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.
