Feb 26, 2012 – Chemical Questions
QUESTION:
Do you believe the only way to avoid more than a mild presence of liquid pesticide 'junk' around a cap is by allowing the product to drip for 20-30 seconds? Do you think making a concerted effort to not get liquid around the outside threads of the cap area is the only way? A related question pertains to the little flakes and chips of pesticide that sometimes do not break down in a tank mix. I have assumed these are generally pieces that stuck to the threads around the cap, and through twisting the cap have flaked off and perhaps landed in a tank mix. I really think I am one of the most careful professionals concerning chemical contamination. Are those chips considered as dangerous as the liquid form? I have had small chips get stuck in filters and I really do not know what to consider them (regular trash or active concentrate). Many of them are not soluble through regular tank mix agitation. What is your opinion, and do other technicians sometimes have a problem with that flaking of product that has accumulated around the cap area?
ANSWER:
Well, I've never really given much thought to this before Christopher, so we'll see where my mind wanders. I suppose it would be normal for trace amounts of liquid to remain around the outside of the threads when you pour the material and then replace the cap. The likely result then would be for diluents to evaporate and leave behind the more pure active ingredient, and this very well could be the flakes that you notice. If so then these flakes could later end up in the tank and be difficult to dissolve back into solution, thus leading to your second observation. And then if these more solid flakes are taken up into the pump they would be filtered out before getting into the narrow passageways in the spray nozzle.
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Do you believe the only way to avoid more than a mild presence of liquid pesticide 'junk' around a cap is by allowing the product to drip for 20-30 seconds? Do you think making a concerted effort to not get liquid around the outside threads of the cap area is the only way? A related question pertains to the little flakes and chips of pesticide that sometimes do not break down in a tank mix. I have assumed these are generally pieces that stuck to the threads around the cap, and through twisting the cap have flaked off and perhaps landed in a tank mix. I really think I am one of the most careful professionals concerning chemical contamination. Are those chips considered as dangerous as the liquid form? I have had small chips get stuck in filters and I really do not know what to consider them (regular trash or active concentrate). Many of them are not soluble through regular tank mix agitation. What is your opinion, and do other technicians sometimes have a problem with that flaking of product that has accumulated around the cap area?
ANSWER:
Well, I've never really given much thought to this before Christopher, so we'll see where my mind wanders. I suppose it would be normal for trace amounts of liquid to remain around the outside of the threads when you pour the material and then replace the cap. The likely result then would be for diluents to evaporate and leave behind the more pure active ingredient, and this very well could be the flakes that you notice. If so then these flakes could later end up in the tank and be difficult to dissolve back into solution, thus leading to your second observation. And then if these more solid flakes are taken up into the pump they would be filtered out before getting into the narrow passageways in the spray nozzle.
So, obviously all I have done so far is recap what you already told me, but your question seems to center on whether or not these little flakes are of any concern to you health-wise. If they do concern you perhaps you can have a dedicated rag available to wipe the threads following each use of the material so that no buildup occurs. Now perhaps the question arises of what to do with that rag that obviously is "contaminated" with pesticide. Well, I suppose you could toss it in the laundry along with your "contaminated" clothing. Or, you could do as you now do with a lot of other equipment that has trace amounts of pesticide on it and just dispose of it in the garbage as you would empty aerosol cans. This has always been an interesting question. How do you dispose of old spray hose, or old shoes, etc? How do you legally wash your service vehicle, knowing that you are washing pesticide off of it and onto the surface below? The answer is that so little actual pesticide is involved that it really can be overlooked, as long as the materials are ending up in a landfill somewhere.
Similarly, when you open the filter you could knock loose most of the material on it and then dispose of the paper or rags with that debris. Even if they are active ingredient the amount is going to be insignificant once it all reaches a landfill. It would seem to be inevitable that we will create some level of pollution, but it still can be dealt with in a responsible manner that does not ultimately pose any danger to our environment. We triple rinse containers that held liquid and pour that rinsate into the tank for further use (and this may also then wash some of the dried flakes in as well). But, we do not triple rinse bags that held granules or dust, so legally disposing of these containers in a sanitary landfill will inevitably carry some of the residual pesticide with it.
I don't look at any of this as bad environmental stewardship. If we use the products properly we end up with very little wasted material, and since insecticides in particular degrade fairly quickly once exposed to the conditions of the environment - UV light, water, heat, soil micro-organisms - those trace amounts in the landfill are not going to be there for long.
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