Herbicides/pesticides
In this assignment, you will use a blog to educate your classmates about an everyday organic
chemical and propose a personal course of action to reduce negative impacts on human health
and the environment.
Herbicides:
Also commonly known as weed killers, are pesticides used to kill unwanted plants
Pesticides:
Are substances or mixture of substances intended for preventing, destroying, repelling or
mitigating any pest?
Benefits Herbicides: Environmental Impacts:
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Advantages
They kill unwanted plants.
They can be safely used whereas in some cases manually removing weeds can destroy the crop.
Herbicides can be used on closely planted crops where other methods cannot be used.
Most of the time one application of the herbicide is enough whereas other methods have to be
continually used.
They are easy to use
They work fast. They can be removed quickly in critical situations.
Herbicides are relatively cheap, and most of the time cheaper than manual weeding.
Non-selective herbicides can effectively clear fields, where houses and roads can then be built.
They can destroy plants bearing diseases.
They help the crops grow by destroying the weed that is robbing the crops water, nutrients and
sunlight.
They are relatively safe on lands which may erode.
Some are biodegradable, and become relatively harmless after decay.
Disadvantages
Some herbicides are non-biodegradable and are harmful for a long period of time.
They are all slightly toxic.
They can cause illnesses. Glyphosate, a herbicide, can cause eye and skin problems and upper
respiratory effects in the user. Paraquat can cause irritations to the skin and may also lead to
death, accidental and even suicidal. Many other diseases and illness can be caused such as
cancer, nausea, headaches, chest pains, and fatigue.
The can be carried into streams by runoff rainwater or leached into underground water supplies
polluting them.
Herbivores may eat the plants treated with herbicides and then carnivores eat the herbivores. The
toxic herbicide would be passed up the food chain increasing in concentration each time resulting
in cancers and even deaths.
Benefits Pesticides: Environmental Impacts:
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Pesticides are poisons. As such, there are many ways that pesticides can be harmful. Although
pesticides are usually used to kill a particular target pest, many will also kill or harm species that
the farmer or other user is not targeting. For example, pesticides applied to crops might be
washed into streams or lakes and harm fish, beneficial insects, birds, or even find their way into
drinking water sources.
Advantages of using pesticides
Cost effectiveness: Pesticides are an economical way of controlling pests. They require low
labour input and allow large areas to be treated quickly and effectively. It has been estimated that
there is a four-fold return on every dollar a farmer spends on pesticides.
Flexibility: A suitable pesticide is available for almost all pest problems with variation in type,
activity and persistence.
Quality, quantity and price of produce: Using pesticides means there is a plentiful supply and
variety of high quality products at reasonable prices. Modern society demands
nutritious food free from damage caused by pests and flowers which look untouched. This would
be very difficult without pesticides.
Prevention of problem: Pesticides are often used to stop the spread of pests in imports and
exports, preventing weeds in gardens and protecting house and furniture from destruction.
Protection of pets and humans: Under the blanket of pesticides is pet flea products, fly and
insect spray and other household products which make life bearable.
Protection of the environment: Currently, weeds are controlled by herbicides, but without
them, land would need to be cultivated, increasing land degradation.
Disadvantages of Pesticides
Reduction of beneficial species: Animals which interact with the targeted pest can also be
affected by he chemical application. The reduction in these other organisms can result in changes
in the biodiversity of an area and affect natural biological balances.
Drift of sprays and vapour: Pesticides can affect other areas during application and can cause
severe problems in different crops, livestock, waterways and the general environment. Wildlife
and fish are the most affected. Taking special note of weather conditions can reduce drift.
Residues in food: There is the possibility of pesticides in human food, either by direct
application onto the food, or by bio-magnification along the food line. Not all levels are
undesirable but unnecessary and dangerous levels must be avoided through good agricultural
practice.
Ground water contamination: Chemicals can reach underground aquifers if there is persistent
product use in agricultural areas.
Resistance: Overuse of the same pesticide can encourage resistance in the target pest.
Poisoning hazards: Pesticide operators can risk poisoning through excessive exposure if safe
handling procedure are not followed and protective clothing is not worn. Poisoning risks depend
on dose, toxicity, duration of exposure and sensitivity.
Other possible health effects: As pesticides used now have been through rigorous testing, most
health problems stem from misuse, abuse or overuse.
Pesticide can keep bugs and stuff off of your plants but when it rains it comes off and flows into
rivers
killing
fish
and
other
aquatic
animals.
How is it used?
Herbicides: Impacts on Human Health:
Herbicides
Chlorophenoxy
Pentachlorophenol
Nitrophenolic
Routes of
Toxicity
Absorbed
by
inhalation,
ingestion,
and dermal
exposure.
Signs and Symptoms
Irritating to skin and mucous
membranes. Causes vomiting,
diarrhea, headache, confusion,
bizarre or aggressive behaviour,
peculiar odor on breath. Metabolic
acidosis, renal failure, irregular
heartbeat.
Absorbed
Irritation of the nose, throat, and
by
eyes. Hyperthermia, muscle spasm,
inhalation,
tremor, labored breathing, and
ingestion,
chest tightness indicating serious
and dermal poisoning.
exposure
Absorbed
Sweating, thirst, fever, headache,
by
confusion,
restlessness.
inhalation,
Characteristic
bright
yellow
ingestion,
staining of the skin and hair often
and dermal present with topical exposure.
exposure.
Common Brands
Banvel
Diamba
MCPA
MCPB
PCP
Chlorophen
Pentacon
Nitrader
Talan
Triforce
Caldor
Basanite
Pesticides Impacts on Human Health:
Pesticides
Arsenic containing
Routes of
Toxicity
Absorbed
by
inhalation,
ingestion,
and dermal
exposure.
Signs and Symptoms
Common Brands
Garlic odor of breath and feces, Zoltax
metallic, taste in mouth, adverse GI Salvo
symptoms,
chronic
muscle Jones Ant Killer
weakness, fatigue, weight loss.
Fungicides
Fumigants
Rodenticiides
Absorbed
by
inhalation
and
ingestion.
Absorbed
through
skin when
product
contains
mercury.
Absorbed
by
inhalation,
ingestion,
and dermal
exposure.
Absorbed
by ingestion
Variables
Terraneb SP
Bravo
Clortran
HCB
Earthcide
Highly variables, many are
irritants, can have serious CNS
effects, can cause pulmonary
edema, can cause severe hypoxia
Chloroform
Lavacide
Meth—O-Gas
Sanifume
Highly variable,
can
cause Havoc
bleeding,
pulmonary
edema, Liqua-Tox
cardiovascular, GI, and CNS Rocol
effects
Tomcat
Current use and disposal:
Safe Disposal of Pesticides
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The best way to dispose of small amounts of excess pesticides is to use them - apply them
- according to the directions on the label. If you cannot use them, ask your neighbors
whether they have a similar pest control problem and can use them.
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If all the remaining pesticide cannot be properly used, check with your local solid waste
management authority, environmental agency, or health department to find out whether
your community has a household hazardous waste collection program or a similar
program for getting rid of unwanted, leftover pesticides. These authorities can also
inform you of any local requirements for pesticide waste disposal.
To identify your local solid waste agency, look in the government section of your phone
book under categories such as solid waste, public works, or garbage, trash, or refuse
collection or you can call 1-800-CLEANUP.
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State and local laws regarding pesticide disposal may be stricter than the Federal
requirements on the label. Be sure to check with your state or local agencies before
disposing of your pesticide containers.
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If the container is partly filled, contact your local solid waste agency.
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If the container is empty, do not reuse it. Place it in the trash, unless the label specifies a
different procedure.
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Do not pour leftover pesticides down the sink, into the toilet, or down a sewer or street
drain. Pesticides may interfere with the operation of wastewater treatment systems or
pollute waterways. Many municipal systems are not equipped to remove all pesticide
residues. If pesticides reach waterways, they may harm fish, plants, and other living
things.
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EPA's guidance to pesticide registrants about instructions for disposal of household-use
pesticides provides more information on this issue.
1. Propose one specific way that the situation could be improved. (e.g. safer
alternatives, better disposal, method of reusing or recycling materials etc.)
Better alternatives:
2. Include at least one multimedia component (e.g. pictures, audio clip or video clip).
Create your own (ideally) or reference accordingly.
Herbicides/pesticides
Herbicides:
Pesticides:
3. Use at least 3 reliable sources and reference your information correctly.
References/ Sources:
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http://peer.tamu.edu/curriculum_modules/environ_hazard/module_4/lesson2.htm
http://www.chromatography-online.org/directory/analtcat-24/page.html
http://www.care2.com/greenliving/pesticide-cautions.html
4. Post your report (approx. 500 words) on the blog by the assigned date
ALL THE QUESTIONS ANSWERED