EMA Lecture 9 Flashcards by Aoife L

What is a contaminant?

Substance released due to human activity

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What is a pollutant (compared to contaminant)

A pollutant causes a biological effect

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What is POP?

Persistent Organic Pollutants are chemical substances that are toxic, persist in environment for long periods of time, bioaccumulate in food chain, and cause health risk to humans and environment

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What is an effect of toxins in the environment?

-Impact the physiology or behaviour of an organism and reduce growth, reproduction or survival
-Can indirectly reduce prey species

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What are some everyday exposure routes of toxins?

Dermal exposure (skin)
Accumulation
Transfer (mother to child)
Oral exposure
Inhalation exposure

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What are some anthropogenic sources of toxic pollutants

-Industrial effluent
-Oil spills
-Pesticide in agricultural runoff
-Sewage waste
-Hazardous waste
-Combustion

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What is CAS

Registry of chemicals

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How many chemicals are registered with CAS?

171 million unique organic and inorganic chemical substances

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What does EU legislation require in relation to medicines for human or animal use?

-They must be subjected to an environmental risk assessment
-Only compulsory for new products since 30th October 2005

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What questions are asked about new medicinal drugs in relation to the environment?

-How much of drug will enter the environment
-How will organisms be affected from exposure
-Is the environmental risk acceptable

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What are the three exposure assessment rates at different spatial scales for PEC?

-Local
-Regional
-European

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What does PEC stand for?

Predicted Environmental Concentration

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What does PNEC stand for?

Predicted No-Effect Concentration

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What is the acceptable risk concentration?

PEC/PNEC <1

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What is an unacceptable risk concentration?

PEC/PNEC >1

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What does ERA stand for?

European Research Area

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What can information from an ERA be used for?

-Compare the relative environmental risk of different drugs
-Minimise the amount of medicinal product released into the environment
-Identify guidelines for proper use and disposal for consumers

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What are some issues in risk assessments?

-Organisms are exposed to low levels over long periods of time - hard to replicate in lab
-Toxicity tests are acute tests, short
-More information is needed on chronic toxicity

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What is an additive drug reaction?

Occurs when the combined effect of two drugs is equal to the sum of each drug being given alone
1 + 1 = 2

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Name an example of additive drug interactions

Heparin and alcohol will increase bleeding

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What is drug synergism?

Occurs when drugs interact with each other and produce an effect that is greater than the sum of their separate actions
1 + 1 = 3

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What’s an example of synergism drug interaction

Nicotine and alcohol

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What is an antagonistic drug reaction?

Occurs when one drug interferes with the action of another, causing neutralisation or a decrease in effect of the other drug

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Why are pesticides used?

Public health, mosquitoes

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How many species of Anopheles carry a protozoan parasite that causes malaria?

60 out 380

What is another use for pesticides?

Agriculture

What are the benefits of pesticide use in farming?

-Increased yields -Chemical herbicides control weeds -Rows of plants can be planted closer together -Insecticides control pests instead of crop rotation

When was pesticides beginning to expand?

After 1945

Why does forestry use pesticides?

-Reduce damage done by insect pests -Applied by aerial methods

What damage did the gypsy moth do in America in 1981?

Defoliation of 40,000 km 2

Why did pesticide use explode after 1945?

More widely available Efforts to increase world food supply

What are the problems of indiscriminate use of pesticides?

-Non target species are killed -Pests develop resistant -Persistent in environment -Food chain magnification

How are pesticides classified?

-Target species -Chemical nature -Mode or time of action

What are chlorinated organics?

Consist of Cl atoms attached to organic moieties Stable and accumulate in lipid tissue Biomagnification and food chain transfer Highly toxic to fish and birds

What does DDT stand for?

dichloro-diphenyl-trichloroethane

What chemical group does DDT belong to

Organochlorines (OCs) or chlorinated hydrocarbons

What is the chemical structure of DDT like?

Has at least one covalently bonded atom of chlorine that has effect on the chemical behaviour

What are some other examples of OCs?

PCBs Aldrin Mirex Toxaphone All are banned or restricted

When was the insecticidal properties of DDT discovered and by whom

1939 by Swiss chemist Paul Muller

What was peak production of DDT?

US - 82,000 tons in 1963

When was DDT banned in the US for agricultural use?

1972

How does DDT kill?

It is a nerve toxin -Interferes with neurotransmission Not species specific Can persist in environment Can kill months later

Why is DDT so harmful to the environment?

-Slow to break down, can be in environment for years -Not water soluble -Bioaccumulate and are stored in fat tissue

How long is the soil life of DDT

50% remains in soil for 2-15 years

How long is the half life of DDT in the aquatic environment?

Over 150 years

What does lipophilic mean?

Soluble in fat, oils and lipids

What does bioaccumulation mean?

Accumulate in fat cells of animals

What is biomagnification?

When something passes through food chains Top predators are exposed to high doses

What can be the effects of toxins on insects?

Death

What is the effect of toxins of fish?

Reproductive effects Neurotoxin effects

What is the effects of toxins on birds?

Eggshell thinning

What is the effects of toxins on mammals?

Liver and kidney damage Neurotoxin effects Teratogenic effects (mice) Carcinogenic effects likely

What is a metabolite of DDT?

DDE

What does DDE stand?

Dichlorodiphenyl dichloroethene

Why is DDE a problem?

Produced slowly by degradation in environment Fat soluble and mimics the action of estradiol and causes decline in androgen synthesis

How is DDE harmful to birds?

Causing egg shell thinning - Caused declines of peregrine falcon, brown pelican, bald eagle and Californian condor

What are organophosphates?

Consists of one or more phosphate groups attached to an organic moiety

When were organophosphates first marketed?

1944

What is DDT still use for today?

-Control of disease carrying organisms in parts of the world -2007 COP in Stockholm concluded it still needed to be used to control disease vectors

What does Cd stand for?

Cadmium

What does Hg stand for?

Mercury

What does HCB stand for?

Hexachlorobenzene

What does PCB stand for?

Polychlorinated biphenyls

How much Persistent organic pollutants need to be eliminated?

14 million tonnes