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gas maskCRITICAL POLLUTANT: WHAT ARE PERSISTENT PESTICIDES?

Pesticides include insect poisons and weed killers. These chemicals were developed to kill insect or weed pests that threaten agricultural or forest crops. Some pesticides, when they are exposed to sunlight and rain, quickly breakdown into less toxic materials.

"Persistent" pesticides are those that do not breakdown in the environment, but remain toxic to fish, animals, and humans for many years. They can bioaccumulate (glossary link), their toxic effects multiplying as they move up the food chain from plants, to animals, and finally us.

BW photo woman
Who is this woman and what did she do to stop pesticide use?
predatory chicks
DDT was considered a miracle when it was invented to control mosquitos that caused human diseases like malaria. Yet DDT almost led to the extinction of bald eagles, and other top level (tertiary level) predator birds.

 

The persistent pesticides included in the "Nasty 9" are:

ddt DDT- used to kill insects, especially mosquitoes

DDE- a bioaccumulative poison created when DDT is broken down

irrigation Aldrin and its byproduct Dieldrin: used to kill insects in agricultural crops and to preserve wood
toxaphene Toxaphene, as well as Dicofol (also known as Kelthane): used to kill insect pests and put into lakes and streams to kill undesirable fish
chloradine Chlordane:
hexachlorine Hexachlorobenzene (HBC)- was used as both a pesticide and fungicide (a fungus killing poison). This chemical, together with Octachlorastyrene and Dioxin, can also be released when household waters are burned in a burning barrel where lower burning temperatures do not allow for materials to be completed incinerated.

Octachlorostyrene. a manufacturing byproduct used as a pesticide. This chemical, together with Octachlorastyrene and Dioxin, can also be released when household waters are burned in a burning barrel where lower burning temperatures do not allow for materials to be completed incinerated.

Mercury pesticides, and 2,4,5-T (Silvex). weed killer used with woody plants. 2, 4, 5-T was a component of Agent Orange which was used as a defoliant during the Vietnam War.

 

poison
Click image to investigate the effects of each of these persistant pesticides.

WHY ARE PERSISTENT PESTICIDES PART OF THE "NASTY 9"?

These chemicals included of Lake Superior's "Nasty 9" because they:

 

DON'T DRINK THIS POP!

Persistent organic pollutants, or "POPs", are highly toxic pesticides and industrial chemicals that do not decompose. They biomagnify or bioaccumulate as they move up through the food chain.

POPs have been linked to adverse effects on human health and animals, such as cancer, damage to the nervous system, reproductive disorders, and disruption of the immune system.

natives
Find out why POPs are an issue for native people who rely on subsistence fishing and hunting by clicking on image.

POPs are still produced by industrial and developing nations as products or by-products of manufacturing processes. They can circulate globally via the atmosphere, oceans, and other pathways. POPs released in one part of the world can travel to regions far from their source of origin. These pollutants have been carried by ocean and air currents to the once pristine Arctic and deposited there in alarming quantities.

POPs include several of the persistent pesticides, industrial PCBs, dioxins, and have been passed up the food chain to human populations, invading body fat and vital organs, and now pose a health danger to Alaskan and Canadian Native people as well as others in the region who depend on fish and game.

List of Persistent Organic Pesticides (POPS)
1 Pesticide 3 Byproduct
 
aldrin 1 hexachlorobenzene 1,2,3
chlordane 1 mirex 1
DDT 1 toxaphene 1
dieldrin 1 polychlorinated biphenyls (PCBs) 2,3
endrin 1 polychlorinated dibenzo-p-dioxins (dioxins) 3
heptachlor 1 polychlorinated dibenzo-p-furans (furans) 3

 

BANNED, BUT NOT FORGOTTEN

The good news it that both Canada and the US have banned the production, selling, and use of these persistent pesticides.

bioaccumulate chartIf persistent pesticides are no longer being manufactured and used, why are they still a problem?

These chemicals are called "persistent" because they do not break down in the environment easily. Through bioaccumulation they can be absorbed by plants, which are eaten by fish and animals, and finally humans. At each step in the food chain, the amount of these toxic chemicals increases.

The large amounts of these pesticides that were used during the 1960's and 1970's and these chemicals still remain in the Lake Superior environment.

Although sale of these persistent pesticides is banned, there are still supplies of these poisons on the back shelf in home garages, on farms, in schools, and other community locations.

Even though these toxic chemicals are banned in the US and Canada, they are still used in other countries around the world. If they enter the atmosphere when they are sprayed or when they are burned, they can be carried on the wind and deposited on the Lake Superior Basin. If we eat food that comes from other countries where these pesticides are still used, we can be exposed to them.

 

SOURCES OF PERSISTENT PESTICIDE POLLUTION

Even though persistent pesticides are banned, there are still pathways where they can pollute the Lake Superior Basin. Could you be exposed to a persistent pesticide from one of these sources? Click on each image to investigate.

 

fishbowl clouds worker
Pesticides absorbed by the fish we eat. Atmosphere Deposition into the Lake. Old pesticides stored at school.
 
storage barn on a farm shore
Old pesticides used or stored at home. Old agricultural pesticides stored on farms. Persistent Pesticides that remain in the lake.

 

PERSISTENT PESTICIDES STILL PERSIST

Check yourself ... if persistent pesticides are no longer being manufactured and used, why are they still a problem?

These chemicals are called "persistent" because they do not break down in the environment easily. Through bioaccumulation they can be absorbed by plants, which are eaten by fish and animals, and finally humans. At each step in the food chain, the amount of these toxic chemicals increases. The large amounts of these pesticides that were used during the 1960s and 1970s and these chemicals still remain in the Lake Superior environment.

sampling
Sampling sediment for critical pollutants in a Lake Superior harbor.

Although sale of these persistent pesticides is banned, there are still supplies of these poisons on the back shelf in home garages, on farms, in schools, and other community locations.

Even though these toxic chemicals are banned in the US and Canada, they are still used in other countries around the world. If they enter the atmosphere when they are sprayed or when they are burned, they can be carried on the wind and deposited on the Lake Superior Basin. If we eat food that comes from other countries where these pesticides are still used, we can be exposed to them.

While progress has been made to reduce new sources of persistent pesticides, we are still dealing with problems caused by past use of these toxic chemicals.

Based upon recent water concentration measurements, the quantities of these pesticides remain in the water column of all five Great Lakes. Although concentrations of these pesticides have declined in the Great Lakes Basin, there are still problems:

Persistent pesticides have been detected in harbor sediments in the Duluth-Superior harbor. The level of toxaphene in Lake Superior has not shown a general decline or breakdown within the environment over the years like the other pesticides.

 

GOAL. TOTAL ELIMINATION OF PERSISTENT PESTICIDES

Our goal is to retrieve and destroy all remaining stockpiles of the banned pesticides including DDT, DDE, aldrin/dieldrin, and toxaphene, as well as dicofol (Kelthane), hexachlorobenzene, mercury pesticides, hexachlorobenzene pesticides, and 2,4,5-T (Silvex) and other pesticides contaminated by dioxin or hexachlorobenzene in the Basin by the year 2000. Here are some strategies to help:

Collect and Dispose of Remaining Stockpiles of Banned Pesticides

sweep logoSweep Lake Superior Clean of Pesticides
Even though these persistent pesticides have not been produced for many years, supplies of them still remain on garage shelves, stored on farms, or stashed in forgotten storage places. If they are not properly disposed of by a person not recognizing their danger, they can re-enter the environment and persist as a poison for many years.

tabling
Community Clean Sweep Program collect household and farm hazardous wastes and dispose of them properly.

The only safe way to dispose of these pesticides is to bring them to a certified Clean Sweep collection site where they will be disposed of by hazardous waste management professionals.

Every year citizens participating in household hazardous waste and agricultural Clean Sweep collection programs in the Lake Superior Basin bring in these pesticides from households and farms.

Are any of these persistent pesticides being stored at your home or farm. If so, search for a Clean Sweep program in your community. Clean Sweep programs can make a big difference. Check out the impact of Clean Sweep Programs in eliminating persistent pesticides from entering the environment.

 

Clean Sweep Collections Of Pesticides In The Lake Superior States (U.S. Programs)

State
Dates of Collection
Substances Collected - pounds
Aldrin/ Dieldrin Chlordane DDT Silvex Toxaphene Total Pesticide
Michigan 1995 147 25 193 Not estimated 0 365
Minnesota 1992 - 1998 74 535 4,959 6,000 83 11,651
Wisconsin 1996 - 1998 0 36 97 28 480 641

 

Learn About the Risk of Pesticide Use and Find Alternatives

Approximately 75 percent of the usage of registered pesticides (which still can contain, as a contaminant, small amounts of dioxin or hexachlorobenzene) is for agricultural purposes.

Off the farm, pesticides are applied to urban landscaping, gardening, residential and commercial property, golf courses, university property and governmental property. The. also affect the health of the Lake Superior Basin.

There are alternatives that will help protect the soil and water, while still controlling pests. Investigate using lower risk pesticides, improving application techniques so the minimum amount of pesticide is used, and avoiding pesticide use all together by using organic methods. Here are some options:

 

barn logoThese programs help promote safer home and farms by reducing exposure to risks that affect human health at home and on the farm including exposure to pesticides, drinking water safety, and more. Click on the windmill to investigate more.


ladybugIntegrated Pest Management or IPM is a new way of managing pest problems in homes, gardens, lawns, and on farms using little or no chemical pesticides. IPM uses other tactics to reduce or eliminate pest problems. Click on the bug to investigate more about starting an IPM program in your school.

 

 

TAKE THE NEXT STEPS...to eliminate Persistent pesticides

man on beach CREATE... your own service learning experience to protect and restore aquatic communities. This section provides you with a template to get started in developing your own service learning project.
girl with net ACT... Take action to help restore and sustain aquatic communities and learn about what others are doing in the Lake Superior Basin and your community. This section will give you hands-on things you can do to help!
group reflects REFLECT.... Share and celebrate your experiences with others. This section lets you share what you learned with others.

 


Copyright 2007 - University of Wisconsin Extension
Comments and questions about this site may be directed to catherine.techtmann@ces.uwex.edu