A fertilizer spill that occurred in Montgomery County, Iowa, on March 11 has led to the deaths of over 749,000 fish in a 50-mile stretch of the East Nishnabotna River to the Missouri border, according to officials.
The Iowa Department of Natural Resources (DNR) said it was notified about the spill at the NEW Cooperative facility in Red Oak on March 11, when approximately 1,500 tons of liquid nitrogen fertilizer (32 percent solution) were discharged into a drainage ditch.
Authorities found that the release occurred because an aboveground storage tank valve was left open for the weekend, according to the department.
The fertilizer flowed several miles downstream of Red Oak in the East Nishnabotna River, reaching Missouri. The Missouri Department of Natural Resources has been notified about the incident.
“DNR Fisheries staff documented the fish kill occurring in all 49.8 miles of the East Nishnabotna and Nishnabotna Rivers downstream of the spill,” the Iowa DNR said in a press release on March 28.
“The kill continued in Missouri’s portion of the Nishnabotna River and ended near the confluence with the Missouri River,” the department added.
Small fish such as minnows, shiners, and chubs make up the majority of the fish killed from the fertilizer spill, with over 707,870 of these species being killed. Other affected species include Carpsucker, Common Carp, Channel Catfish, Grass Carp, and others.
The Iowa DNR said that cleanup efforts at the NEW Cooperative facility are ongoing, and that contaminated soils had been removed from the facility and around a levee west of the facility.
“The contaminated soils will be land applied at approved locations, at agronomic rates consistent with Iowa law,” the department stated.
The DNR said that field test results show a decline in ammonia levels in the river. The department has advised people to avoid recreating on the river and eating dead fish found on or near the river.
Meanwhile, DNR officials said that NEW Cooperative has started pumping water from the east side of the levee following the incident.“The pumped water will be stored in on-site holding tanks until land application can occur. A third-party consultant is collecting samples of the water-fertilizer mixture to determine accurate land application rates,” it added.
