Occurrence of Atrazine and Related Compounds in Sediments of Upper Great Lakes

Abstract

Surface grab and core sediment samples were collected from Lakes Michigan, Superior, and Huron from 2010 to 2012, and concentrations of herbicides atrazine, simazine, and alachlor, as well as desethylatrazine (DEA), were determined. Concentrations of atrazine in surface grabs ranged from 0.01 to 1.7 ng/g dry weight and are significantly higher in the southern basin of Lake Michigan (latitude <44°) than other parts of the three lakes. The highest concentration of alachlor was found in sediments of Saginaw Bay in Lake Huron. The inventory and net fluxes of these herbicides were found to decline exponentially from the south to the north. The concentration ratio of DEA to atrazine (DEA/ATZ) increased with latitude, suggesting degradation of atrazine to DEA during atmospheric transport. DEA/ATZ also increased with sediment depth in the sediment cores. Diffusion of deposited herbicides from the upper sediment into deeper sediments has occurred, on the basis of the observed patterns of concentrations in dated sediment cores. Concentrations of atrazine in pore water were estimated and were higher than those reported for the bulk waters, suggesting the occurrence of solid-phase deposition of atrazine through the water column and that contaminated sediments act as a source releasing atrazine to the overlying water. ■ INTRODUCTIONCurrent agricultural practices often involve extensive use of herbicides. 1 Atrazine [1-chloro-3-ethylamino-5-isopropylamino-2,4,6-triazine], simazine [6-chloro-N,N′-diethyl-1,3,5-triazine-2,4-diamine], and alachlor [2-chloro-2,6-diethyl-N-(methoxymethyl)acetanilide] are among those used in the United States. Atrazine and simazine are both triazines and were initially registered as herbicides in 1958 and 1956, respectively. 2,3 Alachlor, a chloroacetanilide, was first registered in 1969. 4 From 1992 to 2011, reported annual usages on crops were 32 000−36 000 tons for atrazine, 1814−2722 tons for simazine, and 454−22 680 tons for alachlor. 5 These herbicides are primarily used in the "Corn Belt" near the Great Lakes of North America, including the states of Iowa, Illinois, and Indiana and parts of others. 1,5 Their use has been banned by the European Union because of ubiquitous and unpreventable water contamination. Atrazine is classified as a Restricted Use Pesticide in the United States. 6 According to the U.S. Environmental Protection Agency (EPA), atrazine is an endocrine disruptor, 6 simazine may have reproductive or developmental toxicity, 7 and alachlor was classified as a "likely" human carcinogen at high dose. 4 Compared with organochlorine pesticides, atrazine and related compounds are more soluble in water. A major concern is their potential to leach from soils to surface and ground waters that are used as sources of drinking water; 3 thus, most monitoring efforts to date have been conducted for water. Atrazine was found in waters of all five Laurentian Great Lakes. 8−10 In rivers of the Midwestern U.S., elevated concentrations of atrazine, simazine, and alachlor were fou...

Nontarget Screening Reveals Time Trends of Polar Micropollutants in a Riverbank Filtration System

“…The detection of atrazine-desethyl-2-hydroxy at constant levels might be attributed to the release of atrazine (or TPs) from contaminated river sediments prior to infiltration in the RBF system. 83 Other known metabolites of atrazine and simazine were screened for in HRMS1 data, but were not detected. These TPs might have either been absent from the RBF transect or occurred at undetectable concentrations.…”

Metabolic Profiling of Chloroacetanilide Herbicides in Earthworm Coelomic Fluid Using1H NMR and GC–MS

“…19 A recent study (2010− 2012) detected alachlor in sediments samples from the great lakes at median concentrations between 0.001 and 0.18 ng/gdry weight. 20 Metolachlor, metolachlor ESA, metolachlor OA, alachlor ESA, and alachlor were the eighth, 18th, 52nd, 150th, and 293rd, respectively, most frequently detected anthropogenic compounds in a nationwide US study of stream surface water, sampled between 2012 and 2014. 21 Thus, with their toxicity, mobility, and potential to leach into groundwater and runoff into surface waters, it is critical to monitor the nontarget impacts of chloroacetanilide herbicides on soil ecosystems.…”

“…Less than 4.5 × 10 6 kg of alachlor and racemic metolachlor were estimated, while the applications of butachlor and propachlor were not reported . A recent study (2010–2012) detected alachlor in sediments samples from the great lakes at median concentrations between 0.001 and 0.18 ng/g-dry weight . Metolachlor, metolachlor ESA, metolachlor OA, alachlor ESA, and alachlor were the eighth, 18th, 52nd, 150th, and 293rd, respectively, most frequently detected anthropogenic compounds in a nationwide US study of stream surface water, sampled between 2012 and 2014 .…”

Effects of tall fescue biochar on the adsorption behavior of desethyl-atrazine in different types of soil

“…Therefore, the presence of pesticide metabolites in the environment is of great concern. Desethyl-atrazine (DEA) is a metabolite formed by the physicochemical process and microbial degradation of its parent atrazine in soil, which is widely distributed in environmental media (Guo et al 2016;Yu et al 2018). Groundwater research in Iowa (USA) reported a DEA detection frequency of 32.1%, ranked only second to its parent compound atrazine (37.4%) and higher than deisopropylatrazine (DIA) (21.4%) and hydroxyatrazine (HA) (11.4%) (Kolpin et al 2000).…”