LIVESTOCK MANURE STINKS FOR INFANT HEALTH

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Science News, Jan. 16, 2009

 

 

LIVESTOCK MANURE STINKS FOR INFANT HEALTH

 

Megafarm production is associated with infant illness, death rates

 

By Rachel Ehrenberg

 

The manure generated by thousands of cows or pigs doesn't just

stink

it may seriously affect human health.

 

New research examining two decades' worth of

livestock production

data finds a positive relationship between increased production at

industrial farms and infant death rates in the counties where the

farms reside. The study reported in the February American Journal

of

Agricultural Economics implicates air pollution and suggests that

Clean Air Act regulations need to be revamped to address livestock

production of noxious gases.

 

The new work is in line with several studies documenting the ill

effects of megafarms, which typically have thousands of animals

packed

into small areas, comments Peter Thorne, director of the

Environmental

Health Sciences Research Center at the University of Iowa in Iowa

City. Higher rates of lung disease have been found in workers at

large

poultry and swine operations and respiratory problems increase in

communities when these large-scale farms move in, Thorne notes.

 

" This study is a very important contribution, " says Thorne.

" This is

an industry we really need -- it provides food and a lot of jobs

--

the answer isn't for everyone to become vegetarians. " But, he

says, " I

think we need a fundamental change in the way this industry is

going.

There's a very strong case that under the Clean Air Act the EPA

should

be looking seriously at the livestock industry. "

 

The study, by economist Stacy Sneeringer of Wellesley College in

Massachusetts, examined birth and death records from the National

Center for Health Statistics and the increase in " animal units "

per

county across the United States from 1982 to 1997. (Animal units are

a

normalizing unit used by the U.S. Department of Agriculture. One

animal unit equals roughly 1,000 pounds of average live weight; or

250

layer chickens (for eggs); or 1.14 fattened cattle; or 2.67

breeding

hogs.) An increase of 100,000 animal units in a county corresponded

to

123 more infant deaths per year per 100,000 births. Doubling

livestock

numbers was linked to a 7.4 percent increase in infant mortality.

 

Several potentially confounding variables were taken into account,

such as per capita income, the availability of health care,

climate,

land and housing use, possible effects of other industries and

whether

large farms move to areas that already have poor infant health.

 

" I was surprised to see this association -- I kept expecting it

to go

away but it didn't, " Sneeringer says.

 

Farm pollution is typically associated with groundwater

contamination.

Leaks in manure lagoons or runoff from fertilizers or pesticides

get

into streams and other waterways. But increased livestock

production

had greater effects in areas with low well-water usage,

implicating

air pollution.

 

Ammonia, hydrogen sulfide and airborne particulate matter are all

associated with livestock production, Sneeringer says. Exposure to

the

gases has been linked to respiratory distress in infants, while

exposure in the womb has been linked to disorders that occur late

in

pregnancy or shortly after birth, and has also been linked to

spontaneous abortions. Sneeringer found that about 80 percent of

the

infant deaths associated with increased livestock production

occurred

in the first 28 days of life.

 

" Livestock are the number one source of volatilized ammonia in

the

nation, " Sneeringer says.

 

Increasingly, farms that generate manure don't use it as

fertilizer,

Sneeringer points out. Many large livestock operations have no

crops

to fertilize. The manure may be shipped out to become

pelleted

fertilizer elsewhere, or sit in a big, sealed lagoon.

 

Several steps might be taken to assuage the problem, says Thorne.

Aerobic digesters can oxygenate manure as it breaks down,

eliminating

some of the noxious gases that anaerobic bacteria produce.

Fertilizer

could be injected into the ground instead of sprayed onto fields.

And

large livestock facilities could be required to buy additional

surrounding land, increasing the distance between people and

pollution.

 

Citations & References:

 

S. Sneeringer. 2009. Does Animal Feeding Operation Pollution Hurt

Public Health? A National Longitudinal Study of Health

Externalities

Identified by Geographic Shifts in Livestock Production. American

Journal of Agricultural Economics. 91:1. DOI:

10.1111/j.1467-82

76.2008.01161.