Impact of Acrylic-Based Paints effluent on the Physicochemical and Bacteriological quality of soil in Ado-Ekiti, Nigeria

Full text

Orjiakor et al., J. Mater. Environ. Sci., 2020, 11(8), pp. 1230-1240 1230
J. Mater. Environ. Sci., 2020, Volume 11, Issue 8, Page 1230-1240
http://www.jmaterenvironsci.com
Journal of Materials and
Environmental Science
ISSN : 2028-2508
CODEN : JMESCN
Copyright © 2020,
University of Mohammed Premier
Oujda Morocco
Impact of Acrylic-Based Paints effluent on the Physicochemical and
Bacteriological quality of soil in Ado-Ekiti, Nigeria
P. I. Orjiakor 1*, B. Ikhajiagbe 2, F. O. Ekhaise 3
1Department of Microbiology, Faculty of Science, Ekiti State University, Ado-Ekiti, Ekiti State, Nigeria
2Department of Plant Science and Biotechnology, University of Benin, Benin City, Edo State, Nigeria.
3Department of Microbiology, Faculty of Life Sciences, University of Benin, Benin City, Edo State, Nigeria
1. Introduction
Soil is one of the major natural resources as important as water and air. It sustains the existence of plants,
animals, and most importantly humans because; they derive their food from it. This natural resource
determines the distribution of plant species and provides a home for wide varieties of organisms. It also
controls the cycling of water and chemical substances between the atmosphere and the earth, and acts as
both a source and reservoir for atmospheric gases such as oxygen and carbon dioxide) [1]. A good arable
soil, according to environmentalists is characterized by adequate proportion of active organisms
(microorganisms), soil water, soil air and mineral compounds in the right proportion. A destabilization
in the proportion of soil composition, usually leads to unhealthy soil. One of the major factors affecting
soil health and quality is environmental pollution, particularly resulting from increasing
industrialization, rising population growth and over reliance on chemical products [2]. Soil is an efficient
self-purifying medium with a great ability to receive and decompose wastes and pollutants of different
kinds. According to Jolly et al. [3], soil has the capacity to filter out suspended matter, decompose
organic matter by its microbial flora and mineralize essential nutrients. However, if the input of the
Abstract
Paint manufacturing has grown in recent years in response to the increasing demand for
high quality paints. Consequently, large amount of wastes are released into the
environment. This study investigated the impact of acrylic-based paints effluent on the
physicochemical and bacteriological compositions of the receiving soil around paint
production factories within Ado-Ekiti using standard techniques. The paint effluent
increased the receiving soil’s pH, bulk density, particle size, temperature, moisture,
electrical conductivity, but lowered the cation-exchange capacity (CEC), organic matter,
nitrogen, and phosphorus content. These effects were significant (P<0.01) when
compared with the control. Similarly, the total bacteria counts reduced in paint
contaminated, but not significantly different from control (P>0.01). A total of 29 bacteria
was characterized and distributed among 10 genera, namely; Bacillus spp., Pseudomonas
spp., Staphylococcus spp., Arthrobacter spp., Aeromonas spp., Cirobacter spp.,
Alcaligenes spp., Flavobacterium spp., Enterobacter spp. and Micrococcus spp. Bacillus
spp. (24.1%) had the highest frequency and was followed by Pseudomonas spp. (17.2%)
and Flavobacterium spp. (10.3%). The rest isolates had 6.9%. The predominant bacteria,
Bacillus spp., Pseudomonas spp., and Flavobacterium could be more favoured in paint
impacted soils and thus could be considered as paint effluent treatment agents.
Received 18 June 2020,
Revised 06 July 2020,
Accepted 07 July 2020
Keywords
✓ Acrylic oil paint,
✓ Biodegradation,
✓ Bacteria,
✓ Physicochemical
✓ Soil.
paulorjiakor@gmail.com ;
Phone: +234-8033004803

Orjiakor et al., J. Mater. Environ. Sci., 2020, 11(8), pp. 1230-1240 1231
pollutants exceeds the soil purifying limit, the effectiveness of soil microorganism activity is reduced
substantially, and this could lead to marked alteration in the soil physico-chemical and microbiological
properties. As a result, the growth and development of the crop plants become adversely affected [3].
In Nigeria and other developing countries, one of the major pollutants of soil is industrial waste
water [4]. Previous studies have shown that such poorly treated effluent adversely affect the ecosystem.
One of the industrial wastes that is scarcely reported is effluents from paint industry. Globally, paint
manufacturing has grown in recent years in response to the increasing demand for high quality paints by
the general public [4]. The major problem associated with such industry is management of waste water
that accompanies the production process. In Nigeria, Olaoye and Oladeji [4] reported that paint
production utilizes large volume of water without adequate wastewater treatment plant, and
consequently, large quantities of both hazardous and non-hazardous wastes are inherently released to
the soil and water environment, thereby leading to potential health related problems, ecological
imbalance and bioaccumulations in aquatic organisms. water-based or emulsion paints, such as Latex
paint, which is one of most common trending paints, generally, consist of organic and inorganic pigments
and dyestuffs, extenders, cellulosic and non-cellulosic thickeners, latexes, emulsifying agents, anti-
foaming agents, preservatives, solvents and coalescing agents. These organic and inorganic chemical
compounds, when not properly treated before disposal could damage the chemistry and biology
environment [3, 5]. Comparing the importance of the industrial effluents, Chidozie and Nwakanma [5]
reported that pollutants discharged by a paint industry are by far the most significant, especially with
respect to heavy metal compositions. The health and environment effects of heavy metals cannot be over
emphasized. Some of the major health hazards associated with exposure to heavy metals include genetic
mutation, deformation, cancer, kidney damge [3, 6].
Microorganisms are the key components of the soil. They carry out basic biodegradation and
mineral cycling activities in the soil, which keeps the soil fertility and structure intact. Several
microorganisms exist in topsoil, where nutrient sources are abundant than in subsoil [3]. They are
especially abundant in the area immediately next to plant roots (called the rhizosphere), where sloughed-
off cells and chemicals released by roots provide ready food sources. These organisms are the basic
decomposers of organic matter. They also play other important roles in the soil, such as provide nitrogen
through fixation to help growing plants, detoxify harmful chemicals (toxins), suppress disease
organisms, and produce products that might stimulate plant growth [7]. Soil microbes also have other
benefits to humans, and have been found to be vital reservoir for antibiotic-producing organisms used
to fight diseases [8]. Among the group of soil microorganisms, bacteria have been reported to be the
most abundant with a population of about 3.0 x 106 – 5.0 x 108 per gram of soil [9, 10]. However, the
population and optimal activities of soil microbes depends largely on the prevailing environmental
factors, such as nutrients availability, moisture availability, degree of aeration, pH, and temperature.
Bacteria make up the most abundant soil flora, and are also the key players in various biochemical cycles
and are responsible for the recycling of organic compounds [9, 10]. It is therefore, pertinent to monitor
the population of these microorganisms so as to keep the health of the soil. Information on the prevailing
physicochemical quality of the soil will go a long way in understanding the status of soil pollution. This
study was therefore done to determine the impact of paint effluent on the physicochemical and
bacteriological qualities of the receiving soil environment.
2. Materials and method
2.1. Sampling location
The sampling locations are paint effluents contaminated sites around the production unit of two famous
factories (A and B) both located in Ado Ekiti, the State capital of Ekiti, South Western part of Nigeria.

Orjiakor et al., J. Mater. Environ. Sci., 2020, 11(8), pp. 1230-1240 1232
Geographically, Ado-Ekiti is situated between latitude 7.667° N and longitude 5.250° E and bounded in
the north by Kwara State and Kogi State while Osun State occupies the west and Ondo State lies in the
south and extends to the eastern part (Fig. 1). The population of the indigenes is about 2,384,212 and the
inhabitants of the state are mainly farmers, artisans, traders, civil and public servants [11].
Fig. 1: The map of Nigeria with location of Ekiti State in red [11].
2.2. Sample collection
Soil samples from visibly discoloured acrylic paint polluted were collected from acrylic-paint impacted
soil particles found inside the active paint production warehouse facility (indoor) and acrylic-paint
impacted soils from outside the active paint production facility (outdoor) according to the procedure of
Wieser et al. [12]. Indoor samples were collected by scraping-off and gently transferring into clean
plastic containers, while the outdoor samples were collected by scrapping-off the top soil aerobically
exposed up to a depth of 10 mm and gently placing in clean plastic containers before transportation to
the laboratory for further work.
2.3. Physicochemical analyses of soil samples
Analyses of the physicochemical properties of the soil samples were carried out according to
modifications of the methods adopted by Mahawar and Akhtar [13].
2.3.1. Determination of pH values
The pH of the soil samples was measured on site using a portable pH meter (Model: HI 8314 HANNA
instruments). The glass electrode was thoroughly wetted with distilled water. The pH meter was then
switched on and was standardized. The pH meter was standardized with buffer solutions (pH 4 and 9).
About 2g of soil sample each was weighed and 50 mL of distilled water was added and stirred, the pH
meter was then inserted in each sample and readings were taken.
2.3.2. Determination of Electrical Conductivity
Determination of electrical conductivity was carried out using a conductivity meter. The electrode of the
meter was wetted thoroughly and then plugged into the conductivity meter before it was inserted into a
250 mL beaker containing distilled water. The conductivity meter was then switched on, and zero error
was corrected. The distilled water was replaced with raw water samples and the reading was recorded.
2g of sample each was weighed and 50 mL of distilled water was added and stirred, the conductivity
meter was inserted into each sample and readings were recorded.

Orjiakor et al., J. Mater. Environ. Sci., 2020, 11(8), pp. 1230-1240 1233
2.3.3. Determination of moisture content
Five grams of each of the soil samples were weighed into pre-weighed crucible. The crucible and the
content were weighed again. This was then put in the oven at 110oC for 3hrs to a constant weight after
which it was removed, cooled and weighed. The following expression was used to calculate the moisture
content.
 
 
2.3.4. Determination of Bulk density
The oven dry weight of the sample was divided by the volume of the undisturbed sample at filled
moisture condition and the oven dry weight of the entire soil calculated.
  

2.3.5. Determination of Particle
Density Specific density bottle was used in this method; a clean dry 50mL specific gravity bottle was
weighed in air (Wa), some quantities of the air dried soil was added to the flask. The body of the specific
gravity bottle was cleaned to remove the dust that spilled during the transfer of the soil to the flask and
the content with the flask was weighed (Ws). Previously boiled and cooled distilled water was added to
the flask with content little at a time and stirring was done gently to remove air between the particles
(Wsw). After which the temperature of the contents was determined using the thermometer. The soil
was further removed from the flask and the flask was filled with boiled cooled distilled water at the same
temperature as former while the outside of the flask was dried with filter paper. The weight was known
and recorded. Density of the water was determined.
  

 
  
2.3.6. Determination of Total Porosity
This is determined from bulk density (Db) and particle density (DP). It is an index of the relative volume
of pores. It is influenced by the structure and texture of soil. It is calculated using the following formula;
   

2.3.7. Determination of Organic Matter content
The walkley-black wet oxidation method, procedures measure active or decomposable organic matter in
the soil. Oxidizable matter in a soil sample is oxidized by Cr2O72- and the reaction is facilitated by the
heat generated when 2 volumes of concentrated H2SO4 are mixed with 1 volume of 0.167M K2Cr2O7
solution. The excess Cr2O72- is determined by titration with standard FeSO4 solution and the quantity of
substance oxidized is calculated from the amount of Cr2O72- reduced using orthophenanthroline-ferrous
complex indicator (ferroin) which gives a colour change from orange to dark green to light green and
finally to maroon red. Precisely 1g of already grinded soil sample was weighed and transferred to 250mL
conical flask, 2.457g of potassium dichromate was weighed and made up to 50 mL with distilled water.
19.61g of Iron (II) ammonium sulphate was weighed and made up to 100 mL with distilled water. 0.1487

Orjiakor et al., J. Mater. Environ. Sci., 2020, 11(8), pp. 1230-1240 1234
of orthophenanthroline ferrous complex indicator was also weighed and 0.0695g of Iron (II) sulphate
was weighed. The indicator and Iron (II) sulphate were added together and made up to 100 mL with
distilled water. 10mL of potassium dichromate was added to the soil in the 250 mL conical flask, 20 mL
of concentrated sulphuric acid was added to the content rapidly and the flask was swirled immediately
and gently until the soil and reagent are mixed properly. The swirling continued more vigorously for one
minute then the flask was rotated and allowed to stand on a sheet for about 30 mins. After standing for
30 mins, 100mL of distilled water was added as well as the addition of 3-4 drops of ferroin indicator,
thereafter, titration was done with 0.5M iron (II) ammonium sulphate which takes greenish cast and then
changes to dark green. At this point, colour changes sharply from green to brownish red. Blank titration
was made in the same manner. The titre values were recorded.
% Organic carbon = (B-T) × M × 0.003 × 1.33 × 100/weight of sample
B = Blank titre value, T = Sample titre value and M = Molarity of (NH4)2 Fe(SO4)2.6H2O
% Organic matter = % organic carbon × 1.724
2.4. Heavy metal analyses of soil samples
The presence of metals within the soil samples in their elemental form was detected using Atomic
Absorption Spectrophotometer (AAS Buck Scientific Model 210 VGP) and Flame Photometer FP 902
2.5. Enumeration and isolation of bacteria from sample
Soil samples collected were processed based on the technique adopted by Phulpoto et al. [14] with slight
modifications. Precisely 1g of each sample collected from each site was dissolved in 50 mL of sterile
distilled water and placed in flasks (250 mL capacity). The sample containing flasks were then incubated
at 37 oC for 2 h. After incubation, approximately 5 mL of each sample was used as an inoculum for
enrichment procedure. The isolation medium was an enrichment technique, mineral salt media (MSM),
containing 0.5 g/L MgSO4, 0.2 g/L CaCl2, 13.6 g/L KH2PO4, 5 g/L (NH4)2.SO4, 0.05 g/L FeSO4.7H2O,
15 g/L Na2HPO4 [14]. The soil suspension (5 mL) was aseptically added into flasks containing 100 mL
of prepared MSM broth enriched with acrylic paint (Finecoat® Acrylic Emulsion Paints) as carbon
source in concentrations of 1% v/v. The experimental set-ups were incubated at 37 oC for 10 days under
agitation (150 rpm). The total microbial growth absorbance was measured in 3 days intervals at 600 nm.
Experimental set-ups with the highest absorbance values connoting higher microbial presence was used
for microbial isolation. Primary isolation of bacteria was carried out using nutrient agar by plating out
0.1 mL of samples on appropriately prepared culture using pour plate technique. Pure cultures that were
determined were maintained on 2% (w/v) Nutrient agar, and stored at 4°C in a refrigerator. Pure cultures
were sub-cultured onto fresh sterile medium slants every 2-3 weeks to ensure viability. Phenotypic
identification of bacterial isolates was carried out with focus on gram staining reactions, spore test,
motility, hydrogen sulphide production, growth on differential media, indole production, catalase
production, citrate utilization, oxidase production, Methyl Red and Voges Proskauer reactions,
coagulase production, urease production, nitrate reduction, and sugar fermentation tests. The Bergey’s
manual of Determinative Bacteriology was used as a guide and reference.
2.6. Statistical analyses
Statistical methods documented by Paulson [15] were adopted throughout the research work.
Experiments were carried out in triplicates and values were expressed as mean ± standard deviation.
Results were presented in tabular and graphical formats. Where necessary, data obtained were
statistically analysed using different Analysis of variance (ANOVA) adopting probability levels below
5%. Difference in means were analysed using the Duncan’s Multiple Range Test.

Orjiakor et al., J. Mater. Environ. Sci., 2020, 11(8), pp. 1230-1240 1235
3. Results
The effects of acrylic-based paints on some other physicochemical properties of impacted soils in
comparison with the controls were recorded in Table 1. Values of Electrical conductivity (EC) tested
showed that electrical conductivity of the acrylic paints were higher than the electrical conductivities of
the test soil samples. EC values of the samples from the Factory B were significantly higher than their
controls. The same observation was made for EC samples from Factory A, which showed EC values
significantly higher than that of their control. Nitrogen and phosphorus contents of the emulsion paints
were lower compared with the test soil samples. With respect to nitrogen content, the values obtained
for both Factories A and B were lower than that of their respective controls. Similar trend was observed
for the test of phosphorus content, as the Phosphorus values obtained for the test soil samples were
higher than the values obtained for the acrylic paints. The Phosphorus contents of the test soil samples
were also lower than their respective controls. The cation-exchange capacity (CEC) tested for the soil
samples showed a range of between 10.31% and 16.59%. Values of CEC for both Factories A and B
were more than values of their controls. However, for total organic carbon (TOC), they were lower than
in the controls samples.
Table 1: Comparative assessment of effects of acrylic-based paints on selected soil physicochemical
properties of impacted soils in comparison with the controls
Test Samples EC (µS/cm) P (%) N (%) CEC (%) Organic matter (%)
Emulsion Paint (White) 170.07b±0.07 0.18 h±0.00 0.10g±0.00 N/A N/A
Emulsion Paint (Coloured) 214.1a±0.46 0.19 g±0.00 0.11f ±0.00 N/A N/A
Inside the Factory 106.27e±0.12 0.38f±0.00 0.12 f±0.00 10.31f±0.00 1.94f±0.01
Outside the Factory A 82.2f±0.10 0.41 e±0.00 0.17 e±0.00 14.51d ±0.01 2.97e±0.00
Control (Factory A) 71.2 g±0.17 0.61 b±0.00 0.20 d±0.00 15.33c±0.00 4.28c±0.02
Inside the Factory B 150.33c±0.03 0.49 d±0.00 0.22 c±0.00 13.13 e±0.00 3.48d±0.01
Outside the Factory B 115.73 d±0.15 0.58 c±0.00 0.25 b±0.00 16.59b±0.02 5.48b±0.01
Control (Factory A) 106.1e±0.15 0.74 a±0.00 0.28 a±0.00 20.11a±0.00 5.69a±0.00
P-value **P<0.01 **P<0.01 **P<0.01 **P<0.01 **P<0.01
Note: different letter across the row showed that there is a significant difference across the sampling sites when compared to
the Controls. P<0.01, EC – Electrical conductivity; P – Phosphorus; N – Nitrogen; CEC – Cation-Exchange capacity; TOC
– Total Organic Carbon; NA – Not applicable
Table 2 shows the assessment of physical properties of acrylic paints and soils of acrylic paint-impacted
soils tested. The pH of the actual paint samples were slightly alkaline when compared with the pH ranges
for the test samples and their controls. Moisture contents were also obviously less in the test soil samples
compared with the actual paint samples. Moisture contents of the samples from Factory B were slightly
more than the control, while moisture contents from the Factory A were less than the control. Particle
size analyses of the test samples showed a particle size range of between 0.13 mm and 0.5 mm for all
the samples tested. The test samples had a soil porosity range of 22.33 % to 30.67%, and a bulk density
range of between 1.37 g/cm3 and 2.37 g/cm3. All values from samples tested were statistically significant
when compared with their respective controls (Table 2). The soil samples from the two sites evaluated
harboured varying numbers of acrylic-paint utilizing bacterial cells as determined by the total bacterial
counts from the different samples. Table 3 shows the numbers of the culturable bacterial present in the
two sampling sites. For the individual sites, values of bacterial counts from soils collected from outside
the active production facility but within the production compound (precisely at outdoor paint impacted
sites) showed a higher count of bacteria compared with the values of bacterial counts obtained from with
the active production sites. Overall, Factory A sites harboured more bacterial counts (up to 6.2 x 108
CFU/g) than the Factory B sites (7.6 x 107 CFU/g). Bacterial counts for the paint samples from both
factories were zero (Table 3).

Orjiakor et al., J. Mater. Environ. Sci., 2020, 11(8), pp. 1230-1240 1236
Table 2: Physical properties of acrylic paints and soils of acrylic paint-impacted sites
Test Samples pH Moisture (%) Particle Size Soil porosity Bulk Density
(%) (mm) (%) (%) (g/cm3)
Emulsion Paint (White) 8.72a±0.01 89.03 b±0.23 N/A N/A N/A
Emulsion Paint (Coloured) 8.36b±0.02 91.53a±0.03 N/A N/A N/A
Inside the Factory A 7.80e±0.06 16.83e±0.07 0.25b±0.00 29.33 b±0.67 2.37 a±0.09
Outside the Factory A 7.19 g±0.00 17.2d±0.06 0.2c±0.00 22.33 e±0.33 2.97e±0.00
Control (Factory A) 6.6h±0.06 15.9 f±0.10 0.2c±0.00 26.33c±0.33 1.73b±0.09
Inside the Factory B 8.08c±0.02 15.53 g±0.09 0.5a±0.00 30.67a±0.67 1.87b±0.07
Outside the Factory B 7.64 d±0.01 14.8h±0.06 0.2c±0.00 25.0d±0.00 1.37c±0.09
Control (Factory A) 7.39f ±0.01 18.17 c±0.09 0.13d±0.00 25.0 d±0.00 1.53c±0.03
P-value **P<0.01 **P<0.01 **P<0.01 **P<0.01 **P<0.01
Note: different letter across the row showed that there is a significant difference across the sampling sites when compared
to the Controls. P<0.01, NA- Not applicable
Table 3: Total heterotrophic counts of acrylic-paint utilising bacteria from different test sites
Test Sites Test Sample Total Heterotrophic Bacterial counts
Indoor Soil 1.4 x 106 CFU/g
Factory A Outdoor Soil 6.2 x 108 CFU/g
Paint Sample Nil
Indoor Soil 2.3 x 105 CFU/g
Factory B Outdoor Soil 7.6 x 107 CFU/g
Paint Sample Nil
A total of 29 bacterial colonies from the acrylic-enriched medium was recovered and characterized
(Table 4). The bacterial isolates were coded based on their source of isolation. Exactly 16 (55.2%) of
the isolates were from samples from Factory A, while, 13 (44.8%) of the isolates were from samples
from Factory B environment. The 29 bacterial characterized were distributed among ten (10) genera,
namely; Bacillus spp., Pseudomonas spp., Staphylococcus spp., Arthrobacter spp., Aeromonas spp.,
Cirobacter spp., Alcaligenes spp., Flavobacterium spp., Enterobacter spp. Micrococcus spp. Bacillus
spp. (24.1%) had the highest frequency and was followed by Pseudomonas spp. (17.2%) and
Flavobacterium spp. (10.3%). All the remaining isolates had the least frequency (6.9%). (Table 4).
Table 4: Frequency of occurrence of the bacteria isolates from both paint factories
Bacterial isolates Factory A sample Factory B sample Total (%)
Bacillus spp. 4 3 7 (24.1)
Pseudomonas spp. 2 3 5 (17.2)
Staphylococcus spp. 2 0 2 (6.9)
Arthrobacter spp. 2 0 2 (6.9)
Aeromonas spp. 1 1 2 (6.9)
Cirobacter spp. 2 0 2 (6.9)
Alcaligenes spp. 1 1 2 (6.9)
Flavobacterium spp. 2 1 3 (10.3)
Enterobacter spp. 0 2 2 (6.9)
Micrococcus spp. 0 2 2 (6.9)
Total (%) 16 (55.2) 13 (44.8) 29 (100)
4. Discussion
Acrylates and acrylic-containing chemicals are important industrial commodities as they are used in the
production of adhesives, printing inks/printing paste, thickening agents in automotive sprays, as paper
colourants, in lubrication of crude oil drilling bits to reduce friction during drilling, as emulsions in
paints for buildings and other forms of application [16]. During industrial production and application,

Orjiakor et al., J. Mater. Environ. Sci., 2020, 11(8), pp. 1230-1240 1237
there is a large tendency that acrylates and acrylic-containing compounds can be released into the
environment as wastes thereby contaminating surface water bodies and soil systems. According to a
report by the US EPA in 1994 on toxic chemical release inventory, the integrated risk of acrylic-
containing compounds led to the determination of the impact of acrylic pollution on surface water
quality, underground sediments, and land sites. Weideborg et al. [17] and Chang et al. [18] also further
stated that acrylate concentrations of 0.3 ppb to 5 ppm have been detected in terrestrial and aquatic
ecosystems as a result of the applications of these chemicals in sewer grouting with acrylates found to
be stable in the water samples for more than 2 months. This has necessitated the need to investigate the
physicochemical and bacteriological quality of paint waste impacted soil systems.
The proliferation of microorganisms within very many environmental sites is usually dependent
on a variety of physicochemical factors, as such factors govern microbial physiological functionalities
[33]. Soil-borne bacteria most importantly are affected by factors like electrical conductivity, inorganic
matter, moisture content, and pH [19]. The sites studied in this work presented unique properties with
respect to their physicochemical characterisation. The acrylic paint manufacturing companies selected
had significant spillage of acrylic paint on the immediate soil environment. These impacted on the soil
properties and were directly indicative of microbial proliferation tendencies within the soils. With the
exposure of soils at these sites to acrylic paints, it was observed that electrical conductivities were higher
in the test samples than in the control. This could be due to the unique characteristics of acrylic paints
as possessing functional electrically charged ionic groups due to their chemical structure [20]. The
electrical conductivities have been determined as a factor that could affect bacteria growth and
proliferation in defined ecosystems and has formed a component part of analytical chemistry of
environmental samples over years of research [21]. It is important to note that cellular functionalities
with respect to ionic flow and membrane-bound respiration, have been proven to be a major point of
interaction by cells with their environments [22]. Nitrogen and Phosphorus contents on the other hand
were found to be higher in the acrylic paints than in the acrylic paint laden soil samples tested. This
could largely be because of the uptake of nitrogen and phosphorus from the acrylic paints by the
microbial flora. Possible microbial utilization system would have been established for evolutionary
adaptations of the microbial species for the acrylic paints spilled onto the test sites over time [23].
Different kinds of adaptation mechanisms exist, however adaptation due to nutritional circumventions
depending on the kind of nutrients existing within the chemicals impacting the soil samples is one of the
main routes microorganisms especially bacteria adapt to their environment [24].
The reduction in inorganic nutrients like nitrogen and phosphorus within acrylic-paint impacted
soil samples tested in comparison with the actual acrylic paints is also a good indicator of the presence
and growth of acrylic paint utilizing bacteria within the test sites [23]. There was a functional increase
in the cation-exchange capacity of the tested acrylic paint-impacted soil samples in comparison with the
acrylic paint control. This could be attributed to the actual release of cations from metabolic activities
of soil-borne autochthonous bacteria [19]. Such activities are based on the mineral transformations
occurring within the test samples as bacteria utilize the components of acrylic paints [25]. This factor
also goes further to interplay on the pH values of the acrylic paint-exposed soils compared to the pH of
the actual acrylic paints. It was observed that the pH range of the acrylic paint was relatively higher
when compared with the pH of the paint-exposed soils. This could similarly be tied to the mineralization
and free cation exchange potentials occurring within the samples of acrylic paints metabolized by the
soil autochthonous bacteria [26]. The pH is also indicative of the bacterial growth preference for
proliferation. It is evident that the bacteria growth within lower pH values could be directly caused by
the secretion of volatile fatty acids resultant from the bacterial tri-carboxylic acid cycle or Kreb’s cycle

Orjiakor et al., J. Mater. Environ. Sci., 2020, 11(8), pp. 1230-1240 1238
and free cationic conditions that similarly maintain the soil environment in the optimum proliferation
potentials for the inherent bacteria [27]. Due to the difference in the physical properties of test soil
samples (solids) and the acrylic paints (liquids) their moisture content properties were evidently
different. However, comparing the moisture contents of the acrylic paint-impacted samples obtained
from different paint company sites, there were observed differences. This could be attributed to the soil
structures of the different sites. The variations in soil properties were also evident in differences between
values for the particles sizes, bulk densities, soil porosity, and organic matter content recorded. Earlier
explanations have been put forward that soil samples from different sites possessed different physical
properties and this greatly affected the attachment potentials of individual cells of autochthonous
bacteria in the form of biofilms and cell clumps within the soil samples [28]. The rate of cell clumping
and agglutination within the soil samples can be influenced my moisture, soil porosity and particle sizes
of the soil samples, and this in turn plays out on the organic matter within the soil which is a direct
correlation with the microbial loads within such sites.
With respect to the bacterial counts within the test samples, due to the nature of the sites and their
physicochemical properties, there were bacterial counts ranging between 105 and 108. Following quality
control procedures that would have been adopted in the paint production, the acrylic paint samples had
no bacterial load, as counts were zero. This is in line with proper good manufacturing processes and as
a result has reduced the burden of paint spoilage in the finished product. Paint industries are expected to
observe acceptable quality control/assurance practices in their processing lines to aid in the production
of high quality products and the longevity of the applied products on the materials they are painted upon
[29]. On the part of the acrylic paint impacted soil samples; overall, outdoor soil sampling sites yielded
marginally higher bacterial counts than indoor soil sampling sites. As earlier described, the variations in
the bacterial counts between the outdoor and indoor environments showed that there were impacts of
environmental factors that allowed much more bacterial proliferation in the outdoor sites compare to the
indoor site [28]. The reduction in bacterial counts within the indoor environments could also be as a
result of consistent cleaning of the indoor environment which might have reduced bacterial presence in
comparison with the outdoor environment. Soil particles harbour clumps of bacteria in large
communities within certain ecological niches, with average bacterial counts ranging from 102 to 108
depending on the soil type and the environmental factors [30]. It is also important to note that unique
bacterial interactions like mutualism, commensalism, amensalism, and parasitism are also inherent
within such sites, therefore a key influential factor for bacterial growth and proliferation within such
sites is in the particular nutrients present within such sites [31]. This is so because nutrient type
influences selection of specific bacterial species that can metabolise such nutrients in a competitive
selection above other bacteria that lack the physiological machinery for breaking down the nutrient
substrates found within the sites. In this work acrylic paint was used to enrich the soil before the actual
isolation of the bacteria, thereby ensuring that acrylic paint utilizing bacteria were mostly isolated.
Enrichment technique had been exploited in isolation of unique bacteria in a selective format thereby
giving the target physiological group of bacteria some selective advantage over others within the
environment [32]. Applying that in this research, acrylic paint was used as a sole carbon source in
preparing a medium for growth and then the soil samples were mixed with the acrylic-paint medium and
pre-incubated, leading to the extant out-growth of the acrylic paint utilizing bacteria. The 29 bacterial
characterized were distributed among ten (10) genera, namely; Bacillus spp., Pseudomonas spp.,
Staphylococcus spp., Arthrobacter spp., Aeromonas spp., Cirobacter spp., Alcaligenes spp.,
Flavobacterium spp., Enterobacter spp. And Micrococcus spp. Some of these bacteria had been reported
to possess versatile enzymatic machinery needed for organic and inorganic matter bioremediation [8,

Orjiakor et al., J. Mater. Environ. Sci., 2020, 11(8), pp. 1230-1240 1239
14, 19, 29, 31]. Hence, they could be exploited as axenic or consortia culture in bioremediation processes
of polluted sites [33].
Conclusion
This study has shown that acrylic paint impacted soil possessed unique physicochemical properties that
favoured the proliferation of certain bacterial species within them. The knowledge of the soil
bacteriology and chemistry in this study could be applied in soil treatment and reclamation. Also, the
bacteria isolates could be employed as bio-treatment agents for paint effluents prior to disposal.
However, furthers studies on the biodegradation kinetics of each or a mixture of the efficient isolates is
vital to select the most efficient species for biotechnological purposes.
References
1. OO. Olayinka, HO. Adedeji, AA. Akinyemi, OJ. Oresanya, Assessment of the pollution status of
Eleyele Lake, Ibadan, Oyo State, Nigeria. J. Health Pollut. 7(15) (2017) 51–62.
2. E. Koshlaf, AS. Ball, Soil bioremediation approaches for petroleum hydrocarbon polluted
environments. AIMS Microbiol. 3(1) (2017) 25–49.
3. YN. Jolly, A. Islam, SB. Quraishi, Effects of paint industry effluent on soil productivity. J. Bangl.
Acad. Sci. 32 (1) (2008) 41-53.
4. RA. Olaoye, OS. Oladeji, Preliminary assessment of effects of paint industry effluents on local
groundwater regime in Ibadan, Nigeria. Int. J. Eng. Res. 4 (2015) 518-522.
5. K. Chidozie, C. Nwakanma, Assessment of Saclux paint industrial effluents on Nkoho River in Abia
State, Nigeria. J. Ecosyst. Ecogr. 7 (24) (2017) 1-8.
6. EO. Oladele, PG. Odeigah, T. Yahaya, Heamatotoxicity of paint effluent on Swiss albino mice. The
Pacific J. Sci. Technol. 14 (2013) 397-404.
7. R. Jacoby, M. Peukert, A. Succurro, A. Koprivova, S. Kopriva, The role of soil microorganisms in
plant mineral nutrition-Current knowledge and future directions. Front. Plant Sci. 8 (2017) 1617.
8. Y. Woappi, P. Gabani, OV. Singh, Emergence of antibiotic-producing microorganisms in residential
versus recreational microenvironments. Braz. Microbiol. Res. J. 3(3) (2013) 280–294.
9. IN. Ogunmwonyi, OE. Igbinosa, OA. Aiyegoro, EE. Odjadjare, Microbial analysis of different top
soil samples of selected site in Obafemi Awolowo University, Nigeria. Sci. Res. Essay. 3(3) (2008)
120-124.
10. RM. Atals, R. Bartha, Microbial Ecology: Fundamentals and Applications. 4th Edition.Benjamin
Cummings Publishing Company Inc. Addison Wesley Longman Inc. (1998) 300– 350.
11. OR. Salau, T. Ewumi, BE. Owolabi, GO. Ajayi, OE. Ajayi, Regional distribution of malaria in
Ekiti State, Nigeria. World Sci. News. 55 (2016) 89-100.
12. M. Wieser, P. Schumann, K. Martin, P. Altenburger, J. Burghardt, W. Lubitz, HJ. Busse, Agrococcus
citreus sp. nov., isolated from a medieval wall painting of the chapel of Castle Herberstein (Austria).
Int. J. Syst. Bacteriol. 49 (1999) 1165–1170.
13. P. Mahawar, A. Akhtar, A. Physico-chemical characterization of soil and effluent of dye industries
in Kaithun region of Kota, Rajasthan. Int. J. Pure Appl. Biosci. 3 (2) (2015) 419-422.
14. AH. Phulpoto, MA. Qazi, S. Mangi, S. Ahmed, NA. Kanhar, Biodegradation of oil-based paint by
Bacillus species monocultures isolated from the paint warehouses. Int. J. Environ. Sc. Technol. 13
(2016) 125-134.
15. DS. Paulson, Biostatistics and Microbiology: A Survival Manual. Springer Science Business Media,
LLC (2008).

Orjiakor et al., J. Mater. Environ. Sci., 2020, 11(8), pp. 1230-1240 1240
16. J. Charoenpanich, Removal of acrylamide by microorganisms. In: Applied Bioremediation-Active
and passive approaches. InTech (2013) 101-124.
17. M. Weideborg, T. Källqvist, KE. Ødegård, JSverdrup, L. E, and Vik, E. A. (2001). Environmental
risk assessment of acrylamide and methyloacrylamide from a grouting agent used in the tunnel
construction of Romeriksporten, Norway. Water Research. 35-2645.
18. L. Chang, MD. Bruch, NJ. Griskowitz, SK. Dentel, NMR spectroscopy for determination of cationic
polymer concentrations. Water Res. 36 (2002) 25-55.
19. E. Abatenh, B. Gizaw, Z. Tsegaye, M. Wassie, The role of microorganisms in bioremediation – a
review. Open J. Environ. Biol. 2(1) (2017) 38-46.
20. Y. Zhang, Y. Dong, Y. Ren, Y. Zhang, Rapid determination of acrylamide contaminant in
conventional fried foods by gas chromatography with electron capture detector. J. Chrom. 12 (2016)
1116-209.
21. Q. Wang, S. Zhang, Y. Li, W. Klassen, Potential approaches to improving biodegradation of
hydrocarbons for bioremediation of crude oil pollution. Environ. Prot. J. 2 (2011) 47-55
22. S. Sarkar, AT. Martínez, MJ. Martínez. Biochemical and molecular characterization of manganese
peroxidase from Pleurotus ostreatus. Biochem. Biophy. Acta. 1339 (1997) 23-30.
23. MY. Shukor, N. Gusmanizar, J. Ramli, NA. Shamaan, WP. MacCormack, MA. Syed, Isolation and
characterization of an acrylamide-degrading Antarctic bacterium. J. Environ. Biol. 3 (2009a) 57-107
24. M. Rehfuss, J. Urban, Alcaligenes faecalis subsp. Phenolicus subsp. nov. A phenol-degrading,
denitrifying bacterium isolated from a graywater bioprocessor. Syst. Appl. Microbiol. 28(5) (2005)
421
25. MY. Shukor, N. Gusmanizar, NA. Azmi, M. Hamid, J. Ramli, NA. Shamaan, MA. Syed, Isolation
and characterization of an acrylamide-degrading Bacillus cereus. J. Environ. Biol. 36 (2009b) 30-
57.
26. CS. Prabu, AJ. Thatheyus, Biodegradation of acrylamide employing free and immobilized cells of
Pseudomonas aeruginosa. Int. Biodet. Biodegrad. 12 (2007) 60-69.
27. AH. Alwan, SM. Fadil, SH. Khadair, AA. Haloub, DB. Mohammed. Bioremediation of the water
contaminated by waste of hydrocarbon by use Ceratophyllaceae and Potamogetonaceae plants. J.
Gen. Environ. Res. Con. 1 (2013) 106–110.
28. D. Berihun, Y. Solomon, Assessment of the physicochemical and heavy metal concentration from
effluents of paint industry in Addis Ababa, Ethiopia. Int. J. Waste Res. 7 (2017) 306 -363.
29. F. Cappitelli, P. Principi, R. Pedrazzani, L. Toniolo, C. Sorlini, Bacterial and fungal deterioration of
the Milan Cathedral marble treated with protective synthetic resins. Sci. Tot. Environ. 385 (2007)
172–181.
30. R. Boopathy, Factors limiting bioremediation technologies. Biores. Technol. 74 (2000) 63-67.
31. GO. Adams, PT. Fufeyin, SE. Okoro, I. Ehinomen, I (2015) Bioremediation, Biostimulation and
Bioaugmention: A Review. Int. J. Environ. Biorem. Biodegrad. 3 (2015) 28-39.
32. S. Agarry, GK. Latinwo, Biodegradation of diesel oil in soil and its enhancement by application of
bioventing and amendment with brewery waste effluents as biostimulation-bioaugmentation agents.
J. Ecol. Eng. 16 (2015) 82-91.
33. P.I. Orjiakor, C.N. Eze, D.A. Obayomi, J. Bio-kinetics of Acrylic-Based Paints Biodegradation,
Mater. Environ. Sci., 11(1) (2020) 166-175.
(2020) ; http://www.jmaterenvironsci.com