Emily E. Woodward Michelle L. Hladik Dana W. Kolpin 2018 CSV file Sacramento, CA U.S. Geological Survey https://doi.org/10.5066/P91OESMG Nitrapyrin, a nitrification inhibitor, 6-CPA, a nitrapyrin degradate, and three co-applied herbicides (acetochlor, atrazine, and metolachlor) were measured in water samples from seven streams across Iowa and Illinois. Iowa water samples were collected from March 2016 to June 2017, and Illinois water samples were collected from September 2016 to June 2017. The compounds studied are applied to corn, and Iowa and Illinois are the two largest corn producing states in the U.S. The seven stream sites are all adjacent to agricultural fields in corn production. Water samples (1-L) were collected in amber glass bottles using a grab or depth weighted approach. With the exception of one site, Iowa River at Wapello (USGS Site ID 05465500), all water samples were collected using a hydrologic based sampling approach. This means that samples were collected near peak flow during storm events and periodically during base flow conditions. Water samples were filtered (0.7 micrometers), extracted via solid phase extraction (Oasis® MAX cartridge), and analyzed (nitrapyrin and herbicides by gas chromatography with mass-spectrometry; 6-CPA by liquid chromatography tandem mass-spectrometry). The purpose of the data collection was to document off-field transport of nitrapyrin to streams and to document the temporal conditions under which transport is enhanced. This data set is the first to document transport after both spring and fall applications, and this data set can be used to direct future toxicity and ecological studies focused on nitrapyrin. 20160316 20170618 ground condition Complete None planned -96.817016601261 -87.236938476645 43.508403682242 36.518114360445 USGS Thesaurus stream discharge water quality contaminant transport ecotoxicity NAL Agricultural Thesaurus stormwater nitrapyrin herbicide Corn Belt region USGS Metadata Identifier USGS:5b04760de4b0d8682b96357c USGS Common Geographic Areas United States Iowa Illinois Oregon GEO Temporal Keywords Spring Summer Fall Winter year none none Michelle L. Hladik PACIFIC REGION Research Chemist mailing and physical

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Sacramento CA 95819 US 916 278-3183 mhladik@usgs.gov Shannon M. Meppelink, Paul J. Terrio, USGS Toxic Substances Hydrology Program, No formal attribute accuracy tests were conducted No formal logical accuracy tests were conducted Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. No formal positional accuracy tests were conducted No formal positional accuracy tests were conducted U.S. Geological Survey 2018 Name, associated number, and value Reston, VA U.S. Geological Survey https://waterdata.usgs.gov/usa/nwis/ Qualitative (site names and site numbers) and quantitative (discharge values for each sample) 20160316 20170618 current Water Data Site number, site name, and discharge data for the Data Release table were pulled from this source A dataset was compiled summarizing data from the U.S. Geological Survey National Water Information System database and data that was collected in the Organic Chemistry Research Laboratory in Sacramento, CA. 2017 Michelle L. Hladik PACIFIC REGION mailing and physical

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Sacramento CA 95819 US 916 278-3183 mhladik@usgs.gov United States Geological Survey (USGS) site names and numbers Point Iowa and Illinois Stream Data_2016_2017_Nitrapyrin_6CPA_Herbicides This spreadsheet provides site IDs, site names, sampling dates, sampling times, stream discharge, 6-CPA and nitrapyrin concentrations, herbicide concentrations. U.S. Geological Survey Site ID An official U.S. Geological Survey Site ID that can be used to identify site sampling site U.S. Geological Survey National Water Information System U.S. Geological Survey National Water Information System Site Numbers https://waterdata.usgs.gov/nwis/inventory?search_criteria=search_site_no&submitted_form=introduction Site Name An official U.S. Geological Survey Site Name that can be used to identify sampling site U.S. Geological Survey National Water Information System U.S. Geological Survey National Water Information System Site Names https://waterdata.usgs.gov/nwis/inventory?search_criteria=search_station_nm&submitted_form=introduction Date The month, day, and year in which the water sample was collected Producer defined 03/16/16 06/18/17 days Time Time that water sample was collected in CST Producer defined 00:00 24:00 minutes Discharge (m3/sec) Discharge value in stream from day water sample was collected U.S. Geological Survey National Water Information System Stream discharge specific to each site and day Nitrapyrin (ng/L) Concentration of the nitrogen stabilizer, nitrapryin, in water sample Producer defined A concentration value for nitrapyrin analyzed in the water sample (ng/L); blank cells are non-detects. 6-CPA (ng/L) Concentration of nitrapyrin degradate, 6-CPA, in water sample; blank cells are non-detects. Producer defined A concentration value for 6-CPA analyzed in the water sample (ng/L); blank cells are non-detects. Atrazine (ng/L) Concentration of the herbicide atrazine in water sample Producer defined A concentration value for atrazine analyzed in the water sample (ng/L); blank cells are non-detects. Acetochlor (ng/L) Concentration of the herbicide acetochlor in water sample Producer defined A concentration value for acetochlor in the water sample (ng/L); blank cells are non-detects. Metolachlor (ng/L) Concentration of the herbicide metolachlor in water sample Producer defined A concentration value for metolachlor in the water sample (ng/L); blank cells are non-detects. U.S. Geological Survey- ScienceBase U.S. Geological Survey- ScienceBase mailing and physical

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Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. 20220331 Michelle L. Hladik PACIFIC REGION Research Chemist mailing and physical

6000 J Street Placer Hall

Sacramento CA 95819 US 916 278-3183 mhladik@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998