Developing countries drinking water

Very little evidence associating water scarcity and an increase in outbreaks of faecal-oral water-borne infectious diseases exists in developed countries. A recent retrospective study performed in England provides some evidence that both low rainfall and heavy rain precede many drinking water outbreaks [3]. Yet, as stated earlier in this review, the situation is potentially different in developing countries [5-7, 9-12], where water scarcity, including droughts, leads to different circumstances that have a clear incidence in the occurrence of both water-borne and water-washed infectious diseases. 

In developed countries heavy rain events not followed by floods have frequently been associated with outbreaks linked to drinking water supplies derived from... 

Freshwaters are an essential resource which must be available not only in the required quantity but also in a precise quality. Nevertheless, in the last years, this quality has been threatened as a consequence of the increasing industrial activity, population growth and agricultural practices. In fact, only less than 1% of the world s freshwater resources are readily available for human use, and even this resource is unevenly distributed among the countries. A lack of water to meet daily needs is a reality for many people around the world, and water scarcity already affects every continent. In the underdeveloped countries, water scarcity forces people to rely on unsafe sources of drinking water. In the developed countries, this problem is much less critical where contamination of drinking water is the adverse... 

The ecosystem acidification and critical load calculation processes are only partly scientific exercises, being connected closely with economic development of all countries. So, in different projects the hazards of concern include ecosystem damage due to acidification and eutrophication processes (e.g., decreased productivity and biodiversity, soil erosion, drinking water quality, reproduction losses, etc.), firstly, in local scale and, secondly, in regional scale that may lead to transboundary pollution. For more details see Figure 2. 

The mobility of slowly degradable compounds or persistent metabolites present in surface water or bank filtration-enriched ground water is of particular concern in the production of potable water. Certain surfactants, and especially their polar metabolites among others, have the potential to bypass technical purification units used, which may include flocculation, (active charcoal) filtration, ozonation or chlorination. As such, these compounds can reach drinking water destined for human consumption [4-6]. In most cases the origin of surfactant residues and their degradation intermediates in raw water is from wastewater treatment plant (WWTP) effluents (see Chapters 6.1 and 6.2) or direct emissions of wastewater, with the latter still common in many less developed countries. 

Occurrence of surfactants in drinking waters analysed in countries with less developed WWT... 

In developing countries, however, where the low quality of life, poor sanitary conditions, poor standards of food processing, storage and handling, and poor-quality drinking water obtained from contaminated sources, increase morbidity in diseases acquired via the gastrointestinal tracts. 

Dentifrices, more commonly called toothpastes, are a widely used source of fluoride for the majority of the population in the developed world. First introduced in the 1970s, fluoride-containing toothpastes accounted for over 90% of the market in the industrialised nations by the 1990s [151], Because not all countries fluoridate their drinking water, fluoridated toothpastes are, for many people in the world, the most important source of this element for oral health. 

Most epidemiological research has indicated that an intake of at least 10 mg/day for 10 or more years is needed to produce clinical signs of the milderforms of osteosclerosis [8]. Water fluoride concentrations of 4-8 mg/L in temperate climates have not been found to be associated with any signs or symptoms of skeletal fluorosis [6]. This data should be regarded with scepticism in view of reports from a number of developing countries that endemic skeletal fluorosis occurs in individuals whose drinking water contains more than 6 mg/L of fluoride [6]. 

In a sense, drinking water in developed countries can be a closed and totally controllable system. It consists of source, treatment, and... 

International network organized by the IDRC (International Development Research Centre), in collaboration with the National Water Research Institute and the Saint-Lawrence Centre of Environment Canada, to undertake bioanalytical intercalibration exercises with participating laboratories from eight different countries (Argentina, Canada, Chile, Colombia, Costa Rica, India, Mexico and Ukraine). The battery of simple, affordable and robust tests was initially selected to detect the toxic potential of chemical contaminants in drinking water and freshwater sources. Volume 2(7). 

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