Ma. Victoria O. Espaldon

Assessment of Trace Metals during Episodic Events using DGT Passive Sampler: A Proposal for Water Management Enhancement

The potential of the Diffusive Gradient Thin-Films (DGT) as a supplemental method for water quality monitoring was employed has been tested through 3 sampling campaigns to measure the trace metals (Cd, Co, Cr, Cu, Pb, Ni and Zn) present in the surface water of a highly urbanized river. Specifically, the study done in the Pasig River (Philippines) seeks to: assess the applicability of DGT passive sampler in an urban context exhibiting highly contrasted hydrological conditions (greatly influenced by episodic events) and sediment disturbance (dredging) and provide proposal for a better water management. The results indicate that: (1) DGT is highly recommended as part of a routine analysis for water quality monitoring; (2) DGT are able to capture the fluxes even in very contrasted flow regimes; (3) DGT are suitable to trace the labile fluxes of metals from the lake to the estuary; and (4) at the confluence of the Marikina River water management should be intensified. Moreover, recommendations were made for developing pertinent water monitoring protocol and management scheme.