Microplastics: A new finding for a growing public concern

Reservoir fish habitat structure is frequently made of long-lasting, durable artificial materials. Often those materials are plastic. As a FOR group, you may receive questions about the use of plastic to create or supplement fish habitat, especially whether it contributes to microplastics in the environment.

You are not alone. The Reservoir Fisheries Habitat Partnership has talked about this public concern and how to support best practices with the greatest scientific support. At this time, there is no evidence connecting microplastics with the presence of artificial fish structure following current guidelines in the BMP Manual, but several of our member states are pursuing that research now in support of best habitat establishment practices in the future.

Yale provided a quality summary of what is known about microplastics, and just recently announced a major finding regarding the origin of the majority of the ocean's microplastics:

Here's a snippet:

For two decades, researchers worked to solve a mystery in West Coast streams. Why, when it rained, were large numbers of spawning coho salmon dying? As part of an effort to find out, scientists placed fish in water that contained particles of new and old tires. The salmon died, and the researchers then began testing the hundreds of chemicals that had leached into the water.

A 2020 paper revealed the cause of mortality: a chemical called 6PPD that is added to tires to prevent their cracking and degradation. When 6PPD, which occurs in tire dust, is exposed to ground-level ozone, it’s transformed into multiple other chemicals, including 6PPD-quinone, or 6PPD-q. The compound is acutely toxic to four of 11 tested fish species, including coho salmon.

Mystery solved, but not the problem, for the chemical continues to be used by all major tire manufacturers and is found on roads and in waterways around the world. Though no one has studied the impact of 6PPD-q on human health, it’s also been detected in the urine of children, adults, and pregnant women in South China. The pathways and significance of that contamination are, so far, unknown.

Seventy-eight percent of ocean microplastics are synthetic tire rubber, according to one estimate.

Please let your state RFHP representative know if this topic is relevant to your local discussions.