Abstract

Lagos lagoon is known to be highly contaminated due to the increase in human population, industries and influx of contaminants from adjoining creeks. The degree of this contamination can be affected by the seasonal variations in time and space. The spatio-temporal variations in the hydrochemistry and sediments parameters of three (3) Lagos lagoon’s creeks were investigated for six months (June, 2016 to November, 2016). Sub-surface water and sediments were collected with a 1 dm³ water sampler and Van-veen grab, respectively and analyzed. Water temperature, pH, dissolved oxygen and conductivity of the water samples and pH, nutrients (nitrate and phosphate), total organic matter (TOM) and total organic content (TOC), alkalinity, acidity and particle size of the sediment samples were analyzed. The physico-chemical parameters in the water and sediment from the sampled creeks showed none significant differences (P>0.05). The study showed an increasing level of parameters’ rates analyzed, indicating increased contaminants in Abule Eledu and Ogbe creeks. Water temperature maintained a relatively uniform temperature with dissolved oxygen values range of 1.6 to 3.1 mg/L. Conductivity was higher in June to August while high prevalence of nutrients was observed in October and November. Abule Agege and Abule Eledu recorded TOM and TOC that were above 15 mg/kg in June to August while alkalinity and acidity were high in October (6.63 mg/kg) and November (7.72 mg/kg) in the study creeks. The sediment particles size of the creeks ranged from clay, muddy and sandy substratum signifying that they were macrobenthic specific. The increase of the parameters’ concentration indicates that the three creeks are highly impacted by anthropogenic stressors, dependent on the source of pollution occurring at the sites as well as controlled by seasonal variations. Continuous monitoring is required to be done to prevent future heavy metal pollution and total degradation in the water’s quality of the Lagos lagoon’s creeks.

Key words: Physico-chemical characteristics, sediments, creeks pollution, seasonal variation, Lagos lagoon.