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European Journal of Applied Sciences – Vol. 13, No. 1

Publication Date: February 25, 2025

DOI:10.14738/aivp.131.17980.

Iworiso, D. P., & Daokoru-Olukole, C. G. (2025). The Impact of Artisanal Refinery on Bacterial Community in the Soil from Selected

Areas in Rivers and Bayelsa States, Nigeria. European Journal of Applied Sciences, Vol - 13(1). 352-371.

Services for Science and Education – United Kingdom

The Impact of Artisanal Refinery on Bacterial Community in the

Soil from Selected Areas in Rivers and Bayelsa States, Nigeria

Iworiso D. P.

Department of Microbiology,

Faculty of Science, Niger Delta University

Daokoru-Olukole, C. G.

Department of Microbiology,

Faculty of Science, Niger Delta University

ABSTRACT

The soil, which is an intricate and dynamic biological system harboring a vast array

of organisms, is directly affected by human activities as well as activities of illegal

crude oil artisanal refineries. These activities have led to the introduction of

hydrocarbons that range in high level toxicity and danger to human health. Hence

creating problems for the ecological system. This study investigates the impact of

artisanal crude oil refinery activities on soil bacterial communities in the Niger

Delta regions, Okarki, Ododa (Rivers State), and Agba (Bayelsa State). Soil samples

were collected and analysed following standard microbiological procedures, while

the molecular method was used to characterize the bacterial isolates. Total

petroleum hydrocarbon (TPH) concentration of soil samples was also analysed. The

results of the bacteria count obtained from the soil samples for Total Heterotrophic

Bacteria Count (THBC) ranged from 3.53 x 103 to 5.01 x 103 CFU/g, while

Hydrocarbon Utilizing Bacteria Count (HUBC) ranged from 2.46 x 103 to 3.20 x 103

CFU/g. Total petroleum hydrocarbon (TPH) concentrations ranged from 107 to

7489 mg/kg around the refinery sites, which indicates soil contamination potential.

The bacteria species identified were Bacillus, Staphylococcus, Pseudomonans,

Brucella, Acinetobacter, Enterobacter, and Enterococcus. The

molecular identification method reveals the following bacteria strains as Bacillus

cereus, Brucella anthropi, and Stenotrophomonas maltophilia. The study

emphasizes the intricate nature of soil microbial communities in artisanal refinery- affected regions and the need for long-term research to understand ecological

impacts. It calls for effective mitigation strategies and stresses the importance of

sustainable environmental management to address challenges posed by illegal

artisanal crude oil refineries, advocating for a comprehensive approach.

Keywords: Artisanal crude oil refinery, Soil microbial communities, Niger Delta,

Hydrocarbon contamination.

INTRODUCTION

In recent years, pollution from human activities has taken a toll on ecosystems, raising

awareness about the need to protect and assess environmental damage (Obenade and

Amengabara, 2014a; Naanen and Tolani, 2014). One significant concern is the pollution caused

by oil refinery leaks, especially in Nigeria, a major oil producer in Africa (Asimiea and Omokhua,

2013; Nwankwoala et al., 2017). Despite its vast oil reserves, Nigeria struggles to meet its

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353

Iworiso, D. P., & Daokoru-Olukole, C. G. (2025). The Impact of Artisanal Refinery on Bacterial Community in the Soil from Selected Areas in Rivers

and Bayelsa States, Nigeria. European Journal of Applied Sciences, Vol - 13(1). 352-371.

URL: http://dx.doi.org/10.14738/aivp.131.17980

domestic demand for refined products and heavily relies on imports. This shortfall has led to

the emergence of small-scale artisanal refineries, which use simple, cost-effective distillation

processes to produce fuel and other products from crude oil (Akeredolu and Sonibare, 2015;

Asuru and Amadi, 2016). However, these artisanal refineries, while economically attractive,

have significant environmental impacts, including the release of crude oil and its derivatives

into the soil ecosystem, affecting plants, animals, and microorganisms (Maclean and Steve,

2019).

The artisanal refinery operations, which often involve theft and illegal processing of stolen oil,

have a direct impact on soil ecosystems, as many of these activities occur within this

environment. This results in the release of crude oil and its derivatives, affecting the well-being

of soil-dependent organisms (Douglas, 2018; Obenade and Amangabara, 2014a). While

previous studies have discussed the refinery process's negative environmental and social

outcomes, as well as its economic benefits (Obenade and Amengabara, 2014a; Naanen and

Tolani, 2014), little attention has been given to how artisanal refineries influence soil

microorganisms. This review aims to fill this knowledge gap by shedding light on the

consequences of artisanal refinery operations on bacterial communities in the soil highlighting

the need for a comprehensive understanding of these ecological impacts.

Statement of Research Problem

A threat to human health and agricultural practices, artisanal refineries (non-standardized

refineries) have disturbed the activities of soil organisms (bacteria).

Aim and Objectives of the Study

Aim of the Study:

This study investigates the effects of artisanal refinery operations on the bacteria ecology in the

soil.

Objectives of the Study:

The principal objectives of this study were to;

1. The main goal of this study was to determine the diversity and abundance of

heterotrophic and hydrocarbon-using bacteria in soil contaminated by artisanal

refineries.

2. Molecular analysis of isolates of bacteria from the research sites.

3. To ascertain the number of hydrocarbons from petroleum entering the soil that artisanal

refineries have poisoned.

METHODOLOGY

Study Area

The study sites for the research project were situated in a region where illegal crude oil refining

operations were actively occurring. These locations are in Ogbia Local Governemt Area (Agba)

and River State in the Ahoada West local government area (Ododa and Okaki. They share a

common area of vegetation. Ododa is situated next to a river in a forested area, rather far from

the two other locations. Despite the fact that one flow pipe that crossed the vegetation supplied

the crude to all three refinery locations.

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European Journal of Applied Sciences (EJAS) Vol. 13, Issue 1, February-2025

Figure 3.1 Map of study areas

Sample Collection

The central emphasis of this investigation revolved around soil samples. These soil samples

were procured with a sterilized spatula from three distinct areas within the refinery site, and

for each of these locations, five separate spots were sampled, employing sterile bags. At each

site, soil samples were collected between 0-10 cm deep, with a 2-meter gap between each

collection point. Additionally, a control soil sample was taken from locations 30 meters away

from the refining site for comparison. Each soil sample was sent to the lab as soon as possible

to enable analysis

Figure 3.2: Artisanal Refinery Site

Sterilization of Materials

The materials were rinsed with distilled water after being thoroughly cleaned with detergent

and clean tap water, and then they were dried in an oven at 2500 degrees Celsius for 45 minutes.

After that, the materials were wrapped in aluminium foil and autoclaved to achieve sterility,

which lasts for 15 minutes at 1210 degrees Celsius.

Serial Dilution

Ten grams (10g) of soil were weighed out of the soil samples using a sterilized pipette, and they

were then put into different conical flasks that had ninety milliliters of sterile normal saline.

One milliliter was taken into a well labelled sterilized test tube containing 9mls of normal saline