Environmental Concerns:
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Please click the picture above for Big Sky
Farms Inc. and their section on Environmental Challenges.
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The environmental problems associated with the Hog
Industry are numerous. The following provides a brief overview of some of
the issues.
Pathogens
A large variety of bacteria, viruses, protozoa, and parasitic worms can be
transferred from hogs to people. They may be ingested via contaminated
drinking water, or inhaled as aerosols carried by wind when manure is
sprayed on fields.
The US Agriculture Dept. has cautioned that many swine pathogens can be
spread on farms by rodents and cats. Some examples:
Yersinia is a bacterium that causes severe gastrointestinal illness. Japan
has identified Yersinia in imported Canadian pork. In Denmark, pork has
been reported to be the only source of human infection in that country.
Has been demonstrated in hog manure in Quebec.
Streptococcus suis: a meningitis that can infect hog workers
E. coli: some varieties can result in grave illness or even death
Listeria monocytogenes: a meningitis that can be lethal
Brucella: in 1992 there was an outbreak of brucellosis among the workers
in a North Carolina pork processing plant
Bacillus anthracis: there was an outbreak of anthrax in 1989 at a pig farm
in north Wales
Pfiesteria: outbreaks have occurred in various places around the world
associated with intensive swine confinement
Salmonella: pigs now harbor many antibiotic-resistant strains. In Germany
20% of human cases have been shown to originate from swine.
Toxoplasma gondii: an intracellular parasite that is particularly
hazardous to pregnant women A 1991-92 study found that 8.6% of Canadian
market-age pigs were infected with this organism
DID YOU KNOW....
Hogs are one of the primary carriers
and sources of strains of a gastrointestinal bacterial pathogen,
Yersinia enterocolitica, which ranks closely with salmonellae and
shigellae in human gastrointestinal infections in Canada. It
has the unique property of being able to grow at low temperatures,
when most pathogens either vegetate or die off, so is concern
in refrigerated meats, and in wastewater and receiving water
bodies or on soils where fecal material or hog wastes may be
disposed. |
Cryptosporidium: a protozoan that has already been found in some water
supplies in Manitoba. This organism is resistant to chlorination, and
causes a severe gastrointestinal illness.
Ascaris: a large (30 cm) roundworm that lives in the intestine. One female
worm produces 2 million eggs/day. Eggs can remain viable in water and soil
for many months.
Trichinella spiralis is a small roundworm that may be found in cysts in
pork meat. Eating undercooked pork may result in trichinosis in humans,
and can be fatal. According to the Centers for Disease Control and
Prevention in the U.S. 80% of trichinosis cases were due to pork
consumption.
Taenia solium is a tapeworm that is readily transferable to humans.
Many kinds of viruses and other infectious agents: e.g. swine
influenza: the Journal of Occupational Medicine reported an occupational
hazard for pork producers, veterinarians and meat plant employees
In North Carolina, Texas, Minnesota and Iowa there have been outbreaks of
influenza-A viruses that were very similar to human genetic strains.
Swine hepatitis-E virus has been shown to be transferable to humans.
The British Medical Journal reported that BSE (mad cow disease) can be
present in pigs as well as cows.
Drug and vaccine residues
A variety of antibiotics, vaccines and hormones are used because
disease can spread extremely quickly in the crowded conditions of the
barns Disease can cause disastrous economic losses. e.g. in 1997 in the
Netherlands, hog plague required the destruction of hundreds of thousands
of pigs and the disinfection of 60,000 transport vehicles Medication may
be administered in feed, water or injected
DID YOU KNOW....
Like human sewages, hog wastes may be
very high in salt content especially if the supply water source is
high in salts and/if lagooning or other treatment facilities permit
significant evaporation of the liquid wastes to occur. This
may cause problems in soils, in crops adjacent to disposal or
discharge sites and in water supplies (wells, dugouts, reservoirs)
affected by runoff or discharges of the wastes. |
The massive use of antibiotics contributes to the emergence of new
antibiotic-resistant strains of disease organisms A 1998 study reported in
the journal Microbial Drug Resistance showed that “E. coli from swine
may represent a considerable reservoir of antibiotic resistance genes”.
Unlike people, who take antibiotics only when they are already sick, in
intensive livestock operations the drugs are given routinely at rates of
100-1000x the rates for people
There is considerable concern about residues of antibiotics in pork. Some
(e.g. Sulfamethazine) are carcinogenic Antibiotic residues may be high
enough in meat that sensitive individuals may get an allergic reaction on
consuming the meat
Hog farmers that use medicated feed have been shown to harbor a higher
proportion of antibiotic resistance than the general population
Compounds that speed growth of swine, e.g. porcine somatotropin and
beta-agonists increase the leanness of meat and reduce the amount of feed
needed. Some studies suggest that hormone residues in meat may affect
young consumers
The European Union has banned the use of hormones in meat, no longer
permits the
importation of hormone-treated meat
The drug residues are also present in the manure and can gain access to
water
Ochratoxin A is a fungal toxin that can originate from contaminated grain
and has been demonstrated in Canadian pork products. It Is carcinogenic
and suppresses the immune system, and causes kidney damage.
Air pollution
Odor reduces quality of life and decreases property values
On many days people can’t go outdoors and may be unable to sell their
property
Methane from manure contributes to greenhouse gases. At present,
methane from all sources is responsible for 12-20% of greenhouse warming.
Hydrogen sulphide gas causes people to feel ill, headaches,
breathing difficulties as well as experiencing increased reaction time and
mood changes
Ammonia volatilizes readily into the air from lagoons and manure
spread on fields. Studies have found that ammonia in the air contributes
to acid rain
Phosphine gas may arise when fresh swine manure ferments in the
absence of oxygen.
Water pollution
Nitrate in the waste gains easy access to surface and ground water.
Nitrate in drinking water may cause methemoglobinemia, a condition where
blood can no longer carry oxygen effectively. Infants are at greatest
risk.
Chronic consumption of nitrate in drinking water may be associated with
greater risk of stomach cancer
Some studies have implicated nitrate exposure in increased rate of birth
defects, particularly spina bifida
Ammonia is extremely soluble in water. It is toxic to animals, fish
are very sensitive. Promotes growth of bacteria in water systems
Phosphorus tends to leach easily from fields where manure has been
spread because the nutrient proportion in manure does not match the needs
of crops, therefore phosphorus tends to be in excess
DID YOU KNOW....
One other problem with hog wastes
related to the high ammonia content is the oxygen demand associated
with ammonia. Besides being toxic to aquatic life at high
levels, ammonia also stresses aquatic environments because of the
need for oxygen for the oxidation of ammonia to nitrate (and
nitrite).
This often ignored because of the greater
awareness of the toxicity of ammonia but this can be a very
significant stressor to aquatic environments, especially if other
oxygen demanding substances are also present in the wastes, or if
the receiving waterbody has low ambient levels of oxygen. |
In surface water phosphorus and nitrogen feed the growth of noxious algae
that impact on the fisheries and tourism industries
Bluegreen algae may create blooms to the extent that the water may become
toxic to people, livestock and wildlife. Water containing a bluegreen
algal bloom is unsuitable for swimming because the toxins cause skin
irritation and there is the danger of swallowing some water
Heavy metals
Manure contains a variety of heavy metals and salts, for example zinc,
copper, cadmium, nickel, cobalt, lead, boron, selenium
These metals are present in the feed because some, such as copper, enhance
swine growth Much of them are excreted and end up in the manure
Repeated application of manure to the same soils causes accumulation of
these elements
Detergents and disinfectants from barn washing
Carcass disposal
Unscrupulous operators may dispose of dead pigs in an environmentally
unsafe manner, or pigs may end up in local landfills
Hazards to hog industry workers
Up to 25% of workers in Manitoba’s meat packing plants suffer a work-related
injury or illness
People who work in barns are susceptible to organic dust toxic syndrome
from breathing hog dust
Suffer chronic respiratory illnesses such as cough and asthma.
There is a direct correlation between severity of symptoms and number of
hours worked in the barn. Young barn workers are most susceptible to lung
damage
Suffer allergic reactions to endotoxins from airborne bacteria in
the barns Chronic exposure to endotoxins is associated with liver
damage and bowel diseases. Dust masks have little effect because
particles are very small
Hearing loss. The scream of a sow can exceed 100 decibels
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