Perhaps the most logical place to begin treating this topic is to give a definition of pesticides. What is a Pesticide exactly? According to the EPA (Environmental Protection Agency) a Pesticide is:

According to the Environmental Protection Agency Biopesticides are:

How much pesticides do we use?

Not surprisingly 77% of all pesticides in the U.S. are used by the agricultural industry. Another 23% is used in the Urban Sector. So how much is this really?

Here in the U.S. the agricultural industry consumes a whopping 950million pounds (yes, 950,000,000 pounds!!!) per year.

In the Urban Sector, some 244 million pounds are consumed every year.

If we do a little arithmetic, we find that over 1billion, 244 thousand pounds of pesticides are going into the environment every year.

So, what do we use all these pesticides for anyway?
 
 

Currently in the U.S., there are over 17,000 registered pesticide products and over 800 related active ingredients.

How much pesticide related illness occurs?

Based on states with required reporting of pesticide-related health concerns, the EPA estimates approximately 250-500 physician-diagnosed cases occur per 100,000 agricultural workers (including pesticide handlers). It is believed that there is a significant number of cases that are undiagnosed or unreported. This statistic applies only to agricultural workers, and excludes any illness that may occur due to pesticide misuse on a domestic level, say in homes for example.

For more information on how pesticides effect agricultural works click on the following link to the EPA:

Worker Saftey
 
 

As we might well imagine, most pesticides create some risk of harm to humans, animals, or the environment. This is due to the very nature of pesticides themselves; they are after all, designed to "kill or otherwise adversely affect living organisms." Be this as it may, it is hard to deny how useful pesticides are to society. Pesticides are of paramount importance because of their ability to kill potential disease-causing organisms and enabling us to control insects, weeds, and other pests. In the United States, the Office of Pesticide Programs of the Environmental Protection Agency is chiefly responsible for regulating pesticides. Biologically-based pesticides, such as pheromones and microbial pesticides, are becoming increasingly popular and often are safer than traditional chemical pesticides.

So why all this fuss over pesticides anyway?

Here's something that perhaps some of us never really thought of as problem before.

"This study found some sixteen different pesticides in the eight baby food products tested. Of those sixteen pesticides, three are probably human carcinogens, five are possible human carcinogens, eight are neurotoxins, five are endocrine disruptors, and five are classified in the EPA's most toxic designation. More than half of all samples (53 percent) contained detectable levels of pesticides, 18 percent of samples had two or more pesticides in them, and one sample contained three different pesticides (EPW)."

According to the EPA, there were an estimated 74,000 instances of pesticide poisoning in children due to exposure to common household items in 1994. For more information on how to prevent accidental poisoning in the home, as well as more information on just how vulnerable children in particular are to pesticides, click here.

Here are some common household products which are also considered pesticides:

• Cockroach sprays and baits
• Insect repellents for personal use.
• Rat and other rodent poisons.
• Flea and tick sprays, powders, and pet collars.
• Kitchen, laundry, and bath disinfectants and sanitizers.
• Products that kill mold and mildew.
• Some lawn and garden products, such as weed killers.
• Some swimming pool chemicals.

**Spinach and other leafy greens like kale and collards contain lutein (a carotenoid) that is not abundant in these substitutes. Lutein may reduce the risk of macular degeneration, the most common cause of blindness in the elderly.

Sources for the above table: Environmental Working Group, compiled from FDA and EPA data; Center for Science in the Public Interest. Nutrition Action Health Letter, January-February 1995, October 1994, May 1992, December 1991.

Unfortunately, neither of these tables tell us exactly how much pesticides are found in the most contaminated produce. We must be careful not to exaggerate the danger of pesticides on produce too much. Much of what is here presented may well be a sort of worse case scenario. There are some who do claim that while the public's fears about pesticides and produce are not necessarily unfounded, they may be a little exaggerated. "The health benefits of eating fruits and vegetables far out-weigh pesticide risks."

If you ate an apple a day, how many pesticides would you consume in a year? Here's a nifty page that'll give you an estimate. Try out the EWG Supermarket to find out how many pesticides you consume in a typical day of shopping.

Here's a link to some Signs and Symptoms of Pesticide Poisoning.
 
 

Other Pesticide Concerns

In addition to human consumption of pesticides via produce, there is a real concern over the effect pesticides often have on non-target species. A non-target species is any insect/animal etc. not intended to be harmed by a pesticide. Some 90% of all pesticides used never actually reach the intended target species. To give you an idea of some of the potential for unforeseen disaster, some 10,000 migrating robins were killed as a result of exposure to a particular pesticide used on potatoes in Azrodin FL in 1972. We can see similar problems as concerned geckoes, cats and rats in Burma.

The killing of non-target species also has other negative effects. Very often the non-target species that are effected are predators that are beneficial to a farm, such as wasps, ladybugs and preying mantis. Once you take away these essential predators, new pests arise that weren't a problem before (such as moths), thus compounding the problem even further.

Pesticide Resistance and Resurgence

This is a problem that grows increasingly worse all the time, and may well be one which should concern us most. What is pesticide resistance? This is a phenomenon whereby a pesticide that was once highly effective becomes entirely useless (or at least nearly so). This is to say that the target species is no longer effected by a particular pesticide and thus becomes resistant to it. How does this happen? It happens quite simply; it occurs through natural selection. What happens is that the pesticide will kill off a very large portion of whatever species it targets, but not all. Those that survive must have some genetic trait that enables them to survive or resist the effects of the pesticide. As a result, these few reproduce, and pass on their particular resistance to the next generation; only those who have inherited the gene for resistance will survive. In a few generations (which is often a very short period of time when talking about insects or bacteria) all of the species then living will have resistance to the pesticide that once decimated their population. The pests continue then to reproduce, and flourish. This is called Resurgence.

So what do you do then once a pest becomes resistant? One must then either use increasing amounts of the same pesticide, or find a deadlier, more toxic one. This same problem occurred with rabbits and the myxoma virus in Australia.

Why Are We So Reliant on Pesticides?

Crop Protection- The United States in particular is heavily reliant on pesticides to protect their crops. Farmers save $3 to $5 for every $1 spent on pesticides. But even with the use of pesticides, a farmer may still expect to lose approximately 20-30% of his/her crop. Countries that don't use pesticides often lose up to 45% or their crops. It is estimated that without the use of pesticides (or some other means of pest control), the loss to the US economy would be about 15 billion dollars.

 Disease Control- Pesticides can help keep some diseases often spread by insects to a minimum (Malaria, Typhoid Fever, Yellow Fever and Plague).(see DDT below)

Here's a link to some quick pesticide statistics.

A photograph of what DDT looks like under a microscope.

DDT

Most everybody at one time or another has heard some tell of the dreaded pesticide called DDT.  DDT was principially used during and after World War II to control diseases such as Malaria. As we know there are a plethora of diseases that can be spread by such insects as ticks and mosquitos. Here's a list of some of the most comon diseases world wide, as well as how they are carried.

        Insects and ticks are critical vectors in spread of disease to humans and animals

      - most important diseases (world-wide) and vectors

        Malaria - caused by protozoan, Plasmodium; spread by mosquito, Anapheles spp.
        Yellow fever - spread by mosquito, Aedes aegypti and Culex spp.
        Trypanosomiasis (= sleeping sickness) - caused by protozoans, Trypanosoma
         - spread by tsetse fly, Glossina sp.
        Plague (or black death) - caused by bacterium, Pasteurella pestis
                                                  - spread by oriental rat flea, Xenopsylla cheops
        Typhoid fever - caused by bacterium, Rickettsia prowazeki
                                   - spread by body louse, Pediculus humanus

        - pesticides are used:    - in mosquito breeding areas or resting areas
                                          - on people infested with insect pests
                                          - areas where high populations of rodents
                                          - control of mosquito populations in malaria impacted areas

During and after World War II, DDT was primarily used to control mosquitos, and was particularly effective in doing so. Between 1933-1935 there were some100 million cases of malaria, with a resulting 0.75 million deaths in India. In 1966 however, as a result of DDT, there were approximately 0.15 million cases of malaria with only 1500 deaths. The World Health Organization estimates that during the period of its use approximately 25 million lives were saved.

 If DDT is so effective, why is there a problem? Perhaps because of its effectiveness, problems arose due to the abuse and over-use of DDT and other pesticides. "Once DDT became available commercially in 1945, U.S. consumption reached 57 million lbs. in 1950. Domestic consumption peaked in 1959 at 78 million lb and declined to approximately 22 million lb in 1972." There is ample reason to believe that DDT is indeed carcinogenic.

 Perhaps the worst effect of DDT, is the effect it has on predator populations at the top of the food chain due to biomagnification.. DDT is deposited and stored in the fatty tissues of animals and is not metabolized very rapidly by animals. The biological half-life of DDT is about eight years; that is, it takes about eight years for an animal to metabolize half of the amount it assimilates. If ingestion continues at a steady rate, DDT builds up within the animal over time. Once exposure to DDT ceases, DDT buildup is reversible with time. After being banned in the US in 1973 the EPA reported a 90% reduction of DDT in Lake Michigan fish by 1978.

It has been well documented that DDT caused direct death of many birds after urban spraying of DDT for Dutch elm disease. However, the majority of the effects of DDT proved indirect, resulting in a decrease in clutch size, the thinning of egg-shells, a high death rate in embryos, and nestlings in addition to aberrant parental behavior. The decrease in the peregrine falcon Falco peregrinus, is often cited as a classic example of this.
 
 

There are some who refute such findings as those concerning the peregrine falcon, saying the studies were flawed and that the scare of DDT is largely due to myth, rather that fact:

What are some alternatives to Pesticide use as far as Agriculture is concerned?

Do you think the danger in regards to pesticides on produce exaggerated? Are environmentalists using hyperbole as a form of scare tactic to accomplish their goals?

Does the saving of thousands (nay, millions!) of human lives (from diseases such as malaria and others), take precedence over the environmental impact that DDT may have on the local wildlife?

Bibliogrophy:

1. Arms, Karen. Environmental Science. USA: Sanders College Publishing, 1990.

2. Cunningham, Barbara Woodworth Saigo. Enviornmental Science: A Global Concern. USA:

4. Lassila, Kathrin Day. "Pesticide Standoff." The Amicus Journal Spring 1999 v21 p11(1).

5. Ogg, Clyde. (1996, January 12). Pesticide Education Resources. University of Nebraska. <http://ianrwww.unl.edu/ianr/pat/ephome.htm>(1999, November 8).

6. Picking, Andrea. (1999, September 23). The Food Chain: Animals To Humans. Home Page. <http://www.lhup.edu/~smarvel/man/students/Picking/Picking.htm> (1999, October 6).

7. Unknown. Pesticides in Baby Food. Home Page. <http://www.ewg.org/pub/home/reports/Baby_food/baby.gif>

8. Unknown. US EPA Facts and FAQs. Office of Pesticide Programs.< http://www.epa.gov/oppfead1/safety/facts.htm> (1999 July 30).

9. Rauber, Paul. "Poisonberries. (growers seek to delay methyl bromide ban)." Sierra. July-Aug

1996 v81 n4 p20(2).

10. Serim, Ferdi. DDT. Home Page. <http://pmi.princeton.edu/pathways/chm112_98/students/toxicstuff/toxics6c.html>

11. Snyder-Conn, Elaine. Mike Green, et. al. "Restoring Habitat Through Pesticide Management." Endangered Species Bulletin, Jan 1999 v24 i1 p18(1)

Questions, or comments? Please email me at: pcucura@falcon.lhup.edu

-Paul Cucura- (Senior, English)