Abstract: Kutchalli Drilling Waste-Pit Materials (KWPM) in Nigerian National Petroleum Corporation (NNPC) exploration sites in Borno state of Nigeria were investigated for system toxicity to inhabitants (man, animals and plants) via food chain. After the determination of the physiochemical properties of the KWPM, photochemistry and seedling evaluation were assessed for the produce (groundnuts) grown in the different Kutchali experimental waste-pit materials soils. The produce in combination with growers mash were used to compound the feed regime and administered orally to New Zealand inbred rabbits (5/group) at 100 g feed/day for 14 weeks. Electrolytes and some kidney biomarkers of the laboratory rabbit models fed on groundnuts grown in the KWPM were determined to evaluate the functional status of the kidneys The biochemical parameters to assess the kidney (Urea, Creatinine and Electrolytes) of the laboratory rabbits revealed significant difference between those fed on groundnuts harvested from KWPM and those of normal soil, respectively (GP 1: Urea 28± 4.1, Creat. 0.7±0.2, GP 5, Urea 45±3.0, Creat. 2.1±0 and GP 7: Urea 51±3.5, Creat. 1.8±0.3) p<0.05. The parameters used in this study were analysed by atomic emission spectrophotometry and SMAC autoanalyzer supplied Techniconinstruments, NY 10591. All the parameters used to assess the kidney varied from the control at different weeks of the experimental trials (GP 5 and 7 varied significantly from control). The inhabitants of Kutchalli where this research was conducted are predominantly farmers, fishers and cattle rearers, so, if proper waste management is not embarked upon, they including the vegetation may soon face extinction.
INTRODUCTION
Nothing can be said about waste-pit materials without mentioning crude oil or petroleum, because waste-pit materials are generated during crude oil exploration (Doscher, 1981). Nigeria is a major oil producing country with a production total of about 2.29 million barrels per day (mbd) (OPEC Bulletin, 2005) and just recently 1.890 mbd (OPEC Bulletin, 2008).
The economic and industrial growth of Nigeria has enjoyed as a result oil exploration is not without environmental cost. A realization of that chemical contamination of the environment is extensive and significant has emerged, largely as a result of increased awareness and improved methods of evaluation (Anoliefo, 1991).
Ifeadi et al. (1985) reported that Nigeria had more than 1581 wells (45%) drilled on land as against 1196 wells (36%) offshore and 748 wells (21%) in swamps, an indication that more wells are on land than offshore Oil spills on agricultural land generally lead to reduced growth, although low levels of oil contamination may stimulate growth (Lin and Mendelssohn,1998). Reduced growth may also be due to reduction in the level of available plants nutrients or toxic level of certain elements such as maganesse (Udo and Fayemi, 1975; Amadi et al., 1996) and interference with the uptake of soil water by the root system (Anoliefo and Vwioko, 1995; Anoliefo and Isikhuemhen, 2002).
Crude and refined petroleum and oil field chemicals and emissions are highly complex chemical mixtures. Crude petroleum contains hundreds of compounds and the chemical composition varies between geologic formations (Coppock et al., 1995).
Waste-pit materials are generated in petroleum prospecting operations to aid the production and removal of cuttings from earth’s crust (Ekundayo and Benka-Coker, 1994). However, the waste-pit and indeed other wastes generated are not properly disposed off (Ifeadi et al., 1985). A lot of literatures abound on the percentages of pollution due to leakages arising from burst pipelines, high pressure or corrosion, tanks overflow, tank loading failure etc. (Otitoju and Onwurah, 2007; Anoliefo et al., 2006; Osuji and Onojake, 2006). The pollutants generated from these explorative procedures have been implicated in the cause of many biochemical and toxicological effects on plants, aquatic and terrestrial animals (Ovuru et al., 2004).
| Fig. 1: | Map of Nigeria indicating the location of Kutchalli between Maiddugur and Lake Chad. Source: Modified from http://www.cia.gov/cia/publicationsctbook/geos/ni.html, date 29 June 2005 |
The toxic effects on the kidneys were assessed and histological studies carried out. The results revealed that the kidney cells were damaged; crude oil caused a destruction of the renal reserve capacity (Orisakwe et al., 2000; Newman et al., 2000; Orisakwe et al., 2004). Although various research works have been done on crude oil contamination, very little or no work has actually been carried out on the impact waste pit materials emanating from crude oil exploration on plants and animals lives (Osadolor et al., 2009).
The impact of waste-pit materials on the physiology of plants has rarely been studied and therefore, little or no information is available. It is therefore the aim of this research work to provide experimental evidence on the impact of oil prospecting on the physiology of groundnut and invariably on the animals in the environment via food chain.This is of particular interest because currently, Waste-Pit Materials (WPM) generated from exploration activities are not properly disposed of and therefore usually get washed into various water bodies and viable farmlands through leaching sometimes. This study was carried out in Nigeria as indicated in Fig. 1.
MATERIALS AND METHODS
Arachis Hypogea Plant
The plant (Arachis hypogea) used was confirmed by Kutchalli villagers
as those grown within the villages and its environs. The seeds were tested for
viability by floatation technique before planting. The planting was done in
triplicates in June 2005 and germination was monitored until the time of harvest.
The groundnuts seeds harvested from KWPM were used to feed New Zealand inbred
rabbits for 14 weeks.
Animals and Feeding Trials
The rabbit were dewormed by use of invomec super and to improve immunity,
control infection, stress and dehydration, vitalyte were administered, respectively.
A total of 150 male New Zealand rabbits were used for the feeding trials which
were categorized into two stages (I and II). Sixty rabbits were used for stage
I and 90 rabbits were used for stage II experimental feeding trials. All rabbits
were purchased from the rabbitary of Edo State Ministry of Agriculture and Natural
Resources. The vertinary doctor of the ministry certified them healthy. All
rabbits were fed with groundnut harvested from control soil waste-pit materials,
then supplemented with growers mash obtained from Bendel feeds and Flour mills,
Ewu. All rabbits were fed for 14 weeks after acclimatization and weight building
for 4 weeks.
The experimental feeding trials composed of 5 rabbits/group and there were three groups namely: group 1 control, group 5 and 7 wpm. The groundnut seeds harvested from group 5 and group 7 respectively were milled and used to compound the feed at a ratio of 1;20, i.e., by taking 1 g of milled groundnuts from wpm and adding to 19 g of growers mash to form the feed mixture. The mixture was given to the respective groups at a dose of 100 g/day for 14 weeks with water ad libitum. The weights of the rabbits were taken weekly as the experiment lasted.
The rabbits were sacrificed at weeks 4, 8 and 14 and the instology and kidney biochemical parameters (Sodium, Potassium, Chloride, Bicarbonate, Urea and Creatine) were assessed using standard reagents avalar grade (BDH), atomic emission spectrophotometry and kits from Randox Laboratory UK.
Analysis
Sodium and Potassium in plasma were determined by emission spectrophotometry,
while chloride was determined by method of Schales and Schales
(1941) and bicarbonate determined by continuous method by SMAC, Technicon
Instruments NY 10591. The plasma Urea was determined by modified Fearon’s
method while Creatine was analyzed by method of Taussky (1961).
Statistical Analysis
Mean±SED, Student t-test and weight evaluation were carried out.
RESULTS AND DISCUSSION
The results reported in this study are the first part of results of a two stage experimental feeding trials carried out for 14 weeks on laboratory animal model. In this experiment, which lasted for over 14 weeks, the results of the renal functions of laboratory rabbits used are as shown in Table 1.
From Table 1, the levels of Sodium, Potassium, Chloride, Bicarbonate, Urea and Creatine were significantly low in group 1 rabbits (control) when compared with those of groups 5 and 7 in weeks 4, 8 and 14, respectively. Only the Bicarbonate (HCO¯) was not significantly reduced while others - K+, Urea and Creatinine were raised compared with control (p<0.05). This is supported by the stuyd of Newman et al. (2000) and Orisakwe et al. (2004). Recent findings have shown that in cases of toxicity, free radicals are generated enormously within a short period of time which in turn disrupt normal functions physiological (Halliwell and Gutteridge, 1989; Kristensen and Horder, 1996).
Orisakwe et al. (2007), found that paint factory workers had reduced renal and liver functions due to the presence of heavy metals present in their blood, as found in groundnut used in this feeding trials. The impaired renal functions in this work could therefore be attributed to Kutchalli waste-pit materials used as can be seen in the table group 5 and 7, respectively. Some of the heavy metals present in KWPM can be magnify over a period of time (WHO, 1989). This is particularly important because the effects not yet noticeable in the rabbits fed in the laboratory may come later, hence man needs to properly disposed off the waste-pit materials associated with petroleum exploration, because Osadolor et al. (2009), had already established that the groundnuts grown in the kutchalli waste-pit materials which the inhabitants feed on was found to exhibit toxicity.
Conclusively Kutchalli area of Borno state that was used in the study, the inhabitants are predominantly farmers, fishers and cattle rearers due to its green vegetation. Therefore, it strongly suggest proper disposal system probably via bioremediation to avoid harmful carry effects to the generation of the inhabitants yet unborn.
| Table 1: | Assessment of renal function status in feeding Trial stage 1 |