BIO-209 Chapter 8

Environmental science is not just about how we affect the environment it's also about?

how the environment affects us. 

The field of environmental health involves?

monitoring and attempting to reduce people's exposure to chemical and other environmental hazards. 

Toxicology is a branch of science which studies?

toxic substances and how they affect our environment. 

Health is?

a state of wellbeing, not just the absence of disease 

Disease is?

an abnormal change in the body's condition that impairs physical / psychological functions. 

Morbidity means?

illness

Mortality means?  

death

Environmental health focuses on?

factors that cause disease, including elements of the natural, social, cultural, and technological worlds. 

Major sources of environmental health risks:

Infectious agents, trauma, pollution, toxins, and radiation. 

Health organizations used to focus on?

the leading causes of death as a measure of world health. 

Health agencies now calculate disability-adjusted life years (DALYs) as a measure of?

disease burden. 

DALYs combine?

premature deaths and loss of healthy life due to illness / disability. 

Communicable diseases are still responsible for about?

⅓ of all disease-related mortality. 

Millions of children die from?

preventable childhood diseases. 

Pathogens are?

disease-causing organisms. 

Diverse pathogens afflict humans, including?

viruses, bacteria, protozoans (single celled animals), parasitic worms, and flukes. 

The greatest loss of life from an individual disease in a single year was?

the great influenza pandemic of 1918. 

Malaria is?

one of the most prevalent infectious diseases. 

There are about ____ million total cases of malaria yearly, with about ___million deaths per year. 

500 , 1

Emergent diseases are?

those not previously known or that have been absent for at least 20 years. 

Ebola and COVID-19 are both known as?

emergent diseases. 

Toxicology is?

the study of the adverse effects of external factors on an organism or a system. 

Toxicology includes studying the effects of?

chemicals, drugs, ionizing radiation, UV light, etc. 

Environmental toxicology involves?

the interactions, transformation, fate, and effects of toxins in the biosphere, including individual organisms, populations, and whole ecosystems. 

Allergens are?

substances that activate the immune system 

Some allergens act directly as?

antigens 

Antigens are?

substances that are recognized as foreign by white blood cells, stimulating production of antibodies. 

Antibodies are?

proteins produced by our bodies that recognize and bind to foreign cells or chemicals. 

Formaldehyde is a good example of?

a widely used chemical that is a powerful sensitizer of the immune system. 

Formaldehyde concentrations in indoor air can be thousands of times higher than?

in normal outdoor air. 

Sick building syndrome is a condition characterized by?

headaches, allergies, and chronic fatigue caused by poorly vented indoor air contaminated by various contaminants. 

Neurotoxins are?

toxins that harm nerve cells (neurons)

Mutagens are?

agents, such as chemicals and radiation, that damage genetic material (DNA) in cells. 

Teratogens are?

chemicals that cause abnormalities during embryonic growth and development

Carcinogens are?

substances that cause cancer.

Endocrine hormone disrupters are?

chemicals that disrupt normal endocrine hormone functions.

Endocrine hormone disrupters can interfere with?

normal growth, development, and physiology.

Endocrine hormone disrupters are also known as?

environmental estrogens or androgens, they often cause reproductive health problems in females or feminization of males.

Chemicals move between ecosystem components based on?

molecular size, solubility, stability, and reactivity.

Solubility and mobility determine?

when and where chemicals move

Chemicals can be divided into 2 major groups:

water soluble and oil or fat soluble 

Water soluble compounds move rapidly and widely through the environment because?

water is ubiquitous 

Molecules that are oil or fat soluble generally need a ____ to move through the environment.

carrier

Exposure and susceptibility determine?

how we respond. 

There are many routes for toxins to?

enter our bodies. 

Airborne toxins generally cause more?

ill health than any other exposure source; however, food, water, and skin contact can also expose us to a wide variety of hazards. 

Healthy adults may be relatively insensitive to doses that are very dangerous to?

young children or to someone already weakened by other diseases 

Bioaccumulation refers to?

the fact that organisms may selectively absorb and store toxins in their bodies. 

Biomagnification occurs when?

the toxic burden of many organisms at a lower trophic level is accumulated and concentrated by a predator at a higher trophic level

Persistence makes some materials a?

greater threat 

Many substances degrade when exposed to?

sun, air, and water. 

Some materials are?

persistent and can last for years or even centuries as they cycle through ecosystems. 

Examples of persistent materials:

Heavy metals, lead and mercury and many organic compounds such as PVC plastics and chlorinated hydrocarbon pesticides. 

One hundred cups of strong coffee, for instance, contain a?

lethal dose of caffeine. 

100 aspirin tablets, 10 kg (22 lbs) of spinach or rhubarb, or a liter of alcohol would be deadly if?

consumed all at once. 

Taken in small doses, most toxins can be?

broken down or excreted before they do much harm. 

The saying “The dose makes the poison” means that?

almost everything is toxic at very high levels but can be safe if diluted enough. 

The most basic principle of toxicology is?

almost everything is toxic at very high levels but can be safe if diluted enough. 

How a material is delivered and at what rate plays a vital role in?

determining toxicity. 

Dose response curves help us determine?

toxicity. 

A way to describe toxicity of a chemical is to?

determine the dose to which 50 % of the test population is sensitive. 

In the case of a lethal dose (LD), this is called the?

LD50. 

Toxins can have ___ or ___ doses and effects.

Acute, Chronic

Acute effects are caused by?

a single exposure to the toxin and result in an immediate health crisis. 

Chronic effects are?

long lasting, perhaps even permanent.

Chronic effects can result from?

a single dose of a very toxic substance or be due to continuous or repeated sublethal exposure. 

Unlike acute effects, it is usually difficult to assess the specific health risks of?

chronic exposures. 

Detectable levels aren't always?

dangerous 

Increasingly sophisticated measuring capabilities may lead us to believe that?

toxic materials have become more prevalent. 

Our environment may be no more dangerous; we are just better at?

finding trace amounts. 

It can be difficult to determine?

risk. 

Risk is?

the probability of harm times the probability of exposure if that chemical is released into the environment. 

Many factors complicate?

the movement and fate of chemicals both around us and within our bodies. 

Public perception of environmental hazards can be?

inconsistent with actual risks. 

Our perception of risks isn't always?

rational 

Many factors influence how we perceive relative risks associated with?

different situations. 

People with social, political, or economic interests tend to?

downplay certain risks and emphasize others that suit their own agendas. 

Our personal experiences often are?

misleading.

When we have not personally experienced a bad outcome, we feel it is?

more rare and unlikely to occur than it actually may be. 

Risk management combines?

principles of environmental health and toxicology with regulatory decisions based on socioeconomic, technical, and political considerations. 

In spite of often vague and contradictory data, public policymakers must?

make decisions. 

Risk assessment contains:

Hazard identification, exposure assessment, and dose-response assessment

Risk management contains:

socioeconomic, technical political, and regulatory decisions.

Both risk assessment and management contain:

risk characterization.