Seasonal variation of some major ions in a tropical lagoon waters, Aby lagoon (Côte d’Ivoire): Relationship with temperature, salinity and pH

Abstract

In response to continental inputs, the aim of this study was to know some major ions contents in Aby lagoon waters, according to seasons and in relation to temperature, salinity and pH. To do this, concentrations of major ions such as (sodium (Na +), potassium (K +), calcium (Ca2+), magnesium (Mg2+) and sulphates (SO42-) of Aby lagoon waters are determined, according to seasons and in relation to temperature, salinity and pH. From September 2007 to July 2009, during monthly sampling campaigns, temperature, salinity and pH of lagoon’s waters were measured, in situ, at twenty (20) stations distributed along lagoon. Water samples were taken at these stations, at the depth of 0.2 m below the surface, to determine in laboratory, concentrations of major ions using standard methods (Atomic Absorption Spectrometry methods for sodium, potassium, calcium and magnesium and Nephelometric method for sulphates). Seasonal variations of sodium, potassium and calcium concentrations are proportional to temperature, salinity and pH. These ions are under influence of oceanic waters inputs. In contrast, magnesium and sulphates are under anthropogenic influence, these concentrations are not proportional to temperature, salinity and pH. There are significant seasonal differences between major ions concentrations of waters from one season to another. Aby lagoon is under strong anthropogenic influence.

Potassium and calcium content in padelegan water which is used as the raw water for making salt

“…These results are similar to Fianko et al, who got similar results; potassium and calcium had a positive correlation with a value of r=0.73[31]. However, Assemian-Niango et al get different results where potassium and calcium have a weak negative correlation with an r = -0.59[ 32]. The level of DO and temperature showed a weak negative correlation with calcium and potassium concentration.…”

“…Furthermore, it is added that Singapore's potassium value is twice as significant as that of Padelegan. [ 32]. The level of DO and temperature showed a weak negative correlation with calcium and potassium concentration.…”