Spatio-temporal variation in some environmental variables of Bosso Dam, Nigeria

Bosso dam was constructed primarily for the Niger River basin municipal supply of drinking water and for other domestic use. Physico-chemical properties of Bosso Dam, Bosso, Niger state Nigeria were investigated monthly between September, 2015 and February, 2016 to determine seasonal variation, as well as providing a baseline data for monitoring water quality changes prompted by human induced factors. Water samples were collected from three accessible stations of the dam for chemical analyses using standard methods. One – way ANOVA were used to evaluate relationships between environmental variables with PAST. Findings on the physico-chemical status of the water revealed that temperature ranged from 27.0oC-30.5oC, weak acidic to weak alkaline pH range of 6.7-7.3, Dissolved Oxygen Concentration (5.0-8.0mg/l) was marginally high while the BOD range of (2.0-5.0mg/l) was relatively high. The essential primary productivity nutrients, Nitrogen (0.12-0.19mg/l), Phosphate (0.02-0.09mg/l) and Sulphate (9.3-17.7mg/l) were relatively low in all the sampled stations. The lake is not eutrophic, so, various management strategies such as periodic monitoring of physico-chemical parameters should be carried out and hence the need for an effective anthropogenic inputs control programme in the dam. The study further revealed that the dam could be used for irrigation purposes for dry season farming, health wise; the water should undergo a little treatment before consumption even though the dam was constructed purposely for the supply of drinking water to the people of Bosso and the environs.Keywords: physico-chemical, seasonal variation, Bosso Da

Heavy metal content in the African giant snail Archachatina marginata (Swainson, 1821) (Gastropoda: pulmonata: achatinidae) in Southern Nigeria

Heavy metal concentrations in the African giant snail Archachatina marginata (Swainson) from nine localities in southern Nigeria ranged from 0.77 to 7.51 mg kg–1 Pb; 3.06–46.9 mg kg–1 Fe; 0.03–0.40 mg kg–1 Ni; 0.04–0.12 mg kg–1 Cu; 0.71–4.51 mg kg–1 Co; 0.67–1.27 mg kg–1 Mn; 0.99–3.28 mg kg–1 Cd; 0.08–0.22 mg kg–1 Zn; Cr was below the limit of detection. Concentrations of Pb, Fe, Ni, Cu, Co, Cd and Zn in the snail tissue varied significantly (95% confidence limit) between the localities. No significant variation was observed in the concentrations of Cr and Mn. Pb and Cd concentration exceeded the statutory safety limits for these elements in meat. The results indicate a heavy metal pollution of the habitats

Qualitative habitat evaluation index and some selected macroinvertebrate taxa metrics as a diagnostic tool for assessing pollution loads in a municipal river in north central Nigeria

Pollution load in a municipal river in north central Nigeria was assessed using qualitative habitat evaluation index and some selected macroinvertebrate taxa metrics. The study was conducted for a period of twelve (12) months, spanning from March, 2017 to February, 2018, in four sampling stations. Station 1 was the reference site located in a relatively unperturbed area close to the river source. Macroinvertebrates were sampled using the kick sampling method of a D-frame net. Percentages of Ephemeroptera, Plecoptera and Trichoptera (EPT) and Chironomidae+Oligochaeta were calculated to ascertain the ecological state of the river. The Qualitative Habitat Evaluation Index (QHEI) values portray a moderately impaired site. Station 1 QHEI was 76.15% which was the highest value recorded while station 4 was the worst hit among the sampled stations with 42.69%. Percentage EPT calculated showed that station 1 had the highest composition of the group with 13.12% while station 4 % EPT was 0.147. Further lending credence to the heavily perturbed state of station 4 is the percentage Chironomidae + Oligochaeta with 7.34% composition, which is much lower than that of station 1 the relatively unperturbed station. The study was able to elucidate the level of pollution loads in each of the stations sampled and it was noticed that pollution load was increased downstream from station 1 to station 4. A more detailed study on the use of biotic indices to assess the ecological status of rivers in the  North central region of Nigeria were the River Chanchaga is located is recommended to further ascertain the level of disturbance the rivers are undergoing. This can be best done using macroinvertebrates predictive protocols and traits based monitoring approach.Keywords: Ecological Integrity, Pollution loads, QHEI, EPT, River Chanchaga, Nigeri

Seasonal changes in the abundance of benthic macroinvertebrates & physico-chemical condition of Moussa Stream Bida, Nigeria

Seasonal changes in the abundance of benthic macroinvertebrates and physico-chemical condition of Moussa Stream, Bida Nigeria, were studied monthly from January to August 2017. Macroinvertebrates were sampled using modified kick sampling techniques. Three different sampling stations were selected along the course of the Stream. The results from the stream showed that water temperature (24.9-27.50C), Depth  (14.7-45.8cm), Flow velocity (0.14-0.23m/s), Biochemical oxygen demand (2.0-7.0mg/L), pH (6.33-8.6), Conductivity (20-63μ/cm), Alkalinity  (8-30mg/L), Turbidity (61-285NTU), Nitrate (0.87-3.85mg/L) and Phosphate (0.31-1.01mg/L) were within the maximum permissible limit (WHO, SON) except Dissolved oxygen (3.1-10mg/L). Most of the parameters investigated with the exception of depth and flow velocity showed no significant difference (p>0.05) among all the sampling stations. Temperature, depth and flow velocity showed no significant differences with season. pH, DO, BOD5, Turbidity, Conductivity, Alkalinity, Nitrate, and Phosphate were significantly higher during wet season. A total of 471 individuals from 30 species and 20 families of invertebrates were recorded. The overall macroinvertebrates recorded from station 1, 2 and 3 were 166(35.24%), 149(31.63%) and 156(33.12%). Overall, there was significant difference (P<0.05) in number of individuals among the sampling stations. The abundance according to the Orders revealed that Coleopterans, Odonata and Hemipterans were the most common groups encountered. Ephemeroptera Diptera, Mollusca and Oligochaeta were sparingly found in all stations. The percentage and total number of individuals of macroinvertebrates recorded during the study period shows 67.09% (316 individuals) in dry season and the remaining 32.90% (155 individuals) were recorded in rainy season. CCA result correlated positively between species abundances and measured environmental variables. Low density of pollution sensitive macro invertebrates groups and the deteriorating water quality were implications of pollution stress caused by anthropogenic activities. Key words: seasonal changes, macroinvertebrates, stream, Bida