Scientists will be likely monitoring the ecosystem surrounding the areas affected by a massive chemical spill in Ohio for years to come.
The tens of thousands of aquatic life that have died as a result could potentially point to whether ecosystems are safe enough for human activity to persist nearby, experts tell ABC News.
A train carrying several toxic chemicals derailed in East Palestine on Feb. 3, spilling cars full of hazardous materials onto the soil surrounding the derailment.
A controlled burn that occurred over the next several days then expelled even more toxic gases, prompting a mandatory evacuation for residents living within a 1-mile radius of the crash site due to the potentially deadly risks posed by inhalation in high concentrations.
Health officials immediately began testing the soil, air and land to ensure humans were safe to return. While the evacuation order was lifted on Feb. 8, the Ohio Department of Natural Resources announced on Feb. 14 that at least 3,500 aquatic animals along the Ohio River had died as a result of pollutants from the controlled burn seeping into the streams.
By Feb. 23, the number of animals that had died in and around East Palestine jumped to more than 43,000. This is significant because Ohio uses the fish community as an overall indicator of water quality, Michael Booth, a research professor of fish and aquatic ecology at the University of Cincinnati, told ABC News.
"Usually, you can use the community of fish as an indication of what the water quality is at any given time," Booth said.
In addition, 11 animals have been submitted for testing to determine whether their deaths were related to the chemical spill, according to the Ohio Department of Natural Resources.
Experts explore how the ecosystem will recover
Ohio officials tend to use fish as an indicator of water quality because they live in it, so they are exposed to any impurities at a much higher rate, Booth said.
"If you have a mass die-off, that's a pretty good indication you shouldn't be making contact with that water," he said.
Although none of the aquatic animals that died in a five-mile radius of the derailment site were endangered or at-risk, the number is still significant, Booth said. More than 38,000 minnows and about 5,500 other species, such a fish, including darter fish, crayfish and amphibians died, according to the Ohio Department of Natural Resources.
There are likely far more than 43,000 aquatic animals that died, because the smaller organisms in the creek that other aquatic animals feed off of were likely decomposed by the time the regions were surveyed, Allen Burton, a professor at the University of Michigan's School for Environment and Sustainability and Department of Earth & Environmental Sciences, told ABC News.
"In reality, that whole ecosystem, all the aquatic biota were wiped out in that upper stretch [of the Ohio River]," Burton said.
Officials will need to monitor how the fish community bounces back over the coming months and year, Booth said. Over the coming years, researchers will look at factors like whether the fish populations are having trouble reproducing, Booth said. It will likely take multiple life cycles and several years for the streams to recover, Burton said.
Fish communities get impacted by pollution regularly, Booth said. For example, in small streams in Cincinnati, fish populations can be impacted just by people dumping toxic chemicals down a drain. So monitoring the fish populations, and what they feed on -- whether on bugs or algae -- is an indication of the water quality, Booth said.
Although humans typically don't eat minnows, they do eat fish that eat minnows, such as walleye bass, which could potentially be problematic for human health if the minnow had been feeding on contaminated material, he said.
Most of the chemicals that were released in the derailment have a short half-life, Booth said. While the acute effects were immediate -- the mass die-off of tens of thousands of aquatic animals -- it is unclear whether that trend will continue.
One of the concerning aspects of the contamination of the Ohio River is the chemicals' exposure to sunlight, Booth said. If the chemicals went into the subsurface of the water, such as the sediment and the stream bed, they could get converted to something else by sunlight and then get eaten by microbes and other organisms, Booth said.
Much more testing is needed in and around East Palestine, the experts say
Residents have been concerned that proper testing has not been occurring, Andrew Whelton, professor of civil, environmental and ecological engineering at Purdue University, told ABC News. Officials need to test "appropriately" downstream and downrange, Whelton said.
There was nothing living on Sulfur Run or Leslie Run, two streams along the Ohio River that had been contaminated as a result of the derailment, when Whelton visited on Feb. 26, he said. At the bottom of the streams, he recorded seeing a type of mud that typically forms in ponds that have no life in them.
"There was absolutely nothing visibly living in the creeks," Whelton said.
The creeks also contained heavy contamination, with chemicals having been absorbed into the sediment, Whelton said, describing a stench that occurs when you disturb the leaves and creeks in some areas of the contaminated areas.
"When you have a massive introduction of chemicals like that, they will seep into the sediment into the groundwater," Burton said, adding that the chemicals will likely continue to contaminate parts of the streams for a long time unless crews drill into the beds of the stream to determine how far the chemicals seeped in and then dig out to remove the contamination.
"The reality is we're not going to get rid of all of this contamination. This has soaked into the ground and into the streams, I think, for quite a while and if I had children playing in the streams that would not be a good thing," he said.
There is currently no indication of risk to East Palestine Public Water customers, according to the Ohio EPA's website. However, those on private wells are still being urged to have their water tested.
However, the Ohio EPA is only testing the surface water, Burton said.
"They really need to be sampling the sediments to see if those compounds are continuing to leach out from under the surface waters," he said.
Response crews determined that the controlled burn would minimize the risk of an explosion that was likely otherwise, Ohio Gov. Mike DeWine said on Feb. 14. But what officials did not anticipate was the toxic chemical cloud of particulate material that would be created as a result of the burn, Whelton said.
By Feb. 14, that plume of contaminants had traveled down the Ohio River to near Huntsville, West Virginia, the Ohio Environmental Protection Agency announced that day. By March 1, toxic clouds were still moving over parts of Ohio and Pennsylvania, Whelton said.
"There's a very significant amount of chemicals that is moving downstream and that is not being documented by anybody," Whelton said.
The Ohio EPA is aware of the sediment contamination extending 6 miles from the derailment site, and remediation efforts are ongoing, James Lee, the agency's media relations manager, told ABC News via email.
The agency is currently sampling at 25 surface water locations every day, and visual assessments taken on Monday showed aquatic life, Lee said.
"We have seen fish and aquatic bugs in Leslie Run and Bull Creek, and expect fish and aquatic life numbers to continue to increase as the cleanup progresses," Lee said.
A press release from DeWine's office on Monday stated that the Ohio EPA is continuing to oversee the soil excavation from beneath the tracks at the site of the derailment. About 3.2 million gallons of liquid wastewater and about 2,070 tons of solid waste have been hauled out of East Palestine, according to DeWine's office.
A representative from The Ohio Department of Natural Resources declined to offer comment to ABC News. The office of the governor did not immediately respond to ABC News' request for comment.
Monitoring is still required for other environmental disasters years later
Environmental disasters, also known as "technological disasters," occur every two days in the U.S. in the form of vehicle crashes, pipeline leaks, ruptured chemical fires, explosions, and industrial plant spills, Ben Jealous, executive director of the environmental organization Sierra Club, told ABC News.
"East Palestine is a concentrated example of what's happened throughout this country," Jealous said.
When an environmental disaster occurs, cleanup crews partake in a simultaneous sprint and marathon to mitigate the effects, Steve Sempier, deputy director of the Mississippi-Alabama Sea Grant, told ABC News.
In April 2010, when the Deepwater Horizon oil spill occurred, the obvious impacts were easily observable -- oil affecting birds, turtles, dolphins and fish, Sempier said.
The chronic issues, however, are more difficult to discern, Sempier said. More than a decade later, researchers are still monitoring how the oil spill may have impacted marine mammals and other marine life populations.
"It's going to take a while before we know the full impact," he said.
Pearl Harbor is still experiencing impacts from a jet fuel leak in May 2021, as contamination was also discharged to the ground and soil, and a chemical spill that occurred in West Virginia's Elk River caused large-scale drinking contamination in both Canada and the U.S., Whelton, who responded to both disasters, said.
Today, it is hard to determine whether the decimation of the oyster population along the Gulf Coast is due, in mass part, to the oil spill or other factors, such as freshwater intake, harmful algae blooms and climate change, Sempier said.
These environmental disasters are an indication that the U.S. needs to clean up the environment "much more aggressively," Jealous said.
The absence of environmental degradation during the height of the COVID-19 pandemic is indicative of the drastic changes that can be made to ensure cleaner environments, Jealous added.