1, 2, 3-Trichloropropane (TCP) in California Water

TCP, or 1, 2, 3-Trichloropropane, has been found recently in the water of Tulare, CA in excess of the state’s newly established limit of 5 parts per trillion. Water from six wells in Tulare flunked the test for the cancer-causing chemical.

TCP is a waste product from making plastic. For years, it was added to fumigants that farmers put in the soil to kill tiny worms called nematodes.

To solve the TCP problem, the city will install water treatment tanks containing granular activated carbon that strip away the TCP.

Until recently, there was no state standard for the amount of TCP in drinking water, but last year the state said public water systems could have no more than 5 parts per trillion of TCP. The Tulare wells tested at 8 parts per trillion. The cancer risk is low. It is estimated that you would have to drink a couple of liters of TCP-contaminated water daily for several decades to run even a slight risk of getting cancer from it.

There is no federal drinking water regulation of TCP.  This means that if you live anywhere but California, you’ll probably never know whether it’s in your water or not.
TCP has been called a “garbage chemical.” It was most likely added to fumigants not because it was needed but simply to get rid of it and avoid the cost of disposal. (It is widely believed that this is a strong motivation for putting the industrial waste product fluorosilicic acid commonly called “fluoride” into drinking water–just to get rid of it without the expense of toxic waste disposal.)

Tulare is getting four new water treatment tanks containing activated carbon and two new wells to be financed by litigation, still in progress, against Dow Chemical and the Shell Oil Company, the companies who provided TCE in the 1940s to be added to fumigants.

Several cities in California in addition to Tulare have sued the two companies, with Clovis reaching a $22 million settlement in 2016.

TCP is readily removed from water by granular activated carbon, so if you have a good quality home drinking water system–either a carbon filter or a reverse osmosis unit–you don’t have to worry about TCP.

Source Credit: The Fresno Bee.