Ecology and Environmental Health Overview

Study Notes

Branch of science that studies organisms, the environment, and their interactions.
Focuses on life processes, adaptations, habitats, interactions, and biodiversity.

Addresses human health issues influenced by the environment.
Many diseases can be initiated, promoted, or sustained by environmental factors.
Environmental health professionals deal with issues like waste disposal, workplace stress, drinking water purification, food safety, protection from infectious diseases, and long-range environmental problems.

The study of the adverse effects of chemicals on biological systems.
Toxic chemical: substances that can be harmful to the environment or health.
Toxic substance: substances that can be poisonous or cause health effects.
Toxic agent: anything that can cause an adverse biological effect - can be chemical, physical, or biological.
Poison: substances that cause death, injury, or harm to organisms.
Toxin: a poisonous substance produced by living organisms.
Toxicant: chemicals that can affect specific tissues or organs.
Xenobiotic: a chemical substance found in an organism that is not naturally produced.

Age: infants and children are more susceptible to toxicants.
Gender: differences in metabolism, body composition, and hormones can influence susceptibility.
Disease: certain diseases may increase susceptibility to toxic agents.
Lifestyle and diet: affect the body's ability to handle toxicants.
Genetics: individual variations in biochemical processes can affect xenobiotic distribution and sensitivity.

Botulinum toxin - extremely potent neurotoxic proteins produced by the bacterium Clostridium botulinum.
Botulism can be infant, foodborne, or wound-related.
Botulism symptoms can be prevented by antitoxin antibodies.
The general public is not vaccinated against botulism due to its rarity in developed countries.
Muscle weakness of botulism starts in the muscles supplied by cranial nerves.

Young children are at risk for toxicity from plants.
Plant toxins primarily affect the gastrointestinal, cardiovascular, and central nervous systems.
Plant toxins can be classified by their chemical structure, such as:
- Alkaloids
- Proteins and amino acids
- Glycosides
- Oxalates
- Phenols, resins, and volatile oils
- Photo toxins
Plant toxins can be present in fruit and vegetable plants.

Australian funnel-web spiders are considered the most dangerous spiders.
Widow spider venom is neurotoxic and causes latrodectism, a syndrome characterized by pain, nausea, muscle rigidity, cramps, and other symptoms.
Scorpion venom is neurotoxic and interferes with neurotransmission.
The "death stalker" scorpion has potent venom that can be fatal.
Hymenopterans (stinging insects) can produce painful stings causing local tissue injury, but venom amounts are generally not enough for systemic toxicity.
Cnidaria (jellyfish, hydroids, corals, anemones) possess nematocysts (stinging cells) containing barbed threads that can pierce skin. Even dead cnidarians can discharge venom upon chemical or mechanical stimulation.
Mollusks: Blue-ringed octopus (hapaloclaena lunulata and hapalochlaena maculosa) can kill humans within 5 minutes. They have a paralytic neuromuscular venom that blocks nerve conduction.