International Journal of Aquaculture, 2016, Vol.6, No.22, 1
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indicating the place was polluted. This because the stations were characterised by communities that were smaller
r
-selected or opportunistic species with a short life-span like
Chironomus larvae
which were usually numerically
dominant but do not represent a large proportion of the community biomass hence when comparing their weight and
number, their number was more than their weight. This agrees with the works of Agard et al., (1993).
The temperature in this study was high in the month of November, and decreased to the month of February, 2016.
The drop in temperature could be attributed to change in weather from raining season to harmattan from November,
2015 to January, 2016 and a rise in temperature from the month of January to February, 2016 could be attributed to
decrease in harmattan during the month. Sharma et al. (2013), Yogesh and Pendse (2001) reported similar
fluctuation in temperature in various water bodies with season. The mean temperature in this study (23.51°C)
disagrees with the findings of Akaahan et al., (2015); Agouru and Audu (2012) who reported 28.74°C and 27.45°C
respectively on their various studies on same river Benue. The highest temperature was recorded in station B which
could be as a result of biodegradation activities by microbes on waste release from the abattoir.
The pH in this present study ranged between 10-10.2. This disagrees with the findings of Akaahan et al.,
(2015) who
reported that the pH of river Benue was slightly alkaline (6.63), Agouru and Audu (2012) reported 7.77, and
increase in temperature over the month was associated with decrease. The monthly fluctuation could be attributed to
fluctuation in water volume of River Benue during the study period. The high pH during period of high water
volume (i.e. raining season) disagrees with Ebere (2002) and Nweke (2000) who confirmed higher pH in the dry
season than in the raining seasons. Electrical Conductivity, Total Dissolved Solids, Biochemical Oxygen Demand
and Alkalinity correlated negatively with pH while DO correlated positively with pH.
Electrical conductivity indicates the presence of ions in the water which is usually due to the saline intrusion and
leaching of organic waste from the abattoir. The conductivity is an indispensable water quality parameter for
indicating risk associated with salinity. The mean result of electrical conductivity obtained in this study showed
lowest in station A (43.40 ±46.7 µs/cm) and highest in station B (496.50 ±6.38 µs/cm). These values were contrary
to that of Akaahan (2014), Ishaq S et al., (2012) who reported 86.85 µs/cm. The result of stations A and D was
however below the maximum limit of 100.00 µs/cm while station B and was above the limit set by WHO and
Nigerian standard for drinking water quality (WHO, 2004). The mean high electrical conductivity in station A and D
could be attributed to decaying of organic matter which increases the salinity of the water, while low salinity in
stations A and D could be attributed to lack of saline intrusion in the river Benue at Makurdi. Electrical conductivity
was almost uniform across the station throughout the study period showing high values in stations B and C and low
values in station A and D. Electrical conductivity correlated.
Total Dissolved Solids is an index of the amount of dissolved substances from anthropogenic sources in a water
body (Davies, 2013). The high total dissolved solids in stations B and C is an indication of organic pollution from
the abattoir. It is also an indication of high dissolved solids at the abattoir effluent than the river agreeing with the
studies of Emeka et al., (2011). The result of the present study is below the WHO permissible limited limit of 1 500
mg/l.
Biochemical Oxygen Demand is the amount of oxygen necessary for oxidative decomposition of organic matter by
microorganism. In the present study, Biochemical Oxygen ranged highest in station B and C indicating high level of
biological activities going on by microbes by micro organism on the waste discharged from the abattoir resulting in
the use of oxygen, hence high values of BOD. This high value of Biochemical Oxygen Demand in this study agrees
with Sharma et al., (2013) in his study of macro invertebrates’ community and diversity in relation to water quality
status of Kuda River in India. Idowu and Ugwumba (2005) also confirm higher values in polluted areas.
The concentration of Dissolved Oxygen measures the degree of pollution by organic matter, the destruction of
organic substances as well as the self purification capacity of the water body. The depletion of dissolves oxygen at
station B may be attributed to huge amount of organic waste from the abattoir which requires oxygen for chemical
