Assessment Of Ecological Health Status And Socioeconomic Drivers Of Degradation In Two Southwestern Estuarine Systems Of Ghana

Abstract

This study presents findings of the assessments of water and sediment quality, pollution indication, health risks associated with nutrients and metal contamination, and the drivers of degradation in Pra and Ankobra estuaries. Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI) was used to evaluate the water quality, and the values indicated that both estuaries were in the marginal water quality category. Nemerow's Pollution Index (NPI) and Principal Component Analysis (PCA) showed that turbidity (from siltation), As, P04, Fe, Hg, Cu, and Pb contributed to the pollution of the estuaries. Furthermore, the health risks index of Target Hazard Quotient (TI-IQ) and Total I-Iazard Index (THI) evaluated on shellfish (Macrobrachium) from the two estuaries were above USEPA recommended threshold; therefore, there is a likelihood of human health risk impacts on the coastal dwellers surrounding the estuaries. Additionally, the results of sediment analysis revealed a mean number of micro plastic particlesllO g in Pra river as follows; fibre (14.22±4.99), sheet (24.44±13.21), fragment (38.00±25.47), bead (4.22±4.84); and Ankobra, fibre (13 .OO± 7.56), sheet (20.60± 12.59), fragment (8. 70± 11.22), bead (3.30±4.14). Metal concentrations in both estuarine sediments were in the order of Fe > As > Zn > Cu > Pb; concentrations of Cd and Hg were below the detection limit. Pb, Cu, and Zn were within Interim Marine Sediment Quality Guidelines while Fe and As exceeded the guidelines. Furthermore, the respective order of contamination factor and geoaccumulation index of metals were As > Fe> Zn >Pb > Cu (pra) and As > Fe > Pb > Cu (Ankobra). Pollution Load Index (PU) recorded for Pra and Ankobra estuarine sediments were 1.94 and 2.71 , respectively, suggesting the deterioration of both estuaries. Consequently, findings from the use of Driver Pressure State Impact Response (DPSIR) framework to assess the drivers of degradation of the coastal enviroJUllent revealed that the environment is degraded due to the impact of antlu·opogenic activities such as gold mining activities, farming, improper waste disposaJ , and illegal fishing that put pressure on the environment. Unfortunately, the regulatory policies by governmental agencies, efforts of non-governmental organisations, and the nearby coastal communities to address the environmental issues have not yielded the desired results. Therefore, to s these coastal ecosystems and the adjourning communities, there is a need for more urgent interventions to stop further degradation, and to enhance the conservation of both the ecosystems and livelihoods of the coastal dwellers in the area.