We still have not ID'd this liquid, clink on the link below for the newspaper story. Here are the clues we have to work with: PH 6, soluable in water, product was 95% water, did not burn, tested negetive for organophosphates however our ag-test kit is past expiration, tested negetive for latex paint but it may have been to dilute to get a postitive test, milky liquid, less viscous than milk, thinner than milk, formed a film on pavement after a while, local dairy farmer looked at the substance and said it was'nt milk, 2 guys dumped it out of a pressure washer tank and split, no detectible odor, we have not ruled out pesticide, herbicide, construction waste, latex paint waste. Here is the link with the photo: http://www.pe.com/localnews/hemet/stories/PE_News_Local_R_spill08.4...
I have no clues. I am glad we have a Sens IR for these type of runs. Even if it can not ID it there is call back with a chemists. When you find out pass it on. I would like to know. Good Luck
Couple of things, did you run a hydrocarbon pad through the product. A lot of times if you have a mixture of water and a hydrocarbon like hydraulic fluid that is agitated (pressure washer has crack and is looking fluid into water line) it gives that type of appearance. Only other things that would do that would be an organophosphate emulsifing in the water( which you ruled out, your agri-screen from your HazCAT covers your pesiticides), a PH neutral cleaning solution (something used to clean say cars), if the product is leaving a residue when its evaporating, it is a mixture. Which makes me lean towards a water / paint solution. It might not be latex paint, but oil or water based. Its very hard to make any concrete assumptions off the one picture. Since the product is really diluted with water, your might not get a reading at all with your Sens IR(FTIR)-not water friendly technology. You might have to use Raman IR (Ahura)to see it. Also, did you HazCat it at all?
Forgive my ignorance but have you tried to reverse ID it? Instead of figuring out what it is, identifying what it is not. The AHURA is an excellent meter. Have you also tried using SPYLFYTER strips? Have you used a PID to determine if it is a VOC? Haz-Cat is good if available. Have you tried running what facts you do have thru WISER? Just some thoughts
It sounds to me like residual soap from the pressure washer, based on what you're describing. I am thinking the workers rinsed out the tank with water to dissolve what was left in there then just dumped it and left. JMHO
Was the power washer being used on site, or was it parked there for the fast food?
These are just going to be opinions of things it could be.
1. TSP Trisodium phosphate. (a general cleaner used for siding etc to remove mildew and clean the product. Mixed with water it will make a milky white solution.) http://en.wikipedia.org/wiki/Trisodium_phosphate (this is a small possability, TSP is an alkali and with 95 water should have brought the PH over 7)
2. Being that it it the early part of spring you can't rule out pesticide. This is the time of year when landscapers are applying chemicals down to get lawns jump started.
3. If it was paint waste as you made it a possability of, why would it be inside a pressure washer tank? The water used from a pressure washer on a job would stay on the job. You spray it on a building and the water runs to the ground, not back into the tank.
I am a little intrigued that a local farmer said it wasn't milk..... How did the farmer get to the stuff for 1, and were they properly protected? If it turns out to be a pesticide, you could be in a world of trouble...