Polluted river waters in California are causing spinal deformities

80 percent of fish sample collected from California’s San Joaquin River Delta have a permanent spinal deformity, which researchers believe was caused by farm wastewater

Researchers in California’s central valley studied a collection of 1,000 minnows
They found more than 80 percent of the small fish had a spinal deformity
The deformity left the fish’s spines in a zig-zag shape resembling a lightning bolt
The team believe it was caused by exposure to selenium from farm runoff

Published: 22:34 GMT, 25 February 2020 | Updated: 22:34 GMT, 25 February 2020

A team of researchers in California’s San Joaquin Valley have linked widespread spinal deformities in a regional fish to toxic selenium exposure, believed to come from agricultural runoff.

The project, a joint effort from the California Water Science Center, the National Marine Fisheries Service, and UC Davis, began when researchers collected a sample of 1,000 splittail minnows from a pumping station in the San Joaquin River Delta.

The team noticed a severe spinal deformity in the minnows, which left the fish permanently shifted into a kind of zig-zag shape resembling a small lightning bolt.

More than 80 percent of splittail minnows collected from a location in the San Joaquin River Delta had a spinal deformity researchers believe was caused by exposure to selenium through farm runoff

The condition was widespread among the minnows, affecting more than 80 percent.

‘This was not just a few fish, it was the majority of them,’ co-lead Fred Feyrer told EurekAlert!.

To learn more about what had caused the deformities the team looked to the fishes’ ear bones, called otolith, which frequently retain the chemical markers of past exposures.

Using high intensity X-rays borrowed from Cornell University, the team found clear traces of selenium, which they believed was absorbed both from the fishes’ mothers and from their own independent feeding as juveniles.

‘They got it from both directions,’ lead researcher Rachel C. Johnson said.

The researchers believed the selenium exposure was constant for the minnows, with absorption first occurring through their mothers and later continuing as they fed themselves in the contaminated waters

Selenium was first discovered in the San Joaquin Valley in high concentrations during the 1980s, which researchers believe was caused by aggressive farm irrigation practices leeching the chemical out of the ground

Discovering fish with deformities from selenium in the wild is a rare occurrence as they usually either die from natural causes or are eaten by predators

The soil in the western part of the Central Valley is naturally high in selenium, and aggressive irrigation practices to feed the region’s booming $45billion agriculture industry has helped leech the chemical out of the soil and into runoff water.

Selenium was first detected in the San Joaquin Valley in 1983 when polluted waters containing the chemical were found in the Kesterson National Wildlife Refuge.

In the 1980s, researchers also discovered deformities in birds that had been exposed to agricultural drainage water with high levels of selenium.

Selenium exposure in fish has since been traced as far as the San Francisco Estuary, where adult splittail are believed to absorb the chemical by eating Asian clams.

It’s rare to see animals exhibiting the toxic effects of selenium, according to the researchers, because affected fish typically either die and decompose before being discovered, or else are eaten by predators.

WHAT DO EXPERTS PREDICT FOR THE FATE OF THE PLANET’S PLANTS AND ANIMALS?

Nature is in more trouble now than at any time in human history with extinction looming over one million species of plants and animals, experts say.

That’s the key finding of the United Nations‘ (UN) first comprehensive report on biodiversity – the variety of plant and animal life in the world or in a particular habitat.

The report – published on May 6, 2019 – says species are being lost at a rate tens or hundreds of times faster than in the past.

Many of the worst effects can be prevented by changing the way we grow food, produce energy, deal with climate change and dispose of waste, the report said.

The report’s 39-page summary highlighted five ways people are reducing biodiversity:

– Turning forests, grasslands and other areas into farms, cities and other developments. The habitat loss leaves plants and animals homeless. About three-quarters of Earth’s land, two-thirds of its oceans and 85% of crucial wetlands have been severely altered or lost, making it harder for species to survive, the report said.

– Overfishing the world’s oceans. A third of the world’s fish stocks are overfished.

– Permitting climate change from the burning of fossil fuels to make it too hot, wet or dry for some species to survive. Almost half of the world’s land mammals – not including bats – and nearly a quarter of the birds have already had their habitats hit hard by global warming.

– Polluting land and water. Every year, 300 to 400 million tons of heavy metals, solvents and toxic sludge are dumped into the world’s waters.

– Allowing invasive species to crowd out native plants and animals. The number of invasive alien species per country has risen 70 per cent since 1970, with one species of bacteria threatening nearly 400 amphibian species.

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