TEODORO ARDEMANS PIONEER WATER-SUPPLY ENGINEER OF SPAIN1

ABSTRACT: Teodoro Ardemans, first post-Renaissance water expert of Spain, recognized problems of ground-water contamination, influence of minerals on water quality, and mutual interference between closely spaced wells. He is also noted for his achievements in architecture and the writing of the first comprehensive building code for Madrid.     

南运河重金属污染状况及生态风险评价

采集南运河的水样和沉积物样品,对其重金属污染状况和生态风险进行了分析评价。利用电感耦合等离子体质谱仪(ICP-MS)对水、沉积物中铅(Pb)、铬(Cr)、砷(As)、铜(Cu)和镉(Cd)浓度进行分析。结果显示南运河水样中这5种重金属浓度均低于地表水环境质量标准I类水质标准,虽然运河上游沉积物中As和Cd浓度较高,但沉积物中重金属浓度总体上均处于较低水平。地累积指数法计算显示:As和Cd在部分河段达到重度和中度污染水平,Cu、Cr、Pb均处于无污染水平。各种重金属的潜在生态风险指数(Eir)从大到小的顺序为:CdAsCuPbCr,与地累积指数法结果相似。南运河总的潜在生态风险指数(RI)均值为128.85,潜在生态风险程度为"中",沉积物中Cd和As是南运河需要优先控制的重金属污染物。     

Internal eutrophication: How it works and what to do about it—a review

In the 1980s and 1990s, it became increasingly clear that changes in external nutrient loads alone could not entirely explain the severe eutrophication of surface waters in the Netherlands. Nowadays, 'internal eutrophication' has become a widely accepted term in Dutch water management practice to describe the eutrophication of an ecosystem without additional external input of nutrients (N, P, K). This review surveys the principal mechanisms involved in this process. It also discusses possible remedies to combat internal eutrophication.     

Floristic contamination of suburban forests near the city of Ivanovo

In the course of floristic studies in suburban forests near the city of Ivanovo, 206 species of vascular plants have been recorded, including 39 invasive species (18.9%). Information on specific features of distribution and activity of introduced species growing feral and accidental weeds in different forest types is presented. The most aggressive species are distinguished. Factors responsible for the invasion of alien species to forest cenoses and main tendencies in their dynamics are discussed.     

FORMS OF NITROGEN (NO 3 - -N; NO 2 - -N AND NH 2 CONH 2 -N) AND THEIR RELATIONS TO A.O.U. IN THE INDIAN COASTAL WATERS OF ARABIAN SEA

The distribution of three important dissolved forms of nitrogen, viz. nitrate, nitrite and urea in the surface and bottom water samples collected from 27 selected hydrographic profiles, in the Arabian Sea, along the west coast of India is described. Of the three forms, nitrate concentrations were the highest and comparatively higher concentrations were observed in the bottom water. Decomposition of organic matter resulting in the release of the thermodynamically stable nitrogen species, i.e. nitrate, may be the major factor resulting in higher nitrate concentrations at these depths, where the water is also characterized by low values of dissolved oxygen and temperature. The significant positive correlation between A.O.U. and nitrate of the bottom water samples emphasizes the role of oxidative decomposition of organic matter which plays an active role in reducing the oxygen concentrations below the theoretical values since at this depth ( ≈200 m) the net production is taken to be zero. This is also evidenced by the negative correlation of nitrate with dissolved oxygen and temperature, for the bottom samples.     

Differential leaching of nutrients from soluble vs. controlled-release fertilizers

Extremely sandy soils and poorly distributed high annual rainfall in the state of Florida contribute to significant leaching losses of nutrients from routine fertilization practices. A leaching column experiment was conducted to evaluate the leaching losses of nutrients when using currently available N, P, K blend fertilizers for young citrus tree fertilization. Fertilizer blends included NH₄NO₃, Ca(NO₃)₂, IBDU, IBDU plus Escote, Nutralene, Osmocote, and Meister. Following leaching of 1000 ml of water through soil columns, which simulates leaching conditions with 26 cm of rainfall, the amount of NO₃ and NH₄ recovered in the leachate from soil columns amended with an NH₄NO₃ blend accounted for 37% and 88% of the respective nutrients contained in the quantity of blend per column. The corresponding values for soil columns amended with a Ca(NO₃)₂ blend were 48% and 100%. Leraching losses of both NO₃ (<3%) and NH₄ (<4%) were drastically decreased when using controlled-release fertilizers. The recoveries of P and K in 1000 ml of leachate were 1.3% and 8%, respectively, of the nutrients added as Osmocote, which contained coated P and K sources. In the case of the rest of fertilizer blends, the recoveries of P and K in 1000 ml of leachate were as high as 52%–100% and 28%–100%, respectively. Therefore, controlled-release technology offers an important capability for minimizing leaching losses of nutrients.     

Arsenic contamination in the Kanker district of central-east India: geology and health effects

This paper identifies newer areas of arsenic contamination in the District Kanker, which adjoins the District Rajnandgaon where high contamination has been reported earlier. A correlation with the mobile phase episodes of arsenic contamination has been identified, which further hinges on the complex geology of the area. Arsenic concentrations in both surface and groundwater, aquatic organisms (snail and water weeds) soil and vegetation of Kanker district and its adjoining area have been reported here. The region has been found to contain an elevated level of arsenic. All segments of the ecoysystem are contaminated with arsenic at varying degrees. The levels of arsenic vary constantly depending on the season and location. An analysis of groundwater from 89 locations in the Kanker district has shown high values of arsenic, iron and manganese (mean: 144, 914 and 371 μg L⁻¹, respectively). The surface water of the region shows elevated levels of arsenic, which is influenced by the geological mineralised zonation. The most prevalent species in the groundwater is As(III), whereas the surface water of the rivers shows a significant contamination with the As(V) species. The analysis shows a bio-concentration of the toxic metals arsenic, nickel, copper and chromium. Higher arsenic concentrations (groundwater concentrations greater than 50 μg L⁻¹) are associated with sedimentary deposits derived from volcanic rocks, hence mineral leaching appears to be the source of arsenic contamination. Higher levels of arsenic and manganese in the Kanker district have been found to cause impacts on the flora and fauna. A case study of episodic arsenical diarrhoea is presented.     

Spatial and temporal variability of water repellency in a sandy soil contaminated with tar oil and heavy metals

Water repellency can induce preferential flow and thus affect water flow and contaminant transport at hazardous waste sites. Since the spatial patterns of water repellency are mostly unknown, it is problematic to use numerical transport models to predict leachate composition. In this study, the spatial variability of soil water repellency was studied at an industrial site contaminated with tar oil, chromium, copper and arsenic. The persistence of water repellency was assessed by the water drop penetration time (WDPT), and the degree of water repellency was quantified by the ethanol percentage (EP) test. Measurements were made at the soil surface along 3.5-12.1 m long transects at different times between March and October 2002. The spatial variability of WDPT, EP, water content, and organic matter content was quantified by variogram analyses. Both the persistence and the degree of water repellency varied seasonally, with the highest water repellency during the summer months. The correlation lengths of WDPT values ranged between 16 and 406 cm, whereas EP values showed no spatial correlation. For field-moist samples, a critical soil water threshold, below which water repellency prevails, was estimated to be 2.5-4%. For oven dry samples, the WDPT values were dependent on the water content prior to drying. The wide range of correlation lengths and the temporal dynamics of spatial repellency patterns suggest that simulations of solute leaching must consider the spatial and temporal variability of soil hydrophobic properties.     

Exploring the role of local community perceptions in sustainability measurements

Measuring sustainability is an integral part of decision-making processes in order to promote sustainable development. The present paper focuses on sustainability indicators as these are measured on local level and explores two main issues: firstly, the subjective measurement of indicators focusing especially on social dimensions of sustainability, secondly, the incorporation of local perceptions in sustainability assessments. These two issues are explored in the Asopos River basin in Greece, an area where significant environmental degradation has been observed in the past decades and is also under financial pressure due to the ongoing national recession. A large-scale research study was conducted measuring environmental, economic and social indicators while, at a second stage, a model was developed, estimating new indicators that incorporate local communities’ perceptions on what they considered as important for their area. The results of the study reveal that the most important indicators for the sustainable development of the area, according to locals’ perceptions, are environmental quality as well as quality of life. By contrast, trust in local and central institutions and also local enterprises were not considered as important by locals. These results illustrate the importance of combining global and national scale assessment with locally focused social measurements of sustainability in order to better understand what is important for local communities prior to embarking on public policy planning.