Agrochemicals are a major source of nonpoint pollution. Forested corridors along stream channels (riparian zones) are thought to be potential sites for removal of agricultural contaminants from ground and surface waters. First-order riparian wetlands are reputed to be especially effective at groundwater remediation. The study site is a fairly typical (for eastern Maryland) small, first-order stream in an agricultural watershed. Preferential flow supplies most of the stream water within the riparian headwater wetland. This upstream area also contains the highest average stream N and pesticide loads in the entire first-order riparian system. Zones of active groundwater emergence onto the surface display high concentrations of @entity1507 throughout the soil profile and in the exfiltrating water, whereas inactive areas (where there is no visible upwelling) show rapid attenuation of @entity1507 with decreasing depths. @entity12472 degradation products appear to penetrate more readily through the most active upwelling zones, and there is a correlation between zones of high @entity1507 and high @entity12472 metabolite levels. @entity68982 / @entity12472 ratios (DAR) seem to indicate that stream flow is dominated by ground water and that much of the ground water may have reached the stream via preferential flow. Remediative processes appear to be very complex, heterogeneous, and variable in these systems, so additional research is needed before effective formulation and application of riparian zone initiatives and guidelines can be accomplished.

Influence of a riparian wetland on XXXX and herbicides exported from an agricultural field.

@entity12472 :: ('MESH:D001280', 'Chemical') :: ['Atrazine', 'atrazine'] @entity68982 :: ('MESH:C446541', 'Chemical') :: ['Deethylatrazine'] @entity1507 :: ('CHEBI:48107', 'Chemical') :: ['nitrate']
@entity1507 :: (CHEBI:48107,Chemical) :: ['nitrate']
