Tag Archives: Toxicity

Pesticides and salmon: Can we see a light at the end of the tunnel?

Once again, the National Marine Fisheries Service has determined in official findings that three common pesticides — chlorpyrifos, diazinon and malathion — raise the risk of extinction for threatened and endangered salmon.

A crop duster sprays pesticide on a field near an irrigation ditch.
Photo: NOAA/USFWS

By extension, for the first time, the agency also concluded that those same pesticides threaten Puget Sound’s endangered orca population by putting their prey — chinook and other salmon — at risk.

This politically and legally charged issue — which has been around for more than 15 years — has gone beyond a debate over potential harm from pesticides. It also raises uncomfortable questions about whether our society will follow science as we try to solve environmental problems.

The immediate finding of “jeopardy” — meaning that the three pesticides pose a risk of extinction — comes in a biological opinion (PDF 415.6 mb) that is more than 3,700 pages long and covers not just salmon but, for the first time, dozens of other marine species on the Endangered Species List.

The report follows a scientific methodology for assessing the effects of pesticides that arises from suggestions by the National Academy of Sciences. The NAS report (PDF 14.2 mb) attempted to reconcile differing methods of assessing risk that had been used by the Environmental Protection Agency, the U.S. Fish and Wildlife Service and NMFS.

EPA’s original assessment raised no concerns about the effect of these pesticides on the survival of salmon populations. The original lawsuit by environmental groups forced the EPA to “consult” with NMFS, as required by the Endangered Species Act. The result was the first jeopardy finding in 2008. For background, see Water Ways, Aug. 11, 2008, in which I reported that the long wait for regulatory action on pesticides may be about over. Little did I know.

The biological opinion, or BiOp for short, examines both the direct harms to species exposed to pesticides — such as effects on behavior, reproduction and immune function — as well as indirect effects — such as whether the pesticides wipe out insects needed for the fish to eat.

The new BiOp is considered a pilot study for future pesticide assessments.

“Notably,” states the document, “this Opinion represents the first consultation using newly developed approaches and the first to assess all listed species throughout the U.S., its territories, and protectorates. Future Opinions regarding pesticides may utilize different analyses and approaches as the interagency consultation effort proceeds.”

The next step is for the EPA to restrict the use of the pesticides to reduce the risks for salmon and other species. Among suggested measures, the BiOp says those who use pesticides must limit the total amount of chemicals applied in high-risk areas, such as streams. No-spray buffers or similar alternatives are suggested.

Interim no-spray buffers, established by the courts, will remain in effect until the EPA takes action. The interim buffers were put on, taken off, and are back on as a result of the lengthy court battle between the agencies and environmental groups. Pesticide manufacturers have weighed in, arguing about the need for pesticides without undue restrictions.

The Trump administration asked the court for a two-year delay in the release of the BiOp, but NMFS ultimately met the deadline when the judge failed to rule on the request in time to make a difference.

I discussed some of the ongoing intrigue and a bit of history in a Water Ways post last August, after EPA Administrator Scott Pruitt reversed course on an impending ban on chlorpyrifos. The proposed ban, approved during the Obama administration, came in response to studies that showed how the chemical could adversely affect children’s brains.

Although it took legal action to get to this point, agency and independent scientists have worked together to study the problem and come up with solutions. The question now is whether policymakers and politicians will take reasonable steps to reduce the risks based upon these findings, which are complex, evolving and rarely definitive for all time.

As I was going back through the blog posts I’ve written about pesticides, I recalled that President George W. Bush wanted to limit scientific consultations in an effort to streamline the regulatory process — much as President Trump’s people are doing today. Check out Water Ways from March 4, 2009, which shows a video of President Obama reversing the Bush policy and speaking out for increased input from scientists.

When it comes to human health and the environment, it is good to remember that without the work of scientists, many species throughout the world would have been wiped out long ago. Human cancer, disease and brain impairment would be far worse today without regulations based on scientific findings. Science can tell us about the risk of pesticides and other threats to salmon and orcas. But knowledge is not enough. People must take reasonable actions to protect themselves and the environment. And so the story goes on.

Last week, Earthjustice, which represents environmental groups in the legal battle, released the biological opinion, which had been sent by NOAA as part of the legal case. The group posted links to the document and related information in a news release. As far as I know, nobody in the Trump administration has spoken about the findings.

Salmon harmed by copper fail to avoid predators

I guess it’s common knowledge among fish biologists that fish can smell death.

It’s a survival mechanism. When the skin of a fish is damaged, a substance is released into the water. Other fish smell the substance and instinctively take evasive action.

When juvenile coho salmon smell death, they tend to stop moving and become more wary of predators, according to a new study by Jenifer McIntyre and colleagues at the University of Washington and National Oceanic and Atmospheric Administration.

But the most important finding is that the coho exposed to minute levels of copper lose their sense of smell. Their brains don’t register the smell of death, and they get eaten at a much higher rate than coho not exposed to copper. For details, check out the story published today in the Kitsap Sun.

The video shows the response of coho salmon when ground-up fish skin is released into the water. Coho not exposed to copper freeze, as you can see in the upper tank. Coho exposed to copper keep on moving, as if unaware of the danger, making them prime targets for predation.

These are interesting findings, but more research is needed to determine what levels of toxic copper may actually be found in urban streams, where copper typically comes from brake pads and pesticides, and rural streams affected by mining operations.

For further reading, check out the slideshow called “Impacts of copper on the sensory biology and behavior of salmon” (PDF 9.2 mb), which reports on findings by the research group of which McIntyre is a member

Other reports:

“An Overview of Sensory Effects on Juvenile Salmonids Exposed to Dissolved Copper: Applying a Benchmark Concentration Approach to Evaluate Sublethal Neurobehavioral Toxicity”

“Effects of Copper on Aquatic Species: A review of the literature” by Phyllis Weber Scannell.

“Control of Toxic Chemicals in Puget Sound: Assessment of Selected Toxic Chemicals in the Puget Sound Basin, 2007-2011”

Some previous blog entries in “Watching Our Water Ways”:

Nov. 4, 2011: “More results, more questions found in toxic studies”

May 18, 2011: “New study refines Puget Sound pollution issues”

March 10, 2010: “Washington is first to tackle toxic copper in brakes”

June 7, 2009: “Barnacle-free hulls would be a dream come true”