Atrazine Transport through a Soil–Epikarst System

Abstract

Row crop and livestock production contaminate soils and groundwater of the karst aquifers within south‐central Kentucky's Pennyroyal Plateau. Transport of atrazine from field application to the epikarstic drainage system beneath a field with active row‐crop farming was investigated. The Crumps Cave study site is a shallow autogenic drainage system with a recharge area of ∼1 ha that contains two epikarst drains (WF‐1 and WF‐2) which were monitored for atrazine, deethylatrazine (DEA), and deisopropylatrazine (DIA) concentrations from January 2011 to May 2012. Atrazine concentrations in both drains did not increase above winter background levels for nearly 2 mo after application when levels suddenly spiked and reached peak concentrations for the study during an event in May 2011. Atrazine, DEA, and DIA were detected in 100% of samples, and metabolites accounted for 54 to 94% of the monthly total loads, except in May 2011. Median dealkylated metabolite/atrazine ratios (DMAR) were ∼5:1 at both sites, and seasonal DMAR patterns corresponded with changes in soil temperature. These data support the hypothesis that a combination of sorption and degradation in the soil column above the epikarst controlled the transport of atrazine and its metabolites. This resulted in delayed atrazine transport after application and prolonged transport of atrazine and its weakly sorbed metabolites to the epikarst aquifer. Management practices that reduce herbicide inputs, such as diverse crop rotations, cover crops, and use of low‐rate and strong‐sorbing herbicides, would improve groundwater quality in areas of the Corn Belt with intensive row cropping on karst topography. Core Ideas Atrazine leaching to the epikarst was comparable with surface runoff losses. Sorption and degradation in soil controlled atrazine transport. After 10 mo, atrazine concentrations showed zero‐order kinetic declines.

Seasonal δ13CDIC sourcing and geochemical flux in telogenetic epikarst of south‐central Kentucky

“…() observed continuous flow and near immediate repsonses during storm events at an epikarst spring indentified as Waterfall One (WF1), suggesting the existence of a highly fractured and well‐developed epikarst conduit network. WF1 served as the sampling site for this study and is approximately 25 m from the suface and located 30 m from the cave's entrance, with an average drop of 4 m from the waterfall's appearance in the ceiling to floor of the cave (Vanderhoff, ; Groves et al ., ; Lerch et al ., ), where it disappears into the cave floor and joins the water table around 40 m below (Vanderhoff, ; Groves et al ., ). Multiple dye traces and hydrologic investigations conducted at WF1 place the estimated recharge area at around 1 ha and flow is perennial (Bandy et al ., ; Lerch et al, ).…”

Occurrence and spatial-temporal distribution of atrazine and its metabolites in the aquatic environment of the Volturno River estuary, southern Italy

“…Among the 20 European Union (EU) member states for which complete data are available, Italy is the third EU state for the sale of pesticides in 2016 with nearly 60 million kg sold each year (EUROSTAT, 2018). Indeed, recent studies reported the presence of ATR and its DPs in water of Italy (Ghirardelli et al, 2020;Hakoun et al, 2017;Lerch et al, 2018;Sassine et al, 2017;Vonberg et al, 2014a). In the Campania region, southern Italy, thanks to the high fertility of the territory due to the large presence of volcanic soils distributed throughout the region, agricultural activity is highly developed since ancient Roman times.…”

Geospatial Applications of Cave Resource Data to Better Understand Epikarst and Unsaturated Zone Groundwater Flow Path Development

“…To understand these processes, a wide variety of techniques are implemented. Researchers utilized geophysical methods [4], geochemical isotopic tracer methods [5], hydrograph analyses [6], and a combination of these approaches [7]. Recent advances in lidar and photogrammetry techniques produce high resolution models of subsurface conduits that allow for the interactive analysis of cave features after data collection [8][9][10].…”