Wednesday, July 24, 2019

Checking for pesticides in surface water


Katie Noland measures stream-flow in Burnt
Bridge Creek.
In the dense canopy above Vancouver’s Burnt Bridge Creek, songbirds fill the fresh spring air with full-throated warbles that almost drown out the stream-flow readings WSDA environmental specialist Katie Noland calls out from the water.

“Point four eight zero,” she says against the trills as she shuffles her boots a little deeper, “moving to seven point nine, depth of one point five.”

From the grassy bank on the nearshore, teammate Jadey Ryan enters each detail into the database on a tablet.  

WSDA’s Natural Resources Assessment Section (NRAS) uses these recordings and the levels of pesticides found in the surface water samples to measure stream health in a cross section of streams in Washington.

The work began in 2003 as part of Washington’s response to the U.S. Environmental Protection Agency's (EPA) listing of some Chinook salmon under the Endangered Species Act (ESA). As such, all 16 small streams in the survey this year are considered salmon bearing. That means salmon either develop, pass through, or spawn in the stream during their life cycle.  
Jadey Ryan suited up for a day in
the field

WSDA assesses the potential impacts of pesticides on threatened and endangered species and aquatic ecosystems to evaluate if pesticide use is a limiting factor in the recovery of threatened and endangered species.

We’re gathering general pesticide use data, surface water monitoring data, crop types, and crop location data and using it to identify, evaluate and potentially mitigate impacts to ESA-listed species.

Back at Burnt Bridge Creek

The gently flowing water comes up to the knees of Noland’s chest-high, forest green waders – her summer work attire. She’s here twice a month from March through October. 

From the shade of alders and overhanging brambles near the shallows on the far side, she adds a few notes about the aquatic life she observes. 

“One crayfish,” she says, “and a caddisfly.”

“Got it,” says Ryan. 

Switching roles: Jadey Ryan measures stream flow, Katie Noland records the data. 
Source of pesticides

NRAS tests for everything from pesticides used in agriculture and large scale landscaping to those homeowners use on their lawn. Though some of the other monitoring takes place in streams impacted by urban runoff, most of the streams that are monitored flow through agricultural land. 

This sensor records water
 temperature over time. 
Burnt Bridge Creek is the most urban of the monitored creeks this year.

“There’s a little bit of agriculture up at the headwaters, but it’s mostly urban,” Noland explains.

Surface water in both rural and urban areas could carry pesticides. 

WSDA ambassador

Because of the urban locale and the popular trail along the creek, Noland gets a lot of questions from the public at this site. 

“People see us down here and want to know what we’re doing,” she said. “We keep it pretty simple. We tell them that we’re from WSDA and we’re taking water samples to test for pesticides. That sparks a lot of people’s opinions and interests.”

Noland says people generally give her positive feedback. They make comments like: “Great, I’m glad someone is looking into it.” 

What is a pesticide?

Noland says most people don’t know that pesticide is a broad term that covers a lot of chemicals used by homeowners, government agencies managing lands, and agriculture production. 

The chemicals NRAS is checking for include those that prevent, destroy, control, repel, or mitigate any pest or disease – rusts, rats, bugs or weeds to name just a few. So, the chemicals people think of as herbicides, insecticides, fungicides, and rodenticides all fall under the broad category of pesticides. 
Jadey Ryan locates sensors in Burnt Bridge Creek. 

In all, NRAS tests surface water samples for 152 pesticide active ingredients and pesticide breakdown products.

Noland says the pesticides detected in Burnt Bridge Creek are commonly found in surface waters across Washington and many have homeowner and crop uses.

NRAS’ most recent water monitoring report shows there were 76 different pesticide and pesticide-related chemicals detected in 2016. Across 13 monitoring sites statewide, 1,752 pesticide detections were confirmed. 

The findings ranged from the 295 detections at one site to nine detections on the low end. 
Of those 1,752 detections, pesticide concentrations exceeded the WSDA assessment criteria in 108 instances.

When we identify a pesticide as a potential problem for an ESA-listed species, the NRAS team provides information to pesticide users and affected communities through presentations and publications. 

Katie Noland takes water samples for the lab. 
Testing samples

Noland carefully scoops up water samples, pouring them into tinted bottles that will be stored on ice on their way to Washington State Department of Ecology's Manchester Environmental lab for testing. 

“We take a lot of bottles of water out,” says Noland. 

During the fall and winter months, Noland, whose background is in environmental science, collects the data that comes back from the lab and works with the NRAS team to write up the report. 

She says it’s a perfect balance between the field work like she’s doing now, and analysis and writing she also enjoys. She says the field work is great, “but I really, really enjoy data and number crunching.”

You can visit the NRAS publications webpage to read monitoring reports and fact sheets from past years.