Burrowing shrimp control (Imidacloprid)

In April 2017, shellfish growers from Willapa Grays Harbor Oyster Growers Association (WGHOGA) requested a permit to use imidacloprid, a neonicotinoid pesticide, on oyster beds in Willapa Bay and Grays Harbor to control native burrowing shrimp.

Based on the information gathered during our environmental review, review of hundreds of new scientific data and research on neonicotinoid pesticides, and assessment of more than 8,000 public comments, we determined this proposal could not meet Washington's environmental sediment and water quality protection laws. As a result, in April 2018, we denied the request to use the pesticide imidacloprid on shellfish beds to control burrowing shrimp in Willapa Bay and Grays Harbor.

This denial was a tentative determination pending a 30-day public comment period, held spring 2018. We received no new, compelling scientific information that changed the results of our tentative decision. On September 27, 2018, we finalized the denial of the permit. The final decision can be appealed to the Washington Pollution Control Hearings Board within 30 days.

Reasons for the denial include:

Significant, unavoidable impacts to sediment quality and benthic invertebrates.
Negative impacts to juvenile worms and crustaceans in areas treated with imidacloprid and nearby areas covered by incoming tides, including high mortality for Dungeness crabs.
Negative indirect impacts to fish and birds caused by killing sources of food and disrupting the food web.
Concern about non-lethal impacts to invertebrates in the water column and sediment.
A risk of impacts to invertebrates from imidacloprid even at low concentrations.
Increased uncertainty about long-term, non-lethal, and cumulative impacts.

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Willapa Bay and Grays Harbor are experiencing an increasing population of burrowing shrimp. This population has always been highly variable, reasons for which are not fully known. High populations of these native shrimp make tide flats too soft to support traditional shellfish cultivation.

These growers sought a permit to spray the shrimp with imidacloprid to control the population. This included applications for a water quality pollution discharge (NPDES) permit and two sediment impact zones.

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Environmental review

Imidacloprid is a neonicotinoid pesticide. Neonicotinoids are linked to impacts to pollinators. The environmental review considered a wealth of new research, data, and analysis that has become available since the 2015 permit request was evaluated. It focused on the increasing evidence of environmental impacts connected to this type of pesticide. Several new risk assessments have been completed in North America and Europe, providing the best available up-to-date science. As a result of this new information, neonicotinoid pesticides have been banned in many countries and are no longer being sold commercially in many stores across the United States.

Our findings have been adopted in a formal report, called a Final Supplemental Environmental Impact Statement. This review compiled what was learned by reviewing new research and the public input received during a 45-day public comment period. This additional review built on the initial Environmental Impact Statement adopted during the 2015 permit process. Ecology used this information to inform the agency’s decision to deny the pending permit applications.

The Final Supplemental Environmental Impact Statement includes the assessment of environmental impacts and responses to the 8,287 comments received when the draft was released for public review.

This review adds to the initial Environmental Impact Statement adopted in 2015. No preferred alternative was identified.

The supplemental environmental review found:

Significant impacts where the pesticide would be applied.
Significant impacts to sediment quality and benthic invertebrates.
Adverse impacts to juvenile worms and crustaceans in the areas treated with imidacloprid and the nearby areas covered by incoming tides.
Concern about non-lethal impacts to invertebrates in the water column and sediment
Indications that there is a wider area of impact than previously thought.
New information shows a risk of impacts from imidacloprid even at low concentrations.
Likely indirect impacts to fish and birds from disruption to invertebrate food sources.
Little known about direct risk to fish, birds, marine mammals, and human health.
Increased uncertainty about long-term, non-lethal, and cumulative impacts.
Continued knowledge gaps about imidacloprid.

What’s different this time around?

This request was similar — but not identical — to the highly-conditioned permit for imidacloprid issued to WGHOGA in 2015. The 2015 permit was cancelled at the growers’ request and the permit was never used. There are key differences today versus when we permitted imidacloprid in 2015. As part of the environmental review process for the 2017 application, we considered and evaluated new research and analyses that were not available during the previous environmental review.

The body of science around neonicotinoids is rapidly expanding because of national and international concerns surrounding their use and environmental impacts. New research points to greater impacts in land and water ecosystems than previously known.This mounting scientific evidence confirms the harm from this neonicotinoid pesticide poses too great a risk to Washington’s environment.

In December 2016, the U.S. Environmental Protection Agency (EPA) released a new risk assessment on the environmental impacts of imidacloprid, and neonicotinoids in general. As a result of this assessment, EPA produced new levels to measure toxic risk. Health Canada and the European Food Safety Authority have also recently released a similar risk assessment. This and other new informed our decision to deny the permit.

The growers collected monitoring data on their 500-acre commercial scale experimental trials in 2014. However, the growers monitoring report and analysis of this data was not available in time for public review when the 2015 permit was issued. The report showed uneven control of burrowing shrimp even when applied at commercial scale.

Growing national and international concern about the impacts from neonicotinoids, including imidacloprid, on pollinators (e.g., honeybees, other bees, butterflies, etc.) and aquatic life led to a re-examination of both its costs and benefits.

Recently, other states and countries have proposed or set bans or limitations on neonicotinoids based on the updated science. For example, in April 2018, the European Union voted to ban three neonicotinoids, including imidacloprid.

Proposal application process

In April 2017, the growers completed and submitted an application for the required National Pollution Discharge Elimination System (NPDES) permit, and applications for two Sediment Impact Zone authorizations for areas in Willapa Bay and Grays Harbor.

These permits regulate a source of pollution in water (in this case, the discharge of a pesticide) and set rules for the discharge, such as containing that pollution to a specific area and requiring that the effect of the discharge is at — or below — a minor adverse biological effects level.

This new, independent permit application went through the full, normal regulatory process.

This process breaks down into three distinct phases: review of the environmental impacts, a decision on whether or not to develop a permit, and the permit development process.

The Final Supplemental Environmental Impact Statement compiles what was learned by reviewing new research and the public input received during a 45-day public comment period. This additional review builds on the initial Environmental Impact Statement adopted during the 2015 permit process, including new scientific information.

Based on the Final Supplemental Environmental Impact Statement and review and response to comments, we issued a tentative denial for the permit pending the evaluation of and response to comments received during a 30-day public comment period held April 9, 2018 to May 14, 2018. During that period, we received 3,080 comments, the overwhelming majority of which support our decision to deny the permit.

We compiled our findings in a formal report, officially referred to as a Final Supplemental Environmental Impact Statement. We held a 45-day public comment period on the draft of this report from Sept. 18 through Nov. 1, 2017. Two public meetings were held in October, 2017 — one in Lacey and one in South Bend. This included public hearings, briefings for stakeholders, tribes, and natural resource agencies, as well as other opportunities for review and input. We received 8,287 public comments on the draft of this report.

After carefully considering everything we learned from our environmental review and public input, we have determined that this proposal cannot meet Washington's environmental protection laws. As a result, we are denying the request to use the pesticide imidacloprid on shellfish beds in Willapa Bay and Grays Harbor to control burrowing shrimp. This denial of the application means the process will end. We will not proceed with drafting a permit.

Environmental review process

We prepared an Environmental Impact Statement for the 2015 permit process, and we then supplemented it with the most up-to-date research and information available. The Final Supplemental Environmental Impact Statement builds on the Environmental Impact Statement from 2015. It compiles new research and information that wasn't available to us when we prepared the 2015 Environmental Impact Statement.

Permit decision documents:

Historic information on insecticide Carbaryl/Sevin:

Contact information

Rich Doenges
Water Quality Regional Manager
Rich.doenges@ecy.wa.gov
360-407-6271

​Burrowing shrimp control (Imidacloprid)