Department of Environmental Health Science

Kwara State University, Malete

Course Lecturer: Dr. (Mrs.) M. Fadeyibi

EHS 409: Environmental Health Laboratory Practice I (2 Units)

Learning Outcomes
Course Objectives
The objectives of this course are to
1. define biotechnology and environmental biotechnology
2. explain the concept of biotechnology and its implications to the environment
3. identify who needs biotechnology and environmental biotechnology
4. explain the importance of biotechnology and environmental biotechnology
5. discuss how the concept of biotechnology applies to Environmental health
6. explain emerging clean technologies.
7. describe the various branches of biotechnology and their functions
Learning Outcomes

By the end of this course, students will be able to:

1. define and explain the concepts of biotechnology
2. trace the historical origin of biotechnology
3. identify who needs biotechnology and for what purposes
4. describe the various branches of biotechnology and their functions
5. describe the methods of biotechnology
6. discuss the application of biotechnology to disease monitoring and control
7. discuss the application of biotechnology to waste management
8. discuss the application of biotechnology to pollution control and environmental sanitation
9. discuss the merits and demerits of biotechnology
10. explain emerging clean technologies.

Course Content
Introduction to Environmental Health laboratory. Importance and functions of Environmental
Health laboratory (EHL). Construction and organisation of EHL. General laboratory, specific
EHLs, environmental health biology, Environmental Health chemistry, environmental health
physics, arbovirus laboratory. Safety precautions in the laboratory – safety manuals.
Instrumentation: Microscopes, autoclaves, incubators, sterilizers, fridge/ freezers, hot air oven,
lasers, gas chromatography, High-powered liquid chromatography, Atomic Absorption
spectrophotometer (AAS) UV-visible spectrophotometer and many others, colorimeter,
audiometer, dosimeter, cryostat, Polymerase Chain Reaction and many others. Standard Operating
Procedures (SOPs) in field and laboratory practice. Preparation of standard solutions and reagents.
Documentation and storage of laboratory equipment and reagents. Laboratory assessment and

1
chemical hygiene. Sample collection, preservation, transportation and analysis for water, air, food,
soil, objects, fomites and body fluids and body fluids. Application of EHLs in forensics. Sample
collection and analysis from crime scene. Quality assurance and quality control. Concept of
laboratory log book, record keeping and reporting. Field trip to various environmental facilities
such as water treatment plant, waste water treatment plant, solid waste management facilities,
public health laboratories, markets, selected industries, and many others. professional
accreditations of EHL. Role of EHLs in disease control. Accident and emergency management: -
chemical spills, swallowing, fire, falls, exhaustion and many others.

INTRODUCTION TO ENVIRONMENTAL HEALTH

LABORATORY (EHL)
Environmental Health Laboratories are specialized laboratories designed to support the
monitoring, analysis, and control of environmental factors that affect human health. They play a
central role in environmental surveillance, disease prevention, quality assurance of environmental
samples, and enforcement of public health standards.

An Environmental Health Laboratory provides the technical foundation for environmental health
professionals to detect contaminants in water, food, air, soil, surfaces (fomites), and biological
samples. It also supports field investigations, environmental audits, environmental forensics, and
health emergency responses.

Environmental Health Laboratories combine microbiological, chemical, molecular, and physical

analysis using highly specialized machines such as AAS, GC-MS, PCR machines, incubators, and
spectrophotometers. Each type of analysis follows a structured workflow from sample collection,
preparation, and testing to interpretation and compliance assessment.

These laboratories provide the essential scientific evidence needed to:

• detect hazards
• investigate outbreaks

• ensure environmental standards

• protect public health

1. WATER QUALITY ANALYSIS LAB

A Water Quality Analysis Laboratory is a specialized facility where drinking water, surface
water (streams, rivers, lakes), groundwater, and wastewater are tested to determine whether they
are safe and compliant with public health standards. Environmental health professionals utilize
this lab to detect microbial contaminants, chemical pollutants, and physical characteristics of water
because these factors directly influence human health, ecological stability, and water usability.

2
Water quality testing is guided by national and international standards such as the World Health
Organization (WHO) Guidelines for Drinking-water Quality, NSDWQ (Nigeria Standard for
Drinking Water Quality), and EPA standards. Results from the laboratory help identify
contamination sources, assess treatment plant performance, and determine suitability for human
consumption or environmental discharge.

KEY MACHINES / EQUIPMENT AND THEIR FUNCTIONS

1. Autoclave
An autoclave sterilizes glassware, media, filtration units, and other laboratory materials using
steam at 121°C and 15 psi.
• Ensures complete sterilization before microbial analysis

• Prevents cross-contamination between samples

• Used to sterilize waste before disposal

2. Membrane Filtration Unit

This device is used for microbial examination of water.

• Water passes through a sterile membrane filter (0.45 µm pore size)

• Bacteria present in the water are trapped on the membrane

• The membrane is then placed on selective agar for incubation
It is the primary method for detecting E. coli, total coliforms, fecal coliforms, and
heterotrophic bacteria.

3. Incubators (37°C and 44.5°C)

Temperature-controlled cabinets that allow bacteria to grow.

• 37°C incubator → used for total coliforms and heterotrophic bacteria

• 44.5°C incubator → used specifically for fecal coliforms (thermotolerant E. coli)

4. Colony Counter

After incubation, visible bacterial colonies on plates are counted using this device.

• Ensures accurate enumeration

• Reduces eye strain and counting errors

• Results expressed in colony-forming units (CFU/100 mL)

5. pH Meter & Conductivity Meter

3
Used during physical assessment.

• pH meter → measures acidity or alkalinity

• Conductivity meter → determines the ionic concentration (salinity / dissolved minerals)

6. Atomic Absorption Spectrophotometer (AAS)

An advanced instrument for detecting heavy metals such as:

• Lead (Pb)

• Cadmium (Cd)

• Arsenic (As)

• Chromium (Cr)

• Mercury (Hg)
AAS measures how atoms absorb light at specific wavelengths, giving precise metal
concentrations.

7. Gas Chromatography–Mass Spectrometry (GC-MS)

GC-MS is used for organic chemical analysis, including:

• Pesticides

• Volatile organic compounds (VOCs)

• Hydrocarbons

• Industrial solvents
This instrument separates chemical mixtures (GC) and identifies them at molecular level
(MS).

8. Turbidimeter
Measures turbidity, which describes cloudiness caused by suspended particles such as silt,
microbes, and organic matter.

9. UV–Visible Spectrophotometer (UV–Vis)

Used for analyzing chemical parameters such as:

• Nitrates

• Nitrites

• Phosphates
• Sulphates
4
 • Residual chlorine
It works by measuring light absorbance at specific wavelengths.

KEY STEPS IN WATER QUALITY ANALYSIS

1. Sample Collection

Water samples must be collected properly to ensure valid results.

• Sterile sampling bottles (often with sodium thiosulfate for chlorinated water)
• Avoid touching the bottle interior or cap

• Stored at 4°C using icepacks to preserve sample integrity

• Must be analyzed within 6 hours for microbiology and 24 hours for chemical tests

2. Physical Analysis

These basic tests indicate the immediate quality of water:

• pH → Determines corrosion or scaling potential

• Temperature → Affects microbial activity and solubility

• Turbidity → High turbidity may indicate pollution or treatment failure

• Conductivity → Suggests mineral content or possible contamination

Physical parameters provide early clues about the water source and possible pollution.

3. Microbial Analysis

Microbial contamination is one of the most critical aspects of water quality because it directly
affects health.
Procedure (Membrane Filtration Method):

1. Filter 100 mL of water through a 0.45 µm membrane

2. Transfer membrane to selective media (e.g., EMB agar for coliforms)

3. Incubate at 37°C for total coliforms or 44.5°C for fecal coliforms

4. Count colonies using a colony counter

Microbes Tested

• Total coliforms
• Fecal coliforms
5
 • Escherichia coli

• Heterotrophic plate count (HPC)

Results indicate whether water is fecally contaminated or microbiologically unsafe.

4. Chemical Analysis
a. Heavy Metal Testing (AAS)

Water may contain toxic metals due to industrial discharge, mining, old plumbing, or natural
deposits.
AAS quantifies metals even at very low concentrations (µg/L).

b. Nutrients and Other Anions (UV–Vis)

Using reagents and colorimetric reactions, UV–Vis measures:

• Nitrates / Nitrites → linked to fertilizer runoff and eutrophication

• Phosphates → common in detergents and wastewater

• Residual chlorine → indicates water treatment effectiveness

5. Organic Pollutant Screening (GC-MS)

GC-MS identifies trace-level organic pollutants such as:

• Pesticide residues from farms

• Industrial solvents

• Fuel contaminants

• Pharmaceutical residues
These pollutants may cause toxicity or long-term health problems.

6. Reporting & Compliance Checking

Results are compared against:

• WHO drinking water standards

• National water quality standards (e.g., SON, NAFDAC)

The report includes:

• Methods used

• Results for all parameters

• Interpretation of safety

6
 • Recommendation for corrective actions (treatment, flushing, chlorination, etc.)

2. FOOD HYGIENE & SAFETY LAB (Detailed Explanation)

A Food Hygiene & Safety Laboratory is responsible for assessing the microbiological and
chemical safety of food products to ensure they are fit for human consumption. Contaminated food
is a major cause of food-borne illnesses, which may result from pathogens, toxins, spoilage, or
hazardous chemicals like pesticides and drug residues. This laboratory uses both traditional
microbiological methods and advanced analytical technologies to detect contamination, verify
food processing standards, and ensure compliance with national and international food safety
regulations (such as Codex Alimentarius, NAFDAC, WHO, and FDA standards). The main goal
is to protect consumer health by ensuring food is free from disease-causing organisms, harmful
chemical additives, and unacceptable spoilage.

KEY MACHINES / EQUIPMENT AND THEIR FUNCTIONS

1. Laminar Flow Hood

A laminar flow hood provides a sterile working environment by blowing HEPA-filtered air
across the workspace.

• Prevents contamination during sample preparation

• Essential for plating bacteria, preparing media, and transferring cultures

• Protects food samples from airborne microbes

2. Stomacher / Laboratory Blender

This device homogenizes food samples by vigorously shaking or blending them in sterile bags.

• Releases bacteria from solid food surfaces into liquid

• Produces uniform samples for accurate testing

• Used before microbial culture, PCR, and toxin analysis

3. PCR Machine (Thermal Cycler)

The polymerase chain reaction (PCR) machine amplifies DNA from pathogens.
• Rapid detection of microbes like Salmonella, Listeria monocytogenes, Staphylococcus
aureus

• Highly sensitive and specific

• Useful when pathogens are present in very low numbers

7
 • RT-PCR can detect RNA viruses in food

4. ELISA Microplate Reader

ELISA (Enzyme-Linked Immunosorbent Assay) is used to detect specific toxins, allergens, or

bacterial antigens.

• Detects toxins like staphylococcal enterotoxin, aflatoxin, and mycotoxins

• Quantifies substances based on color intensity

• Widely used in food quality and export testing

5. High-Performance Liquid Chromatography (HPLC)

A highly precise analytical instrument used for identifying and quantifying:

• Food additives

• Preservatives

• Artificial sweeteners

• Antibiotic residues
• Pesticides
HPLC separates components in food and measures them based on their chemical
properties.

6. Mass Spectrometer (MS)

Often used together with HPLC (HPLC-MS).

• Identifies chemical structures

• Detects ultra-low quantities of contaminants

• Used for pesticide residues, veterinary drugs, adulterants, and toxins

7. Refrigerated Centrifuge

Separates components of food samples at high speed under chilled conditions.

• Prevents heat-induced degradation of nutrients and chemicals

• Used before molecular and chemical tests to purify samples

8. Incubators
Provide controlled temperatures for growing and identifying microbes.

8
 • Different pathogens require different incubation conditions

• Growth of Salmonella, Listeria, E. coli, S. aureus, etc.

Incubators mimic the conditions that allow bacteria to multiply for detection.

KEY STEPS IN FOOD HYGIENE & SAFETY ANALYSIS

1. Sample Homogenization (Stomacher)

Food samples (meat, vegetables, milk, spices, processed foods) are mixed thoroughly to obtain a
uniform sample.

• Ensures bacteria or chemicals are evenly distributed

• Increases accuracy of microbial, toxin, and chemical detection

• Homogenized samples are used for plating, PCR, and ELISA

2. Microbial Culture for Pathogens

Traditional microbiology remains vital for detecting harmful bacteria.

Common pathogens tested

• Salmonella spp.

• Listeria monocytogenes

• Staphylococcus aureus
• E. coli (including O157:H7)

• Campylobacter spp.

• Yeasts and molds

• Total viable counts (TVC)

Procedure

1. Prepare serial dilutions of homogenized food

2. Plate on selective and differential media

o XLD agar for Salmonella

o PALCAM or Oxford agar for Listeria

o MSA for Staphylococcus

3. Incubate at appropriate temperatures (usually 35–37°C)

4. Identify colonies by morphology, biochemical tests, or automated systems
9
This step confirms the presence of viable pathogenic organisms in the food.

3. Rapid Molecular Detection Using PCR/RT-PCR

PCR allows quick, accurate detection of microbial DNA or RNA.

Advantages:
• Detects pathogens even when present in very small amounts

• Faster than culture (few hours vs. days)

• Allows early detection of food-borne outbreaks

Applications:

• Detection of Listeria monocytogenes genes

• Identification of Salmonella serotypes

• Confirmation of Staphylococcus aureus toxin genes

• Testing for viral contamination using RT-PCR

4. Toxin Detection Using ELISA

ELISA is widely used to detect toxins, allergens, and chemical contaminants.

Examples:

• Aflatoxins in grains, groundnuts, milk

• Staphylococcal enterotoxins in dairy and meat

• Ochratoxin A in cereals and coffee

• Mycotoxins in spices
• Food allergens such as gluten, soy, or peanuts

ELISA results are quantitative, allowing labs to determine compliance with regulatory limits.

5. Chemical Residue Testing (HPLC/MS)

This step determines if food contains harmful chemical pollutants.

Residues tested

• Pesticides (organophosphates, carbamates)

• Veterinary drug residues (antibiotics, hormones)

• Food additives (preservatives, colorants)

10
 • Adulterants (melamine, illegal dyes)

Techniques

• HPLC → separates chemicals for quantification

• HPLC-MS or LC-MS/MS → identifies compounds at trace levels

Chemical analysis is essential for ensuring food meets export standards.

6. Interpretation & Risk Assessment

After collecting data from microbial, molecular, toxin, and chemical tests:
Analysts evaluate:

• Whether pathogens exceed permissible levels

• Whether toxins or allergens are present

• Whether chemical residues comply with national standards

• Whether the food poses any health risk

Output:

• Laboratory report with findings

• Action recommendations such as product recall, reprocessing, or rejection

• Verification that food meets safety regulations before supply or export

3. AIR QUALITY ANALYSIS LAB (Detailed Explanation)

An Air Quality Analysis Laboratory evaluates the cleanliness, safety, and composition of the air in
indoor and outdoor environments. This type of lab focuses on detecting particulate pollution, toxic
gases, and airborne microorganisms that may pose health risks. Air quality data helps
environmental health professionals determine whether air in workplaces, schools, industries, or
communities meets acceptable standards.

Air pollutants such as particulate matter (PM2.5 and PM10), sulfur dioxide (SO₂), nitrogen dioxide
(NO₂), carbon monoxide (CO), ozone (O₃), and biological aerosols can cause respiratory diseases,
allergies, cardiovascular problems, and environmental degradation. Therefore, air quality
laboratories play a vital role in public health protection, environmental monitoring, and industrial
compliance with national and WHO guidelines.

KEY MACHINES / EQUIPMENT AND THEIR FUNCTIONS

1. Air Samplers (Impingers, Impactors, and Filters)

These devices collect airborne particles and microorganisms.

11
 • Impinger: Draws air through a liquid medium to trap microbes and fine particles

• Impactor: Uses airflow to impact particles onto solid media (e.g., agar plates)

• Filter samplers: Capture particulate matter using membranes or glass fiber filters

They are essential for both microbial testing and particulate matter assessment.
2. Gas Analyzers

Electronic instruments that detect and measure the concentration of gases, including:

• Carbon monoxide (CO)

• Nitrogen dioxide (NO₂)

• Sulfur dioxide (SO₂)

• Ozone (O₃)

These analyzers use electrochemical sensors, UV fluorescence, chemiluminescence, or optical

absorption to provide real-time readings of toxic gases.

3. PM2.5/PM10 Monitors

These devices measure particulate matter suspended in air:

• PM10: coarse particles (≤10 µm)

• PM2.5: fine particles (≤2.5 µm) capable of penetrating deep into the lungs
They use laser scattering or beta-attenuation to determine particle concentration (µg/m³).

4. Microbiological Air Sampler

A calibrated device that draws a known volume of air onto culture plates.

• Useful for detecting bacteria, fungi, and spores

• Often used in hospitals, laboratories, and food processing facilities

• Results expressed in CFU/m³

5. FTIR (Fourier Transform Infrared Spectroscopy)

An advanced spectroscopic technique used to analyze the chemical composition of air samples.
• Detects organic vapors and gas mixtures

• Identifies molecular fingerprints of pollutants

• Used in industrial emission monitoring and indoor air assessments

6. Microscope / SEM (Scanning Electron Microscope)
12
Used for detailed analysis of particulate matter.

• Light Microscopes → identify dust types, pollen, mold spores

• SEM → provides high-resolution images of particle shape, size, and surface

characteristics

KEY STEPS IN AIR QUALITY ANALYSIS

1. Air Sample Collection (High-Volume Samplers or Impactors)

Air sampling must be done systematically to obtain representative results.

Common methods

• High-volume samplers: Pull large volumes of air through filters to collect PM10 or
PM2.5

• Low-volume samplers: Collect smaller air quantities for precise chemical analysis

• Cascade impactors: Separate particles based on size

• Impingers and liquid traps: Capture microbes and gases

Collected filters are weighed, cultured, or chemically analyzed depending on the study.

2. Gas Concentration Measurement (Gas Analyzers)

Electronic gas analyzers provide real-time or periodic readings of pollutant gases.

Examples:

• CO analyzer: Measures incomplete combustion from vehicles or generators

• SO₂ analyzer: Evaluates emissions from industries, power plants

• NO₂ analyzer: Helps monitor urban traffic pollution

• Ozone monitor: Used for assessing smog and atmospheric chemistry

Results are compared with national air quality standards for compliance.

3. Microbial Load Testing

Microbial aerosols such as bacteria, fungi, and spores can affect indoor air quality.
Procedure

1. Use a microbiological air sampler or simple settling plates (air-to-plate method)

2. Incubate plates at appropriate temperatures (e.g., 25–30°C for fungi, 37°C for bacteria)
3. Count colonies using a colony counter
13
 4. Report results as CFU/m³

This determines whether indoor spaces like hospitals, labs, and food production areas meet
microbial safety limits.

4. Particulate Characterization (SEM or Gravimetric Analysis)

Particulate matter is examined to understand its source and health impact.

a. Gravimetric Analysis

• Weigh filters before and after air sampling

• Determine PM concentration per cubic meter of air

• Used for PM10, PM2.5, and total suspended particles (TSP)

b. SEM Analysis

SEM provides:

• Particle size distribution

• Surface morphology

• Elemental composition (with EDS attachment)

Used for industrial source identification and environmental research.

5. Reporting & Compliance (WHO/National Standards)

After analysis, results are compared against regulatory guidelines such as:

• WHO Air Quality Guidelines (e.g., PM2.5 < 5 µg/m³ annual mean)

• National standards (e.g., NESREA in Nigeria)

Reports include:
• Gas concentrations (CO, NO₂, SO₂, O₃)

• PM2.5/PM10 levels

• Microbial counts

• Particulate characterization
• Interpretation of results and health implications

• Recommendations for pollution control or mitigation

4. SOIL & SURFACE (FOMITE) ANALYSIS (Detailed Explanation)

14
Soil and surface (fomite) analysis is essential in environmental health, contamination monitoring,
outbreak investigations, and environmental forensics. Soil and fomite testing is widely used in
public health, epidemiology, environmental monitoring, agriculture, waste management, and
industrial pollution control.
Soil can accumulate pollutants such as heavy metals, pesticides, hydrocarbons, and microbes,
while fomites (surfaces frequently touched by people) can harbor pathogenic microorganisms
responsible for disease transmission.

This type of analysis helps determine:

• Whether the environment is contaminated

• Whether surfaces in hospitals, schools, or food facilities are hygienic

• Whether soil contains toxic chemicals harmful to plants, humans, or animals

• The source and spread of pollutants or infectious agents

KEY MACHINES / EQUIPMENT AND THEIR FUNCTIONS

1. Soil Core Samplers / Soil Augers

Tools used to collect soil samples from specific depths.

• Provide undisturbed soil samples

• Allow stratified sampling (topsoil vs subsoil)

• Used for chemical and microbial analysis

2. Incubators

Temperature-controlled units used to grow and isolate microorganisms.

• Support growth of bacteria, fungi, and actinomycetes

• Used for total bacterial count, fecal indicators, and pathogen assessment

3. GC-MS (Gas Chromatography–Mass Spectrometry)

GC separates chemical mixtures, while MS identifies each compound based on molecular

fingerprint. A powerful instrument for detecting organic pollutants, including:

• Petroleum hydrocarbons
• Volatile solvents

• Industrial chemicals
• Pesticides

15
4. ICP-MS (Inductively Coupled Plasma Mass Spectrometry)

An advanced instrumental technique for heavy metal analysis.

• Detects metals at extremely low concentrations (ppb or ppt)

• Common metals tested: Pb, Cd, As, Hg, Cr, Ni

• Used for industrial site investigations, agricultural assessments, and environmental
pollution monitoring

5. PCR Machine (Thermal Cycler)

Used for molecular identification of microbes through DNA amplification.

• Detects pathogens that cannot be easily cultured

• Used for tracking contamination sources in outbreak investigations

• Useful for soil microbiome studies

6. Fluorescence Microscope

Allows visualization of microbes or pollutants that are tagged with fluorescent stains or probes.

• Detects fungal spores, bacterial cells, protozoa

• Used in environmental forensics to identify contamination pathways

• Aids in confirming PCR or culture-based findings

KEY STEPS IN SOIL & SURFACE (FOMITE) ANALYSIS

1. Sample Collection (Sterile Swabs or Soil Augers)

Accurate sample collection is critical for valid test results. Proper labeling and chain-of-custody
records are maintained when samples are used for forensic or legal purposes.
For Surfaces (Fomites)

• Use sterile swabs pre-moistened with saline or neutralizing buffer

• Swab a defined area (e.g., 10 cm grid)

• Ideal for hospitals, kitchens, and public spaces

For Soil

• Use soil core samplers or augers

• Collect samples from multiple depths (surface, 15 cm, 30 cm)

• Store samples at 4°C for microbiology or room temperature for chemical tests
16
2. Microbial Culture for Pathogenic Organisms

After sample preparation, microbial cultures are performed.

Common organisms tested

• Staphylococcus aureus
• Escherichia coli

• Salmonella spp.

• Pseudomonas aeruginosa

• Fungi (e.g., molds, yeasts)

• Spore-forming bacteria (e.g., Bacillus species)

Procedure

1. Prepare serial dilutions of soil or swab extracts

2. Plate on selective/differential media

3. Incubate at appropriate temperatures (20–37°C depending on microbe)

4. Count colonies and report as CFU/g (soil) or CFU/cm² (fomites)

This step helps identify contamination hotspots and hygiene failures.

3. Molecular Identification (DNA Extraction + PCR)

PCR provides rapid and highly specific identification of microbes.

Steps

1. Extract DNA from soil or swab samples

2. Amplify target genes using PCR

3. Analyze PCR bands using gel electrophoresis

4. Confirm species using sequencing if required

Uses

• Detection of pathogens that are difficult to culture

• Tracking contamination sources during outbreak investigations

• Identifying microbial community structure in soils

PCR enhances sensitivity and accuracy of microbial detection.

17
4. Chemical Analysis

Soil and some surfaces may contain chemical contaminants from industrial activities, spills, or
environmental exposure.

a. Heavy Metals (ICP-MS)

ICP-MS detects metals such as:

• Lead (Pb)
• Arsenic (As)

• Cadmium (Cd)
• Chromium (Cr)

• Mercury (Hg)

Metals in soil may accumulate due to mining, waste disposal, pesticides, industrial emissions, or
vehicle exhaust.

b. Hydrocarbons / Organic Solvents (GC-MS)

GC-MS identifies:

• Gasoline and diesel residues

• PAHs (polycyclic aromatic hydrocarbons)

• VOCs (volatile organic compounds)

• Solvents like benzene, toluene

These are common in polluted soils near garages, factories, oil spills, and waste dumps.
Chemical analysis provides insight into pollution sources and potential ecological or human
health risks.

5. Data Interpretation & Risk Assessment

After laboratory results are obtained, environmental health specialists assess:

Microbial Risk

• Are pathogens present at levels that pose health risks?

• Are surfaces hygienic enough for hospitals, schools, or food premises?
• Is soil safe for farming or public use?

18
Chemical Risk

• Do heavy metal or hydrocarbon levels exceed national or WHO limits?

• Is the soil safe for agriculture, playgrounds, or construction?

• Do contaminants indicate industrial pollution or illegal dumping?

Output

• Detailed report

• Recommendations for remediation, disinfection, or further testing

• Identification of pollution sources in environmental forensic cases

5. WASTEWATER & INDUSTRIAL EFFLUENT LAB (Detailed Explanation)

A Wastewater & Industrial Effluent Laboratory evaluates the quality of water discharged from
sewage treatment plants, industries, abattoirs, food-processing facilities, and chemical factories.
The goal is to determine whether the effluent meets legal discharge standards and to assess the
potential environmental and public health risks.

Untreated or poorly treated wastewater can pollute rivers, groundwater, and soil, introducing
pathogens, toxic chemicals, heavy metals, and excessive organic load into the environment.
Therefore, this lab plays a critical role in:
• Environmental protection

• Regulation enforcement (NESREA, WHO, or national standards)

• Monitoring industrial compliance

• Assessing treatment efficiency

• Preventing waterborne diseases

KEY MACHINES / EQUIPMENT AND THEIR FUNCTIONS

1. BOD (Biochemical Oxygen Demand) Analyzer

Measures the amount of oxygen consumed by microorganisms decomposing organic matter in

water over 5 days (BOD₅).

• Indicates organic pollution level

• High BOD = heavily polluted wastewater

Automated BOD analyzers improve accuracy and reduce manual workload.

19
2. COD Digestion Block + Spectrophotometer

COD (Chemical Oxygen Demand) measures the amount of oxygen required to chemically
oxidize organic and inorganic substances.

• Digestion block: heats samples with strong oxidizing agents

• Spectrophotometer: measures resulting color intensity to determine COD concentration

COD gives rapid estimate of organic load, complementing BOD.

3. Dissolved Oxygen (DO) Meter

Measures oxygen available in water.

Low DO in effluent indicates:

• High organic load

• Possible toxicity

• Harmful effects on aquatic life

Essential for both BOD tests and environmental impact studies.

4. Flow Cytometer

Used for high-precision microbial analysis.

• Counts and sorts microorganisms in wastewater

• Detects cell viability, bacterial populations, and microbial community changes

• Useful for advanced treatment plant monitoring

5. Microscope
Used for:

• Identifying protozoa, algae, helminth eggs

• Observing activated sludge microorganisms (e.g., floc structure, filamentous bacteria)

• Evaluating biological treatment efficiency

6. FTIR / GC-MS

This is crucial for industries such as petrochemical, pharmaceutical, textile, and paint factories.

Used to detect industrial pollutants:

• FTIR: identifies functional groups of chemicals in effluent (e.g., solvents, oils, polymers)
20
 • GC-MS: detects and identifies volatile and semi-volatile organic compounds, Industry
chemicals, Hydrocarbons, Pesticides, Surfactants etc.

KEY STEPS IN WASTEWATER & INDUSTRIAL EFFLUENT ANALYSIS

1. Sampling of Treatment Plants or Industrial Outlets

Proper sampling ensures the results represent true effluent quality.

Sampling considerations

• Use clean, labeled, pre-sterilized bottles

• Collect samples at discharge points or treatment stages

• Keep samples at 4°C during transport

• Avoid air bubbles when sampling for DO/BOD tests

• In industrial cases, chain-of-custody forms are used for legal validity

2. Physical Testing: Temperature, pH, TSS, TDS

Physical parameters measured

• Temperature: affects biological processes and solubility

• pH: determines acidity/alkalinity; extreme pH indicates chemical contamination

• TSS (Total Suspended Solids): solids that can clog waterways and harm aquatic life

• TDS (Total Dissolved Solids): dissolved salts, minerals, and metals

These parameters help assess general effluent quality and potential environmental stress.

3. Organic Load Testing – BOD and COD

BOD (Biochemical Oxygen Demand)

• Incubate wastewater for 5 days (BOD₅)

• Measure drops in dissolved oxygen

• High BOD means wastewater is rich in biodegradable organic matter, which can deplete
oxygen in rivers
COD (Chemical Oxygen Demand)

• Fast estimate of total oxidizable substances

• Higher COD may indicate industrial chemicals

• Used for compliance checks
21
Together, BOD and COD reveal the organic pollution level and treatment efficiency.

4. Pathogen Testing – Coliforms and Helminths

Wastewater may contain disease-causing organisms.

Microbial tests include:

• Total coliforms and E. coli: Indicators of fecal contamination

• Fecal streptococci

• Helminth eggs (Ascaris, hookworm, etc.)

Important in wastewater reuse, irrigation safety, sludge application. Techniques involve membrane
filtration, microscopy, or flow cytometry.
5. Industrial Chemical Screening (GC-MS or FTIR)

Many industries discharge harmful, non-biodegradable chemicals.

Testing identifies:

Using FTIR

• Oils, greases, polymers

• Chemical functional groups

• Organic solvents
Using GC-MS

• Volatile organic compounds (VOCs)

• Phenols and aromatic hydrocarbons

• Pesticides
• Detergents

• Pharmaceutical residues

This step helps track industrial pollution sources and ensures legal compliance.

6. Comparison with National Discharge Standards

Results are compared with regulatory thresholds such as:

• NESREA effluent limits (Nigeria)

• WHO discharges guidelines

• Local environmental regulations
22
Parameters checked:

• pH

• BOD₅

• COD
• TSS / TDS

• Heavy metals

• Industrial chemicals

• Microbial indicators

If values exceed limits, corrective actions or penalties may be recommended, such as:

• Improved treatment processes

• Chemical neutralization

• Licensing sanctions
• Pollution control strategies

6. ENVIRONMENTAL FORENSICS LAB

Environmental forensics laboratories investigate the origin, composition, and impact of pollutants
involved in contamination incidents such as oil spills, toxic releases, groundwater pollution, and
hazardous waste dumping. These labs play a crucial role in legal cases, regulatory enforcement,
and environmental protection by identifying sources of contamination and linking them to
responsible parties. Analytical techniques focus on chemical “fingerprinting,” isotopic analysis,
and DNA-based tracking to distinguish different pollution sources and quantify environmental
harm.

Key Machines/Equipment

• DNA sequencer: identifies microbial communities, pathogens, or bio-tracers linked to

pollution events.

• GC-MS (Gas Chromatography–Mass Spectrometry) & LC-MS: profiles organic

contaminants such as hydrocarbons, solvents, petroleum fractions, and industrial
chemicals.

• Radiological detectors: detect radioactive pollutants in soil, air, water, or biological

samples.
• XRF analyzer (X-Ray Fluorescence): rapid onsite or laboratory quantification of heavy
metals in solids.
23
 • Isotope Ratio Mass Spectrometer (IRMS): measures stable isotope ratios to track
pollutant origin (e.g., distinguishing petroleum sources, nitrate pollution origins,
groundwater contamination pathways).

Key Steps

1. Evidence collection with chain-of-custody

Samples (soil, water, air, sediments, tissues) are collected following strict forensic
procedures to preserve integrity and legal admissibility.
2. Source tracking using isotopic and chemical fingerprints
IRMS, GC-MS, and LC-MS establish chemical signatures that can link contaminants to
specific industries, spills, or geographic origins.

3. Pollutant profiling
Comprehensive chemical analysis characterizes contaminants e.g., differentiating crude
oil types, identifying industrial solvents, detecting trace toxicants.

4. Toxicity assessments
Laboratory bioassays or chemical hazard evaluation determine the ecological and human
health risks.

5. Expert reporting & litigation support

Findings are compiled into defensible reports used by environmental agencies, courts,
and investigators for enforcement and remediation planning.
EMERGENCY RESPONSE & OUTBREAK INVESTIGATION LAB

This lab is rapidly deployed during environmental emergencies such as cholera outbreaks, acute
water contamination, chemical poisoning, industrial accidents, or natural disasters affecting
environmental quality. It focuses on fast, field-based diagnostics to enable immediate public health
action. Equipment is portable, allowing testing at contamination sites, refugee camps, disaster
zones, or temporary clinics.

Key Machines/Equipment

• Portable water testing kits: measure pH, turbidity, chlorine, microbial indicators (H₂S
vials, coliform kits).

• Rapid PCR analyzers: detect pathogens like Vibrio cholerae, E. coli, Salmonella,
viruses, or toxin genes within minutes.

• Field incubators: enable on-site microbial culturing even in remote settings.

• Portable GC detectors: screen for volatile toxic chemicals (e.g., industrial gas leaks,
pesticide poisoning).

24
Key Steps

1. Rapid field sampling

Water, food, soil, and environmental swabs are collected immediately from suspected
contamination points, ensuring fast response.

2. Immediate on-site testing

Portable kits and rapid PCR detect microbial pathogens and acute chemical hazards to
guide urgent interventions.
3. Find–source–trace protocol
Investigators trace contamination pathways, identify origin points (e.g., broken sewage
pipe, contaminated well, leaking tank), and map exposure zones.

4. Risk communication to public health authorities

Results are shared with emergency teams, hospitals, and government agencies to initiate
timely public health actions.

5. Follow-up surveillance
Continued monitoring ensures the outbreak or contamination event is controlled and
confirms the effectiveness of remediation measures.

IMPORTANCE AND FUNCTIONS OF ENVIRONMENTAL HEALTH LABORATORIES

Importance:

1. Public Health Protection: Detect environmental hazards before they cause disease
outbreaks.

2. Regulatory Compliance: Support enforcement of environmental laws and guidelines

(e.g., water quality standards).

3. Environmental Monitoring: Provide scientific evidence for environmental policies and

interventions.

4. Research and Innovation: Support studies on pollutants, microbial pathogens, toxicants,

and emerging contaminants.

5. Capacity Building: Train Environmental Health Officers, students, and laboratory

scientists.

6. Emergency Response: Provide analytical support during chemical spills, poisoning,

epidemics, or natural disasters.

Key Functions:
• Analytical testing of water, air, food, soil, and biological samples.

25
 • Environmental surveillance and outbreak investigation.

• Calibration and maintenance of laboratory and field instruments.

• Storage and documentation of samples and reagents.

• Development of Standard Operating Procedures (SOPs) for environmental testing.

• Supporting legal investigations (forensics).

• Quality assurance and quality control (QA/QC).

CONSTRUCTION AND ORGANISATION OF ENVIRONMENTAL HEALTH

LABORATORIES

Construction Considerations
• Location: Away from heavy traffic, vibration, and pollution sources.

• Zoning: Separation of clean and contaminated areas.

• Ventilation: Fume hoods, exhaust systems, and cross-ventilation.

• Lighting and Temperature Control: Essential for analytical accuracy.

• Materials: Fire-resistant and chemical-resistant benches and floors.

• Safety installations:

Emergency showers

Eyewash stations

Fire extinguishers

Spill kits

First-aid units

ORGANISATION of EHL
1. General Laboratory: Routine environmental analysis and general microbiology.

2. Environmental Health Biology Laboratory:

Study of microorganisms, vectors, parasites.

Culture, staining, microscopy.

3. Environmental Health Chemistry Laboratory:

Chemical analysis of water, soil, air, food, and toxic substances.

26
 4. Environmental Health Physics Laboratory:

Radiation measurement

Physical environmental parameters (noise, vibration, light, temperature).

5. Arbovirus Laboratory:
Mosquito/arthropod surveillance

Identification and serotyping

Viral detection using PCR or immunoassays.

SAFETY PRECAUTIONS IN THE LABORATORY

Importance of Laboratory Safety:

• Prevent accidents, contamination, chemical exposure, and infection.

• Protect personnel, equipment, and the community.

Laboratory Safety Manuals:

A safety manual outlines:

• General laboratory rules

• Personal protective equipment (PPE)

• Handling, storage, and disposal of chemicals and biological samples

• Emergency procedures

• Fire and electrical safety

• Spillage response procedures

• First-aid guidelines

Personal Safety Rules:

• No eating, drinking, or smoking.

• Wear appropriate PPE: lab coat, gloves, goggles, masks.

• Keep work surfaces clean and disinfected.

• Label all chemicals and samples clearly.

• Avoid pipetting by mouth.

• Proper waste segregation and disposal.

27
Laboratory Instrumentation:

Environmental Health Laboratories use basic and advanced instruments. Key instruments
include:

Biological and Laboratory Essentials:

• Microscopes (light, binocular, digital)

• Autoclaves: Sterilization using steam under pressure.

• Incubators: Controlled temperature for culturing organisms.

• Hot Air Oven: Dry heat sterilization.

• Sterilizers / UV sterilizers
Refrigeration and Temperature Control

• Fridges / Freezers for sample preservation.

• Cryostats for freezing and sectioning specimens.

Analytical Instruments

• Colorimeter – color intensity measurement.

• UV–Visible Spectrophotometer: quantification of substances based on absorbance.

• Atomic Absorption Spectrophotometer (AAS): metal analysis in environmental samples.

• Gas Chromatography (GC): separation of gases and volatile compounds.

• High-Performance Liquid Chromatography (HPLC): separation and analysis of complex

mixtures.

Physical and Environmental Measurement Devices

• Audiometer: noise level assessment.

• Dosimeter: radiation or chemical dose measurement.

• Lasers: precision measurements and optical analysis.

Molecular and Advanced Equipment

• Polymerase Chain Reaction (PCR): For DNA amplification and pathogen identification
(e.g., arboviruses).
• Others: Depending on specialization (turbidimeters, nephelometers, water analyzers).

28
Standard Operating Procedures (SOPs)

Definition

SOPs are step-by-step written instructions describing how laboratory or field tasks should be
performed to ensure consistency, reliability, and safety.

Importance

• Prevents errors and accidents.

• Enhances reproducibility of results.

• Provides training reference for new staff.

• Ensures legal and regulatory compliance.

Types of SOPs

• Field sampling SOPs

• Laboratory analysis SOPs

• Reagent preparation SOPs

• Equipment operation SOPs

• Sample storage and transportation SOPs

PREPARATION OF STANDARD SOLUTIONS AND REAGENTS

Key Concepts

• Molarity (M)

• Normality (N)

• Percentage (%) solutions

Steps in Preparation
1. Identify required concentration.

2. Calculate solute mass or volume.

3. Dissolve solute in distilled water.

4. Transfer to measuring flask and make up to required volume.

5. Label container with concentration, date, and preparer.

29
DOCUMENTATION AND STORAGE OF LABORATORY EQUIPMENT AND
REAGENTS

Documentation Systems

• Equipment logbook

• Maintenance schedule

• Reagent inventory

• Sample logbook
• Calibration records

Storage Requirements
• Flammable cabinets for volatile chemicals

• Dark storage for light-sensitive reagents

• Refrigerators for perishable reagents

• Proper labeling and expiry tracking

Laboratory Assessment and Chemical Hygiene

Laboratory Assessment

• Routine inspection of laboratory conditions

• Equipment functionality

• Waste management compliance

• Biosecurity assessment

• Hazard identification

Chemical Hygiene Plan

Includes:

• Chemical hazard communication

• Labeling and Material Safety Data Sheets (MSDS)

• Safe handling and storage

• Spill response procedures

• Disposal guidelines

30
SAMPLE COLLECTION, PRESERVATION, TRANSPORTATION AND ANALYSIS

Types of Samples

• Water

• Air
• Food

• Soil

• Objects and fomites

• Body fluids (saliva, urine, blood in environmental contexts)

Sample Collection Rules

• Use sterilized containers

• Avoid contamination

• Label with date, time, location, and code

Preservation

• Refrigeration (4°C)

• Freezing (–20°C)

• Chemical preservatives (e.g., nitric acid for metals)

• Immediate analysis for unstable parameters (e.g., chlorine)

Transportation

• Use cold boxes or ice packs

• Maintain chain of custody

• Protect from sunlight and physical damage

Analysis

• Follow SOPs

• Maintain QA/QC

• Record results accurately

APPLICATION OF ENVIRONMENTAL HEALTH LABORATORIES IN FORENSICS

31
Environmental Forensics

EHLs support:

• Crime scene investigations

• Detection of pollutants used in poisoning

• Soil and trace evidence analysis

• Water contamination tracing

• Identification of biological agents

Sample Collection at Crime Scenes

• Avoid contamination

• Use gloves and sterile tools

• Seal samples in tamper-evident bags

• Maintain chain of custody

• Document all procedures

Quality Assurance and Quality Control (QA/QC)

Quality Assurance

Ensures laboratory systems and procedures are adequate to produce reliable results.

Quality Control

Includes:

• Blanks
• Standards

• Duplicates

• Calibration

• Proficiency testing

LABORATORY LOG BOOK, RECORD KEEPING AND REPORTING

Purpose of a Lab Logbook

• Permanent record of analyses

• Traceability of results

32
 • Evidence for legal and regulatory audits

Contents of Records

• Sample details

• Methods used
• Instruments and conditions

• Observations and results

• Analyst signatures

• Properly formatted reports

FIELD TRIPS TO ENVIRONMENTAL FACILITIES

Students are expected to take notes, observe safety requirements, and relate practical
observations to theoretical knowledge.

Field visits provide practical exposure to the operation of environmental systems such as:

• Water treatment plants

• Wastewater treatment plants

• Solid waste management facilities

• Public health laboratories

• Markets and slaughterhouses

• Food industries

• Manufacturing and processing industries

Professional Accreditation of Environmental Health Laboratories

• Accreditation enhances credibility and ensures adherence to international standards.

• Common accreditation frameworks:

ISO/IEC 17025 – Testing and calibration laboratories

National and regional regulatory authorities

Environmental health professional bodies

ROLE OF EHLS IN DISEASE CONTROL

Environmental Health Laboratories help in:

33
 • Early detection of pathogens and vectors

• Monitoring of potable and wastewater systems

• Outbreak investigations (cholera, arboviruses, foodborne diseases)

• Surveillance of antimicrobial resistance in environmental samples

• Environmental sampling during epidemics and pandemics

ACCIDENT AND EMERGENCY MANAGEMENT

Common Laboratory Emergencies

1. Chemical spills

2. Chemical ingestion or swallowing

3. Fire outbreaks

4. Falls and physical injuries

5. Heat exhaustion or fainting

6. Electrical accidents

Emergency Response Procedures

• Activate emergency alarms

• Evacuate personnel when appropriate

• Use spill kits for chemical spills

• Flush skin/eye exposures immediately with running water

• Use fire extinguishers for small fires

• Seek medical help for injuries

• Document all incidents in accident report forms

34