Laboratory and field studies have consistently shown that CFCs are stable in the aerobic environments and their concentrations of groundwater can reflect atmospheric values at the time of recharge (Oster et al. Wetlands play an important role in climatic regulation, water conservation and purification, and the maintenance of biological diversity.However, their functions can easily be disturbed in areas with over-exploitations.

Apparent groundwater ages based on CFC- and He-dating techniques and model-based travel times could not be statistically differentiated, and all were strongly correlated with depth.

Confinement of 3He was high because of the rapid vertical flow velocity (of the order of 1 m/yr), resulting in clear delineation of groundwater travel times based on the He and CFC ages indicates that dispersion has had a minimal effect on the tracer-based ages of water in this aquifer.

The correspondence between the H-3/He-3 and CFC ages indicates that dispersion has had a minimal effect on the tracer-based ages of water in this aquifer.

Differences between the tracer-based apparent ages for seven of the 10 samples were smaller than the error values, A slight bias toward older apparent ages, found not to be statistically significant, was noted for the H-3/He-3-dating technique relative to the CFC-dating technique.

Wetlands are typically highly productive ecosystems with soils containing high levels of labile organic matter (Kadlec and Wallace ).

When groundwater moves through wetlands, aerobic condition in shallow groundwater could easily become anoxic condition because of the consumption of the available oxygen during decomposition processes (Seitzinger ).

This result may be caused by enrichment of local air in CFC-11 and CFC-12 from urban and industrial sources in the northeastern United States and minor contamination from sampling equipment.

The demonstrated validity of the combined tracer-dating techniques to determine the age of water in the Kirkwood-Cohansey aquifer system indicates that groundwater flow models can be refined when apparent ages based on H-3/He-3- and CFC-dating are used as calibration targets.

can help to resolve the extent to which groundwater mixing occurs, and therefore provide indications of the likely groundwater flow mechanisms.

Modelling shows that diffusive retardation of these age tracers is likely to be low owing to the high moisture content of the chalk unsaturated zone.

Groundwater age dating through the combination of transient tracer methods (chlorofluorocarbons (CFCs) and tritium/helium 3 (H-3/He-3)) and groundwater flow path analysis is useful for investigating groundwater travel times, flow patterns, and recharge rates, as demonstrated by this study of the homogeneous shallow, unconfined Kirkwood-Cohansey aquifer system in the southern New Jersey coastal plain.