بررسی کیفیت میکروبی و کلرزنی آب آشامیدنی روستاهای شهرستان میانه و نقش شرکت آب و فاضلاب روستایی در بهبود کیفیت آن

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه مهندسی بهداشت محیط، دانشکده بهداشت ، دانشگاه علوم پزشکی تبریز، تبریز، ایران.

2 مرکز تحقیلات سلامت و محیط زیست، دانشکده بهداشت ، دانشگاه علوم پزشکی تبریز

چکیده

هدف از این مطالعه، بررسی کیفیـت میکروبی آب آشامیدنی روسـتاهای شهرستان میانه و نقش شرکت آب و فاضلاب روستایی (آبفار) در بهبود کیفیت میکروبی آب می‌باشد. تعداد50 روسـتا بصورت تصادفی طبقه بندی شده براساس تخصیص متناسب انتخاب و از هر روستای منتخب در هر ماه یک نمونه میکروبی از شبکه توزیع و در کل 150 نمونه میکروبی طی مدت 3 ماه بر اساس 4 معیار کلیفرم کل، کلیفرم گرماپای (اشرشیاکلی)، میزان کلر آزاد باقیمانده و pH مورد سنجش قرار گرفت. بر اساس نتایج حاصله، درصد مطلوبیت کلر آزاد باقیمانده در روستاهای تحت پوشش، غیرتحت پوشش و کل روستاها به ترتیب 23/28، 02/12 و 57/20 درصد می‌باشد. بر اساس رهنمود سازمان جهانی بهداشت و مطلوبیت شاخص اشرشیاکلی، کیفیت میکروبی آب آشامیدنی در روستاهای تحت پوشش در وضعیت عالی (66/94 درصد)، در روستاهای غیر تحت پوشش در وضعیت ضعیف (68 درصد) و در کل روستاهای شهرستان میانه در وضعیت خوب (34/81 درصد) می‌باشد. بطور کلی، وضعیت کیفیت میکروبی آب آشامیدنی در روستاهای تحت پوشش نسبت به روستاهای غیر تحت پوشش بسیار مطلوب‌ می‌باشد. این نتایج بیانگر نقش بسیار مهم و موثر شرکت آب و فاضلاب روستایی در تامین آب سالم و بهداشتی از نقطه نظر کیفیت میکروبی در مناطق روستایی می‌باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Investigation on microbial quality of drinking water in rural areas of Mianeh and the role of Rural Water and Wastewater Company in improving its quality

نویسندگان [English]

  • Gholam Hossein Safari 1
  • Saber Salem 2
  • Mohammad Mosaferi 2
1 Department of Environmental Health Engineering, School of Public Health, Tabriz University of Medical Sciences, Tabriz, Iran.
2 Health and Environment Research Center, School of Public Health, Tabriz University of Medical Sciences, Tabriz, Iran.
چکیده [English]

Abstract
The objective of the study was to monitor the microbial quality of drinking water in rural areas of Mianeh County, determining the access of the rural populations to safe drinking water in terms of microbial quality and the role of Mianeh Rural Water and Wastewater Company (Abfar) in improving quality of drinking water. 50 villages (25 villages under coverage and 25 village's non-coverage by Abfar) were randomly selected based on proportional allocation and one sample from each village per month and a total of 150 samples were analyzed over 3 months based on 4 criteria: total coliform, Fecal coliform (Escherichia coli), free residual chlorine and pH. The findings indicated that the desirability of free residue chlorine in under coverage, non-coverage by Abfar, and total Mianeh’s villages were 28.23, 12.02, and 20.57 %, respectively. The index of lack of Escherichia coli in October and November and December was 92%, 92%, and 100% in the coverage villages, 64%, 84%, and 56% in the non-coverage villages, 78%, 88%, and 78% in all surveyed villages. According to the guidelines of the World Health Organization (WHO and desirability of Escherichia coli index, the microbial quality of drinking water in coverage villages, non-coverage villages by Abfar, and all villages were in the status of excellent (94.66%), poor (68%) and good (81.34%), respectively. In general, the microbial quality of drinking water in the coverage villages was more favorable than the non-coverage villages by Abfar. These results indicate the very important and effective role of the Rural Water and Wastewater Company in providing safe water in rural areas in terms of microbial quality.


Introduction
Water supply management for drinking and public uses in towns and villages is very important. More than 80% of diseases worldwide are water-borne diseases. Therefore, water quality control and prevention of communicable diseases are very important in the management drinking water supply. The world's population will reach 8.5 billion in 2025. Worldwide, only 38% of people have access to safe drinking water. One of the World Water Organization's (WHO) goals is to provide safe drinking water for all until 2025. Most of the deprived people of safe drinking water live in Asia and Africa, mostly in rural areas.
The World Health Organization reported that 1.1 billion people worldwide do not have access to safe sources of safe drinking water and in 2005, about 1.6 million children under the age of 5 (average 4,500 children a day) died from unhealthy and unsanitary drinking water. Also, according to the WHO report, 2.2 million people out of 4 billion people with diarrhea died each year due to lack of access to safe drinking water, of which about 85% live in small communities and villages. Based on scientific findings, insufficient quantity, inadequate quality, and poor sanitation of water resources are the main causes of the occurrence and prevalence of mortality globally, which can be prevented and controlled.
Therefore, control of drinking water in rural communities is very important and needs special attention. To our knowledge, so far no comprehensive study has been conducted in Miyaneh County to evaluate the microbial quality of rural water. Therefore, due to the importance of this issue, this study was conducted to provide a clear picture of the microbial quality of drinking water in rural areas of Miyaneh County determining the access of the rural populations to safe drinking water in terms of microbial quality and the role of Mianeh Rural Water and Wastewater Company (Abfar) in improving quality of drinking water.
Methodology
The target population of this descriptive cross-sectional study was all the villages with the population of Mianeh County. From this target population, 85 villages with health houses have been selected as the study population. From the study population, 50 villages (25 villages covered and 25 villages not covered by Abfar) were randomly selected as statistical populations based on proportional allocation. In this study, a total of 150 drinking water samples were taken over a period of 3 months (one sample from each selected village per month). The microbial quality of drinking water in 50 villages of Mianeh was measured based on 4 criteria, i.e. total coliform (TC), fecal coliform (FC), residual free chlorine, and pH. All steps of sampling, transportation, and experiments were performed according to standard methods for the examination of water and wastewater. The cultivation of the samples to evaluate the number of total coliforms and fecal coliforms was performed using the most probable number (MPN) technique and the 9-tube method in two presumptive and confirmed phases. Residual free chlorine and water pH were measured using a DDP test kit in the sampling site. Finally, the statistical analysis of the results was performed by SPSS and Excel software.
The results showed that the desirability index for lack of total coliform bacteria test in drinking water in the villages covered by Abfar was 84%, 92%, and 96%, in villages non-covered by Abfar was 64%, 84%, and 52% and in all the surveyed villages was 74%, 88% and 74% in months October, November, and December, respectively. Also, the desirability index for lack of heat-resistant E.coli bacteria test in drinking water in the villages covered by Abfar was 92%, 92%, and 100%, in villages non-covered by Abfar was 64%, 84%, and 56% and in all the surveyed villages was 78%, 88% and 78% in months October, November, and December, respectively (table 2). Based on the results, the percentage of residual free chlorine in the covered, non-covered, and total villages was 28.23, 12.02, and 20.57%, respectively (figure 2). The statistical analysis of results showed that there was a significant difference between the covered and non-covered villages by Abfar in terms of the amount of residual free chlorine and microbial contamination of drinking water to total coliform and fecal coliform (P < 0.001). The pH of drinking water in the covered and non-covered villages by Abfar was in the admissible limit of 6.5-8.5 (figure 3). There was not a significant difference between the covered and non-covered villages by Abfar in terms of pH (P= 0.43).
In general, the performance of health workers in the process of drinking water except in daily measurement of residual free chlorine (with 100% coverage) was less than expected. Also, the performance of Abfar in regular and daily chlorination of drinking water in the covered villages was much lower than expected. So that, out of 25 villages covered by Abfar, only drinking water in 9 villages (36%) have been chlorinated, and the average free residual chlorine in 6 to 7 villages (24-28%) was in the admissible limit of 0.5-0.8 mg/L.
Conclusion
According to 2006 guidelines of WHO on evaluation of the microbial quality of drinking water, the microbial quality of drinking water in covered villages was in the excellent range (with the desirability index for lack of E.coli test 94.66%), in non-covered villages was in poor range (with the desirability index for lack of E.coli test 68%) and in all the surveyed villages was in a good range (with the desirability index for lack of E.coli test 81.34%) (Figure 6). In general, despite the poor performance of Abfar in the chlorination of drinking water, the microbial quality of drinking water in covered villages by Abfatr was very favorable compared to non-covered villages. These results indicate the very important and effective role of Abfar in providing safe drinking water in terms of microbial quality in rural areas. Therefore, the necessary measures should be taken to cover the villages by Abfar, as well as regular and continuous chlorination of drinking water in these villages. In addition, the performance of health workers in the process of controlling drinking water should be improved especially in villages with microbial contamination drinking water.
(94.66%), poor (68%) and good (81.34%), respectively. In general, the microbial quality of drinking water in the coverage villages was more favorable than the non-coverage villages by Abfar. These results indicate the very important and effective role of the Rural Water and Wastewater Company in providing safe water in rural areas in terms of microbial quality.

کلیدواژه‌ها [English]

  • "Mianeh"
  • "Drinking water"
  • "Microbial quality"
  • "rural areas"
  • "Rural Water and Wastewater Company"