International Journal of Animal and Veterinary Advances 1(2): 54-58, 2009
ISSN: 2041-2908
© M axwell Scientific Organization, 2009
Submitted Date: July 27, 2009
Accepted Date: August 19, 2009
Published Date: October 30, 2009
Level of Heavy Metals in Freshwater Crab (Cardisoma guahumi) Obtained from
Ahmadu Bello University Reservoir, Zaria Nigeria
1
D.S. Abolud e, 2 O.A. Davies and 1 D.W. Avong
1
Department of Biological Sciences, Ahmadu Bello University, Zaria, Nigeria.
2
Department of Fisheries & Aquatic Environment, Rivers State University of Science and
Techno logy , Port Harcourt. Nigeria
Abstract: The levels of Calcium (Ca), Potassium (K), M anganese (M n), Iron (Fe), Lead (Pb), Zinc (Zn ),
Bromine (Br), Arsenic (A s), Rubidium (Rb), Strontium (Sr), Vanadium (V), Niobium (Nb) and Zirconium (Zr)
in crabs Cardisoma guahumi has been evalua ted. Th e crabs we re collected in the A hma du B ello U niversity
Reservo ir and analysed for the above metals using Energy Dispersive X-Ray Fluorescence (EDXRF)
Technique. The data indicated variable levels of some of the metals in the crab samples. Enrichments of some
of the metals were higher than others, in some stations and on the different body comp onents. The most
concentrated was calcium (46500±16300ppm) while the least concentration was obtained in Niobium
(29.3ppm ). Correlation co efficient betw een the various stations and betw een the various bo dy co mpo nents
shows significant differences (P#0.05). Concentrations of some metals in Ahm adu B ello University Reservo ir,
Zaria were found to be higher than the WHO recommended safe reference values. The high level of some of
the metals in the crab C. guahumi suggested that the crab can be used as bio-indicator.
Key w ords: Concen tration, freshwater crab, heavy m etals and ma n-made reservo ir
INTRODUCTION
Heavy metals contamination in wa ter may arise in
many ways. Some of them are being mobilized by man to
the atmosphere and hydrosphere at rates compared to and
sometimes exceeding those by weathering process. The
several human activities that may result to water pollution
include agriculture, irrigation, fire, urbanization, mining
and industrialization (Goudie, 1990). These activities
have been docu men ted to have im pacted neg atively in
some specified Nigerian surface waters especially in the
Niger-Delta region (Izonfuo and Bariwe ni, 2001). Also
these activities have affected the soils of industrial areas
in southern Nigeria (Olajire et al., 2003). As a
consequence, mod ifications of their co ncen trations in
aquatic organism s are to be expected (Abubakar and
Garba , 2006).
Anthropogenic heav y me tals follow ing their
introduction to water bodies through atmospheric fallout
or through the use of domestic antiseptic soaps and
pesticides in our farms are washed into the water and
concentrated by aquatic organisms (Goldb erg, 1972).
Discharge of industrial wastes also constitute about 62%
of total source of heavy metal such as Lead (Pb), Zinc
(Zn), Copper (Cu), Nickel (Ni), Cadm ium (Cd ),
Chromium (Cr) and Manganese (M n)
which are
respo nsible not on ly for degrading the water quality of a
river or sea but for killing a number of aquatic organisms
(Abubakar and Garba, 2006). These metals are toxic after
large accumulation in the body of flora and fauna and
later pass on through the food chain from fish to man
(Ayodele and Abubakar, 2001). Although some of these
metals may be essential, some may be hazardous for
human metabolism especially when their concen tration is
high (Sheriff et al., 1979). The presence of heavy metals
in aquatic animals is becoming a threat, thereby making
them unfit for human consumption. Heavy metals found
in crustac eans are known to affect the enzyme balance as
well as demobilize them (Herkovits et al., 1996 ).
Baseline inform ation on the pond ecosystem status in
the northe rn parts of Nigeria including Zaria is scanty, as
a result, it leads to a few published works on water
chemistry, quality and management (Balarabe, 2001). The
objectives of the rese arch w ork are to determine the types
of metals and the levels of their concentration obtained in
crabs found in the Ahmadu Bello University freshwater
Reservoir.
MATERIALS AND METHODS
Study Area: Kubanni Reservoir: Zaria, one of the
largest cities in Kaduna State, Nigeria is situated in the
northern guinea savannah zone. It possesses a tropical
continental climate with distinct wet and dry seasons
Kubanni Rive r is located in Zaria. The river lies
approxim ately betw een latitude 11º8'N , 11º10'N and
longitude 7º41'E, 7º42'E on the Zaria sheet no 102 of
Nigerian ordinance survey map. The Kubanni River
drains this area in a dendritic pattern, with its major
drainage artery dissecting Zaria. Its wa terway is made up
of about 157 channels which drain the entire basin as the
river flows in a north-south, East direction at the ge ntle
Corresponding Author: D.S. Abolude, Department of Biological Sciences, Ahmadu Bello University, Zaria, Nigeria
54
Int. J. Anim. Veter. Adv., 1(2): 54-58, 2009
gradients carrying along its course superficial deposits of
alluvial sands, silts, eroded detritus, younger laterite and
organic matter derived from the catchment zones
(Abolude, 2007 ).
The Kubanni River takes off from the Kampa gi hills
at an elevation of the approximately 711meters, it thus
acquires enough inertia and gravitational force for the
drainage of the entire basin before empting its bed-load
finally into the Galma River a major tributary of the
Kad una R iver (Abolude, 2007 ).
Along its course, the Kubanni waterw ay meanders
through deep gullies created by the weathering of granite
basement rock (Ewa et al., 1999 ). Altho ugh most of the
channels which v ary co nsiderably b oth from station to
station and from time to time are seasonal flowing m ostly
during and shortly after the rains, the flood plains re main
wet due to the shallow water table and perhaps because of
the various recharge sources through the unconsolidated
surface layers underlain by impervious bedrocks
(Thomas, 1976). There is therefore sufficient water for
seaso nal irrigation and dam emb ankmen t.
Upstream, there is a dam across its valley (A.B.U.
Reservoir) which is used by the A hma du B ello U niversity
com mun ity and p artly by the peo ple in Sam aru Zaria for
its water supply. Downstream, attempt to conserved river
water include construction of earth or sand barrages or by
artificially the enlarging and deepening pools (Adakole,
1995). There are two major uses of the river, Agriculture
(irrigation, Fishing and watering cattle) and dom estic
(drinking, washing and bathing). Heaps of refuse dumps,
human faeces, cattle dump could be found on the slopes
of the Kubanni River valley. Both municipal and
industrial effluents are ch annelled into the river without
respect to their quality.
Station 5: Site chosen along same axis o ccup ied by
Centre for Energy Research and raining (CER T). It is a
point along the Kubanni River just before the entry point
of sewage (from the treatme nt plant of the A hma du B ello
University) into the K ubanni R iver.
Selection of Sampling Stations: Five (5) established
sampling stations were selected and marked along the
Kubanni Reservoir from the point Kub anni River enters
into the Reservoir to the across the dam, titled station 1-5.
These sampling stations were selected to reflect
progression of pollution. The stations are as described.
Elemental Analysis: Heavy metal composition and
concentration of the crab samples collected from the
reservoir were determined using Energy D ispersive XRay Fluorescence (EDXRT) Technique at the Centre for
Energy Research and T raining (CE RT ), Ahmad u Bello
University, Zaria.
Station 1: Sampling point close to the Institute of
Development Research (IDR), takes care of agricultural,
domestic and other wastes from the university. It is the
point wh ere Ku banni R iver enters the Reservoir.
Method of Eleme ntal An alysis: Pellets of 19 mm
diameter were prepared from 0 .3-0.5g pow der m ixed w ith
three drops of organic liquid binder and pressed
afterwards at 10 tons with a hydraulic press.
Measuremen ts were performed using an annular 25
mCi 1 0 9 Cd as the excitation source, that emits Ag-K Xrays [22.1 KeV] in which case all elements with lower
characteristics excitation energies were accessible for
detection in the samples. The system consists furthermo re
of a Si (Li) detector, with a resolution of 170 eV for the
5.90 KeV line, coupled to a computer controlled ADCcard.
Quantitative analysis of the samples was carried out
using the Emission Transmission (E-T) method, for which
a number of quantification methods has been developed
and applied (Leroux and Mahmoud, 1996; Giauque et al.,
Collection of Crab: Crab samples were collected from
the described established stations on Kubanni R eservoir
using Ma li traps which w ere set and left for at least three
(3) days. They were placed in clean polythene bags and
taken to the laboratory.
Laboratory Analysis: Crab Weighing and Measurement
The collected crab specimens were weighed using the
electronic Mettler Ba lance (Model P1200N ). The length
[from the tip of the first claws stretched to the other
claws), body width and d epth w ere measured w ith a pair
of Van ier calliper.
Drying: The crab samples were dried in an oven
(Gakenkamp oven] at 110ºc.
Separation of body com ponents: The crab sample was
separated into four various pa rts, which are the claws, the
legs back carapa ce and front carapace.
Preparation of Crab Powder: Each crab sample was
ground manually to powder with an agate mortar and
pestle to grain size of less than 125:m forms with pretreated mortal and pestle. Cleaning of the mortal and
pestle took p lace after each crushing to pow der form to
avoid contamination (Prendez and Carrasco, 2003). The
crab powder were bagged into coded new plastic bags and
sealed, then taking for analysis for heavy metals.
Station 2: Samp ling point halfway betw een w here
Kubanni River and Kud ungi Stream enters the Reservoir.
It takes care of agricultural, chemicals and other wastes
from the adjacent farmland.
Station 3: Samp ling point below where Kudungi Stream
enters the adjacent farmland.
Station 4: The sou thern end point of AB U R eservoir. It
takes care of the wastes from the adjacent farmland
settlements.
55
Int. J. Anim. Veter. Adv., 1(2): 54-58, 2009
1979; Markowicz, 1979; Tang et al; 1986; Markowicz
and Van Grieken, 1993; Kump, 1996; Bernasconi et al.,
1996). These quantification methods provide different
approaches to correct the matrix absorption as well as
enhancement effects. In this work quantification was
carried out using a modified version of E-T method
(Kump, 1996; Angeyo et al., 1998; Funtua, 1999a; 1999b)
and it involves the use of pure target material (Mo) to
measure the absorption factor in the sample.
The Mo target serves as a source o f mon ochromatic
X-rays, which are excited throug h the samp le by primary
radiation and then penetrate the sample on the w ay to the
detector. In this way, the absorption factor is
experimentally determined which the program uses in the
quantification of concentration of the elemen ts. In
addition, the contribution to the Mo-K peak intensity by
the Zr-K is subtracted for each sample.
Sensitivity calibration of the system was performed
using thick pure m etal foils (T i, Fe, Co, Ni, Cu, Z n, Zr,
Nb, Mo, Sn, Ta, Pb) and stable chemical compound
(K 2 CO 3 , CaCO 3 , Ce2 O 3 , W O 3 , ThO 2 , U 3 O 8 ). The spectra
for the sam ples w ere collected for 3000 s with the 1 0 9 Cd
source and 2000 s for the 5 5 Fe source and the spectra were
then evaluated using the AXIL-QX AS program
(Bernasconi, 1996 ).
least (36100±144ppm ). More ov er, wh ile the highest
(465000±163ppm) Ca claw was obtained at Station 3, the
least (318000±108ppm) was obtained at Station 1.
The correlation coefficient shows significant
difference (P#0.05) in the various body components and
also in each station there is significant difference (P#0.05)
in the body components. The distribution of Ca in the
body componen ts were: back carapace > claws > legs >
front carapace. Ca is the major constituent that makes up
the carapac e (shell).
M anganese (Mn, ppm ): Manganese was only obtained
at Station 5 but was not obtained from the legs of Crabs
at Station 5. The concentration ranged from 2400 ± 1125
to 2910 ± 1130 ppm. There was no significant difference
(P$0.05) between Mn obtained from the body
componen ts.
Iron (Fe, ppm ): Fe was not found in all the stations
except in Station 2, 3 and 5. Even in these three stations,
Fe was not found in all the body components. The Iron
concentration obtained ranged from 1390±95 to 2900
±467ppm.
W hile the highest Fe concentration on the back
carapace (2900±467 ppm) was obtained at Stations 2, the
least (2260±840ppm ) was at Station 3. The highest
(2310±695ppm) Fe in legs was obtained at Station 2, the
least (1390±95ppm) was obtained at Station 5. While the
highest (2880±874ppm) Fe in claws was obtained at
Station 2, the least (1660±120ppm) was obtained at
Station 5. So also the highest (2570±606ppm) Fe in front
carapace was obtained at Station 5, the least
(2030±467ppm) was obtained at Station 2. The correlation
coefficient show s that there was no significant difference
(P$0.05) between the stations or in the body com ponents
of each station.
109
Cd source was use d for the analysis of K , Ca, T i,
V, Cr, Fe, Co, Ni, Cu, Zn, Ta, W, Ga, As, Se, Pb, Br, Rb,
Sr, Th, Y, U, Zr, Nb, and Mo.
RESULTS
The results of the analysis using Energy Dispersive
X-Ray Fluorescence Technique are as presented in the
Table 1. The result shows the level of concentration of the
metals in the crab Cardisoma guahumi obtained in the
Reservo ir from different sampling stations. Som e metals
were not detected in som e of the sampling stations w ith
the exception o f Ca and Sr. the trend or the metal
accumulation in the crab C. guahumi is Nb< Zr< Rb < Br
<As < Pb < Z n < Sr < M n < Fe < V < K< Ca. This is not in
support of the fact that the crude generalization order of
metals toxicity w as reported as Co < N i < Cr <Pb < Zn <
Cd < Cu < Ag < Hg (R iley and Skirrow, 1974 ).
Lead (Pb, ppm ): Lead was only obtained at Station 5 and
only in the claws with concentration of 238±16ppm.
Zinc (Zn, ppm ): Zinc was obtained at Stations 3 and 5.
At Station 3, it was o btained in the front carapace with a
concentration of 498±58ppm and in Station 5 in the back
carapace (442±1 5ppm ) and legs (304±05ppm).
Potassium (K, ppm ): Potassium was not detected in all
the stations, it was found only at Station 5. At Station 5,
K was found in the claws with concentration of
(34300±9990ppm) and legs with (32400ppm). The
correlation coefficient show s significant difference in
concentration of the two body compo nents that w ere
obtained (P#0.05).
Bromine (Br, p pm ): Bromine was only obtained at
Station 5 in the claws with concentration of 85±5ppm.
Arsenic (As, ppm ): Arse nic w as obtained at Station 5
only. It was obtained in the back carapace with
concentration of 160±10ppm.
Calcium (Ca, pp m): Calcium w as w idely distributed in
all the body com ponents examined from all the stations.
The concentration of Ca ranged from 20 3000± 100 to
465000± 163ppm.
W hile the highest concentration of Ca in the front
carapace (354000±159ppm) was obtained at Station 1, the
least (203000±100ppm) was obtained at Station 2. The
highest concen tration (463000 ±108ppm) of Ca back
carapace was obtained at station 1, but Station 5 had the
Rubidium (Rb, ppm ): Rubidium was obtained at Station
5 only from the back carapace with a concentration of
75.6±31.1 ppm concentration.
Strontium (Sr, ppm ): Strontium was widely distributed
in all the body components examined from all the stations
(Table 1). The conc entration rang ed from 380±46 to
1610±57ppm. The correlation coefficient shows
significant difference (P#0.05) in the various stations and
56
Int. J. Anim. Veter. Adv., 1(2): 54-58, 2009
Table 1:Elemental composition of the anatomical components of the crab (Ca rdisom a gu ahu mi) o b ta in fr om A B U R es er vo ir (i n p p m)
Station 1
Station 2
Station 3
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Element
CF
CB
CW
L
CF
CB
CW
L
CF
CB
CW
L
K
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
Ca
35400
463000
318000
364000
203000
437000
401000
344000
314000
420000
465000
454000
±159
±164
±108
±145
±100
±151
±147
±136
±161
±147
±163
±165
Mn
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
Fe
BDL
BDL
BDL
BDL
2030
2900
2880
2310
BDL
2260
BDL
2620
±467
±467
±874
±695
±840
±94
Pb
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
Zn
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
498±58
BDL
BDL
BDL
Br
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
As
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
Rb
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
Sr
918±35 1100±39 1290±41 1010±35
683±28
1500±48
1190±43
1150±39
972±4
11470±49
1610±57
1470±56
V
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
Nb
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
Zr
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
Table 1: (Continuted)
Station4
Station5
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------CF
CB
CW
L
CF
CB
CW
L
BDL
BDL
BDL
BDL
BDL
BDL
34300±9990
32400
278000± 1
41414000±160
338000±119
287000±144
243000±137
361000±44
436000±15
4444000±153
BDL
BDL
BDL
BDL
2400±1125
2650±110
2910 ±1130
BDL
BDL
BDL
BDL
BDL
25070±606
BDL
1660±120
1390±95
BDL
BDL
BDL
BDL
BDL
BDL
238±16
BDL
BDL
BDL
BDL
BDL
BDL
442±15
BDL
304±5
BDL
BDL
BDL
BDL
BDL
BDL
85±5
BDL
BDL
BDL
BDL
BDL
BDL
160±10
BDL
BDL
BDL
BDL
BDL
BDL
BDL
75.6±±31
BDL
BDL
1040±37
1420±48
1400±41
1090±43
957±35
380±46
1450±42
1340±36
BDL
BDL
BDL
BDL
BDL
BDL
7710±212
BDL
BDL
BDL
BDL
BDL
BDL
BDL
2 9 .3 ± 5
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
3 0 .5 ±4
CF = C arapa ce fron t, CW = claw s, PP M = Pa rt per m illion, CB = C arapa ce bac k, L = legs, B DL = B elow detectio n limit
also in each station crab, there is significant difference
(P#0.05) observed in the body components. While the
highest Sr concentration in the front carapace
(1040±37ppm) was obtained at Station 4, the least
(683±28ppm) was obtained at Station 2. Moreover, the
highest (1500±48ppm) Sr back carapace was obtained at
Station 2, the least (380±46ppm) was obtained at Station
5. So also, while the highest (1610±57ppm) Sr claw was
obtained at Station 3, the least (1190±43ppm) was
obtained at Station 2. In addition, the highest
(1470±56ppm) Sr in legs was obtained at station 3, the
least (1010±35.2ppm) was obtained at Station 1.
concentration of 1610ppm does not exceed the WHO
limit of 2433ppm, but Lead with concentration of 238ppm
exceeded the WH O limit of 10ppm. Iron also with highest
concentration of 2880±874ppm exceeded the W HO limit
of 1220ppm.
Aquatic organisms were reported to be selective in
metal accum ulation due to toxicity effects (Ayodele and
Abu bakar, 2002). The mode of action of heav y me tals on
biological systems is thought to be through enzymes
systems, although extra ordinary concentrations may
result in direct tissue damage (Abubakar and Garba,
2006). Some aquatic animals can regulate their body
burden, crab Carcinus maenus can regulate its body level
of Zn, after exposure to sea water containing 500 times
the normal concentration of Zn, with the concentration by
2 and 4 factors respectively (Abubakar and Garba , 2006).
Regulation of metal body burden by aquatic organisms
can be through three principal mechanisms, via gut, urine
and diffusion through the body surface. Crustaceans
excre te Zn, Cu, Co, Mn, and Hg in the urine (Bernard and
Lane, 1961).This could be responsible for the low
detection of Z n and other m etals.
Vanadium (V, ppm ): Vanadium was obtained at Station
5 only in the claws with 7710±212ppm concentration.
Niobium (Nb, pp m): Niobium was only obtained at
Station 5 in the claws with 29.3±5ppm concentration.
Zirconium (Zr, ppm): Zirconium was only obtained at
Station 5 in the legs w ith 30.5±4ppm c oncentration.
DISCUSSION
CONCLUSION
Calcium and Strontium were obtained in all the
stations and in all the body components because they
constitute the major part of the elements that make up the
shell of all crustaceans. Most of the metals detected did
not exceed the tolerable limit. Zinc with the highest
concentration of 498±158 ppm does not exceed the WHO
limit of 500 ppm . Also Strontium with the highest
The result of the analysis has shown that crab
Cardisoma guahumi can be used as bio-indicator as it
contains variable levels of the metals analysed with high
enrichment of Ca, Fe, Pb, and Sr observed. In orde r to
reduce excessive discharge of m etals into the rese rvoir
there should be reduction of farming activities around the
57
Int. J. Anim. Veter. Adv., 1(2): 54-58, 2009
reservoir. Furthermore, the consum ption of crab
C. guahumi obtained from Station 5 by humans m ay pose
risk from ingestion of tox ic metals at unacceptable
concentration.
matrices by X-ray fluorescence with incoherent
scattered radiation as an internal standa rd. Anal.
Chem., 51: 512-516.
Goldberg, E.D., 1972. The Changing Chemistry of the
Oceans (D. Drysseu and Jagnereds). Wiley Inter
science Division, New Y ork, pp: 250-255.
Goudie, A., 1990. The Human Impact on the Natural
Env ironm ent. 3rd Edn. The M IT Press Cambridge,
Massach usetts.
Herkovits, J., C.S. Perez -Coll and F.O. Herkovits, 1996.
Ecotoxicity in the Recognista River. Province of
Buenos Aires, Argentina. A Preliminary study.
Environ. Health Perspect., 104(2): 183.
Izonfuo, L.W. and A. Bariweni, 2001. The Effects of
Urban Runoff water and Human activities on some
physico-chemical parameters of the Epe Creek in
the Niger-Delta.
J.
Appl.
Sci.
Environ.
Management, 5(1): 47-55.
Kump, P., 1996. QAE S. Quantitative Analysis of
Environmental Samples, Instruction Manual,
Ljubljana.
Leroux, J. and M. M ahmoud, 1996. X-ray quantitative
analy sis by an emission-transmission, method. Anal.
Chem., 38: 76-82.
Markowicz, A.A., 1979. A method for correction for
absorption matrix effects in samples of intermediate
thickness in EDXRF analysis. X-ray Spectrum,
8: 14-18.
Markowicz, A.A. and R.E. Van Grieken, 1993.
Quantification in XR F Analysis of Interm ediate
Thickness Samples. In: Handbook of X-ray
Spectroscopy. R.E. Van Grieken and
A.A.
Markowicz. (Eds). Marcel Decker Inc. New Y ork.
pp: 339-358.
Olajire, A.A., E.T. Ayodele, G.O. Oyediran and E.A.
Olugbemi, 2003. Levels and Speciation of Heavy
Metals in Soils of Industrial Southern Nigeria.
Environ. Monitoring Assessment, 85(2):135-155.
Prendez, M. and M.A. Carrasco, 2003. Elemental
composition of surface waters in the Antarctic
Peninsula and interaction s with the environmen t.
Environ. Geochem. Health, 25: 347-363.
Riley, J.P. and G. Skirrow, 1974. Chemical
Oceanography, 2 n d Edn. Vol. 1, Bergmann Press,
London, pp: 489-491.
Sheriff, M.K., R.M. Aw adallah and A.E. Moham ed,
1979. Determination of trace elements of Egyptian
Crops by INAA. J. Radioanal Chem. 53: 145-151.
Tang, S.M., P. Kump, C.T. Yap and M.G. Bilal, 1986.
Calculation of relative fluorescence intensity for
annular source geom etry by Monte Carlo method. XRay Spectrum. 15: 289-293.
Thomas, M.F., 1966. Some Geomorphological
Implications of Deep W eathering Patterns in
Crystalline Rocks in Nigeria. Tans. Inst. Br G eorg.,
40: 173-193. In: Horizontal and vertical distribution
of selected metals in the Kubanni River, Nigeria as
Determined by Neutron Activation Analysis. Ewa,
I.O.B ., M.O.A. Oladipo and L.A. Dim, (Eds.). 1991.
Commun. Soil Sci. Plant Anal., 30(7-8): 1081-1090.
REFERENCES
Abolude, D.S., 2007. Water quality and metal
concentration in sediments and fish from Ahmadu
Bello University Reservoir, Zaria Using Neutron
Activation An alysis and Atomic Absorption
Spectrophotometer. Unpublished Ph.D. Thesis,
Department of Biolo gical Sciences A hma du B ello
University, pp: 6-30.
Abu bakar, M. and S. Garba, 2006. Level of havy mtals in
terrestrial crabs. Best J., (4): 47-80.
Adakole, J.A., 1995. The effects of pollution on a stretch
of River Kubanni, Zaria. Unpublished M.Sc. Thesis
Deptartment of Biological Science, ABU Zaria,
Nigeria. pp: 121.
Angeyo, K.H., J.P. Patel, J.M . Mangala and D.G.S.
Naroya, 1998. Optimization of X-ray fluorescence
elemental analysis an example from Kenya. Appl.
Rad. Isot., 49: 885-891.
Ayodele, J.T. and M. Abubakar, 2001. Chromium and
C o p p e r i n w a t e r , se d im e n t s a n d th e ir
bioaccumulation by freshwater Bivalves in Tiga
Lake, Kano-Nigeria. J. Environ. Sci., 5(1): 177-184.
Ayodele, J.T. and M . Abub akar, 2002. Trace Metal
Determination in Sediment and in two species of
freshwater molluscs in Tiga Lake, Kano Nigeria. Nig.
J. Basic Appl. Sci., 2(1): 81-90.
Balarabe, M.L., 2001. Effect of Limnological
characteristic on Zooplankton composition and
distribution in Dumbi and Kwangila Ponds, Zaria,
Nigeria. Ph.D. Thesis, Department of Biological
Sciences, Ahmadu Bello University. pp: 7-21.
Bernard, F.J. and C.E. Lane, 1961. Regulation of body
metal burden by crustaceans crabs. Biol. B ull. Mar.
Lab. Wood H ole, 121: 438.
Bernasconi, G.B., 1996. AXIL-QX AS, Instruction
Manuals IAEA , Vien na.
Bernasconi, G.B., S.A. Bamford, B. Dosan, N.
Haselberger, A. Markowicz, A. Mahmoud and V .
Valcovic, 1996. Applicability of annular source
excited systems in quantitative XRF analysis. X-ray
Spectrum, 23: 65-70.
Ewa, I.O.B ., M.O .A. O ladipo and L .A. D im, 1999.
Horizontal and vertical distribution of selected metals
in the Kubanni R iver, Nigeria as determined by
Neutron Activation analysis. Co mm un. Soil Sci.
Plant Anal., 30(7-8): 1081-1090.
Funtua, I.I., 1999a. Analysis of Nb-Ta ores by energy
dispersive X-ray fluorescence spectrometry. J. Trace
Microprobe. Tech., 17(2): 189-195.
Funtua, I.I., 1999b. Application of the transmission
emission method in EDXRF for the determination of
trace elements in geological and biological materials.
J. Trace Microprobe Tech., 17(3): 293-297.
Giauque, R.D., R.B. Garreth and L.Y. Goda, 1979.
Determination of trace elements in light element
58