Basic Concepts Toxicollogy (2)

8/13/2019 Basic Concepts Toxicollogy (2)

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ING. ANDRS VELASCO, MSc


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HISTORICAL BACKGROUND

Paracelsus (1493-1541)

Every substance istoxic, there is not

even one that isnt Dosis sola facitvenenum

The dose is whatmakes the differencebetween poison andremedy.


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Bernardino Ramazzini(1633-1714)

He is called the fatherof occupationalmedicine

When you get to thebed of your patient ask

him what he does for aliving to see if his job isthe cause of hisdisease.


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James Marsh (1794-1896)

British scientist thatcreated the analytic

method to detect andvalidate arsenic,known as the MarsTest.


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FACTORS THAT INFLUENCED

POLLUTION GROWTH

THE INDUSTRIALREVOLUTION

At the end of theXVIII Century there

was a breakpoint inpollution relatedtopics.


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CHEMICALSPRODUCTION

Pesticides Medicines and

pharmaceutical products

Chemical and industrialproducts

Drugs

FACTORS THAT INFLUENCED POLLUTIONGROWTH


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CHEMICAL DISASTERS


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TOXICOLOGY

TOXICOLOGY CONCEPT

(BALLANTYNE 1999)

Science that studies the interaction betweenchemical agents and biological systems, in

order to quantitatively determine thepotential of the chemical agents to causedamage in living organisms.


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ENVIRONMENTAL TOXICOLOGY

Inter disciplinary science that

studies the negative effects ofthe chemical agents inbiological systems.


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STUDIES

ACTION MECHANISM

DIAGNOSE

PREVENTION

TREATMENT

INTOXICATION

TOXIC


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MAIN CONCEPTS

XENOBIOTIC AGENT

Chemical substance that is not a natural component ofthe exposed organism.

Synonyms:

Strange substance or compound

Exogenous substance or compound.


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MAIN CONCEPTS

TOXIC

Chemical substancecapable of causingdamage to a biologicalsystem, affecting its

functions or causingdeath under certainexposure conditions.


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MAIN CONCEPTS

TOXIC CONTAMINANT

The forms of matter that exceed naturalconcentrations in a certain moment and system,causing damages and negative effects on it.

TOXICITY

Chemical substance self capacity to producenegative effects on a living organism.


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TOXIC COMPONENTES IN A

CONTAMINANT AGENT

HEAVY METALS Cd,Cr,Co,Cu,Fe,Zn,Mo,Mn,

Hg,Ni,Pb,Sn,Se,V

ORGANIC

COMPOUNDS

VOCs PCBs

Pesticides,

Dioxins y Furans

PATHOGEN

MICROORGANISMS

Fecal Coliforms, Helmints,

Nematods, Virus


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HEAVY METALS The main exponents: O, Si, Al, Fe, Ca, K, Mg, Ti y P;

sometimes they represent up to 99% of the totalcomposition of a substance (the rest is called traces).

They are took by plants and animals in small amounts and

can be accumulated up to toxic levels. Methalic elements with 6 g/m3 in free state. They

include:

Essential elements with non-toxic effects such as Iron.

Essential elements in low concentrations and toxic in highconcentrations, such as : Cu, Zn, Ni.

Toxic elements (traces) such as: Cd, Pb, Hg.


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HEAVY METALS EFFECTS

Eventhough we asume that heavy metals have apretty high level of toxicity, their hazard and riskmanifest just when absorption and accumulationin the organism exceeds certain limits consideredas phisiologically acceptable.

Reduces performance or quality of vegetalproduction.

Phisiological changes in animals and plants.

Intoxication / death


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TOXICITY OF A SUBSTANCE: CAPACITY OF ASUBSTANCE TO CAUSE DAMAGE OR DEATH

IN A LIVNG ORGANISM

VERY TOXIC:

LITTLE DSEEFFECTS

NOT VERY TOXIC:

GREAT DOSEEFFECTS


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ENVIONMENTAL TOXICOLOGY

ACCUMULATIVE EFFECT: When the adverse effects

are unperceptible and the addition of these littleeffects show their signs when they are irreversible.

THRESHOLD EFFECTS: The effects are shown whenthe amount exceeds certain limit, it depends on thecharacteristics of the substance and the system.

INTERACTION EFFECT: When two or moresubstances interact, either in a chemical way(resulting in another substance), or in a biologicalway (causing effects that they couldnt cause by

themselves).


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BIO-CONCENTRATION: Highest chemicalconcentration found in the living organism

compared to the concentration found in theenvironment.

BIO-MAGNIFICATION: Pogressive increase of thesubstance concentration as it gets transferedthrough the food chain.

CONTAMINANT CYCLE IN THE

ENVIRONMENT


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PERSISTENCE IN THE ENVIRONMENT:

It refers to the physical, chemical andbiological changes of a contaminantthroughout time.

Decomposition process of the substance inphysical environments through biologicalsystems.

CONTAMINANT CYCLE IN THEENVIRONMENT


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CONTAMINANT CYCLE IN THE

ENVIRONMENT1. MOVEMENT:

Complex and not very known process thatdepends on the chemical and physicalproperties of the substance and in thecharacteristics of the environment.

The gas, liquids and solids movement takesplace in the envronment through air, water,soil, sediments, plant and animals.


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2. PHYSICAL, CHEMICAL AND BIOLOGICALTRANSFORMATION

WATER SOLUBILITY: It establishes the substancecapability to migrate in the envorinment; if thesubstance is more soluble, the easiest for the

environment to bio-degradate it.

DENSITY: The fluids that are more dense than waterpenetrate and go to te bottom of the water body, the

lighter ones tend to stay on the surface.

STEAM PRESSURE: The volatility degree of thechemical.


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3. ACCUMULATION IN TWO OR MORE SITES

PRECIPITATION RATE: High precipitation rates and

very water-soluble contaminants contribute to theirdegradation or migration to other sites.

TEMPRATURE: This variable influences in steam

pressure, water solubility and the chemicalsmovement in the ground.

WIND SPEED AND DIRECTION: Influences in dust

generation and contaminants migration.

CONTAMINANT CYCLE IN THEENVIRONMENT


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MAIN CONCEPTS

EXPOSURE

Its a measure of the contact between the chemical

agent and the living organism; it depends on theconcentration and the time.


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MAIN CONCEPTS

ROUTS OR WAYS OF EXPOSURE

Is the path that a chemical agent followsin the environment from the place whereit is liberated up to the point when itmakes contact with the population or theexposed individual.


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EXPOSURE ROUTES

HumanIncome of

Chemical agents

Medicines

(oral)

Occupational

Exposure

(oral,dermic,respiratory)

Occasional

Exposure

(accidents, cosmetic uses)

AirWater

Food


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HUMAN EXPOSURE TO TOXIC AGENTS

1. FORMS:

ONE AGENT, SEVERAL SOURCES:

PLUMBUM


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1. FORMS:

ONE SOURCE, SEVERAL AGENTS:

COMBUSTION GASES

PESTICIDES

FERTILIZERS



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1. FORMS:

SEVERAL SOURCES, SEVERAL AGENTS

PLUMBUM

TOBACCO

MERCURY



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EXPOSURE ROUTS


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ACUTE EXPOSURE


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CHRONIC EXPOSURE


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MAIN CONCEPTS

EFFECT

Any deviation of the normalperformance of the organism, caused

by toxic substances exposure.


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ACUTE EFFECT


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CHRONIC EFFECT


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Toxicodynamics

WHAT DOES THE BODY DO WITH THE

INCOMING SUBSTANCES?

ABSORPTION DISTRIBUTION

STORAGE

METABOLISM O BIOTRANSFORMATION

DISPOSAL / ELIMINATION


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TYPES OF EFFECTS

Reversible Effect

Irreversible EffectAcute Effect

Chronic EffectLocal Effect

Systemic Effect


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MAIN CONCEPTS

INTOXICATION

Pathological process caused by exposureto endogenous or exogenous chemical

substances, which is evidenced by clinicsigns and symptoms or throughlaboratory tests.


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MAIN CONCEPTS

DOSE:

The total amount of a substance that theorganism is exposed to.

Usually the dose refers to the total amountof a material that penetrates an organismusing some of the specific exposure routes.


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MAIN CONCEPTS

TOXIC DOSE:

Dose that produces some toxic effect.

LETHAL DOSE:

Dose that produces death.

DL100 ( Lethal dose 100)

DL50 (Lethal Dose 50)

Basic Concepts Toxicollogy (2)

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