Toxicology: Introduction to Transport and Fate

These flashcards cover key concepts on toxicology, including transport and fate of contaminants, properties affecting toxicity, exposure, dose-response relationships, and testing methods.

What is transport in toxicology?

Transport refers to the movements of contaminants within or between environmental media, such as from soil to water or air to humans.

How can humans be exposed during the transport phase?

Humans can be exposed if contaminants reach drinking water, air, or food sources.

What does fate in toxicology refer to?

Fate refers to the physical, chemical, or biological transformations of contaminants in the environment.

What is volatility in toxicology?

Volatility is the tendency of a substance to evaporate; for example, alcohol and hydrocarbons are highly volatile.

Define polarity in the context of toxicology.

Polarity is the property of substances that determines their solubility in water; high polarity substances are highly soluble in water.

What is solubility?

Solubility is the ability of a substance to dissolve in a solvent, affecting its distribution in the environment.

What is bioaccumulation?

Bioaccumulation is the buildup of chemicals in individual organisms over time.

What is biomagnification?

Biomagnification is the increase in concentration of chemicals in organisms at each level of the food chain.

How does molecular weight affect chemical persistence?

Higher molecular weight chemicals, like DDT, tend to be more persistent in the environment due to slower degradation processes.

What is the significance of oxidation states in toxicology?

The oxidation state affects the chemical reactivity and environmental behavior of a substance; for example, Cr(VI) is more toxic than Cr(III).

What is toxicology?

Toxicology is the science of the effects of toxic substances, including their fate and transport in the body.

What characterizes a receptor in toxicology?

A receptor is an organism receiving exposure or dose, impacting how they respond to chemicals.

Define exposure in toxicology.

Exposure is defined as the amount of chemical that passes the human envelope, which separates the interior of the body from the environment.

What factors influence individual responses to chemicals?

Factors include age, general health, and genetic makeup.

What is meant by 'routes of exposure'?

Routes of exposure are the ways chemicals enter the body, including ingestion, inhalation, and skin absorption.

What is considered chronic exposure?

Chronic exposure refers to repeated or continuous exposure to a low dose of a chemical over a long period.

What is the goal of exposure assessment in toxicology?

To quantify exposure in order to understand potential harm and determine safe limits for chemicals.

What are dose-response relationships?

Dose-response relationships are the quantitative correlations between the amount of substance taken in and the resulting effects in the body.

What does LD₅₀ stand for?

LD₅₀ stands for the lethal dose that kills 50% of a test population.

What is the difference between acute and chronic toxicity?

Acute toxicity involves a quick response to a high single dose, while chronic toxicity results from long-term exposure to lower doses.

What does Paracelsus’ principle state?

Paracelsus' principle states that 'the dose makes the poison,' meaning every chemical is harmful at some exposure level.

What are the two key characteristics of dose-response curves?

The two key characteristics are slope (potency of effect) and threshold (potential for safe dose).

What is a no-threshold toxicant?

A no-threshold toxicant is harmful at any dose, with no safe exposure level.

What is represented by the No Observed Adverse Effect Level (NOAEL)?

NOAEL is the highest dose at which no harmful effects are observed in a study.

What is the purpose of toxicity testing?

Toxicity testing assesses the effects of substances to establish safe exposure levels and understand their health impacts.

What are biomarkers?

Biomarkers are measurable indicators of biological processes or responses to a chemical exposure.

What does toxicodynamics refer to?

Toxicodynamics involves the effects of toxicants in the body and the physiological responses they produce.

What determines the persistence of a chemical in the environment?

Persistence is quantified as a half-life in air, water, or soil, influenced by environmental conditions.

What is a biologically effective dose?

A biologically effective dose is the amount of a chemical available to interact with vulnerable tissue.

What factors can influence the biological effect of a substance?

Factors include absorption, distribution, metabolism, and excretion of the substance in the body.