Selenium in soil and endemic diseases in China

Selenium is an essential element for humans, animals and some species of microorganisms. The biological function of selenium shows dual characteristics. The selenium content range between toxic and deficient concentration is very narrow. The present paper discusses the geographical distribution of two forms (total and water-soluble) of selenium in topsoil (plough layer for cultivated soils, eluvial horizon for natural soils) and evaluates its relationship with some human health problems in China. Topsoil samples, 354 in total, including 156 natural and 198 cultivated soils of 21 main soil types were collected. The total Se concentration in soil samples was determined with DAN (di-aminonaphthalene)-fluorescence spectrophotometer method. Soil water-soluble Se concentration was determined with the same method after extraction with water (water/soil = 5:1). The results showed that the geometric and arithmetic means of total Se concentration in soil, for all samples, were 0.173 mg/kg and 0.239 mg/kg, respectively, with the lowest value being 0.022 mg/kg and the highest being 3.806 mg/kg. For the cultivated soil, the geometric mean of total Se was 0.188 mg/kg, its arithmetic mean was 0.269 mg/kg and higher than those in the natural soil, 0.154 mg/kg and 0.206 mg/kg, respectively. The geometric and arithmetic means of water-soluble Se in soil for all the samples were 4.0 and 6.4 microg/kg, the lowest 0.6 microg/kg and the highest value being 109.4 microg/kg. For the cultivated soils, the average concentration of water-soluble Se was 4.3 microg/kg, similar to that of natural soil, they are and 4.4 microg/kg by geometric mean. Two sequences of the soil types, arranged separately in the concentration of total Se and water-soluble Se, are different and this demonstrates that the proportions of the two forms of selenium existing in various soils are different. The percentages of water-soluble Se to total Se in different types of soils varied from 1.07 to 6.69%. However, generally the laterite and other subtropic soil still have relatively high absolute water-soluble Se contents because of their higher total Se contents. A very significant correlation between total Se and water-soluble Se has been found in cultivated soil with a correlation coefficient of 0.58 (P < 0.01). The relationships between soil Se and human endemic diseases Keshan disease, Kashin-Back diseases and selenosis have been discussed. The reference criteria for evaluating Se deficiency and Se excess in soil were suggested.     

Geochemistry of well water and cardiovascular diseases in Sri Lanka

A survey carried out on the incidence of cardiovascular diseases in Sri Lanka in relation to the hardness of drinking water reveals that a correlation exists which is geographically related. This correlation however, cannot be considered as a causal relationship and other factors possibly exist that could also play a major role in the incidence of cardiovascular diseases, e.g. trace elements.     

海啸过后，谢谢你还来斯里兰卡

海啸过后是最坏的时刻，也是最好的时刻，到斯里兰卡旅行，值得装进心里的东西很多。     

Endemic goitre,the factors controlling iodine deficiency in soils

Iodine concentrations in soils derived from a selection of very different parent rocks but within a small well-defined area of uniform environmental conditions have been studied. The results indicate that iodine in soils is independent of parent rock type, and that the maturing of young soils such as those found in areas of endemic goitre is the most important influence on iodine deficiency. The iodine is retained and enriched during vegetative recycling processes.     

Actinomycetes in relation to taste and odour in drinking water: myths, tenets and truths

Actinomycetes are a complex group of bacteria present in a wide variety of environments, either as dormant spores or actively growing. Some actinomycetes produce two potent terpenoids (geosmin and 2-methylisoborneol (MIB)) and pyrazines, common causes of drinking water off flavours, and have been implicated in taste and odour episodes. However, isolation from a water source is not evidence that actinomycetes caused a taste and odour event. Dormant spores of actinomycetes may be isolated from aquatic environments in high concentrations, despite production in the terrestrial environment. Similarly, odourous compounds produced by actinomycetes may be produced terrestrially and washed into aquatic environments, with or without the actinomycetes that produced them. Actinomycetes may exist as actively growing mycelium in small, specialized habitats within an aquatic system, but their odourous compounds may influence a wider area. This paper attempts to elucidate the types and activities of actinomycetes that may be found in, or interact with, drinking water supplies.     

Measurement of dissolved organic nitrogen in a drinking water treatment plant: size fraction, fate, and relation to water quality parameters

This paper investigates the characteristics of dissolved organic nitrogen (DON) in raw water from the Huangpu River and also in water undergoing treatment in the full-scale Yangshupu drinking water treatment plant (YDWTP) in Shanghai, China. The average DON concentration of the raw water was 0.34 mg/L, which comprised a relatively small portion (~ 5%) of the mass of total dissolved nitrogen (TDN). The molecular weight (MW) distribution of dissolved organic matter (DOM) was divided into five groups: > 30, 10-30, 3-10, 1-3 and < 1 kDa using a series of ultrafiltration membranes. Dissolved organic carbon (DOC), UV absorbance at wavelength of 254 nm (UV254) and DON of each MW fraction were analyzed. DON showed a similar fraction distribution as DOC and UV254. The < 1 kDa fraction dominated the composition of DON, DOC and UV254 as well as the major N-nitrosodimethylamine formation potential (NDMAFP) in the raw water. However, this DON fraction cannot be effectively removed in the treatment line at the YDWTP including pre-ozonation, clarification and sand filtration processes. The results from linear regression analysis showed that DON is moderately correlated to DOC, UV254 and trihalomethane formation potential (FP), and strongly correlated to haloacetic acids FP and NDMAFP. Therefore, DON could serve as a surrogate parameter to evaluate the reactivity of DOM and disinfection by-products FP.     

基于Infoworks ICM的斯里兰卡科伦坡港口城雨水系统规划设计

斯里兰卡科伦坡港口城雨水系统规划设计是国外填海区域雨水系统规划设计的典型实例,介绍了雨水系统规划设计新思路,结合LID措施,打造生态雨水管理体系;并介绍了使用水力模拟软件Infoworks ICM对传统雨水管网规划设计方案进行校核的基本方法以及其他相关内容;研究了潮汐水位及设计重现期对雨水管网排水能力的影响,根据降雨模型模拟结果反复调整、优化雨水管网规划设计方案,优化后的雨水管网系统满足设计要求,运行状况良好。     

Environmental,economic and social analysis of materials for doors and windows in Sri Lanka

This paper compares the environmental, economic and social impacts of two types of doors and windows (elements), namely timber and aluminum taking into consideration the life cycle perspective. These elements are widely used for the buildings in Sri Lanka. Thus, it will help in the decision-making process when selecting materials for these elements. Major materials used for these elements are timber, brass, glass, paint, aluminum, rubber, steel and PVC boards. Environmental burdens associated with these materials are analyzed in terms of embodied energy, and environmental impacts that are relevant to Sri Lanka, such as global warming (GWP), acidification (ACP) and nutrient enrichment (NEP). Economic analysis is done using market prices of materials and affordability for those materials. Social concerns such as thermal comfort, good interior (aesthetics), ability to construct fast, and durability are analyzed based on the data collected through the questionnaires and also, interviews with the stakeholders of the buildings such as engineers, architects, building contractors and building users. It was found that timber elements are superior to aluminum elements in environmental scores (GWP, ACP and NEP). On economic score, also, timber elements are better. But on social score, aluminum elements are better than timber. It was also found that the higher the recycling percentage of aluminum, the higher the environmental favorability of the aluminum.     

Housing and home-making in low-income urban settlements: Sri Lanka and Colombia

Enabling the making of home is central to the practices of housing, but constructing home is more than building adequate shelter. It is about establishing, nurturing and managing social relationships and bringing together spaces, objects and elements to represent and celebrate desired relationships, events and memories. Drawing on empirical data from Sri Lanka and Colombia, this paper examines in detail the practices of home-making in low-income settlements. By focussing on people’s conceptions of home and by identifying key social and societal practices, the paper offers insights into the processes of home-making among ordinary dwellers in developing countries and calls for culturally sensitive and holistic housing interventions which support and complement these processes.

Seismicity and seismotectonics in and around Sri Lanka: a synoptic review

Bulletin of Engineering Geology and the Environment - Seismicity and seismotectonics in and around Sri Lanka are reviewed, considering the country in both the local and regional contexts. Seismic...     

Selenium in environmental and drinking waters of Belgium

The tetravalent and hexavalent selenium content of water samples can be determined by conventional energy-dispersive X-ray fluorescence after different preconcentration steps. Selenium values of nearly three-hundred different environmental and drinking water samples in Belgium are reported. The results are quite low, ranging from the detection limits up to 1 microgram 1-1. The concentration levels are compared to literature data and the speciation is discussed. The contribution of drinking water to the daily intake of selenium in Belgium ranges from less than 0.2 to 5%.     

Geochemical provinces and the incidence of dental diseases in Sri Lanka.

A survey carried out on the incidence of dental diseases and the distribution of fluoride in drinking water wells in Sri Lanka shows that 3 areas in particular had abundant fluoride (greater than 2ppm). Dental fluorosis was common in areas with high fluoride content while those areas with very little or no fluoride, such as the central region of Sri Lanka, had a high incidence of dental caries. The intensity of rain fall played a major role in the leaching of fluoride ions from soils and it is perhaps this factor which is responsible for the occurrence of a low fluoride zone in the central part of Sri Lanka. The presence of areas containing high fluoride and hence dental fluorosis coincided with geochemical provinces. In these areas, mineral deposits such as apatite and serpentine and also hot spring regions with exhalations of fluorine are found.     

Determining the optimal fluoride concentration in drinking water for fluoride endemic regions in South India

Fluoride ion in drinking water is known for both beneficial and detrimental effects on health. The prevalence of fluorosis is mainly due to the intake of large quantities of fluoride through drinking water owing to more than 90% bioavailability. The objective of this study is to predict optimal fluoride level in drinking water for fluoride endemic regions by comprising the levels of fluoride and other water quality parameters in drinking water, prevalence of fluorosis, fluoride intake through water, food and beverages such as tea and coffee and also considering the progressive accumulation of fluoride in animal bones, by comparing with non fluoride endemic areas comprise of the same geological features with the aid of regression analysis. Result of this study shows that increase of fluoride level above 1.33 mg/l in drinking water increases the community fluorosis index (CFI) value more than 0.6, an optimum index value above which fluorosis is considered to be a public health problem. Regression plot between water fluoride and bone fluoride levels indicates that, every increase of 0.5 mg/l unit of water fluoride level increases the bone fluoride level of 52 mg/kg unit within 2 to 3 years. Furthermore, the consumption of drinking water containing more than 0.65 mg/l of fluoride can raise the total fluoride intake per day more than 4 mg, which is the optimum fluoride dose level recommended for adults by the Agency for Toxic Substances and Disease Registry. From the result, the people in fluoride endemic areas in South India are advised to consume drinking water with fluoride level within the limit of 0.5 to 0.65 mg/l to avoid further fluorosis risk.     

Variability of invertebrate abundance in drinking water distribution systems in the Netherlands in relation to biostability and sediment volumes

A survey of invertebrates in drinking water from treatment works, internal taps and hydrants on mains was carried out by almost all water companies in the Netherlands from September 1993 to August 1995. Aquatic sow bugs (Asellidae, 1-12 mm) and oligochaeta worms (Oligochaeta, 1-100 mm), both known to have caused rare though embarrassing consumer complaints, were found to form 98% of the mean biomass in water flushed from mains. Their numbers in the mains water ranged up to 1500 (mean 37) Asellidae m⁻³ and up to 9900 (mean 135) Oligochaeta m⁻³. Smaller crustaceans (0.5-2 mm) dominated the numbers in water from mains. e.g. water fleas (Cladocera and Copepoda up to 14,000 m⁻³). Common invertebrates in treated water and in tap water were Rotifera (<1 mm) and nematode worms (Nematoda, <2 mm). No Asellidae, large Oligochaeta (>5 mm) or other large invertebrates were found in 1560 samples of 200 l treated water or tap water.Large variations in invertebrate abundance were found within and between distribution systems. Of the variability of mean biomass in mains per system, 55%, 60% and 63% could statistically be explained by differences in the Biofilm Formation Rate, non-particulate organic matter and the permanganate index of the treated water of the treatment works respectively. A similar correlation was found between mean invertebrate biomass and mean sediment volumes in the distribution systems (R² = 52%).     

应用灰色关联分析研究饮用水二氧化氯消毒

以粪肠球菌为例,应用灰色关联分析方法,研究了影响二氧化氯消毒各因素的主次顺序.结果表明,影响二氧化氯消毒效果各因素的主次顺序为:接触时间＞二氧化氯浓度＞ CT值＞细菌浓度＞温度＞ pH,该研究方法可为实际生产提供理论依据.     

援斯里兰卡国际会议中心维修改造项目的电气设计

根据建筑功能的调整、精装修设计以及中国现行相关设计规范的要求,本文对斯里兰卡国际会议中心的变配电、照明／动力配电、火灾报警及安防、电气节能等系统的改造设计进行分析和阐述。     

A comparative study of human exposures to household air pollution from commonly used cookstoves in Sri Lanka

Solid fuel burning cookstoves are a major source of household air pollution (HAP) and a significant environmental health risk in Sri Lanka. We report results of the first field study in Sri Lanka to include direct measurements of both real‐time indoor concentrations and personal exposures of fine particulate matter (PM_2.5) in households using the two most common stove types in Sri Lanka. A purposive sample of 53 households was selected in the rural community of Kopiwatta in central Sri Lanka, roughly balanced for stove type (traditional or improved ‘Anagi’) and ventilation (chimney present or absent). At each household, 48‐h continuous real‐time measurements of indoor kitchen PM_2.5 and personal (primary cook) PM_2.5 concentrations were measured using the RTI MicroPEM^? personal exposure monitor. Questionnaires were used to collect data related to household demographics, characteristics, and self‐reported health symptoms. All primary cooks were female and of an average age of 47 years, with 66% having completed primary education. Median income was slightly over half the national median monthly income. Use of Anagi stoves was positively associated with a higher education level of the primary cook (P = 0.026), although not associated with household income (P = 0.18). The MicroPEM monitors were well‐received by participants, and this study's valid data capture rate exceeded 97%. Participant wearing compliance during waking hours was on average 87.2% on Day 1 and 83.3% on Day 2. Periods of non‐compliance occurred solely during non‐cooking times. The measured median 48‐h average indoor PM_2.5 concentration for households with Anagi stoves was 64 μg/m³ if a chimney was present and 181 μg/m³ if not. For households using traditional stoves, these values were 70 μg/m³ if a chimney was present and 371 μg/m³ if not. Overall, measured indoor PM_2.5 concentrations ranged from a minimum of 33 μg/m³ to a maximum of 940 μg/m³, while personal exposure concentrations ranged from 34 to 522 μg/m³. Linear mixed effects modeling of the dependence of indoor concentrations on stove type and presence or absence of chimney showed a significant chimney effect (65% reduction; P < 0.001) and an almost significant stove effect (24% reduction; P = 0.054). Primary cooks in households without chimneys were exposed to substantially higher levels of HAP than those in households with chimneys, while exposures in households with traditional stoves were moderately higher than those with improved Anagi stoves. As expected, simultaneously measuring both indoor concentrations and personal exposure levels indicate significant exposure misclassification bias will likely result from the use of a stationary monitor as a proxy for personal exposure. While personal exposure monitoring is more complex and expensive than deploying simple stationary devices, the value an active personal PM monitor like the MicroPEM adds to an exposure study should be considered in future study designs.     

Weathering and aggregate suitability—A case history from the “Victoria” project,Sri Lanka

The Victoria Project under construction near Kandy in Sri Lanka, required 1.7 million tonnes of aggregate to be quarried in slightly weathered gneiss. This paper describes an investigation into the strength and durability of the as-produced aggregate which contained a small proportion of weathered fragments. These tests were carried out before full scale production commenced as part of an aggregate acceptance test programme. A range of laboratory tests and the results of petrographic examination were correlated with simple counts of weathered aggregate fragments in stockpiles. It was found that the properties of the aggregate from normal production differed little from those of completely fresh aggregate, and that there was excellent correlation between all testing methods.     

斯里兰卡遗韵——杰弗里·巴瓦与地域建筑的实践

记述了作者参观杰弗里·巴瓦的几个建筑作品,介绍了巴瓦的其它有名建筑,重点分析了巴瓦地域建筑的基本要素。     

Contribution to the study of drinking water, danube water and biocenose contamination with chlorinated insecticides

The present paper deals with the methods of determination of BHC isomers, of DDE, DDT and HCB in waters, drinking and surface waters from the Danube; in two sorts of fish living in the Danube: herbivorous (Cyprinus carpio L., Abramis ballerus L., and Chondrostoma nasus L.) and carnivorous (Esox lucius L., Lepomis gibbosus L., Aspius asptus L. and Perca fluviatilis L.); in sediment and water plants using GLC and TLC.In the period 1971–1974, the mean concentrations of the compounds studied were: in drinking water from 0.00 to 0.12 μg/1; in the waters from the Danube from 0.006 to 0.197 μg/1; in predominantly herbivorous fish from 0.00 to 2.58 mg/kg; in sediment from 0.01 to 2.11 mg/kg; and in water plants from 0.002 to 0.032 mg/kg.The mean levels of the studied compounds found in the fish were 1000–10,000 times higher than those of the water. Comparing the average contents of the BHC isomers as well as of DDT and DDE in fish, considerably higher concentrations of DDT and DDE were found as compared with the BHC levels, mainly in carnivorous fish. Differences in the contents of the insecticides studied are due to their different cumulative properties.