ABSTRACT
This study was aimed at determining the level of compliance to the minimum standard distance between septic tanks and boreholes in Isihor, Benin City, Edo state. Fourty boreholes were selected and their lateral distances from in-situ septic tanks were measured. Physio-chemical and microbiological analyses were carried out on water samples from eight of the fourty boreholes; (four closest to and four farthest from the septic tanks). Twenty parameters namely: pH, electrical conductivity, total suspended solid, temperature, turbidity, color, iron, nitrite, lead, phosphate, calcium, copper, total dissolved solid, Zinc, appearance, taste, odour, total coliform count, total feacal coliform, total solid were assessed in the month of October 2019. The results of the analyses were compared against the standards set by WHO, NSDWQ and NAFDAC, and the results showed that out of the twenty parameters assessed only pH and TSS did not meet the prescribed limits. TSS value range was 2.0-3.67 and pH was 4.3-5.4 indicating acidity. Correlation analysis carried out on the water quality data showed no strong correlation between the distances from septic tanks and the various water quality parameters however there was significant correlation between Nitrite concentration and distance from septic tank with coefficient of correlation R =-0.77. Nitrite can occur from the oxidation of nitrogenous waste products in septic tanks and although there was correlation the nitrite levels were still within acceptable limits. The study revealed that Nigerians are not adhering to the minimum standard distance that should exist between septic tank and boreholes. This is attributed mostly to impracticability due to the non-availability of land space and the paramount failure relevant authorities to provide piped borne water for the citizenry. It is recommended that water from boreholes around the study area be checked regularly for pollution level and effort should be made by the regulatory bodies to look into the feasibility of enforcing adherence to the standard minimum distance between boreholes and septic tanks to protect the health of the populace
CHAPTER ONE
INTRODUCTION
1.0 Background of study
The sources of ground-water pollution are many and varied because in addition to natural processes practically every type of facility or structure installed by man and each and every one of his activities may eventually contribute to ground-water quality problems. The quality of ground water is most commonly affected by waste disposal. Other major sources result from agricultural activities and ground-water development.
In addition to these three major categories, there are other potential sources of pollution, such as mining, spills, leakage from underground pipes and tanks, and road salting. Regardless of the general believe that many people have of pollution being a modern phenomenon, it has occurred through out most of human history, certainly since mankind ceased to be nomadic and started to make settlements Water pollution occurred when humans began to farm the land and settle in villages and towns many thousands of years ago. For instance, the first clearing and ploughing of land for growing cereals will have released significant amounts of nitrogen from the soil into rivers, lakes and groundwater which is another cause of pollution (morris et all 2003)
This Nigerian Code of Practice for well construction specifies the minimum requirements for drillers, supervising personnel and equipment to ensure cost effective water well construction and sustainable groundwater resources development in Nigeria. It also specifies the procedures governing the location, construction, maintenance and abandonment of water well, and the installation of pumps and pumping equipment; to conserve and protect the groundwater resources of the nation against contamination and to ensure safety of all water well construction activities. The code is applicable to all wells to be constructed, rehabilitated or abandoned, regardless of depth, for public and private water consumption in the Federal Republic of Nigeria.(NWRI 2010). The code specifies a minimum distance of separation between borehole and septic as twenty metres(20m), as against 30m as earlier specified by the world health challenges (who).