You can gain ideas on toxico-kinetics from this presentation. Different aspects regarding bio-concentration and bioaccumulation. In addition, demerits of different toxic chemicals from food industries are discussed with examples.

1. Mechanisms of Environmental
Toxicants
V.Vijitha
Lectrurer (Prob.)
Dept. of Biosystems Technology
FoT, UoJ

2. Biotransformation of Xenobiotics
• Xenobiotics: Chemical substance found within an organism
that is not naturally produced.
• Toxicokinetic: Study of “how a substance gets into the
body and what happens to it in the body”
• Four processes are involved in toxicokinetic
Absorption
Distribution
Metabolism
Excretion
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3. • Absorption
The substance enters the body
• Distribution
The substance moves from the site of entry to other areas of
the body
• Metabolism
The body transforms the substance into new chemicals
(metabolites)
• Excretion
The substance or its metabolites leave the body
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5. • Frequently the terms toxicokinetic and disposition have
the same meaning
• Disposition is often used in place of toxicokinetic to
describe the,
• Movement of chemicals through the body over the course of
time and
• How the body disposes the xenobiotic
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6. Most important aspects of disposition
1. Duration and concentration of a substance at the
portal of entry
2. Rate and amount of the substance that can be
absorbed
3. Distribution in the body and concentration of the
substance at specific body sites
4. Efficiency of biotransformation and nature of the
metabolites
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7. 6. Ability of the substance or its metabolites to pass
through cell membranes and come into contact with
specific cell components
7. Amount and duration of storage of the substance
or its metabolites in body tissues
8. Rate and sites of excretion of the substance
9. Age and health status of the person exposed
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Most important aspects of disposition, cont…

8. Bioconcentration and Bioaccumulation
• Bioconcentration is the intake and retention of a
substance in an organisms entirely by respiration
• from water in aquatic ecosystems
• from air in terrestrial ecosystems
• Bioaccumulation is the intake and concentration of a
chemical in the organism by all possible ways including,
• Contact
• Respiration
• Ingestion
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9. • Bioaccumulation: Build-up of something inside an
organism.
• It is typically the build-up of harmful chemicals that are
not able to be broken down or excreted fast enough.
• These chemicals can build up to levels that cause the
organisms harm.
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10. Biomagnification in food chain
• It is related to bioaccumulation.
• It is the increased accumulation of chemicals at each
level of the food chain.
• The chemicals starts to accumulate at lower levels in the
bottom of the food chain and then magnify as the food
chain progresses.
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12. • Plants that are exposed to and absorb chemicals in the water or
soil will accumulate.
• This process happens when such chemicals can't break down.
• As an animal starts to eat these plants they are also consuming the
chemicals
• The more plants they eat, the more chemical they consume.
• The amount of chemical magnifies or the amount increases at
each level.
• This means that animals at the top of the food chain accumulate
the highest levels of the chemical through biomagnification
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13. What is the difference between bioaccumulation and
biomagnification ???
• Bioaccumulation: Build-up of potentially harmful
chemicals in the body's tissue at one level of the food
chain
• Biomagnification: Build-up of chemicals in larger
amounts as the food chain progresses
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14. Hazard toxic chemicals from
food industry
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15. Types of hazard toxic chemicals used in food industries:
Direct food additives
Colour additives
Food borne toxicants
Organic toxicants
Mycotoxins
Phycotoxin
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16. • Foods can be viewed as complex mixtures of chemicals.
• Many non-nutrients are also exist in foods.
• Those are:
Food additives
Food contaminants
Food colours
Processing-induced toxicants
Naturally occurring toxicants
• These chemical may be toxic under certain circumstances of
exposure
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17. Food additives
• Direct food additives are added to a food for a specific
purpose.
• Example:
• Xanthan gum is used in salad dressings, chocolate,
bakery fillings, puddings & other foods to add texture
• Aspartame is a non-nutritive sweetener
• Olestra is a non-caloric fat replacer which is used for
the deep fat frying of chips
• Aspartame and Olestra are examples of the types of
substances for which potential usage levels are high.
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18. • Most direct additives are identified on the ingredient
label of foods.
• Some food additives can potentially cause harmful side
effects.
• Example:
• Butylated hydroxy anisole (BHA) is a preservative.
• It is used in foods including potato chips, crackers, beer,
baked goods and cereal.
• It is classified as a preservative "reasonably anticipated
to be a human carcinogen."
• Sulfites are added to baked goods, wine, condiments and
snack foods
• It could cause hives, nausea, diarrhea and shortness of
breath in some people. 18

19. Colour additives
• Colour additive: Any dye, pigment, or substance that imparts
colour when it is added to food or drink
• Artificial colouring is used in thousands of foods, including soda,
candies, snack foods, baked goods, pickles, and salad dressings
• Reasons for adding colour additives in foods:
Make the food look more appealing
Attractive to consumers, especially to children
Much cheaper
Longer shelf-life
Brighter than most natural food colourings 19

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21. 1. Increases inflammation and disrupts the functioning of
the immune system
• Inflammatory response in the body due to the artificial colours
leads to the activation of the immune system
• Therefore increases the number of white blood cells entering the
bloodstream
• Artificial dyes contain small molecules which can attach to
proteins in our bodies.
• It disrupt the immune system as the immune system finds
difficulty to defend the body against them.
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22. 2. Contain cancer-causing, toxic contaminants
• Some of the most commonly used food dyes (Red 40, Yellow 5,
and Yellow 6) are contaminated with known carcinogens.
• Those are 4-aminobiphenyl, 4-aminoazobenzene, and
benzidine
• Citrus Red 2: Bladder and other tumours in mice and bladder
tumours in rats.
• Red 3: Thyroid tumours in rats.
• Blue 2: Brain and bladder tumours in rats.
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23. 3. Causes hypersensitivity, especially in children
• Red 40: Hypersensitivity in children.
• Yellow 5: Hyperactivity, hypersensitivity, and other unfavourable
behavioural effects in children
Negatively impacts the functioning of the liver and other
vital organs
Linked to respiratory disorders: Asthma and bronchitis
Negatively impacts nerve cell development
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24. Food borne toxicants
• Toxic substances in food itself can produce harmful
effects on humans and animals by ingestion.
1. Bacillus cereus
• Widely distributed in nature
• Bacteria produce a toxin that causes illness
• Cause vomiting
• Found in rice products and other starchy foods (potatoes,
pasta) and cheese products
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25. 2. Campylobacter jejuni
• Found: Intestinal tracts of animals, birds, raw milk, untreated
water, and sewage sludge
• Transmit: Contaminated water, raw milk, and raw or
undercooked meat, poultry, or shellfish
• Cause: Fever, headache, and muscle pain followed by
diarrhea, abdominal pain, and nausea
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26. 3. Clostridium botulinum
• It grows only in little or no oxygen.
• It affects the nervous system & symptoms usually appear in
18-36 hours.
• Can be fatal in 3-10 days if not treated.
Found: Soil, water, plants and intestinal tracts of animals and fish
Transmission: Improperly canned foods, garlic in oil, vacuum-
packed and tightly wrapped food
Symptoms: Double vision, droopy eyelids, trouble speaking and
swallowing, and difficulty in breathing
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27. Organic Toxicants
• Organic contaminants are carbon based chemicals.
• Two major class:
1. Phycotoxins
2. Mycotoxins
• Types of Mycotoxins
Aflatoxins : Aspergillus
Trichothecenes : Fusarium
Ochratoxins/Citrinin : Penicillium
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28. Mycotoxins
• These occurs naturally and are produced by certain moulds
(fungi).
• The moulds grow on a variety of different crops and
foodstuffs often under warm and humid conditions.
• Eg: Cereals, nuts, spices, dried fruits, apples and coffee beans
• Mycotoxins cause adverse health effects and leads to serious
health threat to both humans and livestock
• Eg: Immune deficiency, cancer
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31. • Aflatoxins
These are the most poisonous mycotoxins.
These are produced by certain moulds (Aspergillus flavus and
Aspergillus parasiticus)
Grows in soil, decaying vegetation, hay, and grains
Crops that are frequently affected by Aspergillus spp. are
cereals (corn, sorghum, wheat and rice),
oilseeds (soybean, peanut, sunflower and cotton seeds)
spices (chili peppers, black pepper, coriander, turmeric and ginger)
tree nuts (pistachio, almond, walnut, coconut and Brazil nut)
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32. The toxins can also be found in the milk of animals that
are fed contaminated feed, in the form of aflatoxin M1
Large doses of aflatoxins can lead to acute poisoning
and threat life, usually through damage to the liver
Aflatoxins have also been shown to be genotoxic
(damage DNA) and cause cancer in animal species
There is also evidence that they can cause liver cancer in
humans
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33. • Trichothecenes
These are common field toxins found in grains and silages
Susceptibility to trichothecenes varies based on,
type & concentration of mycotoxin, mycotoxin
species/breed of animal
management systems
Swine are often considered one of the more sensitive species.
Clinical signs: Reduced feed intake, lower weight gains,
intestinal hemorrhaging, diarrhea, an increase in intestinal
pathogen occurrence, lost milk production, reproductive failure
and even mortality.
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34. • Ochratoxins/Citrinin
It can be produced both during field conditions and storage
of feedstuffs
These are found in both temperate and tropical regions
Though mycotoxins can impact many species, ochratoxin
will be rapidly degraded in a correctly functioning rumen.
So, it is assumed to be a lesser threat to ruminants.
Very high levels of ochratoxin (>3 ppm) can cause increased
mortality.
Clinical signs: Kidney damage, liver damage and immune
suppression
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35. Phycotoxins
These are natural metabolites produced by micro-algae.
Phycotoxins are small to medium-sized natural products
and belong to many different groups of chemical
compounds.
Through accumulation in the food chain, these toxins
may concentrate in different marine organisms.
The route of human exposure to phycotoxins is usually
oral. 35

36. Human poisoning due to ingestion of seafood
contaminated by phycotoxins has occurred in the
past.
Impacts: Disturb the normal functioning of neuronal and other
excitable tissues and lead to adverse effects in humans
Okadaic acid and related compounds disrupt major mechanisms
that controlling the cellular functions
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Mechanism of phycotoxins

38. THANK YOU
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