Determination of selected neonicotinoid insecticides by liquid chromatography with thermal lens spectrometric detection

We studied the analysis of trace amounts of neonicotinoid insecticides by liquid chromatography coupled with a thermal lens spectrometric detector (TLS). This multi-residue analysis method is based on the reversed phase separation on C₁₈ column, isocratic elution and collinear dual beam TLS detection. The insecticides thiamethoxam, imidacloprid, acetamiprid and thiacloprid were detected with retention times of 4.4, 5.7, 6.5 and 8.5 min and limits of quantifications of 50, 89, 10, and 25 μg/L, respectively. The retention times agreed well with those obtained by the same chromatographic method but using a diode-array detector (DAD). The limits of quantifications for imidacloprid were identical in both techniques. However, the limits of quantifications for thiamethoxam, acetamiprid and thiacloprid were up to 8.5 times lower using the TLS detector compared to the diode-array detector. The applicability of the developed procedure was tested on spiked river water and potato samples.     

Shorter fries? An alternative policy to support a reduction of nitrogen contamination from agricultural crop production

Feeding the growing population of the world poses significant policy challenges for the sustainability of global ecosystems. A prime example is the degradation of water quality due to the growing imbalance in the terrestrial nitrogen (N) cycle linked to increasing production of reactive N (Nr). Environmental impacts such as groundwater quality degradation and eutrophication of coastal estuaries tend to be local in nature but may be closely connected to global economic factors. Environmental accounting of the N fluxes entering, leaving or remaining in Prince Edward Island (PEI), a small agricultural region, demonstrate the importance of a single industry (potato production) in controlling the local N cycle. The resulting burden of Nr has its most profound effect on groundwater, the sole source of drinking water and the primary pathway of N to the Province's economically and ecologically important estuaries. At the same time, agriculture is a vital part of the local economy, and regulators are faced with the challenge of meeting environmental goals and still maintaining an industry that is competitive and responsive to global market trends. New, innovative policy alternatives are needed to foster more effective implementation of sustainable agricultural practices. An approach that focuses on influencing consumer choices toward more environmentally responsible production practices at the point of origin may help remove some of the important, non-technical barriers to sustainable food production practices. In practice, a system that documents the environmental performance throughout the full supply chain from producer to retailer would have to be implemented.     

Lactic acid production with undefined mixed culture fermentation of potato peel waste

Potato peel waste (PPW) as zero value byproduct generated from food processing plant contains a large quantity of starch, non-starch polysaccharide, lignin, protein, and lipid. PPW as one promising carbon source can be managed and utilized to value added bioproducts through a simple fermentation process using undefined mixed cultures inoculated from wastewater treatment plant sludge. A series of non-pH controlled batch fermentations under different conditions such as pretreatment process, enzymatic hydrolysis, temperature, and solids loading were studied. Lactic acid (LA) was the major product, followed by acetic acid (AA) and ethanol under fermentation conditions without the presence of added hydrolytic enzymes. The maximum yields of LA, AA, and ethanol were respectively, 0.22 g g^?1, 0.06 g g^?1, and 0.05 g g^?1. The highest LA concentration of 14.7 g L^?1 was obtained from a bioreactor with initial solids loading of 60 g L^?1 at 35 °C.     

Environmental assessment of propionic acid produced in an agricultural biomass-based biorefinery system

This paper presents an environmental system study of the production of propionic acid in a biorefinery system based on agricultural by-products. Here, propionic acid is produced by fermentation of glycerol, a by-product from biodiesel production, as carbon source and potato juice, a by-product from starch production, as nitrogen source. Biomass-based propionic acid leads to a greenhouse gas reduction of 60% compared to propionic acid from fossil sources. However, the primary energy input is about twice as high for the biomass-based propionic acid. The choice of input energy and the efficiency of the process, as well as the technology applied, have high impacts on the environmental performance of the biorefinery concept. There is a potential for increased integration both on the input of substrates and the output of end products of the biorefinery system, which will further improve its environmental performance.     

Soil loss due to harvesting of various crop types in contrasting agro-ecological environments

Soil erosion studies on cropland usually only consider water, wind and tillage erosion. However, significant amounts of soil are also lost from the field during the harvest of crops such as sugar beet (Beta vulgaris L.), potato (Solanum tuberosum L.), chicory roots (Cichorium intybus L.), cassava (Manihot spp.) and sweet potato (Ipomoea batatas (L.) Lam). During the harvest soil adhering to the crop, loose soil or soil clods and rock fragments are exported from the field together with these crops.This soil erosion process is referred to as ‘soil losses due to crop harvesting’ (SLCH). Most of the studies investigated SLCH variability and its controlling factors for one crop type in similar agro-ecological environments and for comparable harvesting techniques. In this study, a compilation of SLCH studies was made in order to investigate the effect of crop type, agricultural systems, ecological conditions and harvesting technique on SLCH variability. SLCH rates ranged from few to tens of Mg ha⁻¹ harvest⁻¹ and SLCH was highly variable both in space and time. Comparison of four studies on SLCH for sugar beet revealed that harvesting technique and soil moisture content at harvesting time can be equally important for SLCH variability. The occurrence of soil clods harvested with the crop explained why SLCH was significantly larger for mechanically harvested potato in Belgium compared to manually harvested potato in China. SLCH values for manually harvested sugar beet, potato, cassava and sweet potato in China and Uganda were in general smaller than SLCH values for mechanically harvested sugar beet, potato and witloof chicory roots measured in Belgium and France. However, SLCH may also vary significantly within Europe due to differences in harvesting techniques. Soil moisture content at harvesting time was besides harvesting technique one of the key factors controlling SLCH variability. There were no systematic differences in SLCH between crop types, although the soil–crop contact area–crop mass ratio could explain more than 40% of the means from several SLCH studies.     

马铃薯加工项目恶臭的环境影响与污染防治措施研究

马铃薯淀粉生产企业排放废水中有机物浓度较高,来源于污水处理站的污水接及处理设施以及污泥处理设备在废水的贮输及生化处理过程中产生恶臭气体,对大气环境及周围居民的日常生活影响较大.通过对污水处理厂产生臭气的构筑物单元及从环评角度对污水处理厂产生恶臭的环境影响评价方法进行研究,同时结合大气防护距离的确定综合评价分析,规定污染防治措施,减少恶臭影响,保护和改善周围的大气环境.     

表达马铃薯Y病毒外壳蛋白基因的转基因烟草抗病机制

根据已报道的马铃薯Y病毒坏死株系(PVY^N)核苷酸序列，克隆了PVY^N外壳蛋白(CP)基因，通过根癌农杆菌(Agrobacterium tumefaciens)LBA4404介导的方法，转化烟草NC89，获得了38株PCR呈阳性的转基因植株．攻毒试验发现，转基因植株对PVY^N的抗性水平存在着差异，其中有4株表现为高度抗病性．Southern blot表明，PVY^N CP基因已经整合到烟草染色体中，转基因的拷贝数与植株的抗病性成正相关．Northern blot表明，PVY^N CP基因在RNA水平上得到了表达，而且PVY^N CP RNA在细胞中的积累量与转基因植株的抗病性呈明显的负相关．Western blot表明，高度抗病植株未检测到转基因CP蛋白质，而抗病和感病植株都检测到了PVY^N CP蛋白，且不同抗性的转基因植物中转基因蛋白质的积累有一定的差异．实验结果表明，表达PVY^N CP基因的转基因烟草其抗病机制类似于转录后的基因沉默，即抗病件可能是RNA介导的．     

等离子体发射光谱法等三种方法测定马铃薯中镉

采用IRISER/SDuoICP测定马铃薯中的镉元素含量,并与火焰原子吸收法和石墨炉原子吸收法的测定作一比较,3种方法的检测限分别为0 001mg/L、0 004mg/L和0 25ng/L,加标回收率均在95%～102%范围内,相对标准差<10%。     

Long-term thermophilic mono-digestion of rendering wastes and co-digestion with potato pulp

In this study, mono-digestion of rendering wastes and co-digestion of rendering wastes with potato pulp were studied for the first time in continuous stirred tank reactor (CSTR) experiments at 55 °C. Rendering wastes have high protein and lipid contents and are considered good substrates for methane production. However, accumulation of digestion intermediate products viz., volatile fatty acids (VFAs), long chain fatty acids (LCFAs) and ammonia nitrogen (NH₄-N and/or free NH₃) can cause process imbalance during the digestion. Mono-digestion of rendering wastes at an organic loading rate (OLR) of 1.5 kg volatile solids (VS)/m³ d and hydraulic retention time (HRT) of 50 d was unstable and resulted in methane yields of 450 dm³/kg VS_fed. On the other hand, co-digestion of rendering wastes with potato pulp (60% wet weight, WW) at the same OLR and HRT improved the process stability and increased methane yields (500–680 dm³/kg VS_fed). Thus, it can be concluded that co-digestion of rendering wastes with potato pulp could improve the process stability and methane yields from these difficult to treat industrial waste materials.     

马铃薯连作对土壤微生物群落结构和功能的影响

采用BIOLOG技术,研究马铃薯连作对土壤微生物群落结构和功能的影响。研究发现：连作土壤湿热灭菌后,细菌、放线菌及微生物总量都明显升高,真菌数量显著降低。连作土壤添加马铃薯残茬后,细菌数量降低,真菌数量增加。连作土壤中微生物对多聚化合物和碳水化合物的利用能力较高;湿热灭菌后,土壤微生物对6类碳源的利用率有升有降,表现为对羧酸类化合物、芳香化合物的利用率升高,对多聚化合物、碳水化合物、氨基酸、胺类化合物的利用率降低,微生物丰富度和均匀度降低。土壤病源微生物可能是马铃薯连作障碍发生的原因之一。