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Sunscreen a new suspect in slow dying of Cowichan River

COWICHAN LAKE — On soft, early summer mornings, Joe Saysell would get himself a cup of tea, settle back in his deck chair outside the small house he built for his wife, Gail, and enjoy nature’s free light show.

COWICHAN LAKE — On soft, early summer mornings, Joe Saysell would get himself a cup of tea, settle back in his deck chair outside the small house he built for his wife, Gail, and enjoy nature’s free light show.

Shafts of sunlight, lancing through the numinous green beneath old growth cedars, Douglas fir and broad leaf maples arching over the Cowichan River, would glimmer on the wings of countless mayflies, stoneflies and caddis flies.

Each consecutive hatch of insects would struggle through the surface film on B.C.’s blue-ribbon heritage stream, flutter skyward, then drift upstream in gossamer clouds carried on the river of air that always runs counter to the current sweeping down through Willow Run about 50 kilometres upstream from the Island’s east coast.

“Whenever there’s a hatch, it’s magic,” muses Saysell, a long-retired logger and fishing guide. “It’s like shimmering snow flurries. You watch the flies whirling above the river and up into the tree branches looking for mates.”

But these mornings, he doesn’t watch. There’s no point. The insects have all but vanished. Hatches that once began in mid-April and continued into July, he says, are now finished in a scant two weeks.

And science from as far away as Hawaii, Australia and the Caribbean, from the snow-fed streams of the Alps to the sewers of Barcelona, hints at commonly used sunscreens as a leading suspect in the insects’ disappearance.

There are other factors, of course. New property-holders who strip the willows that provide critical insect habitat from the banks to mistakenly improve cosmetics — mistakenly because soon they’re frantically replanting to prevent erosion of their river frontage. Logging that’s altered the seasonal flows of the river. Industrial water extraction for a pulp mill and use of the river to dilute municipal sewer effluents. Climate change.

The chief concern for Saysell, though, is the slick left on the water by swimmers who are widely advised to slather on sunscreen to protect themselves from harmful solar radiation. The precautionary advice is understandable. The U.S. National Cancer Institute reports that cases of melanoma, the deadliest from of skin cancer, have tripled since 1970, and the melanoma death rate for white men, the highest risk group, has more than doubled.

Might declines in aquatic insect populations that Saysell says he’s witnessing be an unintended environmental consequence of an important public-health effort to prevent skin cancer?

“Right now, we should be seeing a stream of caddis flies moving up the river. Mayflies. Clouds of midges,” Saysell says. “I went walking up and down the river this morning. I couldn’t find any caddis flies. Not one. There should be lots of them. It’s been like that for the last two or three years.”

Saysell, who has spent more than 60 years on the Cowichan and knows it as well as he knows his own skin, worries that the hatches of winged insects are vanishing because of sunscreen residues left by tourists who drift the river’s beautiful upper reaches during the summer on inflated inner tubes and air mattresses.

“Any hot weekend day I can see 1,000 to 1,200 tubers drifting past,” he says. “We call it the Tuber Hatch.”

In the U.S., researchers discovered that 1,200 swimmers would go through 76.8 kilograms of sunscreen a day and that the mist from aerosol sunscreen carries for 450 metres.

“When there are tourists in the water causing sunscreen pollution, a lot of it will be on the surface causing a sheen — where most of the insect adults will be exposed to high concentrations,” says U.S.-based Craig Downs, lead scientist on an influential 2015 paper published in the Archives of Environmental Contamination and Toxicology that outlined the alarming new risk for marine organisms.

“Trout fry will be especially exposed because of their feeding habits near the surface of the water, while in their embryonic forms they will be exposed from the source of sediment that is dependent on past contamination from sunscreen pollution.”

On the Cowichan River, there’s much potential for just such contamination. Tubing has emerged as such a popular pastime that entrepreneurs now rent inner tubes at the outlet on Cowichan Lake and retrieve them hours later when the drifters pull out at a small sandy beach kilometres downstream.

River is renowned

Fourteen years ago, the Cowichan was designated as both a national and a provincial heritage river in honour of its long history as B.C.’s most famous trout-fishing stream. For millennia, its salmon runs served as a feast bowl for the Cowichan Tribes.

It’s been renowned among sports anglers for more than a hundred years. Early in the last century, fly-fishing clubs in New York and London posted the daily action on their bulletin boards, catches were reported in the New York Times and it was a favourite of the Prince of Wales.

Paul Smith, who wrote nostalgically about the river for the Victoria Daily Colonist’s Sunday Magazine almost 70 years ago, began fishing the upper Cowichan in 1898 when a fly-fishing trip meant travelling by horse from Cowichan Bay.

“There were few fishermen and these mostly, as I remember, globe-trotting Englishmen of the old aristocracy. They had come from the ends of the earth to fish in the Cowichan,” he wrote. These “frosty-eyed” artists, he said, shamed him out of angling with worms. And it was the insect hatches in June and July that provided these connoisseurs of the dry fly with “the best fishing that was to be had.”

Those elite anglers made pilgrimage by steamship, train and stagecoach. Now they come by jet plane. Their angling on the Cowichan has served as a century-long mainstay in a provincial sports fishing sector that today contributes more than $250 million to B.C.’s annual gross domestic product.

Today, the secluded pools, swimming holes and rapids — all flanked by a 20-kilometre trail — are no longer the exclusive preserve of angling gentry with split cane Hardy rods and delicate dry flies. Protected by its heritage status and a 1,414-hectare strip park, the Cowichan has evolved into a shared-use mecca for hikers, white-water kayakers, campers, picnickers, swimmers and tubers. And most of them use sunscreen.

Saysell doesn’t blame the tourists for the plight of the insects. Nor does he object to the tubers’ desire to stay safe while they share the beauty of the river as it eddies through the forest.

He does worry about whether such a simple thing as the sunscreen that swimmers and tubers use — a large provincial government sign urges them to do so at the launch point — translates into an ecological hazard when it inevitably washes off in the river.

Nanoparticles in the food chain

Consider the aquatic life cycles of those caddis flies that Saysell couldn’t find. In their larval stage, caddis flies encase themselves in tiny suits of armour for protection as they crawl around the undersides of river stones. As pupae, they rise into the water column and wait to transform into winged adults that fly upstream in search of mates to renew their life cycle.

And like all the other insects that spend most of their lives in the water, they provide a crucial part of the food chain for the river’s prized game fish. Aquatic larvae provide up to 80 per cent of the diets of resident rainbow, brown and cutthroat trout and the transient juveniles of steelhead, chinook, coho and chum salmon. Their importance is evident from the many fly patterns devised by anglers seeking to mimic them in all their forms.

Scientific research increasingly suggests that Saysell’s worries have genuine merit.

A growing sheaf of studies shows that the tiniest components that are added to sunscreen to block harmful ultraviolet rays — nanoparticles of titanium dioxide, copper oxide, zinc oxide and cerium oxide, so tiny it takes 100,000 of them to make up the width of  human hair — pose grave risks to small aquatic organisms.

One metallic compound’s nanoparticles are associated with diminished survival of amphibian larvae. Another’s nanoparticles are primarily consumed by midge larvae that are in turn consumed by tadpoles and juvenile fish. Others compromise the biology of aquatic bacteria exposed to minute quantities for less than an hour. All seem to contribute to making embryonic aquatic creatures more susceptible to other toxic agents.

Midge larvae are the predominant insect food source for fish, particularly trout and the baby salmon and steelhead that rear in freshwater before migrating to the sea to become adults.

At least four other compounds used as UV filters in sunscreen have now been identified as hormone disrupters that force genetic changes upon the larvae of at least one known midge species.

The compound oxybenzone, an organic ingredient used in many sunscreens, has been linked with DNA damage, endocrine disruption and deformities in coral larvae and with embryonic deformities in fish, sea urchins and shrimp. It appears to be the cause of neurological changes that warp the behaviour of fish that are critical to the food web, sustaining sea turtles, marine mammals and marine birds.

“Basically, for fish, these chemicals can cause ‘feminization’ of the males and sexually immature juveniles,” Downs says. “If a population goes ‘all female’ it won’t last another generation before going locally extinct. It will also cause changes in the behaviour of male fish, making them less territorial and (in a forthcoming study) less eager to mate.

“Many of these chemicals can cause abnormal development in the embryos as well as reduce the viability of sperm to fertilize an egg. They won’t kill you outright but will slowly kill the population, making them ‘reproductive zombies.’”

The evidence of oxybenzone’s impact is sufficiently compelling that the state of Hawaii this year approved legislation banning the sale or distribution of all but medically necessary sunscreens containing the compound.

Insects measure river health

What troubles Saysell as he watches the Cowichan River’s insect hatches dwindle away is a discovery by researchers of the persistence of sunscreen contamination.

Again, Downs says the worry is credible. Many of the chemicals at issue behave like oil and water — they don’t dissolve. Some rise to the surface and float as a film, others settle into the sediment or beach sand. This means that insects that spend part of their lives on the bottom, such as caddis fly larvae, then rise in the water column and pass through the surface film, can be highly exposed throughout their life cycle.

Hawaii’s law banning oxybenzone cites elevated levels found in waters off popular swimming beaches and warns that “contamination is constantly refreshed and renewed every day by swimmers and beachgoers.”

Downs’s interest in the persistence of sunscreen contaminants was triggered when a local resident in the Caribbean drew his attention to the oily slick that coated the water over a reef in the U.S. Virgin Islands long after masses of tourist swimmers and snorkellers had left for the day.

His subsequent research found that oxybenzone damaged coral DNA and caused “severe and lethal deformities” in coral larvae at concentrations as low as 62 parts per trillion, equivalent to a single raindrop in six-and-a-half Olympic-sized swimming pools.

To make things worse, swimmers aren’t the only source of sunscreen’s nanoparticles and organic contaminants. These compounds also enter the water through municipal sewage systems after people shower to wash off sunscreen following a day outdoors; through septic fields that leak into ground or surface waters; even through flushed toilets — researchers found that oxybenzone is detectable in human urine 30 minutes after sunscreen is applied to the skin.

One 2012 study in northwestern Spain found sunscreen contaminants pervasive in sewage, surface and drinking water. Five years later, a study of treated waste water in New York had similar findings.

And Environmental Working Group, a non-profit advocacy organization that concerns itself with toxicity of household chemicals, warns that “when zinc oxide and titanium dioxide nanoparticles wash off skin, they enter the environment with unknown effects.”

While the working group says the metallic nanoparticles are worthwhile because of their effectiveness and public-health value in protecting human skin from UV radiation, it also warns that “the implications for nanoparticle pollution of the environment have not been sufficiently assessed. … Sunscreen ingredients have been shown to damage coral, accumulate in fish and the environment, and disrupt hormones in fish and amphibians.”

Nor is it only the river that concerns Saysell.

“What about Cowichan Lake?” he asks. “Every beach in the lake will have swimmers wearing sunscreen. That’s where our juvenile coho go. They migrate to the lake beaches right after they hatch.”

And while the Cowichan is Saysell’s main concern, there are plenty of other lakes and rivers around the province where families slap on the sunscreen and go for a leisurely float or swim. The Shushwap, Similkameen, Okanagan, Thompson and Kettle rivers all attract tubing enthusiasts. And beach swimming on lakes and rivers is ubiquitous summer fun from the Peace River district to the Fraser Valley and from the Rockies to the coast.

The Cowichan River was listed by the Outdoor Recreation Council of B.C. as one of B.C.’s most endangered rivers in 2018. It made the list in 2016, too. Habitat damage, low summer flows and high water temperatures that hurt juvenile fish survival were reasons for the listing.

A study by the Cowichan Valley Regional District estimates that on average, the number of returning spawners for Cowichan River coho and chinook, the juveniles of which spend a year rearing in the river, have declined by approximately 90 per cent.

Although trout stocks are generally considered healthy, spawning returns of chinook declined by 56 per cent from 1995 to 2006. These large chinooks, prized by sports anglers dwindled from returns of more than 25,000 to about 1,300. The stocks have begun to rebuild, probably a result of reductions in the harvest coupled with improved marine conditions. In recent years, returns reached  8,000 but remain a shadow of past abundance.

Cowichan River coho, too, declined steeply. Historically, coho returns to the Cowichan exceeded 70,000. By 2007 they had declined to fewer than 1,000. And steelhead are a concern in many Vancouver Island rivers, including the Cowichan.


What’s to be done?

First, Saysell hopes, swimmers and tubers will educate themselves about sunscreen’s effects and look for brands that don’t include the most problematic compounds. And he says we should all start thinking about other alternative behaviours — wearing beach clothing that blocks UV, for example — that can help reduce sunscreen use. Authorities, he says, also need to educate themselves about how to manage and reconcile the conflicting values of promoting sunscreen use for worthwhile public health with its serious, however unintended, ecological side-effects for other species.

Second, he says, provincial and federal environmental authorities should start paying attention and begin systematically collecting accurate data.

“Where has all our insect life gone?” he asks. “Well, the province has never done a comprehensive study of the biomass of those insects in the Cowichan River, so we don’t know. We need detailed studies of the river’s insect life.

“These insects are the canaries in our coal mine. They are what sustain all the life in this river. Fish, birds, frogs — without those insects we’ll lose all the life in this heritage river. It’s the death of 1,000 cuts, you know. Death of 1,000 cuts. And it’s all going to unravel suddenly.

“Our grandkids are going to say: ‘You had such a paradise and you couldn’t ruin it fast enough.’”