Fish & Fish Impacts
Fish & Fish Food Impacts. I’m Greg Martin with today’s Line On Agriculture.
Dr. John Stark, Director of WSU-Puyallup’s
STARK: Believe it or not we really don’t know much about what’s in water for example in terms of pesticides and the reason for this is that it’s very expensive to do this, to go out and sample water and to do it over time. Back in the late 90’s and early 2000’s USGS conducted the NAWQA Survey and what they found was they took surface water and ground water throughout the United States and found pesticides and primarily mixtures of pesticides everywhere they looked.
These pesticides no matter how much they become diluted still can have a profound effect on water populations.
STARK: Once animals are exposed, organisms are exposed they can die off or percentages of populations can die off and the remaining individuals can be impaired and not only in one way but quite often in many different ways which can have a negative effect on these populations to survive and do well. We have mixtures. We know there are lots of mixtures out there not only of pesticides but of other chemicals and teasing out the effects of mixtures is a very difficult proposition.
Stark says one of the most frustrating parts of pesticides are the unknown parts.
STARK: If you look at a pesticide label you’ll see something like this, 2% active ingredient, 98% inert ingredients or 20% active ingredients, 80% inert ingredients. Does anybody know what those inert ingredients are? That’s because they’re trade secrets and you don’t know what they are but in general what they are are adjuvants which are used to spread materials over plants and sunscreens to increase longevity in the environment.
Interestingly those inert ingredients can be as deadly to fish as the pesticides themselves.
STARK: Inert ingredients can act as xenoestrogens which interfere with the ability of organisms to reproduce and develop correctly and they can act as suffocants in aquatic organisms where they coat gills and trachea and there’s less oxygen exchange resulting in all kinds of impairments as well. Then we have breakdown products of these pesticides. Some of these breakdown products which occur through natural processes and other mechanisms are even more toxic than the parent compound.
That’s today’s Line On Agriculture. I’m Greg Martin on the Northwest Ag Information Network.