Citizen science is a research tool capable of addressing major environmental challenges, including contamination of water resources by agrichemicals, such as nutrients and pesticides. The objectives of this study were (1) to identify the proportion of accurate observations by citizen scientists using rapid assessment water quality tools, and (2) to characterize how a user’s prior experience with water quality tools was associated with the accuracy of citizen scientists. To achieve these objectives, we conducted group testing with over 136 citizen scientists and compared their results from water quality testing of water samples to results obtained using laboratory analytical methods. Following brief training, we observed that accuracy of reported results varies based on the user’s experience level where experienced and expert users shared consistent and reliable measurements. Where erroneous measures were reported, citizen scientists tend to overestimate contaminant concentrations when using colorimetric water quality tools. Additionally, we identified differences in accuracy related to the types of water quality assessment tools used by citizen scientists from each experience group. This study demonstrates the importance of evaluating participant background experience in designing citizen science campaigns.

Precipitation induced runoff is an important pathway for agrichemicals to enter surface water systems and expose aquatic organisms to endocrine-disrupting compounds such as pesticides and steroid hormones. The objectives of this study were to investigate the distribution of agrichemicals between dissolved and sediment-bound phases during spring pulses of agrichemicals and to evaluate the role of suspended sediment in agrichemical bioavailability to aquatic organisms. To accomplish these objectives, suspended sediment and water samples were collected every 3 days from a field site along the Elkhorn River, located at the downstream end of a heavily agricultural watershed, and were screened for 21 pesticides and 21 steroids. Adult female fathead minnows (Pimephales promelas) were exposed in field mesocosms to river water containing varying sediment loads. Changes in organism hepatic gene expression of two estrogen-responsive genes, vitellogenin (VTG) and estrogen receptor alpha (ERα), as well as the androgen receptor (AR) were analyzed during periods of both low and high river discharge. Trends in agrichemical concentrations of both the dissolved and sediment phases as a function of time show that, while sediment may act as both a source and a sink for agrichemicals following precipitation events, the overall driver for molecular defeminization in this system is direct exposure to the sediment-associated compounds. This study suggests that endocrine disrupting effects observed in organisms in turbid water could be attributed to direct exposure of contaminated sediment.

In the Midwestern United States, waterways such as the Elkhorn River experience an annual spring pulse of runoff that carries sediments, nutrients, and organic compounds downstream. The objective of the present study was to elucidate relationships between contaminant load in Elkhorn River water and biological impacts on female fathead minnows throughout the entire spring agrichemical pulse. Fish were maintained in on-site outdoor microcosms at the Elkhorn River Research Station. The start of the spring pulse was determined using commercially available atrazine strips that detected atrazine when concentrations exceeded 3 ppb. Once the pulse began, 5 serial 7-d exposures were conducted. Concentrations of atrazine, its metabolites, and 5 other herbicides were quantified using gas chromatography-mass spectrometry. Agrichemicals peaked during the first and second weeks of the pulse, with a smaller peak occurring during week 4, but the peaks were not directly associated with runoff events (as estimated from river discharge). Elevated agrichemical concentrations were associated with biological impacts, but not solely responsible. In the present study, differences in the abiotic environment were found to play a significant role in the defeminization of exposed female fathead minnows.