Variations in Water Quality Index and Physicochemical Properties of Surface Water and Bottom Sediments of Selected Coastal Beaches of Niger Delta, Southern Nigeria

Thisstudyaimedtodeterminevariationsinwater quality index (WQI)andphysicochemicalpropertiesofsurfacewaterandbottomsedimentsofselectedcoastalbeachesofNigerDelta,SouthernNigeria.Thewaterqualityoftheriveriscategorizedintofiveclasses,whichareclassesI,II,III,IVandVbasedontheWQI(derivedfromthedeterminationofDO,BOD,COD,TSSandammoniaandpH).Waterandbottomsedimentsampleswereanalysedusingstandardprocedures.Duringthewetseason,physicochemicalparameterssuchaspotential hydrogen(pH),electricalconductivity(EC),dissolved oxygen(DO),total dissolved solids(TDS)andsalinityshowedsignificantdifference(p<0.05)acrossallthelocations.Duringthedryseason,parameterslikeEC,EA,pH,sodium(Na),sulphate(SO₄),chloride(Cl^-),potassium(K),effective cation exchange capacity(ECEC)andcalcium(Ca)showedsignificantdifference(p<0.05)acrossallthesixsampledbeacheswhilephosphate(PO₄)didnotshowanyclearsignificantdifferenceacrossallthesampledlocations.ThegeneraltrendinthelevelsofphysicochemicalparametersrevealedthattemperatureandpHwerewithinthoserecommendedbyWorld Health Organization (WHO)andUnited States Environmental Protection Agency(USEPA)forbothwetanddryseasonbutECandTDSwereabovetheWHOandUSEPAlimit.Twentyone(21)waterqualityparametersfromsixsamplinglocationswerestudiedandbyapplyingWQI,thestateofthesixbeachwaterwasveryunsuitablefordrinking,swimmingandrecreationalactivitiesasatthetimeofthisstudy.Thewaterisonlysuitableforirrigationpurpose.