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PubMed1990

Soak-away systems and possible groundwater pollution problems in developing countries.

People in the developing countries do not have adequate sanitation and everyone defaecates somewhere. Those who do not have a toilet or latrine have to resort to indiscriminate defaecation either in the sea shore such as in the Lagos lagoon in Nigeria, or vacant plots and open drains as in Iddo area of Lagos and sides of rural footpaths. Water closets (W.C.s) are the most accepted sanitation system, but the cost of operating and maintaining them is high. As a result sewerage is not appropriate for the majority of people in developing countries whose greater population live in rural areas and small towns. The majority of people in urban areas use septic tanks and very often most of these septic tanks are not properly designed or sometimes located too close to sources of water supply, which then become contaminated. It is generally believed that systems like septic tanks, pit latrines and aqua privies are capable of totally eliminating these pathogens. There are many problems associated with the physical, chemical and biological processes that may result in groundwater pollution from septic tanks. Many experiments have shown that faecal organisms do not travel any significant distance radially as a result of concentration gradient. They are, however, carried with groundwater flow. The task is to prevent pathogens from getting into the aquifer. This paper attempts to highlight the ability of some enteric viruses to survive septic tank wastewater treatment.

Developing Countries↗
PubMed2002

Industrial waste disposal in the United States as a historical problem.

This paper explores the manner in which historians have dealt with the issue of industrial pollution in the United States. It reviews the existing literature, suggesting reasons for the subject's neglect in the past. It also raises a series of questions for historians of pollution to focus upon. These questions include the need to understand societal values and knowledge that determined how society reacted to past pollution that threatened its health and the quality of its environment; the need to identify major turning points in the understanding and regulation of these wastes; the need to clarify how different professional groups have related to the issue of industrial pollution; the need to explore the development of indicators for measuring and regulating industrial pollution; and, the importance of clarifying what past responsible parties understood about the risks of industrial pollutants and how they had grained this knowledge. These issues are important not only to clarify the historical record but also to inform public policy.

Environmental Pollution↗
PubMed2002

Identification of bacteria in drinking and purified water during the monitoring of a typical water purification system.

BACKGROUND: A typical purification system that provides purified water which meets ionic and organic chemical standards, must be protected from microbial proliferation to minimize cross-contamination for use in cleaning and preparations in pharmaceutical industries and in health environments. METHODOLOGY: Samples of water were taken directly from the public distribution water tank at twelve different stages of a typical purification system were analyzed for the identification of isolated bacteria. Two miniature kits were used: (i) identification system (api 20 NE, Bio-Mérieux) for non-enteric and non-fermenting gram-negative rods; and (ii) identification system (BBL crystal, Becton and Dickson) for enteric and non-fermenting gram-negative rods. The efficiency of the chemical sanitizers used in the stages of the system, over the isolated and identified bacteria in the sampling water, was evaluated by the minimum inhibitory concentration (MIC) method. RESULTS: The 78 isolated colonies were identified as the following bacteria genera: Pseudomonas, Flavobacterium and Acinetobacter. According to the miniature kits used in the identification, there was a prevalence of isolation of P. aeruginosa 32.05%, P. picketti (Ralstonia picketti) 23.08%, P. vesiculares 12.82%,P. diminuta 11.54%, F. aureum 6.42%, P. fluorescens 5.13%, A. lwoffi 2.56%, P. putida 2.56%, P. alcaligenes 1.28%, P. paucimobilis 1.28%, and F. multivorum 1.28%. CONCLUSIONS: We found that research was required for the identification of gram-negative non-fermenting bacteria, which were isolated from drinking water and water purification systems, since Pseudomonas genera represents opportunistic pathogens which disperse and adhere easily to surfaces, forming a biofilm which interferes with the cleaning and disinfection procedures in hospital and industrial environments.

Acinetobacter↗
PubMed2003

Acute health effects after accidental exposure to styrene from drinking water in Spain.

OBJECTIVES: We studied subjective health symptoms in a population accidentally exposed to high styrene concentrations in drinking tap water. The contamination occurred during the reparation of a water tank. METHODS: Residents of 27 apartments in two buildings using the contaminated water were contacted. A questionnaire on subjective symptoms was administered to 84 out of 93 persons living in the apartments at the time of the accident. Styrene concentration was measured in samples of water collected two days after the accident. The means of exposure associated with appearance of symptoms were examined through case-control analyses. RESULTS: Styrene in water reached concentrations up to 900 microg/L. Symptoms were reported by 46 persons (attack rate 55 %). The most frequent symptoms were irritation of the throat (26%), nose (19%), eyes (18%) and the skin (14%). General gastrointestinal symptoms were observed with 11% reporting abdominal pain and 7% diarrhea. The factors most strongly associated with symptoms were drinking tap water (OR = 7.8, 95% CI 1.3-48), exposure to vapors from the basement (OR = 10.4, 2.3-47) and eating foods prepared with tap water (OR = 8.6, 1.9-40). All residents in the ground floor reported symptoms. CONCLUSIONS: This accidental contamination led to very high styrene concentrations in water and was related to a high prevalence of subjective symptoms of the eyes, respiratory tract and skin. Similar exposures have been described in workers but not in subjects exposed at their residence. Various gastrointestinal symptoms were also observed in this population probably due to a local irritative effect.

Accidents↗
PubMed1989

[A laboratory and field study on the disposal of domestic waste water based on soil permeation].

The present study was conducted to get information necessary for the disposal of domestic waste water by soil permeation. The clarifying ability of soil was examined by conducting laboratory experiments using soil columns and making inquiries about practical disposal facilities based on soil permeation using trenches. In the column experiment, soil columns were prepared by packing polyvinyl chloride pipes with volcanic-ash loam, river sand, or an equivolume mixture of both, and secondary effluent of domestic waste water was poured into each soil column at a daily rate of 100 l/m2. In this experiment, loam and sand loam, both containing fine silt and clay, gave BOD removals of over 95% when the influent BOD load per 1 m3 of soil was less than 10 g/d and gave the coliform group removals of 100% when the influent coliform group load per 1 m3 soil was less than 10(9)/d. Loam and sand loam gave T-P removals of over 90%. The P adsorption capacity of soil was limited to less than 12% of the absorption coefficient of phosphoric acid. All the soils gave low T-N removals, mostly less than 50%. The trench disposal gave high removals of 90-97% for BOD, 90-97% for T-P, and 94-99% for the coliform group but low removals of 11-49% for T-N, showing a trend similar to that of the column disposal. Thus, we can roughly estimate the effectiveness of actual soil permeation disposal from the results of the column experiments. In the waste water permeation region, the extent of waste water permeation exceeded 700 cm horizontally from the trench, but the waste water load within 100 cm laterally from the trench occupied 60.3% of the total. The concentrations of T-C and T-N at almost all observation spots in the permeation region were lower than in the control region, and were not caused to accumulate in soil by waste water loading. In contrast, T-P was accumulated concentratively in the depth range from 50-100 cm right below the trench. The conditions for effective disposal of domestic waste water by soil permeation have been estimated to be: (1) the soil should contain more than 30% silt and clay, (2) the absorption coefficient of phosphoric acid should be more than 1000, (3) the permeation rate should be 1.0-1.8 mm/min, and (4) the soil volume to be permeated should be more than 6.86 m3/person.

Permeability↗