(PDF) Occupational Medicine and Toxicology

ENVIRONMENTAL AND
OCCUPATIONAL
TOXICOLOGY

Table of Contents
INTRODUCTION...........................................................................................................................1
TASK...............................................................................................................................................1
Various classes of health hazards...........................................................................................1
Hazardous chemical which pose toxic effects........................................................................3
Characteristics of hazardous chemical and its uses................................................................4
Toxicological information and mechanism of action of Nitrogen Oxide...............................5
Effects of hazardous chemicals on human health...................................................................6
Methods to reduce the risk of the hazardous chemical...........................................................7
Availability of a medical test that detect about person who get exposure to hazardous
chemical..................................................................................................................................8
CONCLUSION................................................................................................................................8
REFERENCES..............................................................................................................................10

INTRODUCTION
Environmental and occupational toxicology refers to a branch of science that deals with
study of such toxic chemicals in environment and at work place which harms the health of an
individual. There are various kinds of toxic chemicals that are released from the factories or
working areas and leads to several diseases in human beings (Nordberg, Fowler & Nordberg,
2014). It includes a method to understand and manage chemical and biological hazards that are
encountered at work. Occupational toxicology is helpful in certain aspects like to make decision
within hierarchical control, setting exposure standards for workplace chemicals along with
biological monitoring for the sane. This assignment will discuss about various classes of health
hazards and chemical substance with that has toxic effects on health. It also includes description
about availability of medical test that detect about person who get exposure to hazardous
chemical.
TASK
Various classes of health hazards
The health hazards group refers to different types hazardous substances that cause n
adverse health issues to people such as acute toxicity, respiratory sensitization (such as breathing
difficulties, asthma or allergy), eye irritation or carcinogenicity (ability to cause cancer) and
many more. It includes these products which are toxic to human health while they comes in
contact with the same and leads top critical disease. The various classes of health hazards are
given below:
(WHMIS 2015 Hazard Classes and Categories, 2017)
Acute Toxicity (Oral/Dermal/Inhalation): This refers to the group of those chemical
toxic products that fatal while they comes in contact with skin or swallowed by people like
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Illustration 1: WHMIS 2015 Hazard Classes and Categories, 2017

chlorinated solvents. It impacts on health occurred following skin contact, ingestion exposure to
a single or multiple dose which is given within 24 hours and an inhalation exposure of 4 hours
(Martenies & Perry, 2013) .
Skin Corrosion/Irritation: This class of skin corrosion includes certain substances that
results into burns, irritation and many more issues relevant to skin such as fumes or some
chemical . For example, acids, bases, fat-dissolving solvents etc.
Serious Eye Damage/Eye Irritation: There are various kinds of chemicals or acids that
cause eye damage or irritation such as sulphuric acid, sulphurous acid, hydrochloric acid, nitric
acid, acetic acid, chromic acid and hydrofluoric acid.
Respiratory or Skin Sensitization: This group of products are responsible for several
respiratory issues like allergies, asthma, rhinitis etc. It includes pollen grains, allergens and other
solvents that cause issues relevant to skin sensitization and respiration.
Germ Cell Mutagenicity: The term mutagenicity refers to those substances which are
responsible for several genetic effects in individuals. It basically includes permanent changes
called mutations which are introduced by mutagens to body cells that can be passed on to future
generations as well.
Carcinogenicity: This class of products can be described about cancer causing agents
that are accountable for different kinds of cancers various organs of human body. The agents are
known carcinogens which cause cancer by introducing cancerous cell along with carried out
multi division of those infectious cells (Baxter and et. al., 2010) .
Reproductive Toxicology: There are different types of chemical substances which are
accountable for several reproductive problems in people. Such goods chemicals are responsible
for damaging fertile capacity or the unborn foetus. The poly-chlorinated organic compounds,
pesticides, phthalates, bis-phenol A, brominated flame retardants and heavy metals are known
for disturbing reproductive ability.
Target Organ Systemic Toxicity - Single Exposure: This category of products are
accountable for causing damage to several organs such as liver, kidneys or blood following
single exposure. Such chemicals are causing certain problems like respiratory irritation,
drowsiness, dizziness and so on.
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Target Organ Systemic Toxicity - Repeated Exposure: This refers to group of such
hazardous substance that are accountable for various long term issues relevant to health of people
and damage certain organs following repeated exposure to the same.
Aspiration Toxicity: This class of hazardous chemicals is very critical as they fatal if
swallowed or inhales by airways. Aspiration is all about an entry of liquid or solid directly
through oral and nasal cavity. It is responsible for certain acute impacts of human health such as
chemical pneumonia, pulmonary injury or death following aspiration (Appenzeller & Tsatsakis,
2012) .
Hazardous chemical which pose toxic effects
There are various kinds of hazardous chemicals that impacts negatively on human health
as well as environment to cause damage. These substances are much toxic as they make natural
environment poisonous and spoil certain organ of human body along with introducing various
difficulties for other species of Earth. It is necessary to determine about effects of such toxic
chemicals compounds and take an appropriate steps to avoid health issues in proper manner. The
different hazardous substances are Hydrogen cyanide, Hydrogen sulphide, Nitrogen dioxide,
Ricin, Organophosphate pesticides, Arsenic and many more.
Nitrogen dioxide: The nitrogen dioxide can be described as chemical compound which
is considered as an acute toxin and cause certain problems. The chemical formula of this
compound is NO2 It is nasty smelling gas which is an important pollutant also because it
contributes to synthesis of photochemical smog that impacts negatively on human healthy as
well. This compound of formed naturally i.e., 1% that is produced by plants, soil and water but
mostly it comes from motor vehicle exhaust i.e., 80%. In general, the major source of nitrogen
dioxide is burning of fossil fuels like coal, gas and oil (Field& Withers, 2012) .
Toxic effects of Nitrogen Dioxide Acute poisoning: This refers that highly exposure to this compound may cause
inflammation of mucous membrane and upper & lower respiratory tracts. Nitrogen
dioxide is accountable for several health issues but they are non- specific and have
resemblance with poisoning of ammonia gas, chlorine gas, and carbon monoxide. Chronic poisoning: The chronic poisoning includes that prolonged exposure to very high
level of nitrogen dioxide that primarily targets respiratory tracts and cause fever, rapid
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breathing coupled with rapid heart rate, severe seizure of breath, chest pain, diaphoresis
and persistent dry cough. Biochemical effects: This kind of effects refers that when high amount of nitrogen
dioxide is accountable for the allosteric inhibition of glutathione peroxidase and
glutathione S-transferase. Thus, these both are essential enzymes that are usually found in
antioxidant defence system of mucous membrane which helps to catalyse nucleophilic
attack by reduced glutathione (GSH) on non-polar compounds that contain an
electrophilic carbon and nitrogen (Gupta, 2015) .
 Reproductive effects: The reproductive system must be healthy that includes several
organs or cells which are responsible for producing new progeny. The nitrogen dioxide
disturbs production of Sertoli cells that are considered as nurse cell of testicles which are
part of seminiferous tubules and helps on process of spermatogenesis. This compound is
also accountable for disrupting the balance of reactive oxygen species that leads to inhibit
oocyte production, maturation to fertilisation development of embryo and pregnancy.
Characteristics of hazardous chemical and its uses
The nitrogen dioxide is a chemical compound having formula of NO2 which is an
intermediate in process of industrial formation of nitric acid. It converts into reddish brown gas
at higher temperatures that has characteristic sharp, biting odour and known as prominent air
pollutant as well. The characteristics and uses of this chemical compound is given below:
(Source: Nitrogen dioxide, 2015)
Characteristic of Nitrogen Oxide
 This substance is reddish brown gas above 21.2 degree Celsius having pungent smell and
acrid odour.
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Illustration 2:
Nitrogen dioxide, 2015

 It will become yellowish brown liquid below 21.2 degree Celsius and turns into
dinitrogen tetroxide which is colourless compound.
 The bond length between atoms of nitrogen and oxygen is 119.7pm that is consistent with
bond order betwixt one or two (gbinosa and et. al., 2013) .
 This compound is one of most prominent air pollutant and a poison by inhalation.
 The melting point of nitrogen dioxide is -11.2 decree Celsius (261.95 K) and boiling
point is 21.1°C (293.25 K).
 Molar mass of this chemical compound is 46.0055 and density is 1443 kg/m³, liquid
3.4 kg/m³, gas at 294.25 K.
 This compound is generally present in form of gas in small quantity in smog and auto
mobile exhaust fumes.
Uses of Nitrogen Oxide
 This compound is highly reactive in nature and performs as catalyst in several reactions
to make required main product.
 It is considered as a good oxidizer which is also utilised in certain reactions in which it
will combust with many compounds such as hydrocarbons.
 It is useful substance to proceed hydrolysis as it hydrolyses to give nitric acid and nitrous
acid which are useful fro several purposes.
 Nitrogen oxide is used as an intermediate in production of nitric acid and nitrating agent
in synthesis of chemical explosives.
 It work as a polymerization inhibitor for acrylates, used as flour bleaching and room
temperature sterilization agent.
 This compound is utilised in Titan rockets, to launch Project Gemini, in manoeuvring
thrusters of the Space Shuttle, and in unmanned space probes sent to various planets.
Toxicological information and mechanism of action of Nitrogen Oxide
There are different kinds of toxic chemicals which are released at work place into natural
environment that are inhales by people which cause several health issues. It includes various
chemical substances that are toxic in nature and leads to several long and short term problems in
human body (Carson, 2018) . These elements has an ability to damage organs, inhibit in
functioning and reduce capacity of immune system. For example, Nitrogen is one of such toxic
compound which impacts negatively on environment as well as human body.
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Toxicological information about Nitrogen Oxide: This chemical will harm in its
gaseous state as it diffuses into epithelial lining fluid of respiratory epithelium to get dissolved
and react with an antioxidant. Hence, it will cause several health issues such as
bronchoconstriction, inflammation, reduced immune response, and may have effects on heart as
well. Inhaling or swallowing Nitrogen dioxide is accountable for affecting haemoglobin in red
blood cells.
Mechanism of action of Nitrogen Oxide
There are various kinds of biological reactions in which the chemical compound named
as nitrogen oxide is participates in reactions. In this aspects, the reaction of NO2 is carried out
with oxymyoglobin and haemoglobin that are predominant hemeproteins in biological systems.
Similarly, different reactions are conducted in metabolism of human body and many of that will
include nitrogen oxide to proceed whole process (Bak and Hayes & Dechsakulthorn, 2012) .
This chemical compound is also performed as catalyst in several reactions and helps to speed up
the same to get desired product compound.
Effects of hazardous chemicals on human health
Health Effect Description Symptoms
Asthma This disease refers to
inflammation in bronchiole
tubes with sticky secretion and
affects breathing passage of
lungs.
 Wheezing
 Cough
 Shortness of breathe
 Tachycardia
 Chest tightness
Damage reproductive organs The selected chemical
compound disturbs formation of
Sertoli cells that are helpful in
synthesis of spermatozoa and
inhibit maturation to oocytes
along with development of
embryo.
 Abnormal uterine
bleeding.
 Unusual or heavy
vaginal discharge.
 Painful urination.
 Painful sexual
intercourse.
Disturbs respiratory tracts The inhalation of nitrogen
dioxide results attacks on
 Nasal congestion,
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respiratory system and leads to
several relevant health issues
such as interrupts into
functioning of lungs and many
other problems in human body.
 Runny nose
 Nasal discharge
 Nasal breathing,
 Sneezing,
 Sore or scratchy throat,
 Painful swallowing
 Cough
Methods to reduce the risk of the hazardous chemical
Hazardous chemicals impacts negatively on health of people them it is mandatory to take
several steps to reduce them in proper manner. It is necessary to focus on this issues and make
some beneficial solutions which provide support to reduce harmful impacts of nitrogen dioxide.
The toxic chemical compounds have various harmful effects on human body which cause several
critical health issues such as asthma, infection in lungs, damage reproductive organs and many
more (WHMIS, 2015) . Several techniques can be used to decrease relevant risks which are as
follows:
 It is necessary to use ventilation while using gas stove to reduce concentration of nitrogen
dioxide which mat inhaled through breathing.
 The government should made several strict rules for sing motor vehicles to use ozone
friendly fuels to decrease amount of nitrogen dioxide and reduce pollution as well.
 People can avoid gas stoves and utilise electric cooking machines which helps to reduce
risks of health problems successfully.
 The plantation of trees will render help to reduce polluted or toxic compounds from
environment that results into decreasing certain health issues properly.
 The nitrogen dioxide is considered as poisonous substance as it will is harmful for natural
environment as well as human body then it should be reduced to by using eco-friendly
equipments or tools in regular life.
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Availability of a medical test that detect about person who get exposure to hazardous chemical
Single or repeated exposure to hazardous chemicals leads to several short and long term
health problems. Similarly, the nitrogen dioxide has certain toxic effects on human body that
cause various infections in organs and interrupts into their functioning properly. Thus, detection
of such exposure is must so that an appropriate treatment can be provide to an individual to
reduce harmful impacts on human functioning systems ( Hazard Classes and Categories, 2017) .
Different tests which are useful to detect exposure of an individual to nitrogen dioxide which are
as follows:
Urine Metals Challenge Test: In this test, the sample of urine is taken and determine
amount of particular toxic chemical compound which is responsible for specific infection.
Dark field Microscopy: This refers to blood tests in which small sample of blood will
tested by using special form of lighting besides of staining of living cells (Parrón and et. al.,
2014).
Stool Testing: This includes the DNA testing of stool sample for abnormal bacteria,
yeast and parasites which is due to presence of specific toxic chemical.
MELISA Testing: The term MELISA stands for Memory Lymphocyte
Immunostimulation Assay that is a kind of blood test which provide support to detect type IV
hypersensitivity to toxic metals and chemicals.
Urine Porphyrins: This involves to test poryphorins which are intermediate steps in
creating heme which are used in blood. It is helpful to determine presence of toxic chemicals,
heavy metals and certain environmental compounds (Nitrogen dioxide, 2015).
ELISA: This factor ELISA is an abbreviated form of enzyme-linked immunosorbent
assay that is also a blood test which helps to identify reactivity of immune cells to various toxic
compounds.
CONCLUSION
The above report had concluded that the topic of environmental and occupational
toxicology can be described as section of science which deals with study of such toxic chemicals
in environment and at work place which harms the health of an individual. It is compulsory to
determine about effects of such toxic chemicals compounds and take an appropriate steps to
avoid health issues in proper manner. The toxic elements like nitrogen dioxide has an ability to
damage organs, inhibit in functioning and reduce capacity of immune system. There are different
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types of toxic chemicals which leads to various health problems while comes in contact with skin
or swallowed.
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REFERENCES
Books and journals
Nordberg, G. F., Fowler, B. A., & Nordberg, M. (Eds.). (2014). Handbook on the Toxicology of
Metals. Academic press.
Martenies, S. E., & Perry, M. J. (2013). Environmental and occupational pesticide exposure and
human sperm parameters: a systematic review. Toxicology, 307, 66-73.
Baxter, P. J and et. al., (Eds.). (2010). Hunter's diseases of occupations. CRC Press.
Appenzeller, B. M., & Tsatsakis, A. M. (2012). Hair analysis for biomonitoring of environmental
and occupational exposure to organic pollutants: state of the art, critical review and
future needs. Toxicology letters, 210(2), 119-140.
Field, R. W., & Withers, B. L. (2012). Occupational and environmental causes of lung
cancer. Clinics in chest medicine, 33(4), 681-703.
Gupta, R. C. (Ed.). (2015). Handbook of toxicology of chemical warfare agents. Academic Press.
Igbinosa, E. O and et. al., (2013). Toxicological profile of chlorophenols and their derivatives in
the environment: the public health perspective. The Scientific World Journal, 2013.
Carson, B. L. (2018). Toxicology Biological Monitoring of Metals in Humans: 0. CRC Press.
Bakand, S., Hayes, A., & Dechsakulthorn, F. (2012). Nanoparticles: a review of particle
toxicology following inhalation exposure. Inhalation toxicology, 24(2), 125-135.
Online
WHMIS 2015 Hazard Classes and Categories. 2017. [Online]. Available through:
<https://eversafe.ca/whmis-2015-hazard-classes-and-categories/>
Nitrogen dioxide. 2015. [Online]. Available through:
<http://www.newworldencyclopedia.org/entry/Nitrogen_dioxide>
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