Assessment of heavy metals contamination in the sediment of Yardantsi reservoir, Gusau Nigeria

The magnitude and ecological relevance of metals pollution in the sediment of Yardantsi Reservoir, Gusau Nigeria, which serve as main source of water for irrigation and municipalities was assessed by applying sets of complementary sediment quality assessment methods; The contamination factor (Cf); and comparisons with concentration based sediment quality guidelines (CBSQGs) of target heavy metals. The sediment metals concentrations in the reservoir were investigated from May, 2015 to April, 2017. Sediment samples were collected from five sampling stations and analysed using Shimadzu AA6800 Atomic Absorbtion Spectrophotometry. The results showed that Cd has a mean concentration of (1.81cmol/kg). Cu (3.40cmol/kg), Cr (0.99cmol/kg), Fe (46.71cmol/kg), Ni (0.50cmol/kg), Pb (0.14cmol/kg), and Zn (13.87cmol/kg). Contamination factor (Cf) and CBSQGs suggested that cadmium concentration was slightly higher as Cf>6 and exceeded threshold effects concentrations (TECs). This may cause adverse biological effects and the reservoir was in potential risk with regards to Cd concentration, while the rest of the metals were found to be lower than the proposed TECs and has Cf<1 indicating that there are no harmful effects from these metals. It is suggested that the reservoir input should be monitored and the sediment sources be mitigated.Keywords: Assessment, contamination, heavy metals, reservoir, sedimen

Assessment of surface water physico-chemical parameters of Yardantsi Reservoir, Gusau Nigeria

The Yardantsi Reservoir, Gusau Nigeria serves multitude of purposes for the Gusau populace. It is the main source of water for domestic purpose, irrigation, and fishing. The reservoir receives both organic and inorganic waste through runoffs and seepage from the catchment areas. The physico- chemical parameters of the surface water were investigated monthly from May, 2015 to April, 2017. Samples were collected from five sampling stations and analyzed using standard procedures for examination of water and waste water. The data obtained was subjected to multivariate analysis using Microsoft office excels and SPSS. The results showed the following mean seasonal variation of surface water temperature (26.62±0.34– 30.12±0.17ᴼC),transparency (48.82±1.08- 22.07±0.87cm), mean depth (2.12±0.05-2.65±0.04m), pH (7.61±0.15-7.96±0.13), electrical conductivity (186.32±3.84- 108.05±5.43µS/cm), total dissolved solids (96.00±1.95- 63.70±3.68mg/L), dissolved oxygen (7.80±0.11-6.91±0.10mg/L), biochemical oxygen demand (2.71±0.09-2.48±0.05mg/L), alkalinity (40.57±0.69–27.87±0.51mg/L), hardness (59.20±1.01– 32.18±0.94mg/L), NO3-N (2.28±0.08-4.44±0.07mg/L), PO4-P (123.72±1.44-173.48 ± 2.78 mg/L), sulphate (31.62±1.45-71.80±1.82mg/L)  and chloride (74.08±1.67- 37.64±0.96mg/L) for dry and rainy seasons respectively. The results revealed that a highly significant seasonal variation (p<0.01) was exhibited in all parameters with the exception of pH which shows no significant seasonal variation (p>0.05) and biochemical oxygen demand, which shows a significant seasonal variation (p<0.05). The results of this survey showed that the parameters observed indicated that most of them fall within the recommended range set by World Health Organization (WHO) and Nigerian Standard for Drinking Water Quality (NSDWQ).Keywords: Dissolved oxygen, electrical conductivity, pH, reservoir, temperatur