Click image for caption and other photo
story to find out more.
Evaluate Pollution-Fighting Polyacrylamides
By Marcia Wood
July 29, 2002
An environmentally friendly compound
already employed to stop soil from eroding can also keep nutrients and bacteria
from leaving fields or farmyards. New studies by Agricultural Research Service
(ARS) scientists at the agencys
Northwest Irrigation and Soils
Research Laboratory, Kimberly, Idaho, pinpoint the pollution-fighting
potential of these compounds, called polyacrylamides or PAMs. The goal: keep
pollutants from making their way to ponds, lakes, streams and rivers.
Earlier work by the Kimberly researchers showed that mixing small amounts of
PAM, a powder, into irrigation water can reduce soil erosion by up to 99
percent. PAM does that by holding soil particles in place. Otherwise, they
might wash away as irrigation water travels down furrows or falls from overhead
sprinklers. The teams work helped open the door to use of PAM on more
than one million acres of American farmland.
More recently, the scientists analyzed PAMs prowess in grabbing
nutrients such as nitrogen and phosphorus. Excess amounts of these and other
nutrients from fertilizers can become pollutants, according to ARS soil
microbiologist James A. Entry at Kimberly.
The team also scrutinized PAMs interaction with disease-causing
bacteria found in cow, pig and fish manure. Entry and colleagues showed that
PAM alone reduced nutrients and manure-borne pathogens in water samples by 90
percent. When PAM was combined with aluminum sulfate or calcium oxide, the
pollutants were reduced by as much as 99 percent.
PAMs and their use to trap pollutants are routine in the wastewater
treatment industry. But the ARS farm-oriented studies are a first.
An article in the July
2002 issue of the ARS monthly magazine, Agricultural Research, tells
ARS is the U.S. Department of
Agricultures chief scientific research agency.