MOD 1

Question 1

Study of toxic substances is

Answer 1

toxicants

Question 2

study of posions is

Answer 2

effect of toxicants

Question 3

Xenobiotic

Answer 3

• any substance that is foreign to an organism
• may produce useful results ex pharmaceuticals or be toxic ex lead

Question 4

Anthropogenic

Answer 4

Caused/produced by humans
used to describe the orgiing of a compound which otherwise would not occur naturally

ex fossil fuel
polyester

so w out human activity it would not be a thing

Question 5

dose

Answer 5

know the exact amount
of how much smth is given

can be intravenous, ingestested

Question 6

concentration

Answer 6

exposure to somehting
dk exactly how much of it went inside

Question 7

Toxicant

Answer 7

poisonus agent
- produces adverse biological effects
- ex. metals, PAHs, PCBs

Question 8

Toxin

Answer 8

toxic substance produced by a living org
ex. snake, mycotoxin, tetrodoxin etc

Question 9

History

Paracelsus believed

Answer 9

that it was NOT the substance that was toxic but rather the AMOUNT THAT WAS TOXIC

Question 10

Whos the father of toxicology

Answer 10

paracelsus

Question 11

who said ; the dose makes the poison

Answer 11

paracelsus

Question 12

Bernardino Ramazzini

Answer 12

• showed that occupational exposures could be involved in the causation of disease

Question 13

NO EXPOSURE = NO EFFECT

what is the exception

Answer 13

if you prevent it early enough then there would be NO effect

Question 14

true exposure is when

Answer 14

it acc gets to the target / “bottom” of human
ex. if snakes bites , true exp. is when someone dies

Question 15

in order for the exposure to have effect - 4 steps need to take place:

Answer 15

1. released into the enviroment
2. be exposed to target organism
3. be taken up by target org -> modification
4. cause a response in the target org

Question 16

what are the diff classes of enviromental toxins

5

Answer 16

radiation
inorganic
organic
pesticides
complex effluents

Question 17

give ex of each type of enviromental toxin

Answer 17

Rad - Japan’s Fukushima Daiichi nuclear plant release

Inorganic → metals, ammonia

Organic → dioxins, furans, polycyclic aromatic hydrocarbons (PAHs)

Pesticides → insecticides, herbicides, fungicides

Complex effluents → sewage treatment plant (STP), mine, pulp & paper

Question 18

explain the chimney sweep situation

Answer 18

chimney soot was removed by chimney sweepers

sweepers had an inc in scrotal cancer
- this was bc The cancer was attributed to exposure to polycyclic aromatic hydrocarbons (PAHs).

• Chimney soot, containing these PAHs, would cling to the skin of the young boys, particularly in areas that were poorly washed, leading to chronic exposure and cancer formation
• Pervical Pott was the one who first observed this condition

Question 19

who is percival pott

Answer 19

made the link btwn chimney sweepers and the scrotal cancer

made one of the earliest links between occupational exposure and cancer, marking a significant moment in the history of public health and toxicology

Question 20

explain mad hatter situation

Answer 20

hat makers used a process known as carroting in felt hat production
- this involved treating the animal fur with mercury nitrate to roughen the hair - making it easy to turn into felt
- The rooms where hatters worked were usually poorly ventilated, causing them to inhale toxic mercury vapors over long periods

• this caused mercury exposure which led to neuropathology (damage to the nervous system).

Symptoms included tremors, irritability, memory loss, hallucinations, and other neurological disorders.

Question 21

historic need for ecotoxicology

Pre-Industrial Revolution

Answer 21

Societies were mostly small, rural-based communities.

These communities generated limited waste.

The natural environment (labeled here as the “receiving environment”) was capable of naturally absorbing or neutralizing the waste without major ecological harm.

Question 22

historic need for ecotoxicology

Post-Industrial Revolution

Answer 22

Urbanization and industrialization led to large-scale waste production.

Many developing countries transitioned from rural lifestyles to industrialized civilizations.

As a result, the volume and toxicity of waste increased, often overwhelming the natural capacity of the environment to process or detoxify it.

The receiving environment could no longer “cope with” this level of waste, leading to environmental degradation and health hazards.

Question 23

pollution def

Answer 23

a substance in the enviro that produces adverse effects
it can impacts ecosystems, organisms, and human health
POLLUTANTS ARE NOT NECESSARILY TOXICANTS

Question 24

compare toxicant w pollutant

Answer 24

A toxicant is a substance that causes direct harm to biological systems through toxicity, a pollutant on other hand may cause indirect harm, even if it not toxic in low doses.

POLLUTANTS ARE NOT NECESSARILY TOXICANTS

for ex. Phosphorous
Phosphorous is a nutrient, not a poison. Plants need it to grow.

But when too much phosphorous enters lakes or rivers (often from fertilizers or sewage), it causes:

Excessive algae growth (called algal blooms).

These blooms block sunlight and, when they die, they’re broken down by bacteria that consume oxygen in the water.

This leads to oxygen depletion (hypoxia) → fish and other aquatic life suffocate and die.

So in this case, phosphorous isn’t directly toxic, but it creates a chain reaction that destroys ecosystems — that’s indirect harm.

Question 25

many pollutants are toxicants. give examples

Answer 25

Mercury poisoning Damages nervous system ✅ Direct toxicant Oil spill Coats fish gills, kills birds ✅ Direct physical + toxic PCBs in food chain Accumulate in fat, disrupt hormones ✅ Direct + bioaccumulative

Question 26

Dilution Paradigm (Older View) | explain it

Answer 26

Phrase: “The solution to pollution is dilution.” Meaning: In the past, it was widely believed that releasing pollutants into large bodies of air or water (like the ocean or atmosphere) would dilute them enough to avoid harm. Assumed that the environment had unlimited capacity to absorb waste without consequences. Example: Dumping industrial chemicals into rivers thinking the water flow would "wash it away" safely. ✅ This approach ignored long-term effects, accumulation, or global impacts.

Question 27

Boomerang Paradigm (Modern View) Phrase: “What you throw away can come back and hurt you.” | explain

Answer 27

Meaning: Pollution doesn't just disappear — it can cycle back through ecosystems, food chains, and climate systems to ultimately harm the polluters themselves. Emphasizes interconnectedness of humans and nature. Example: Mercury dumped into rivers accumulates in fish → humans eat the fish → suffer mercury poisoning. This new paradigm acknowledges bioaccumulation, persistent pollutants, and global spread of contaminants (e.g., PCBs found in Arctic animals far from pollution sources).