Freshwater quality in urban areas: a case study from Rome, Italy

Water quality in streams running in urban areas can be strongly altered by the impact of human activities. Different kinds of water quality degradation were investigated in the streams running in the ‘Appia Antica’ Regional Park, placed in the southern suburbs of Rome. Water quality was assessed in 21 sampling points located in eight streams by the analysis of chemical [chemical oxygen demand (COD), nitrates, ammonia, total phosphorus], biological (IBE index), microbial (total coliforms, faecal coliforms, Escherichia coli, faecal streptococci, sulphite-reducing clostridia) ecosystemic (IFF index), and hydrological (flow) parameters. On the whole the results indicate an in depth degradation of water quality. However, IBE and IFF showed local condition of water stress that were not individuated by chemical parameters. A multidisciplinary approach is necessary to highlight the different pressures on water quality of urban freshwaters. The presence of buffer zones in urban green areas does not avoid the impact arising from the surrounding urban area.     

水中总磷量的密闭微波增压消解快速测定

研究了用聚四氟乙烯密封带密封容器，利用微波加热技术，在较高的温度和压力下消解样品，快速测定环境水样中总磷量的方法；讨论了微波功率、微波消解时间、酸度等因素对测定结果的影响，与标准方法对照，经t检验法及F检验法检验，测定结果没有显著性差异，多次加标回收率在98％－103％之间，相对标准偏差≤1．3％，结果令人满意；该法具有操作简便、快速、不污染环境、宜于大批量样品的测定、便于推广普及等优点，可用于其它样品的分析测定。     

激光热透镜分析法测定土壤中水溶性磷

采用激光热透镜分析法进行了土壤中水溶性磷的测定。研究了测定磷的各种影响因素及土壤中水溶性磷的浸提率与固液比和浸提时间的关系，表明聚乙烯醇的存在能增强热透镜信号强度，并使显色体系稳定５ｈ以上。采用该方法进行土壤中水溶性磷的测定，磷含量在１．５～３０μｇ／Ｌ之间与热透镜信号强度成线性关系，检出限为０．３μｇ／Ｌ。为土壤分析中痕量磷的测定提供了一种高灵敏度分析方法。     

流动注射光度法测定水中总磷量

采用流动注射光度法测定了水中总磷量。水样经硫酸和过硫酸钾在125℃消解后,所得样品溶液中磷(PO_4~(3-))与钼酸铵生成杂多酸,经还原成钼蓝后测定其吸光度。总磷的质量浓度在1.0mg·L~(-1)以内与其吸光度呈线性关系,方法的检出限(3S/N)为0.003mg·L~(-1),测定下限(10S/N)为0.012mg·L~(-1)。方法用于测定水样中总磷的含量,相对标准偏差(n=7)在1.5%～3.0%之间,加标回收率在95.7%～102.5%之间。     

磷肥和有机肥对莲藕根状茎品质和铁膜形成的影响

以莲藕为材料,研究了施用磷肥和有机肥及两者混施对莲藕根状茎品质和表面铁膜形成的影响,以期为高产优质莲藕的种植提供理论依据。结果表明,磷肥处理后莲藕根状茎中蛋白质和淀粉含量分别比对照增加了145．4％和61．5％,并且还原糖含量和维生素C含量也比对照提高了48．2％和112．7％,根状茎表面铁膜的铁含量显著低于对照。有机肥处理下蛋白质和还原糖含量分别比对照提高了54．0％和47.2％,但莲藕根状茎中的淀粉、维生素含量以及铁膜的产生与对照无显著差异。磷肥＋有机肥处理的效果仅次于磷肥。可见磷肥施用后有效提高了莲藕品质并减轻了根状茎表面铁膜沉积,这对于提高种藕效益具有非常重要意义。     

钼酸铵分光光度法测定水质中总磷时砷的干扰消除研究

采用单一影响因素和正交因素水平研究相结合,试验不同形态砷对钼酸铵分光光度法测磷过程的干扰、干扰的主要因素、硫代硫酸钠最佳加入量及最佳显色时间.结果表明不同形态砷的干扰强度依次是,五价砷[As(V)]大于三价砷[As(Ⅲ)],而三价砷[As(Ⅲ)]又远远大于二甲基砷[DMAA].当As(V)浓度小于2.0 mg/L时,显色时间为测定的主要影响因素;当As(V)的浓度为0.1～5.0 mg/L时,考虑到操作以及实际水样中As(V)的含量等因素,选择硫代硫酸钠0.5 mL(40 mg/mL)为最佳量1,5 min为最佳显色时间。     

Pesticides in water and the performance of the liquid-phase microextraction based techniques. A review

The control of pesticides in surface, drinking and groundwater is nowadays a real necessity. In the European Community, their concentration must comply with the established parametric and environmental quality standards (EQSs). Regarding the new legislation, this article updates the information concerning the monitoring of pesticides and the technical specifications for their measurement in water samples where ultra-sensitive analytical methods are required. For some compounds, like pesticides, there is still a need to improve the performance of the existing methods. High sensitive techniques like gas chromatography tandem mass spectrometry (GC–MS/MS) and liquid chromatography coupled with mass spectrometry (LC–MS) have been developed. However, for most of the substances present at trace and ultra-trace levels the extraction and preconcentration steps are so far essential for their detection. Advances at a micro scale have been made and different types of microextractions are being developed. Liquid-phase microextraction (LPME) is an example. The study of this technique has increased in the last years and some innovations have been recently reported for pesticides water analysis. This article reviews the new developed LPME-based techniques and compares its performance with the analytical specifications established for pesticides water monitoring. The results show that LPME-based techniques can be a promising tool to improve the nowadays performance of methods used in pesticides water control.