TEMPORAL AND SEASONAL-VARIATIONS OF HYDROGEN-PEROXIDE LEVELS IN ESTUARINE WATERS

Hydrogen peroxide variability on the Patuxent River at both estuarine and freshwater locations are reported. Estuarine peroxide ranged from 11 to 350 nM and exhibited both diel and seasonal variability. Upriver , high organic, freshwaters showed similar H2O2 profiles to those obse rved in the estuary. These are the first H2O2 data reported for this e stuarine environment. Concentrations are similar in magnitude and rang e to values reported in both fresh and marine systems. The diel H2O2 v ariability presented here is similar in structure to marine and freshw aters with an amplitude intermediate between the former and the latter . Possible implications for submicromolar levels of this chemically an d biologically labile species in estuarine systems are also discussed.