ENVIRON 102 Lecture Notes - Lecture 14: Environmental Toxicology, Lead Poisoning, Sunscreen
4 May 2018
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Department
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Environment and Health
3.31.15 Lecture Notes
ENVIRONMENT AND TOXICOLOGY
Testing on animals
Make up – cruelty free?
o How are these products approved for safety?
o Individual ingredients have been tested by other companies
Different species react in different ways
Better than testing on humans or releasing the drug and finding out the consequences
Living conditions of animals who are tested
Nanomaterials: dimensions less than 100 nanometers used in a lot of things – sunscreen, tennis
rackets, solar panels
Environment and health risks
Physical hazards (floods, storms, landslides, radon, etc.)
Chemical hazards (pollutants, etc.)
Biological hazards (viruses, bacterial infections, etc.)
Cultural and lifestyle hazards (drinking, smoking, bad diet, crime in neighborhood, etc.)
There are environmental influences on many of these
Toxicology: the science of poisons
The study of poisonous substances and their effects
Environmental toxicology focuses on effects (human wildlife) of chemical poisons released into
the environment
Are chemicals good or bad?
Chemistry and biology are key to understanding toxicity
How does it behave in the environment?
o Persistence (half-life)
o Movement – where does it go?
o Solubility in water, volatility
How does it behave in an organism?
o Absorbance/uptake (respiration, ingestion, dermal)
o Persistence? Metabolism?
o Water/fat solubility; where odes it go in the body?
o Toxicity
From exposure to toxicity
How do we know if an exposure is a problem?
Key concept: The dose makes the poison. ~Paracelsus
o Ex: Aspirin
▪ 300-1000 mg beneficial
▪ 1000-30000 mg toxic
Dose-response curve with toxicity threshold
Monotonic dose response – always one direction – the less, the better
Non-monotonic would be something like less – toxic
LD50: dose required to kill 50% if people taking it
Types of toxicity
Time course categories:
o Acute – quick (e.g., farmworker pesticide exposure leading to outright death)
o Chronic – long-term (e.g., polluted air and chemical carcinogenesis)
Physiological effects
o Carcinogens: cause cancer
find more resources at oneclass.com
find more resources at oneclass.com
o Teratogens: cause birth defects
o Allergens: cause unnecessary immune response
o Neurotoxins: damage nervous system
o Endocrine disruptors: interfere with hormones
o Many more – notes that a single compound can often exert many effects
People are still poisoned (short-term, high-dose acute effects by pollution
Mostly in developing worlds
Dakar, Senegal: Animals died, then children – why?
o Recycling of batteries contains toxic metals and done by children
o Lead poisoning
Low-dose chronic effects increasing important
Air Pollution
Air pollution responsible for 7 million deaths a year (1 in 7)
o WHO 2012
In the US, particulate pollution causes 1/5 of all lung cancers
Other problems include heart attacks, lung disease, neurological damage, and possibly asthma
Worldwide health costs of urban air pollution are estimated at $1 billion a year
Genetics and Environment
Environmentally caused diseases are influenced by genetic susceptibility
o More than 90% of lung cancer is caused by cigarette smoking
o BUT only 10-15% of smokers will develop lung cancer
Everyone carries genetic variants that increase their susceptibility to some diseases
o The same environmental factors will differentially affect the development of disease
Most diseases are a combination of genetics and environmental factors
Vulnerable populations
Children or pregnant mothers
o Behavior
o Metabolism
o Developmental status
Elderly, sick
Genetics
o Single-gene diseases make up about 5-10% of human disease
Poor and minorities: Environmental Justice
Epidemiology to discover problems
1950-60s: Thalidomide used as a morning sickness pill resulted in ~10,000 children with
deformed limbs
o No tests performed on animals but not pregnant animals
o Europe, Japan, and Canada, but not in the US
o Francis Kelsey: part of the FDA in the 1950s who refused to approve Thalidomide because
it wasn’t tested on pregnant animals
Toxicity testing to discover problems
Bacteria, cells in culture
Fish, other non-mammalian eukaryotes
Rodents
Cats, dogs, primates
Humans?
How many animals do we need?
Note: Animals are studied for their own welfare and as canaries in a coal mine to warn of
effects on humans
How well are we doing?
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Testing on animals: how are these products approved for safety, individual ingredients have been tested by other companies. Nanomaterials: dimensions less than 100 nanometers used in a lot of things sunscreen, tennis. Better than testing on humans or releasing the drug and finding out the consequences. Living conditions of animals who are tested rackets, solar panels. Physical hazards (floods, storms, landslides, radon, etc. ) Cultural and lifestyle hazards (drinking, smoking, bad diet, crime in neighborhood, etc. ) There are environmental influences on many of these. The study of poisonous substances and their effects. Environmental toxicology focuses on effects (human wildlife) of chemical poisons released into the environment. Chemistry and biology are key to understanding toxicity: persistence (half-life) How does it behave in the environment: movement where does it go, solubility in water, volatility. Metabolism: water/fat solubility; where odes it go in the body, toxicity. How do we know if an exposure is a problem: 300-1000 mg beneficial, 1000-30000 mg toxic.
