The impact of water pollution from formal and informal urban developments along the Plankenbrug River on water quality and health risk / J.M. Barnes.

[摘要] ENGLISH ABSTRACT:The Plankenbrug River runs past the dense settlement of Kayamandi, on the outskirts ofStellenbosch. This site was chosen to study the impact of water pollution from formal andinformal urban developments on water quality and associated health factors.Aims of the study: (1) To determine some basic epidemiological characteristics of theexposed population of Kayamandi, their sanitation problems and reasons for poor hygiene;(2) To determine the microbiological and chemical pollution load patterns in the PlankenbrugRiver over time; (3) To investigate the spectrum of organisms present in the river (other thanthe indicator E. coli) and their epidemiological implications for health; (4) To establish thepossible presence of organisms resistant to chlorine or to antibiotics in the river belowKayamandi as indicators of environmental hazard.Methods: During the period 5 May 1998 to 10 February 2003 microbiological and chemicalanalyses have been carried out every 6 weeks on water samples obtained at various pointsalong the Plankenbrug River. Two large surveys (n=2196 persons and n=3568 persons) ofthe community of Kayamandi have been undertaken and door-to-door education campaignswere carried out with the aid of trained community health workers.Results: Below Kayamandi the river contains dangerously high levels of faecalcontamination and it constitutes a health hazard to all persons coming into contact with thewater. Up to 13 million Escherichia coli per 100 ml water was recorded (cut-off level asindicator of human safety is 1000 organisms per 100 ml water). Not all the faecalcontamination originated from Kayamandi. Substantial amounts of faecal contaminationsporadically entered the river at different points below Kayamandi. The pollution loadresulting from these intrusions were sometimes larger than that contributed by the whole ofKayamandi.Water samples below Kayamandi were screened to ascertain what other pathogens werepresent. Amongst the organisms were 0 haemolytic Streptococcus Group A and B,Mycobacterium intracellulare, Staphylococcus spp, Klebsiella spp., Pseudomonas spp. andmany others. The list of pathogens found had such serious implications that a confidentialhealth warning was sent out to health care centres and other affected organisations in thearea. |3 haemolytic Streptococcus Group A has never before been reported as isolated inviable form from free-flowing natural waters. Signs of increased resistance to chorine were found in organisms isolated from the river water. There were also organisms showing signsof resistance to commonly used antibiotics. The E. coli organisms that survived variouslevels of chlorine treatment also showed increased resistance to amoxycillin when comparedto untreated E. coli organisms sampled from the Plankenbrug River.During the community phase of the project in Kayamandi a reduction in the pollutionlevels occurred over the summers of 2000 and 2001 (note that improved does not yet meansafe by any means). This can be ascribed to the multi-pronged approach of the project.Attention was given to service and repair of sanitation facilities, a strong accent on door-todoorcommunity education about better sanitation behaviour, creation of a central reportingpoint for blockages and breakages, and training of artisans (plumbers, bricklayers, etc) fromthe community to help with upkeep. The community showed encouraging signs of wantingbetter sanitation education. The improvement in pollution levels is however in danger ofreverting back to the previous dangerous situation if better support and co-operation cannotbe obtained from the relevant authorities. There were 16.9% of households who reportedone or more cases of diarrhoea during the survey period (5 weeks) - a very high prevalenceseeing that the survey was carried out during a wet and cold winter period.Conclusions: Active planning and other steps to cope with the sewage intrusions into theriver should be instituted without delay. The water quality of the Plankenbrug Riverdownstream from Kayamandi is extremely poor. The water constitutes a serious healthhazard and a threat to downstream economic activities. The settlement of Kayamandidemonstrated that education, when coupled with maintenance and repairs of existing toiletfacilities, can bring about a reduction in pollution loads, but that this should be an ongoingprocess and not be reduced to sporadic attempts.

[发布机构] Stellenbosch University