Project ID: 2005NE89B

Title: Androgenic Growth Promoters in Nebraska Rivers: Detection and Toxicity

Project Type: Research

Focus Categories: Surface Water, Toxic Substances, Agriculture

Keywords: animal feedlot operations, steroids, passive organic samplers, caged fish

Start Date: 03/01/2005

End Date: 02/28/2006

Federal Funds: $10,000

Non-Federal Matching Funds: $20,000

Congressional District: 2nd

Principal Investigators:
Alan S. Kolok

Daniel Snow

Abstract

In the last few years, reports from across the United States have indicated that the reproductive systems of freshwater fish are being altered by contaminants in the water. Males are being demasculinized, while females are being defeminized, most likely through the process of endocrine disruption. In rural areas such as Nebraska, the source of these biologically active compounds can include: effluent from wastewater treatment facilities, runoff from row crop agricultural landscapes, as well as runoff associated with animal feedlot operations. Understanding the environmental impact of contaminants from these sources requires in situ identification of the chemicals present as well as documentation of the impact that these chemicals have sentinel aquatic organisms. This study represents an initial attempt to generate relationships between concentrations of androgenic contaminants and endocrine disruptive activity at a variety of locations on a rural stream in northeast Nebraska.

Passive organic contaminant integrative samplers (POCIS) will be deployed alongside fish cages stocked with juvenile fathead minnows. The samplers and fish cages will be deployed in early spring downstream from: a cattle feedlot, a wastewater treatment facility, and an area of intense row-crop (corn, soybeans) agriculture. A site immediately downstream from a state wildlife management area will be used as a reference site. The POCIS will be used to quantify concentrations of the anabolic steroids: trenbolone acetate, melengesterol acetate and 17-beta estradiol. Measurements on the minnows will include: quantification of secondary sexual characteristics, concentrations of sex steroids and concentrations of plasma vitellogenin, an egg precursor protein normally only found in the blood of female fish.

This project will have two specific outcomes. The first will be to develop and calibrate an integrated field sampling system, which can be used to estimate concentrations of androgenic steroids. The second will be to use the data from the passive samplers and the caged fish to generate relationships between concentrations of androgenic contaminants and endocrine disruptive activity. These two objectives will be addressed simultaneously with the passive water samplers deployed directly adjacent to the minnow cages. We hypothesize that runoff from cattle feedlots will represent a major source of androgenic steroids that act as endocrine disruptors on fish living in the proximity of this effluent.

Progress/Completion Report PDF