Definition
Persistent Organic Pollutants are organic compounds that are resistant to biological, photolytic and chemical degradation. It has ability to be persistent in environment without broken down into less hazardous compunds.
Characteristics
- Lipophilic and Hydrophobic
- Transport to long distance
- Semi-Volatility
- Persistence in environment
- Bio-accumulation in Food chain
- Bio-concentration into Fats and oil tissues
- Toxic, carcinogen and mutagens
- Have large lifespan
- Sticks to soil very strongly that only breakdown by volatilization.
- Acute, toxic to humans
- Highly Concentration in marine mammals
Causes
It comes from industrial areas, combustion products and burning of other waste materials. Many kind of POPs like PCDDs are produced from coal burning plants and municipal waste incineration.
Effects
- It affects reproductive system, immune system, nervous system and endocrine system.
- Also cause behavioral disease like thyroid, cancer and diabetes.
- Mothers who eats fishes contaminated with POPs leads to many problems in babies like short and long memory, short attention spans, low intellectual functioning etc.
- Marine and aquatic life has severe effects like metabolic imbalance and immune system dysfunction.
Environmental behavior / Physical & Chemical properties
1. Semi Volatility
They are semi - volatile means that they are immobile in soil but when enters into atmosphere, they travel a long distance before broken down into other compounds. They volatilize from hot region and condense into cooler region.
2. Persistent in Environment
Persistence is actually a length of time in which organic compound remain in the environment before breaking down or converting into other compunds
Dissipation is another term which means to disappearance of a compound into another one by degradation and followed by mobility. POPs have high capability to persist in Environment.
3. Long Range Transport
Overall, they are resistant to degradation and persistent in environment so they sticks to soil, vegetation and others so that they can't degrade. They can be seperate out from soil only by volatilization. They volatilize from soil and enters the air to travel a long distance because to non-resistance to degradation.
4. Lipophilic
They are water hating and fat loving. Therefore they bio-accumulate in human fat tissues like adipose tissue and cause harmful effects. High lipophilicity cause them to dissolve into fat and oil tissue of organisms and they are persistent in nature so they bio-concentrate there.
5. Bio-accumulate in food chain
In addition, they affect the top level of food chain who eats the smaller organisms. They bio-accumulate into their fat tissues to stay there.
6. High concentration in marine mammals
Immune dysfunction, Thyroid diseases and vitamin deficiencies are found in marine mammals because of Pops.
7. Acute and Toxic
It's highly toxic for both animals and humans as carcinogen, mutagen and teratogens. Some pesticides like aldrin, dieldrin and toxaphene caused mass poisoning called Yusho and Yu Cheng in China.
Dirty Dozens
12 Pops that are toxic and are now banned in US. Let's discuss!
1. Aldrin- Organochlorine insecticides
Used to control insects on corn and potatoes crops to protect its wood from termites.
It strongly binds to soil and only seperate by semi-volatilization
It's carcinogen and mutagens
It's banned in US
It cause nausea, headache, vomiting, dizziness and malaise.
Occupational exposure may cause liver and biliary cancer.
It's oxidized into dieldrin (neurotoxin) inside insects.
Bio-concentrate into fat and oil tissues of living organisms.
2. Chlordane - manufactured pesticides
It's used to control termites on agricultural crops.
It cause digestive and nervous system damage and breast cancer
It's also banned in US.
It's strongly bind to soil and have lifespan of about 2-15years.
It also bio-accumulate and bio-concentrate into food chain.
3. DDT - Synthetic Pesticides
It's used for mosquito controls in certain parts of world.
It also bio-accumulate and bio-concentrate that has half life of 20 years.
They has major factor in bald eagles, bird's egg shell thin, peregrine falcon population decline.
Carcinogen
Cause diabetes in those babies whose mothers eat contaminated food
It's also found in Cow milk sample but now it's banned in US.
4. Dieldrin - insecticide
It's similar to aldrin because it's formed from oxidation of Aldrin.
It cause Parkinson's disease, nervous disorders, immune system, reproductive disease along with breast cancer.
Toxic and banned in US.
5. Heptachlor - insecticide
Similar to chlordane
10 years life span
Banned in US
Carcinogen
6. Hexachlorobenzene -Fungicide
Use as seed treatment on wheat crops.
In animals cause liver, thyroid and kidney disorders
In humans, it cause thyroid, hair loss, ulceration, skin lesions, carcinogen etc.
Banned in US.
Passed to child via placenta and breast milk
Toxic to aquatic life because of bio-concentration and bio-accumulation.
7. Endrin- insecticides & Rodenticide
It's absorbed on sediments in surface water.
Insecticides is used on cotton, maize and rice while Rodenticide is used for mice and volves.
Bio-concentrate
10 years half life
Nervous system damage and poisoning affects the children.
8. Mirex- insecticides and flame retardant
It's used as insecticides to control fire ants but also used as flame retardant in electronics, paints, rubber, paper and plastic.
It's banned in US but still used as flame retardant.
In animals it damage liver and in humans it's carcinogen.
9. PCDDs - Dioxins
Teratogens, carcinogen and mutagens.
It's lipophilic and bio-concentrate into aquatic life.
It comes from burning of municipal waste incineration, coal burning and trash burn barrels, diesel trucks and burning wood.
In humans, it cause cancer, liver disease reproductive, sexual disease, immune system, nervous system destroy and thyroid disease.
In animals, liver damage, endometriosis, diabetic, immune system and nervous system etc.
Bio-concentrate and bio-accumulate.
10. PCDFs
Highly toxic
Similar to PCDDs
11. Toxaphene
Toxic and banned in US.
Cause kidney, lungs, nervous system damage and can be fatal.
12. PCBs
Click here to see PCBs in detail.
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