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Non-profit groups monitor for sunscreen contamination in Cowichan watershed

With all of these human bodies comes plenty of sunscreen
Tubing on the Cowichan River is a popular summer pastime. A group of researchers is looking into how sunscreen is affecting the Cowichan watershed. (Gazette file)

Submitted by Thea Rodgers

When the safest way to socialize is outdoors and the recommendation is to stay close to home, where do you go with your family on a sunny, summer weekend?

For many Vancouver Islanders, the Cowichan Valley was just the place in 2020. An influx of island locals arrived in the valley last summer with the goal of safely floating, swimming, fishing, boating, and lounging in the blue gems of the valley — Cowichan Lake and the Cowichan River.

With all of these human bodies comes plenty of sunscreen, a necessary part of any sun safety routine. Incidences and awareness of skin cancer are increasing in Canada (the federal government suggests one in 73 Canadian women and one in 59 Canadian men will develop melanoma, a deadly skin cancer, during their lifetime). The use of sunscreen has similarly been on the rise.

Keeping your skin safe from the sun is a no-brainer. What’s important to re-think is which products you reach for, and when or how often you apply them, as not all sunscreens are created equal.

A new project underway in the Cowichan Valley is investigating how sunscreen compounds known as ultraviolet filters are distributed in the environment. These compounds — with familiar names like oxybenzone, avobenzone, or octocrylene — are added to chemical sunscreens to protect your skin from sun damage.

Chemical sunscreens make use of ultraviolet filter compounds to harness a miniature chemical reaction at the surface of your skin which protects it from UV radiation from the sun.

This differs from mineral (also sometimes called “physical”) sunscreens, which use zinc or titanium oxides to physically reflect the sun’s energy away from our skin.

One of the draws of chemical sunscreens is they tend to go on clear, helping avoid the pasty white streaks commonly associated with mineral sunscreens. But as emerging research is showing, it may be time to bring those white streaks back into style.

Collecting the data

The British Columbia Conservation Foundation, a non-profit organization headquartered in Surrey with a regional office in Nanaimo, is collaborating with Vancouver Island University’s Chemistry Department and Applied Environmental Research Lab to detect sunscreen compounds in the Cowichan watershed.

Last summer, from June through September, staff and volunteers donned their sun hats, shades and nitrile gloves before dispersing to collect vials of water at sites throughout the lake and river. This water would be submitted for analysis using a technique called mass spectrometry.

Because it is one of the most common ultraviolet filters added to sunscreens, oxybenzone was used as an indicator chemical. Initial samples showed oxybenzone was indeed detectable in the river, which prompted further sampling to understand the scope of the issue.

Sixty-eight water samples were collected, showing a pattern of oxybenzone distribution closely linked to “hot zones” of recreational use. Another five samples were collected outside the Cowichan watershed for comparison. While concentrations in the Cowichan watershed thankfully hovered below levels immediately harmful for aquatic life in 2020, the areas with highest contamination are also areas where species like trout and freshwater mussels are known to reside. Samples from outside of the Cowichan also suggest that small lake systems (e.g. Westwood Lake in Nanaimo) are at a very high risk for contamination.

What’s the issue?

Recent research shows many UV filter compounds can be bad news for aquatic life. The most widely cited is a suggested link between UV filters and coral bleaching, which prompted state officials in Hawai’i to proactively ban the over-the-counter sale of sunscreens containing oxybenzone and octinoxate as of January 2021.

Other research coming out of Europe, Asia and South America has shown it’s not just corals affected by UV filters: invertebrates, fish, and mammals are also at risk.

Some UV filters mimic estrogen, a female reproductive hormone. Fish exposed to high doses of UV filters may change how they produce proteins related to sperm and egg production; it may even influence the total count and viability of eggs themselves.

UV filters can also accumulate in tissue (a process known as “bioaccumulation”), and can concentrate up the food web into predators (a process known as “biomagnification”).

The Cowichan River supports a fishery that has sustained the Hul’q’umi’num’ people for millennia; in addition to being one of the top sportfishing destinations on the island for anglers targeting trout and steelhead.

Fish are an integral part of the Cowichan River ecosystem, which begs the question: after washing off the bodies of beach-goers and into the water, are UV filters accumulating in fish?

Research is slated to continue in 2021 thanks to funding support from the Habitat Conservation Trust Foundation and the RBC Foundation, as well as local business supporters, the B.C. Ministry of Environment, and community volunteers.

While researchers from the VIU-AERL lab and BCCF are pioneering an exciting new method of analysis to find out if the fish are affected, here are some things you can do to minimize your personal impact on the river in the meantime:

• Avoid applying sunscreen immediately before getting in the water. Most chemical sunscreens take 20 minutes after application to become effective — if you apply sunscreen then immediately hop in the water, you’ve washed your money away, reduced your sun protection, and could potentially be harming life below the surface.

• Instead, try some alternatives: “river-safe” sunscreens usually contain non-nanotized zinc oxide as the main medicinal ingredient, which is effective immediately after applying. Use this on sensitive and hard-to-cover areas like your face, feet and back of your hands.

• If you know you’ll be getting wet and won’t be able to avoid washing sunscreen off, cover up your skin with high-UPF clothing instead, like a breathable sun shirt and wide-brimmed hat.

We’re all itching to get back out there — let’s recreate safely this summer and with the fish in mind.

For more information or to learn how you can be involved with sunscreen sampling in 2021, please contact Thea Rodgers, at