.4 Tg, 4.8–19.4 Tg, 18.6–61.3 Tg, 18.8–49.7 Tg, 6.7–31.3 Tg, 2.3–4.7 Tg, and8.5–34.1 Tg, respectively. The emissions of pollutants released from crop residue burning were found to be spatially variable, with the burning of crop residue mainly occurring in Northeast, North and South China. In addition, pollutant emissions per unit area(10 km ×10 km) were mostly concentrated in the central and eastern regions of China. Emissions of CO_2, NOx, VOCs, OC and TC were mainly from rice straw burning, while burning of corn and wheat residues contributed most to emissions of CO, PM_(2.5) and EC. The increased ratio of PM_(2.5) emissions from crop residue burning to the total emitted from industry during the study period is attributed to the implementation of strict emissions management policies in Chinese industry. This study also provides baseline data for assessment of the regional atmospheric environment.     

农用地土壤环境分类管理研究

通过分析国内外农用地土壤环境分类管理经验,结合我国土壤环境质量状况,以土壤环境风险管控为主线,将农用地土壤分为优先保护类、安全利用类和严格管控类3个类别,并提出相应的分类管理措施,保障农产品质量安全和人体健康。