Nitrapyrin, 6-CPA, and herbicide concentrations in agricultural soils, subsurface drains, and corresponding streams in the Midwestern US

Nitrapyrin is a nitrification inhibitor that is co-applied with N-fertilizer in agroecosystems. Over the course of one year (March 2016 to June 2017), 192 water samples from seven streams across Iowa and Illinois were analyzed for nitrapyrin, its degradate 6-chloropicolinic acid (6-CPA), and three widely used herbicides acetochlor, atrazine, and metolachlor. Additional environmental samples were collected and analyzed in spring 2017: 63 water samples from eight subsurface drains, and 33 soil samples from a field in Iowa that received direct application of nitrapyrin (only for nitrapyrin and herbicides). Nitrapyrin was detected in all seven streams (56% detection) with concentrations ranging from 4 to 1,200 ng/L; 6-CPA was detected in six of the seven streams (13% detection) with concentrations ranging from 2 to 13 ng/L. Nitrapyrin was detected in only two of the eight subsurface drains and in 10% of drain samples (10% detection), and with concentrations ranginged from 3 to 12 ng/L; 6-CPA was detected in six of the eight subsurface drains and in (33% of drain samples withdetection), and concentrations ranginged from 2 to 6 ng/L. Nitrapyrin was detected in 67% of the soil samples collected, and concentrations ranged from 0.9 to 42 ng/g. Generally, all three herbicides were detected more frequently and at higher concentrations than nitrapyrin in the streams, subsurface drains, and soils. There are 3 csv datasets related to this data release. Please find in each of the child items the data and metadata.

硝吡咯菌素（nitrapyrin）是一种硝化抑制剂，常与氮肥配施应用于农业生态系统中。本研究于2016年3月至2017年6月的一年周期内，采集了美国艾奥瓦州与伊利诺伊州境内七条溪流的192份水样，针对硝吡咯菌素、其降解产物6-氯皮考啉酸（6-chloropicolinic acid，简称6-CPA）以及三种广泛使用的除草剂——乙草胺（acetochlor）、莠去津（atrazine）和甲草胺（metolachlor）开展了检测分析。
2017年春季，研究团队额外采集并分析了两类环境样品：来自八条地下排水管道的63份水样，以及取自艾奥瓦州某田块的33份土壤样品——该田块曾直接施用硝吡咯菌素（本次仅针对硝吡咯菌素与除草剂开展检测）。
七条溪流中均检出硝吡咯菌素，检出率为56%，浓度范围为4~1200 ng/L；七条溪流中有六条检出6-CPA，检出率为13%，浓度范围为2~13 ng/L。
八条地下排水管道中仅两条检出硝吡咯菌素，排水样品总检出率为10%，浓度范围为3~12 ng/L；八条管道中有六条检出6-CPA，检出率为33%，浓度范围为2~6 ng/L。
本次采集的土壤样品中，67%检出硝吡咯菌素，浓度范围为0.9~42 ng/g。
总体而言，在溪流、地下排水系统与土壤样品中，三种除草剂的检出频率均更高，浓度水平也均高于硝吡咯菌素。
本数据发布关联三份CSV格式数据集，各子项中均包含对应数据与元数据。