Evaluation of the Level and Impact of Selected Physiochemical Parameters of Fertilizer Effluent on Obinna River, Adani, Enugu State, Nigeria

Chizoba Chinelo Agu,Matthew Chukwudi Menkiti,Bernard Ibezim Okolo,Patrick Chukwudi Nnaji

doi:10.4236/jwarp.2014.67069

Abstract

This work quantitatively evaluates the level and impact of selected physiochemical properties of fertilizer effluent on the Obinna River of Adani, Enugu State, Nigeria. The fertilizer effluent originated from surrounding farms and flushed into the Obinna River. Water samples were collected from designated points along the river and analysed for physical, chemical and biological properties using standard methods of APHA. Impact of selected key parameters such as nitrate, phosphate, manganese, dissolved oxygen, biochemical oxygen demand and heavy metals (lead, iron and manganese), was studied. The results of the parameters were compared with the World Health Organisation (WHO) permissible standard for freshwater. Measured concentrations of phosphate (5.00, 7.21, 3.92 mg/L), manganese (1.53, 1.18, 1.47 mg/L) and lead (18.9, 21.7, 39.7 ppm) were found to be above the WHO standard while nitrate (0.04, 0.03, 0.03 mg/L) and iron (0.001, 0.001, 0.1 mg/L) were within the standard. The mean concentrations of heavy metals increased in the following order: Fe (0.034) 1 to downstream S3, with manganese and lead being above WHO standard. The results showed a level of significance for the chi-square distribution and correlation coefficients while the analysis of variance (ANOVA) results was conflicting. It could be inferred that the impact of the selected parameters contributed to the pollution of Obinna River.

Highlights

A major cause of freshwater scarcity is the application of agricultural chemicals such as chemical fertilizers and pesticides for assured “better” resource harvesting
It is located at Adani, Uzo-Uwani local government area in Enugu state, Nigeria
According to Taiwo [2] and Ogunfowokan [22], “organic matter decomposition in surface water produces inorganic nutrients such as ammonia, nitrate and phosphate with resulting effects of eutrophication and other serious ecological problems of such water body”; 2) the use of phosphate based fertilizer during the 2006 rice planting season might have resulted in the increased in phosphate load at S2; 3) nitrate may be the limiting factor in the river

Summary

Introduction

A major cause of freshwater scarcity is the application of agricultural chemicals such as chemical fertilizers and pesticides for assured “better” resource harvesting. These chemical fertilizers contain volumes of elements ranging from macro nutrients such as nitrates, phosphates and potassium to secondary plant nutrients and trace elements such as calcium, magnesium, sulphur, boron, manganese, iron, molybdenum and copper. The use of these agricultural chemicals induces pressure on ecosystems and can directly or indirectly, positively or negatively affect the services of a functioning ecosystem. Increasing the nutrient (phosphorous and nitrate) concentrations in freshwater, can lead to eutrophication in lakes and rivers as a result of a decrease in the amount of oxygen available to aquatic life, killing fish and other aquatic organisms [7]

Methods

Results

Conclusion