EFFECTS OF ANTHROPOGENIC INPUTS IN THE WATERS OF A TIDAL CREEK IN THE WOURI ESTUARY, CAMEROON

We examined chemical and physical properties of a tidal creek in the Wouri Estuary located in Southwest Cameroon. This creek supports human and mangrove forest ecosystems. The goal is to evaluate the impact of semidiurnal tide cycles, and an exponentially growing population on water quality. Spatial measurements were made using a multi-parameter probe, twelve water and sediment samples were collected approximately every 1 km from the open estuary along the 11 km creek at both high and low tide. These samples were analyzed for alkalinity, and measurements were made for physicochemical properties. pH values were relatively constant (6.8 ± 0.1) during high and low tide, 2 km away from the open estuary to 11 km along the creek. However, from the first location at the open estuary to the second station, 2 km away, pH was 6.95 at high tide and 6.15 at low tide. TDS concentrations at high tide steadily decreased from 71 mg/L to 10 mg/L over the 7 km reach into the creek, and steadily increased to 21 over the last 4 km. Alkalinity was nearly constant up to 7 km in the creek at high tide (24 mg/L CaCO₃). From 8 km alkalinity spiked to 170 mg/L CaCO₃, decreased to 93 mg/L CaCO₃, and then steadily decreased to 64 mg/L CaCO₃ at the last station. At low tide, alkalinity remained relatively constant until 7km from where it peaked to 103.5 mg/L CaCO₃. After the peak it decreased steadily to 38.5 mg/L CaCO₃ at the last station. Trends in the data show consistency from the open estuary to about 7 km into the creek. The differences in trends from the mouth to 7km in the creek and from 7km to the last sample station may be attributed to significant anthropogenic inputs in the last segment of the creek.