net flux of heavy metals between estuarine and nearshore environments: a case study of the isipingo estuary, kwazulu-natal, south africa

this study examines the transport of seventeen heavy metals between the isipingo estuary andthe adjacent sea. results demonstrate variability of fluxes in terms of prevalence, concentration and seasonality.summer neap and spring tides had approximately twice the number of heavy metals compared to winter andspring seasons. spring and winter seasons yielded higher concentrations and a greater number of metals on thespring tides whilst autumn yielded the fewest metals on both tides. export dominance characterized thesystem and this was evident in the annual fluxes with 14 metals (al, as, ba, cr, cu, fe, mn, mo, pb, se, sr,ti, v and zr) being exported while 3 (cu, ni and zn) were imported into the estuary over the four seasons,pointing to potential contamination from marine sources. whilst human utilization of the catchment is oftenreported as the primary cause of degradation of the isipingo estuary, this study demonstrates that some of thecontamination may also originate from the nearshore environment.