University of Virginia Library

Board Standard

The board standard permits up to one part
per billion (ppb) of endrin in the raw water
intake of drinking water supplies. The
subsequent reservoir samples tested one-tenth
of 1 ppb or less, Bailey said yesterday. That
amount approaches the detectable limit or
accuracy of the laboratory equipment-it can't
read below 0.1 ppb precisely, he noted.

In the Mechum itself, levels of 2.1 ppb, or
twice the board standard, were found. That was
the highest concentration detected in the
incident, he said.