Environmental health is the branch of public health concerned with all aspects of the natural and built environment affecting human health. In order to effectively control factors that may affect health, the requirements that must be met in order to create a healthy environment must be determined.[1] The major sub-disciplines of environmental health are environmental science, toxicology, environmental epidemiology, and environmental and occupational medicine.[2]
Definitions
WHO definitions
Environmental health was defined in a 1989 document by the World Health Organization (WHO) as: Those aspects of human health and disease that are determined by factors in the environment.[citation needed] It is also referred to as the theory and practice of accessing and controlling factors in the environment that can potentially affect health.[citation needed]
A 1990 WHO document states that environmental health, as used by the WHO Regional Office for Europe, "includes both the direct pathological effects of chemicals, radiation and some biological agents, and the effects (often indirect) on health and well being of the broad physical, psychological, social and cultural environment, which includes housing, urban development, land use and transport."[3]
As of 2016, the WHO website on environmental health states that "Environmental health addresses all the physical, chemical, and biological factors external to a person, and all the related factors impacting behaviours. It encompasses the assessment and control of those environmental factors that can potentially affect health. It is targeted towards preventing disease and creating health-supportive environments. This definition excludes behaviour not related to environment, as well as behaviour related to the social and cultural environment, as well as genetics."[4]
The WHO has also defined environmental health services as "those services which implement environmental health policies through monitoring and control activities. They also carry out that role by promoting the improvement of environmental parameters and by encouraging the use of environmentally friendly and healthy technologies and behaviors. They also have a leading role in developing and suggesting new policy areas."[5][6]
Other considerations
The term environmental medicine may be seen as a medical specialty, or branch of the broader field of environmental health.[7][8] Terminology is not fully established, and in many European countries they are used interchangeably.[9]
Children's environmental health is the academic discipline that studies how environmental exposures in early life—chemical, nutritional, and social—influence health and development in childhood and across the entire human life span.[10]
Other terms referring to or concerning environmental health include environmental public health and health protection.
Disciplines
Five basic disciplines generally contribute to the field of environmental health: environmental epidemiology,
2. Pesticide
A pesticide is any substance or mixture of substances intended for
preventing , destroying , repelling , or mitigating any pest.
Pest include insects, plant pathogens, weeds, birds, and microbes
etc.
3. Classification on the basis of Targeted
Organism
Pesticides
Algicides
Virucides
Rodenticide
Fungicides
Herbicides
insecticide
Avicides Bactericide
miticides
nematicide
5. Chemical Pesticides
1. Organochlorides, which have a high persistence in the
environment of up to about 15 years (DDT, dieldrin and aldrin
2. Organophosphates, which have an intermediate persistence of
several months (parathion, carbaryl and malathion)
3. Carbamates, which have a low persistence of around two weeks
(Tenik, Zectran and Zineb)
4. Synthetic pyrethroids, which are nonpersistent, contact and
residual acting insecticides (cypermethrin, permethrin), suitable for
a wide range of crops and target insect
6. Biopesticides
Biopesticides are certain type of pesticides derived from such
natural materials as plants, animal and microbes like bacteria,
fungi etc.
7.
8. Microbial Pesticides
Microbial pesticides are composed of microscopic living organisms (viruses,
bacteria, fungi, protozoa, or nematodes) or toxin produced by these organisms
Applied as conventional insecticidal sprays, dusts, or granules.
Their greatest strength is their specificity as most are essentially nontoxic and
non pathogenic to animals and humans.
Microbial pesticides includes insecticides, fungicides, herbicides and growth
regulators of microbial origin.
9. Some of the important microbial pesticides
a. Bacillus thuringiensis
Discovered in Japan in early 20th century and first become a
commercial product in France in 1938.
Control lepidopterous pests like
American bollworm in cotton
and stem borers in rice.
Fig: Bacillus thuringiensis
When ingested by pest larvae, Bt releases toxins which damage the mid
gut of the pest, eventually killing it.
Main sources for the production of Bt preparations are the strains of the
subspecies kurstaki, galeriae and dendrolimus
10. e. Metarizium anisopliae
•It infects spittlegbugs, rhinoceros beetles.
f. Beauveria bassiana
• Controls Colorado potato beetle.
g. Verticillum lecanii:
•Controls aphids and whiteflies.
h. Nomuraea riley:
• Controls soybean caterpillars.
i.Baculoviruses (Bvs)
• Control lepidopterous and hymenopterous pests.
•Rod shaped, circular double stranded super coiled DNA.
Fig: Metarhizium anisopliae
Fig: Beauveria
11. Pesticides derived from plants
Generally act in one of two ways
Contact poison
Stomach poison
About 250000 plant species evaluated
2121 useful in pest management
1005 exhibited insecticidal activity
384antifeedants
297 repellents
27 attractants
31 growth inhibiting properties
12. Plant-incorporated- protectants (PIPs)
Pesticidal substances that plant produce from the genetic material that
has been added to the plant.
As the pest feed on such plants they will eventually die.
Botanical pesticides:
These are naturally occurring plant material that may be crude
preparation of the plant parts ground to produce a dust or powder that
can be used in full strength or dilute form in a carrier such as clay, talc
or diatomaceous earth.
“Azadirachtin” effects the reproductive and digestive process of pest.
Several plant based insecticides as nicotinoids, natural pyrethroids,
rotenoids, neem products etc are used.
13. 4.Biochemical pesticides
They are naturally occurring substance to control pest by non-toxic
mechanisms.
Biochemical pesticides include substances as insect sex pheromones, that
interfere with mating that attract insect pest
to traps.
The synthetic attractants-
are used in one of four ways:
i. As a lure in traps used to monitor pest populations;
ii. As a lure in traps designed to “trap out” a pest population;
iii. As a broadcast signal intended to disrupt insect mating
iv. As an attractant in a bait containing an insecticide
Fig: weevil pheromone trap
14. Biopesticides are usually inherently less toxic than conventional
pesticides.
Biopesticides generally affect only the target pest and closely
related organisms,
Biopesticides often decompose quickly, avoiding the pollution
problems caused by conventional pesticides.
Biopesticides can greatly decrease the use of conventional
pesticides, while crop yields remain high.
Cheap, renewable can be handled safely.
Difficult for insects to develop resistance to these pesticides.
15. Slow effect
Lack persistence and wide spectrum activity
Rapidly degraded by UV lights so residual action is slow.
Seasonal availability of plants products indicates the needs for storage.
They are not available easily
Poor water solubility and generally not systemic in nature
All products applied followed by growers have not been scientifically
verified.
16. Fate of Pesticides
Once a pesticide is applied, several things may happen.
It may be taken up by plants and/or ingested by animals, insects,
worms, or microorganisms in the soil
It may move downward in the soil and adhere to soil particles, or it
may dissolve
It may volatilize
It may be broken down into less toxic compounds
It may be leached or moved out of the plants root zone by rain or
irrigation water or
It may be carried away by runoff water or erosion
17. Factors Affecting Fate Of Pesticides
There are four major factors which affect the fate of pesticides.
They are as follows:
1. Properties of the pesticide
2. Properties of the soil
3. Conditions of the site
4. Management practices
19. Biosafety Levels
• Biosafety: Containment principles, techniques and practices implemented
to avoid unintentional exposure to pathogens or toxins or their accidental
release.
• Biosecurity : Protection, control and accountability for valuable biological
materials in laboratories, in order to restrict access and avoid loss, theft,
misuse, diversion or deliberate release
20. Biological materials:
Samples (blood, urine, tissue, secretions etc.) in common use in
laboratories and research units are a source of risk sometimes
identified but often unrecognized and difficult to assess
Microorganisms including those which are genetically modified, cell
cultures and human endoblasts capable of causing infection, allergy
or intoxication
Biological risk: Probability of being exposed to a biological hazard
- Directly: agent triggering the disease
- Indirectly: toxin
21. Biological agents are divided into 4 hazard groups:
By the pathogenicity of biological agents
By the risk of illness of the exposed person
By the risk of spread in the community
By the existence of a prophylaxis or an effective treatment
22. Groups Characteristics Examples
1 Does not cause disease in humans. Lactobacillus, Adenovirus,
E. coli…
2 Could cause illness in humans and be a danger to workers ;
Their spread in the community is unlikely ; There is usually
effective prophylaxis or treatment.
Staphylococcus aureus,
influenza virus, measles
virus, Hepatitis virus A, B,
C, E, Plasmodium…
3 Could cause serious illness in humans and pose a serious
danger to workers ; Spread to the community is
possible, but there is usually effective prophylaxis or
treatment
SARS-CoV-2, Yellow fever
virus, Dengue virus,
HIV, Rift valley fever
virus, West Nile virus…
4 Cause serious illness in humans and pose a serious danger
to workers ; The risk of their spread to the community is
high ; There is usually no prophylaxis or effective treatment.
Lassa virus, Ebola virus,
Crime Congo virus …
Classification of biological agents
23. Facilities: Types of laboratory – Biosecurity level and corresponding
Microbiological Safety Cabinets
Containment
level
Local Specific
equipment
Good practices
BSL1
Room ventilated and insulated by a
door and closed windows. Easily
washable benches, walls and floors.
Autoclave in the
building
Protective clothing. Clean and
tidy mats. GLP
BSL2
BSL1 + Regulated access for
authorized personnel , making of
premises, hermetic closure for
fumigation (optional), sinks with non-
manual controls. Autoclave
Microbiological
safety cabinet
(MSC)
Secure
centrifuges.
PPE : Blouse, gloves, glasses,
use of needle box, use of
disposable materials,
inactivation of contaminated
material (alcohol 70 etc.) and
waste
BSL3
BSL2 + airlock, filtration of incoming
and outgoing air, intercom (optional),
negative pressure with alarm system,
generator, shower (optional)
MSC II, double
entry autoclave
Same layouts as in BSL2
+ wearing overboots and
overcoats
BSL4
BSL3 + Emergency ventilation
system, intercom compulsory, double
airlock, shower compulsory
MSC III
Same layouts as in BSL3
+ use a protective suit
MSC I
MSC II
MSC III
25. Facilities:
Appropriate size, structure and location
Space to avoid contamination of samples with separation of
activities, limited access
Storage areas: controlled temperature, defined limits, alarm, backup
Good maintenance
27. Waste disposal pathways
• minimise waste and do not accumulate large amounts in the laboratory. Regular disposal
from the laboratories must be part of the laboratory WHS program.
• segregate waste - have a separate residue container if you are generating a large
amount of any particular type of waste. Ensure the waste container is compatible with the
waste you are collecting.
• label the waste residue container with the appropriate waste label.
• store waste in a suitable area prior to collection. For example, chemicals and solvents
should be stored in ventilated areas and residue container lids must be secure. Ensure
container is not leaking and no spillage on the exterior of the container. Primary container
should be placed in a suitable bund.
• handle waste only if you are aware of the hazards associated with the waste and
appropriate risk controls are used.
• dispose waste as per relevant UOW guidelines.
• record all disposal on Waste Tracking Log to ensure evidence of correct waste
management.
28. Waste disposal pathways
Risk-free (non-infectious waste)
Waste
At risk of infection
Solid
Pungent or sharp
Other liquids
Chemical
Regular trash can
HDPE containers
Decontamination/
neutralization
before elimination
Incineration
Yellow trash can
