A Presentation Classes of Toxic Chemicals and Their Effects on Human and Aquatic Animals for Term Paper.

1. Classes of Toxic Chemicals and Their Effects on
Human and Aquatic Animals
Department of Fisheries Management
Bangabandhu Sheikh Mujibur Rahman Agricultural
University, Gazipur-1706
Shoaibe Hossain Talukder Shefat
Faculty of Fisheries
Sylhet Agricultural University, Sylhet-3100

2. ChemicalsHazardous
to Health
Harmful to
Environment
Toxic Chemicals

3. Toxic Chemicals
Carcinogens
MutagensTeratogens
Classes of Toxic Chemicals

4.  A carcinogen is any substance, radionuclide or radiation that
promotes carcinogenesis, the formation of cancer.
 Pro-carcinogen: A pro-carcinogen is a precursor to a
carcinogen. They are not carcinogenic themselves, but turns
into carcinogenic form after entering the body.
 Nitrites
 Benzo-pyrene
 Acetyl-aminofluorene
Carcinogens

5. Co-carcinogens
Co-carcinogen is a chemical
that promotes the effects of a
carcinogen but not
carcinogenic on their own and
insufficient to initiate
carcinogenesis.
Occupational Carcinogens
Occupational carcinogens are
agents that pose a risk of cancer
in several specific work-
locations.
 Sodium Arsenite
 Beta carotene
 UV radiation
 Arsenic
 Asbestos
 Benzene
 Cadmium

6. Radioactive
Non-
Radioactive
Natural
Types of Carcinogens

7. Carcinogens Chemical
Carcinogens
Physical
Carcinogens
Types of Carcinogens

8. • Solvents
• Chemicals
Skin
Absorption
• Diet
• Drinks
Ingestion
• Breathing
gases
• Fumes
• Vapors
Inhalation
How Carcinogens Enter the Body?

9. Carcinogenesis, also
called oncogenesis or
tumorigenesis, is the
formation of a cancer,
whereby normal cells
are transformed into
cancer cells.
Carcinogenesis and Effects
 Lungs Cancer
 Breast Cancer
 Colon Cancer
 Stomach Cancer

10. Mutagens
Physical
Or
Chemical
Agents
Likely to
Carcinogen
Change
Genetic
Material
Increase
Mutation
Affect
DNA
Trans. and
Replication
Mutagens

11. History of Invention
 Swiss Physician Paracelsus (1567): An Unidentified
Substance Causes Disease
 John Hill (1761) identified Cancer, caused by Chemical
 Yamagawa and Ichikawa: Coal tar Malignant cancer
 Hermann Muller (1927): Demonstrated Mutagenic Property
 Chemical Mutagens were identified after 1940s
 Bruce Ames (1970): “Ames test” to identify mutagens

12. Types of Mutagens
 Physical: x-rays, gamma, alpha
 Chemical: Alkaloids, Bromine, Benzene
 Biological: Virus, Bacteria
 Other mutagen includes
 Intercalating agents
 DNA reactive chemicals
 Base analogs
 Metals

13. Effects of Mutagens
 Changes in DNA
 Affects DNA Transcription
 Affect DNA Replication
 Causes chromosomal breakdown
 Lead to Cancer
 Change Chromosome Numbers

14.  Ames Test
 Plant Assays
 Cell Culture Assay
 Animal Test Systems
 Transgenic Mouse Assay
 Chromosome Check Systems
 Escherichia coli Systems
 Sex-Linked Recessive Lethal Test
Mutagen Test System

15.  Alkylating Agent: Cyclophosphamide, Cisplatin
 Intercalating Agent: Daunorubicin, Doxorubicin
 Ionizing Radiation: Radiation Therapy
Used in Anti-cancer therapy
Use of Mutagens

16.  Teratogens are substances that may produce physical
or functional defects in the human embryo or fetus
after the pregnant woman is exposed to the substance
such as Mercury.
Teratogens
 Aristotle and Hippocrates said: A pregnant woman's
experiences or emotions can affect the formation of
the fetus.

17. Teratogens
Physical
Teratogen
Chemical
Teratogen
Infectious
Agents
Types of Teratogens

18. Pharmaceuticals
Illegal Drugs
Tobacco and
Alcohol
Chemical Teratogens

19.  Hyper-acetylation
 Cholesterol Imbalance
 Folate Metabolism Alteration
 Folate Antagonism
 Retinoic Acid Imbalance
 Endocrine Disruptors
 Vascular Disruption
 Oxidative Stress
Mechanisms of Action

20. Alcohol
 Affect Sperm Life Span
 Fetal Growth Retard
 Cognitive Deficits
Aspirin  Bleeding Problems
Diethyl-
stilbestrol
 Cancer
Lead
 Death
 Anemia
 Mental retardation
Teratogens & Their Effects

21. Thalidomide
 Fetal Death
 Abnormalities
Cocaine  Spontaneous Abortion
 Neurological Problem
AIDS
 Growth failure
 Low birth weight
 Developmental Delay
Rubella  Mental Retardation
 Physical Problem, Possible Death
Teratogens & Their Effects

22. Sources
Fish
CrustaceansMollusks
Other Toxic Chemicals
 Allergens: Cause unnecessary immune response

23. Sensitizers may cause
little or no reaction upon
first exposure. Repeated
exposures may result in
severe allergic reactions.
Sensitizers Irritants
Irritants causes reversible
inflammation, irritation to
the eyes, respiratory tract,
skin, and mucous
membranes.
 Iso-cyanates
 Nickel salts
 Beryllium compounds
 Formaldehyde
 Ammonia
 Formaldehyde
 Halogens
 Sulfuar Di-oxide

24.  Metabolic impairment
Effects of Toxic Chemicals on Aquatic Animals
 Cellular damage
 Physiological changes
 Behavioral changes
 Susceptibility to disease
 Reproductive effort
 Larval viability
 Age/Size structure
 Recruitment

25. Effects of Toxic Chemicals on Aquatic Animals
 Increased Mortality
 Biomass reduction
 Species abundance
 Species distribution
 Trophic interactions
 Reduced secondary production
 Reduction in population performance
 Disruption in energetics and cellular processes
 Increased degeneration of oocytes
 Atrophy of digestive tubule epithelium
 Suppressed ovarian development

26.  Necrotic neurons in embryos
Effects of Toxic Chemicals on Aquatic Animals
 Altered feeding, respiration and egg production
 Reduced viability of early developmental stages
 Reduced yolk reserves
 Delayed embryonic development
 Morphological abnormalities
 Reduced respiration, delayed molting, and reduced growth
 Altered lipid storage utilization
 Cytological damage to gills and digestive gland
 Chromosomal aberrations and increased chromatid exchange

27. Toxic Chemicals and Fisheries
 It has been reported that freshwater fishes are more
susceptible to infectious disease and in particular,
neoplastic and atherosclerotic diseases of marine
fishes.
 Marine elasmobranch such as sharks, stingrays etc. are
much less affected by cancer than freshwater fishes

28. Toxic Chemicals in Fish
 Mercury: Long-lived species like, tuna, shark, swordfish.
 Methylmercury: Sport Fish
 PCBs: Fish and shellfish
 Venoms: Stonefish, Lionfish
 Shellfish Poisons: ASP, DSP, NSP, PSP
 Botulin: Canned Products
 Sodium Benzoate: Used in preservation
 Others: DDTs and Dieldrin, Aflatoxin, Polybrominated
Diphenyl Ethers

29.  Through eating fish, the chemicals will build up in the body
 If the level of chemicals are low enough, there is a chance to
get rid.
 Eating a fish with lot of chemicals, it will take long time to
get rid.
 Through passing of years, cancer or diabetes may develop.
 The growth and brain development of children may also be
affected.
So we have to be conscious.
What To Do Now ?