cam,

Are they still redoing the irrigation for other parts of the CG? Since I can't see, hear or smell what happens, here is my guess. Every time they make a repair, they shut off valves to the working part of the garden. The whitish water is air mixed with water when they finished their repairs and open the valve to the rest of the garden. They have not flushed the lines because it is for non-potable use and it cost money to do. It also is a problem to dispose of the flush water. Each plot owner flushes out their portion when they irrigate, The glue smell is from the pvc solvent and glue made to do the repairs. Nothing is harmful to you or your vegetable. The plants do not pickup any of the inert chemical from the soil. Aloha

Thanks for your reply.

It isn't air because the white stuff lays in a heap on the ground. My surmise now is that the pvc in the old part of the system is disintegrating. More people are watering their plots now and the water the other day came out yellow but at least transparent. It still had that chemical smell.

How do we know that the solvents and/or disintegration products don't get picked up by the plants?

Cam,

I haven't heard of pvc pipe disintegrating, cracking and leaking but not disintegrating. The plastic is inert and last many, many year when underground. I have heard of leaking pool filter material with the filter material (usually diatmaceous earth) which is a white material. If you can check the water source to the garden. Take a sample and let a lab do an analysis.

Here a link concerning chemical harmful to plants:
http://www.ehow.com/list_7659143_list-used-kill-trees-
There are many herbacides that can kill(toxic to) plants. Many companies/University Ag Depts have tested what chemical plants uptake and store in the leaves and fruit/nuts. There are many solvent chemicals. The important thing to know is the part per million concentration of the chemical in the water. The EPA has lists of the tolerable amounts of chemicals(PPM) in drinkable water and the amounts are allowed to be higher in water used for agriculture. The best way to know what you are dealing with is to take a sample and get it test by a lab or Agricultural extension service in your area. The lab or Extension Service will have all the allowable limits for the chemicals. Let us know what you find out. GL JMHO Aloha