132 Advances in Environmental Biology, 2(3): ... ISSN 1995-0756

132
Advances in Environmental Biology, 2(3): 132-136, 2008
ISSN 1995-0756
© 2008, American-Eurasian Network for Scientific Information
This is a refereed journal and all articles are professionally screened and reviewed
O RIGINAL A RTICLE
Water Quality of Bodo Creek in the Lower Niger Delta Basin
1
J. Onwugbuta-Enyi, 2N. Zabbey, 2E.S. Erondu
1
Department of Biology, School of Science, Rivers State College of Education, Rumuolumeni, Port Harcourt,
Rivers State, Nigeria.
2
Department of Animal Science and Fisheries, University of Port Harcourt, PMB 5323 Choba, Port Harcourt,
Rivers State, Nigeria.
J. Onwugbuta-Enyi, N. Zabbey, E.S. Erondu, W ater Quality of Bodo Creek in the Lower Niger Delta
Basin, Adv. Environ. Biol., 2(3): 132-136, 2008
ABSTRACT
The dynamics of some physicochemical parameters of Bodo creek on the upper reaches of the AndoniBonny river system were studied between December 2005 and July 2006. There were significant differences
(P<0.05) in Secchi Disc Transparency and salinity, while temperature, pH, Dissolved Oxygen (DO), Biological
Oxygen Demand (BOD), phosphate and nitrate concentrations were similar (P>0.05) between the spatial grids.
The values recorded ranged from 26.7 to 30.10 C (Temperature); 73-157 cm (Secchi Disc Transparency); 6.5-8.6
(pH); 6.2-22.7% 0 (Salinity); 4.6-11.8 mg/l (DO); 0.7-8.2 mg/l (BOD); 0.047-2.300 mg/l (Phosphate) and 0.013
to 0.873 mg/l nitrate. There were obvious seasonal fluxes in the ecological variables (P<0.05), except nitrate
concentrations that were not statistically significant (P>0.05). The usefulness of the results in future monitoring
and possible reasons for the observed environmental gradients are discussed.
Key words: Bodo Creek, biotopes, environment gradient, monitoring, seasonal flux
Introduction
Traditionally, Bodo creek has been a strong
livelihood support base for the people of the area and
beyond. The creek serves for fishing and small-scale
aquaculture, transportation, cassava fermentation, fuel
wood production and domestic waste disposal. In
addition, the tranquility of the mangrove-sheltered
waterfronts provides the needed haven for solitude
and relaxation. Besides, mangrove canopy and
moveable spaces underneath the shade offer the poor
locals a benign environment for defecation.
Powell et al.[18] reported that the bulk of periwinkle,
Tympanotonus fuscatus traded in the markets of
Bodo, Bori and Onne communities originate from
Bodo creek. The creek had also supported some
forms of industrial development, namely, an
uncompleted 500 hectares fish farm owned by the
Niger Delta Basin Development Authority (NDBDA)
and Bodo W est Oilfield.
Since then Bodo creek had been precluded from
chronic anthropogenic disturbances apart from fishing
activities and logging pressure. However, the ongoing
Bodo-Bonny road and bridges project awarded by the
Federal Government of Nigeria (FGN) will traverse
Bodo creek complex to link Bonny Island. Intensive
suction sand dredging has begun at the Dor Nwezor
sector of the creek to provide the quantum of sharp
sand required for the road embankments. This intense
dredging activity has resulted in serious ecological
imbalance in the adjoining creek waters as evident
from the high water turbidity due to sediment
resuspension[10], which is indicative of water quality
alteration.
Previous studies have shown that water quality
affects species composition, assemblages and
distribution of plankton[4], benthos[7,11,9] and
fish[4,13]. No reliable data exist in published form
on the ecology of Bodo creek. Snowden and
Ekweozor[20] raised concerns as to the dependency
Corresponding Author:
J. Onwugbuta-Enyi, Department of Biology, School of Science, Rivers State College of
Education, Rumuolumeni, Port Harcourt, Rivers State, Nigeria.
E-mail: [email protected]
Adv. Environ. Biol., 2(3): 132-136, 2008
on post impact studies data when baseline data for
comparison are lacking. Information on Bodo creek,
especially on the relatively “near-pristine” Kpador
channel would aid in future monitoring programmes.
Thus, the present study was aimed at providing
preliminary information on the physicochemical
characteristics of the Kpador sector of Bodo creek in
the lower Niger Delta basin of Rivers State, Nigeria.
M aterials and methods
Study Area
The study was carried out on the Kpador sector
of Bodo creek and lies between latitudes 6 o 75¢, 7 o
15¢ N, and longitudes 5 o 31¢ E and 5 o 35¢E with an
annual rainfall of between 2000-3000 mm in the
Niger Delta. Rainfall decreases sharply as one moves
inland. The rainy season spans from April to
November (eight months) whereas the short dry
season lasts for four months from December to
March with occasional rainfal[25]. Bodo creek is a
nexus of creeks and creeklets adjoining Bodo
Community on the upper reaches of the AndoniBonny river system. Based on the pattern of
hydrology, Bodo creek complex could be described
as a “mixing sponge” for the waters from the Andoni
and Bonny river estuaries. Two major channels: Dor
Nwezor and Kpador link Bodo Creek to Opobo
channel - an adjunct between Andoni and Bonny
rivers - and Bonny River, respectively . Inlet, both
channels ramify to form numerous creeklets, some of
which end blindly in mangrove swamps while others
interconnect causing the mixing of the flood and ebb
tidal waters from the dual sources.
Sampling Stations
A total of four sampling stations were
established at approximately one km apart to
accommodate different biotopes.
Station 1: located upstream where the Kpador main
channel tapers to have a link with Goi creek, locally
called Dor Vibor.
Station 2: (code named Kpador 1): central to the
other three stations. Between stations 1 and 2, a gulflike area exists to the left downstream. At low tide,
the gulf area is exposed as mudflats dissected by
minor channels, all of which unite progressively into
a common sub-channel that debouches into station 2.
Station 3: (Tekpokuru): sited on a minor channel
that radiates from the main channel at station 2.
Station 3 channel extends westward to join a first
order stream that drains a tropical rainforest.
133
Station 4: (Kpador 11): located downstream on the
main channel to other stations. The station was sited
close to the mouth of a minor channel that branches
to the right, leading to the Bodo W est flowstation.
Generally, the marginal vegetation of the
sampling stations are mangroves, usually a
characteristic of such a brackish water environment
in a tropical setting. Red mangroves (Rhizophora
spp) predominated the mangal flora of the area.
Other macrophytes are the white mangrove (Avicenia
africana), mangrove fern (Acrosticum aureum) and a
few pockets of nypa palm (Nypa fructicans). The
latter
was observed only along the vicinity of
station 4.
Field and laboratory procedures
Sampling lasted from December 2005 to July
2006. Dry season samples were collected in the core
dry months (December, January, February) while wet
season samplings were done from May to July. The
monthly sampling was done during high water slacks
at midstream of each station. Subsurface water
temperature was measured in-situ to the nearest 0.1 o C
using a Mercury-inglass thermometer. Transparency
was determined with a 30 cm diameter Secchi disc.
Samples for other water quality parameters were
collected, preserved and transported in an ice-chest
according to standard procedures[2].
The pH was determined using a pH meter
(Mettler Delta 340). Dissolved Oxygen (DO) and
BOD were measured using the modified W inkler
method and the 5-day BOD test respectively[2].
Nitrate and Phosphate were measured with brucine
and Ascorbic acid methods respectively. Salinity was
determined using hand held refractometer (S/mill-E
0-100%0).
Data were analysed in a randomised complete
block design with four stations (blocks) and six
months (treatments). The monthly data were later
pooled and analysed as dry and wet seasons to
estimate the effects of season on the parameters.
Analysis of variance (ANOVA) was done at P=0.05
and where significant differences were observed,
mean separation was done using the least significant
difference (LSD) option[23].
Results and discussion
Results
The physicochemical results of the study area are
presented in Tables 1, 2 and 3. Temperature had a
range of 26.7 to 30.1 o C among the four stations
(Table 1). A maximum mean temperature of 28.7 o C
was recorded at station 2, whereas, station 3 had
least mean temperature (28.2 o C). Significant
variations (P<0.05) in temperature occurred across
Adv. Environ. Biol., 2(3): 132-136, 2008
the sampled months, having a peak of 30.0 o C in
February (Table 2). Secchi disc transparency
fluctuated between 73 and 157 cm. Transparency
showed decreasing mean values amongst the spatial
grids in the sequence: Station 3 < 1 < 2 < 4.
Variations in transparency between months (Table 2)
and stations (Table 3) were significant (P<0.05). The
parameter (transparency) had a time-series peak in
December (mean=142 cm) and spatial peak for
station 4.
Hydrogen ion concentration (pH) varied from 6.5
to 8.6 (Table 1), while spatial pH (Table 3)
variations were not statistically significant (P>0.05).
By season, pH values recorded were higher in the
wet months (7.8) than in the dry months (7.1) as
presented in Table 2. Salinity (%o) differed
significantly (P<0.05) between sampled stations and
months. Overall, station 1 had the least mean salinity
(11.6%0), while a mean salinity maxima (16.1%0)
was recorded at station 4 (Table 1). Seasonally,
salinity peaked in February with the following trend:
February > January > December > June > May =
July.
The DO variations between months and stations
were significant (P<0.05) and ranged from 4.6 to
11.8 mg/L (Table 1), 5.7 to 11.7 mg/L among
months (Table 2) and 7.7 to 8.7 mg/L among stations
(Table 3). The BOD had a range of 0.3 to 8.2 mg/L
(Table 1) with significant differences (P<0.05)
between months (Table 2), while the variations
between the spatial grids (Table 3) were insignificant
(P>0.05). The mean BOD peaked in July (8.2 mg/L),
whereas least mean BOD (1.0 mg/L) was recorded in
December.
The concentration of phosphate varied from
0.075 to 2.300 mg/L (Table 1). Phosphate peaked at
station 4 (0.624 mg/L) but the lowest concentration
(0.520 mg/L) was recorded in station 3. Phosphate
values show significant variation over time. W et
season Phosphate contents were generally higher
relative to the dry months (Table 2). Nitrate ranged
between 0.013 mg/L and 0.462 mg/L (Table 1). The
nutritive salt did not vary (P>0.05) between the
sampled stations. Nitrate varied (P<0.05) between
months with a peak mean value of 0.284 mg/L in
May and the least value of 0.057 mg/L in December.
Discussion
In aquatic ecosystems, variations exist between
the different environmental compartments with regard
to physical, chemical and biological characteristics.
H owever, ecological conditions are mutually
reinforcing and to a large extent determine the biotic
c o m po nent and structural p atterns. Surfa c e
te m p e r a tu r e r a n g e ( 2 6 .7 -3 0 .1 o C ). A ltho ugh
insignificant variations were recorded between the
spatial grids, the least mean value (28.2 o C) reported
134
for station 3 is normal considering the nature of the
biotope. Fresh water from a first order stream
draining a tropical rainforest debouches into station
3 channel headwaters. Mixing between the plunging
freshwater and inflowing brackishwater leads to a
drop in temperature. King and Nkanta[12] attributed
low temperature recorded in their studies of
Mfangmfang pond to floating leaves of macrophytes
which precluded the effects of sun’s radiation.
Similarly, Elakhame[20] attributed low temperature
recorded in Epie creek floodplain to shade made by
overhanging fronds of raffia palms surrounding the
location.
Transparency values recorded in this study are
comparatively higher than those reported on the main
Bonny River[24]. No major inland river drains into
Bodo creek complex. Thus, it is plausible that finely
divided particles in the creek environment leading to
cloudiness originate within the creek basin due to the
abrasive effects of tidal currents or from inflowing
tidal or storm waters. It has been observed that
heavier particles settle out of suspension along
gradients[14] such as when floodwater from Bonny
River ingresses into Bodo creek. Moreover, reduced
water currents which characterized the high water
slacks at which time sampling was done enhances
mud deposition within the upper reaches of
estuaries[14].
Seasonally, pH of the area straddles between
mild acidity and alkalinity. The pH range (6.5-8.6)
recorded agrees with the pH of brackish water bodies
reported by Imevbore. The pH values fall within the
optimum range of most aquatic organisms and will
support rich primary productivity, Shrimp and fish
production[13,17,3]. Following theVenice system of
salinity classification (Venice, 1959), the studied area
remained mesohaline [6.2-13.1%o] throughout the
wet months. On the contrary, in the dry season,
station 1 was consistently mesohaline, whereas
stations 2, 3 and 4 oscillated between meso and
polyhaline (13-22.7%0) salinities.
Fluctuations in DO and BOD between seemingly
physiologically stressful concentrations and relatively
high mean DO content than BOD suggests a
cleansing effect by the tidal fluxes. These resilient
properties of DO and BOD prevent the variables
from reaching critical levels.
Besides silica,
phosphate and nitrogen are regarded as nutrient
elements because they must be present as soluble
salts for plants to grow[19].
In this study, phosphate was more concentrated
than nitrate. A plausible reason underlying the
concentration differential is the unique behavior of
phosphorus in shallow waters. Phosphorus in its
soluble state (phosphate) quickly adsorbs at the
surface of mud and re-enters the water column
through processes that are not well known[19].
Adv. Environ. Biol., 2(3): 132-136, 2008
135
Table 1: Physicochem ical Param eters in the D ifferent Sam pling Stations (Bodo Creek)
Param eters ( o C)
Stations
------------------------------------------------------------------------------------------------------------------1
2
3
4
Tem perature (o C)
27.0 – 30.0
26.7 – 30.0
27.0 – 30.0
26.8 – 30.1
28.4±0.9
28.7±1.2
28.2±1.0
28.6±1.2
Transparency (cm )
73 – 140
80 – 150
77 – 120
92 – 157
107±21.6
113±25.5
104±15.7
128±26.1
PH
6.5 – 8.2
6.8 – 8.2
6.5 – 8.6
6.9 – 8.3
7.5±0.7
7.5±0.8
7.4±0.9
7.6±0.6
Salinity (% 0)
6.2 - 16.0
8.0 – 21.6
9.1 – 20.8
10.6 -22.7
11.6±3.1
14.7±5.1
13.5±4.1
16.1±4.8
D O (m g/L)
7.0 – 11.6
4.6 – 11.7
5.4 – 11.5
5.6 – 11.8
8.7±4.5
7.7±2.7
8.2±2.2
7.9±2.2
BO D (m g/L)
1.1 – 8.2
1.8 – 8.2
0.3 – 8.0
0.7 – 8.2
4.6±2.6
4.5±2.2
4.2±2.4
4.2±2.4
3PO 4 (m g/L)
0.200 – 1.980
0.094 – 1.650
0.094 – 1.650
0.075 – 2300
0.593±0.65
0.522±0.61
0.520±0.59
0.624±0.81
N O 3 - (m g/L)
0.027 – 0.400
0.013 – 0.462
0.013 – 0.265
0.013 – 0.168
0.199±0.16
0.181±0.14
0.097±0.09
0.099±0.05
Table 2: Variations in M onthly M ean Physicochem ical Param eters of Bodo Creek
M onth
Tem pt (o C) Transparency(cm ) pH
D O (m g/L)
BOD (m g/L)
Salinity (% 0)
D ecem ber
29.2 b
142 a
6.8 c
d
d
5.7
1.0
14.7 b
January
29.0 b
127 b
7.2 c
6.9 bc
3.5 c
19.0 a
a
b
d
February
30.0
124
7.8
5.7
c
3.4
20.1 a
M ay
28.0 c
120 b
8.2 a
9.8 b
c
3.4
9.3 c
June
27.8 c
87 c
8.3 a
8.9 b
b
6.8
11.6 c
July
26.9 d
81 c
6.8 c
11.7 a
8.2 a
9.3 c
M ean
28.5
113
7.5
6.1
4.4
14.0
SEM (df =15)
0.34
4.9
0.12
0.54
0.30
1.06
a-d
M eans with sim ilar superscript in the sam e colum n are not significantly different (P>0.05).
Table 3: Variations
Station
1
2
3
4
M ean
SEM (df =15)
a-c
M ean with sim ilar
in Spatial M ean Physicochem ical Param eters of Bodo Creek
Tem pt (o C) Transparency(cm ) pH
D O (m g/L)
BOD (m g/L)
Salinity (% )
28.4
107 b
8.7
11.6 c
7.4
4.6
26.7
113 b
7.7
14.7 ab
7.5
4.5
28.2
104 c
8.2
13.5 b
7.4
4.2
28.6
129 a
7.9
16.1 a
7.6
4.2
2 8.0
113.3
7.5
8.1
4.4
14.0
0.58
8.5
0.22
0.44
0.25
0.87
superscript in the sam e colum n are not significantly different (P>0.05).
Generally, phosphate and nitrate concentrations
recorded in this study hover around natural contents
reported for surface waters[21]. The nutrient quality
observed tended to be superior to some results on the
Niger Delta[25,6,16]. Even though mangrove
wetlands are rated high nutrient environments[15],
input of nitrate and phosphate into Bodo creek
through runoffs from adjoining agrarian lands cannot
be overemphasized. This exogenous claim for the
rich nitrate-phosphate status is further strengthened
by the fact that the bedrock of the Niger delta is
essentially poor in these nutrients[16].
Virtually every island forest within the Bodo
creek complex had been converted to functional
farmlands. It is not unlikely that fertilizers applied
during farming cycles, often times, may be washed
by rains and carried in runoff into the creek, thus
contributing to the annual nutrient budget. The low
concentration of the nutritive ions in the dry season,
which ideally, is the period of peak nutrient
mineralization, is not unconnected to the fact that
phytoplankton proliferation peaks in the dry season.
Increases in the micro floral population corresponds
with maximum nutrient concentration in surface
PO 43-(m g/L)
0.920 b
0.211 c
0.078 c
0.163 c
0.122 c
1.895 a
0.565
0.094
PO 43-(m g/L)
0.593
0.522
0.520
0.624
0.565
0.87
N O 3-(m g/L)
0.057 b
0.106 b
0.109 b
0.284 a
0.218 a
0.090 b
0.144
0.0791
N O 3-(m g/L)
0.199
0.181
0.097
0.099
0.576
0.0646
waters. The general trend of insignificant variations
recorded for most of the parameters between spatial
grids suggests similarity in the hydro-climatic
conditions of the area.
Finally, the need to carry out comprehensive
Environmental Impact Assessment Studies before the
commencement of any major developmental project
is stressed. This becomes more pertinent when such
projects are planned to interfere with sensitive and
already over-stretched ecosystems.
References
1.
2.
3.
Alabaster, J.S. and R. Lloyd, 1986. Water
Q u a lity C r ite r ia fo r fr e s h w a te r F is h .
Butterworths, London, U.K.
American Public Health Association (APHA),
AW W A and W PCF. 1998. Standard methods for
the Examination of Water and Wastewater, 20 th
edition. W ashington DC, USA.
African Regional Aquaculture Centre (ARAC),
1990. Site Selection Studies for a Shrimp Farm
Project at Bodo-Rivers State. Final Report
Adv. Environ. Biol., 2(3): 132-136, 2008
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
submitted to Integrated Fish Farm Limited,
Lagos, Nigeria.
Boney, A.D., 1983. Phytoplankton. Edward
Arnold, London, UK.
Boyd, C.E., 1981. Water Quality in Warm water
Fish Ponds. Auburn University Alabama.
Chindah, A.C., 2003. The Physicochemistry,
Phytoplankton and Periphyton of a Swamp
Forest Stream in the Lower Niger Delta. Scientia
Africana , 2(182): 106-116.
Dance, K.W . and H.B.N. Hynes, 1980. Some
effects of agricultural land use on stream insect
communities. Environ. Poll., 22: 19 - 28.
Elakhame, L.A.,1995. The Biology and Ecology
of fishes in Epie Creek Floodplain with
Particular Reference to Odediginni Lake, Niger
Delta, Nigeria, PhD Thesis University of Port
Harcourt.
Hart, A.I. and N. Zabbey, 2005. PhysicChemistry and Benthic Fauna of W oji Creek in
the Lower Niger Delta Nigeria. Environ. And
Ecol., 23(2): 361-368.
Hodgson, G., 1994. The Environmental Impact
of Marine Dredging in Hong Kong. Coast.
Manag.Trop.Asia (2): 1-8.
Jones, A.R., 1987. Temporal Pattern in
Macrobenthic Communities of the Hawksbury
Estuary, New South W ales, Aus.J. Of Mar. and
Freshwater Res., 38: 607-624.
King, R.P. and N.A. Nkanta, 1991. The Status
and Seasonality in the Physico-chemical
hydrology of a Nigerian Rainforest Pond. Japan
J.hydrob, 52(1): 1-12.
Kutty, M.N., 1987. Site Selection for
Aquaculture-Chemical Features of Water. Lecture
Paper presented at the African Regional
A q uaculture Centre (AR A C ) fo r Senior
Aquaculture Course, Aluu, and Port Harcourt.
Mclusky, D.S., 1989. Estuarine Ecology.
Chapman and Hall, New York, USA.
Mitsch, W .J. and J.G. Gosselink, 2000.
Wetlands. John W iley and Sons, New York,
USA.
136
16. Ogamba, E.N., A.C. Chindah, I.K.E. Ekweozor
and J.N. Onwuteaka, 2004. W ater Quality and
Phytoplankton Distribution in Elechi Creek
Complex of the Niger Delta. J. of Nig. Environ.
Soc., 2(2): 121-130.
17. Onuoha, G.C. and F.O. Nwadukwe, 1987. W ater
Quality Monitoring. In Proc. Of the Aquaculture
Training Programme (ATP) held in the African
Regional Aquaculture Centre (ARAC), Aluu,
Rivers State, Nigeria. 7 Sept. - 6Oct, pp. 17-24.
18. Powell, C.B., A.I. Hart and S. Deekae, 1985.
Market Survey of the Periwinkle Tympanotonus
fuscatus in Rivers State: Sizes, Prices and
Exploitation levels. In Proc. Of Fisheries Society
of Nigeria (FISON) Conference, Port Harcourt,
26 th - 29 th November, 55-61.
19. Royce, W ., 1984. Introduction to the Practice of
Fishery Science. Academic Press, London, UK.
20. Snowden, R.J. and Ekweozor, I.K.E 1990. The
Littoral Infauna of the W est African Estuary: a
baseline Survey for the Monitoring of Oil
Pollution. Mar. Biol., 105(1): 51-59.
21. UNESCO/W HO/UNEP, 1992. W ater Quality
Assessments - A guide to use of biota,
sed im e nts a nd wa te r in E nvironm ental
Monitoring. 2 n d edition.
22. Venice System, 1959. Symposium on the
Classification of Brackish W aters. Venice. Apr
4-8, 1958. Arch. Oceangr.limnol., 11: 1-248.
23. W ahua, T.A.T., 1999. Applied Statistics for
Scientific Studies. Africa-link Books, Ibadan,
Nigeria.
24. W okoma-Aleleye, I.P. and S.A. Hart, 1999. The
Effect of Industrial Activities on the Primary
Productivity in the lower Bonny Estuary, Rivers
State, Nigeria. J. Appl. Sc. Environ..mgt., 2:
139-42.
25. Yakubu, A.F., F.D. Sikoki and J.R.M. Horsfall,
1998. An Investigation into the Physicochemical
Conditions and Planktonic Organisms of the
Lower Reaches of the Nun River, Nigeria. J.
Appl.Sc. Environ. Mgt., 1(1): 38-42.