MEV 018: Unit 12 – Environmental Monitoring of Toxicants

-

 UNIT 12: ENVIRONMENTAL MONITORING OF TOXICANTS

12.0 Introduction

Toxicants—substances that cause adverse effects on living organisms—can enter the environment through industrial, agricultural, and urban activities. Environmental monitoring is a critical process used to detect, quantify, and track these toxicants in various media such as air, water, soil, and waste. It helps in risk assessment, regulatory compliance, and environmental protection. This unit explores different types of monitoring, sampling methods, and analytical techniques used in environmental toxicant assessment.

12.1 Objectives

After studying this unit, learners will be able to:

  • Understand the purpose and importance of environmental monitoring.
  • Describe the major types of environmental monitoring.
  • Explain monitoring concepts, sampling methods, and analytical techniques.
  • Identify appropriate techniques for air, water, soil, and waste analysis.
  • Appreciate the role of monitoring in pollution control and public health.

12.2 Types of Environmental Monitoring

Environmental monitoring is classified based on the environmental media and type of pollutant. The major categories include:

12.2.1 Air Quality Monitoring

  • Purpose: To assess concentrations of air pollutants like SO₂, NOx, CO, ozone, PM2.5, and volatile organic compounds (VOCs).
  • Techniques:
    • High Volume Samplers
    • Gas analyzers (e.g., UV fluorescence for SO₂)
    • Real-time monitoring stations
  • Importance: Vital for tracking urban air pollution, occupational exposure, and public health risks.

12.2.2 Water Quality Monitoring

  • Purpose: To detect pollutants such as heavy metals, pathogens, nitrates, pesticides, and pH changes in surface water, groundwater, and wastewater.
  • Parameters Monitored:
    • Physical (temperature, turbidity)
    • Chemical (pH, DO, BOD, COD, TDS, heavy metals)
    • Biological (coliform bacteria, algal blooms)
  • Techniques:
    • Spectrophotometry, Atomic Absorption Spectroscopy (AAS), and microbial assays

12.2.3 Waste Monitoring

  • Scope: Covers solid waste (municipal, industrial, biomedical) and liquid effluents.
  • Monitoring Aspects:
    • Composition analysis
    • Leachate quality in landfills
    • Toxic content (e.g., dioxins, PCBs)
  • Tools:
    • TCLP (Toxicity Characteristic Leaching Procedure)
    • Gas chromatography for organic pollutants

12.2.4 Soil Monitoring

  • Purpose: To detect contamination due to industrial discharge, pesticides, fertilizers, and solid waste disposal.
  • Analyzed for:
    • Heavy metals (Pb, Cd, Hg)
    • Hydrocarbons, pesticide residues
    • Soil pH, cation exchange capacity (CEC), nutrient status
  • Techniques:
    • Core sampling, X-ray fluorescence (XRF), ICP-MS

12.3 Monitoring Concept and Design

Environmental monitoring is guided by scientifically sound designs and objectives. Key components include:

  • Goal Definition: Regulatory compliance, pollution trend analysis, impact assessment.
  • Site Selection: Based on emission sources, population density, ecological sensitivity.
  • Temporal Design: Continuous, periodic, or event-based monitoring.
  • Quality Assurance: Standard operating procedures, calibration, control samples.
  • Data Interpretation: Using baseline data, comparison with permissible limits.

12.4 Environmental Sampling

Sampling is a crucial step to ensure accurate results. It involves:

  • Types of Sampling:
    • Grab sampling (single time-point)
    • Composite sampling (multiple time points or locations)
  • Sample Containers: Must be non-reactive, sterile for biological samples, light-proof for light-sensitive substances.
  • Preservation and Transport: Use of cool boxes, preservatives (e.g., nitric acid for metals), labeling, and chain-of-custody documentation.

12.5 Techniques for Monitoring

The techniques used for monitoring depend on the pollutant and environmental matrix. Common methods include:

  • Spectrophotometry: For analyzingcolor-forming reactions (e.g., nitrates, phosphates)
  • Gas Chromatography (GC): For volatile organic compounds (VOCs), pesticides
  • High Performance Liquid Chromatography (HPLC): For non-volatile organics
  • Atomic Absorption Spectroscopy (AAS): For heavy metals like lead, mercury
  • Mass Spectrometry (MS): For high-precision identification of complex molecules
  • Biosensors: Detect specific toxicants using biological molecules (e.g., enzymes)

12.6 Environmental Analysis Techniques

Post-sampling, analysis techniques aim to quantify toxicants precisely:

  • Gravimetric and Volumetric Methods: Basic estimation of solids and ions
  • Chromatographic Techniques: Separation and identification of compounds (GC, HPLC)
  • Electrochemical Methods: pH meters, conductivity meters, ion-selective electrodes
  • Biological Testing: Bioassays for toxicity using algae, daphnia, or fish

Modern advancements also include:

  • Remote Sensing: Satellite-based monitoring of air and water quality
  • IoT-based Monitoring: Real-time sensor networks for pollution hotspots

12.7 Let Us Sum Up

Environmental monitoring of toxicants is essential for safeguarding ecosystems and human health. It includes a wide range of activities such as air, water, soil, and waste quality assessments using physical, chemical, and biological techniques. Accurate sampling, rigorous analytical procedures, and data interpretation play a crucial role in identifying pollution trends and guiding regulatory actions.

12.8 Key Words

  • Toxicants: Harmful substances released into the environment.
  • Environmental Monitoring: Systematic collection of data to assess environmental quality.
  • Air Quality Monitoring: Measuring air pollutant concentrations.
  • Water Quality Parameters: Indicators of chemical and biological water health.
  • Chromatography: Technique to separate and analyze mixtures.
  • Biosensors: Analytical devices using biological components to detect pollutants.
  • Remote Sensing: Monitoring using satellite imagery or aerial technology.

 

Comments

Post a Comment

Popular Posts

Jcert Class 8 Daffodil Chapter 1a: The Naive Friends Solutions

-
Chapter 1a : The Naive Friends Answer the following questions: 1. Which questions made Keshav and Shyama curious about the egg? Ans.         How did the chick come out? How big would the eggs? How many? What colours would they? What did they eat? Such types of questions made Keshav and Shyama curious about the egg. 2. What three things did the children do to protect the eggs? Ans.         The children done three things are: (i)          Adjustment of food. (ii)        Adjustment of water. (iii)      Adjustment of roof. 3. Why did Keshav think of making a cushion for the eggs? Ans.         When Keshav saw the egg on direct sun light, he thaught making a cushion for the eggs. 4. What excuse did Keshav give for not showing the eggs to Shyama? Ans.     ...
Read more

Jcert Class 8 भाषा मंजरी Chapter 3 मित्रता Solutions

-
अध्याय - 3 : मित्रता 1. आप किस प्रकार कह सकते हैं कि मित्रों के चुनाव की उपयुक्तता पर हमारे जीवन की सफलता निर्भर करती है? उ. मित्रों के चुनाव की उपयुक्तता पर हमारे जीवन की सफलता निर्भर करती है क्योंकि संगति का गुप्त प्रभाव हमारे आचरण पर पड़ता है और यदि हमें अच्छी संगति, अच्छे मित्र मिलते हैं तो वे हमें सफलता की ओर ले जाते हैं जबकि बुरी संगति हमारे जीवन को खाक में मिला देती है।  2. 'विश्वासपात्र मित्र जीवन की एक औषध है।' आशय स्पष्ट कीजिए। उ. 'विश्वासपात्र मित्र जीवन की एक औषध है'- ऐसा इसलिए कहा गया है कि यदि हमें विश्वासी मित्र मिल गया तो हम अपने जीवन में चाहे जैसा भी कदम उठाएँ, उस कदम की आलोचना करके वह हमें सही दिशा की ओर उन्मुख करेगा। हम अपनी गलती रूपी बीमारी को उसकी आलोचना रूपी औषधि से दूर कर सकेंगे।  3. मित्र का चुनाव करते समय हमें किन बातों का ध्यान रखना चाहिए? उ. मित्र का चुनाव करते समय हमें निम्नलिखित बातों का ध्यान रखना चाहिए हमारे अच्छे विचारों (संकल्पों) को दृढ़ करने वाला हो। हमें दोषों और त्रुटियों से बचाए। हमारे सत्य, पवित्रता ...
Read more

Jcert Class 8 भाषा मंजरी Chapter 8 अमरूद का पेड Solutions

-
अध्याय - 8 : अमरूद का पेड 1. लेखक को क्यों लगता है कि इन सब पिछड़े खयालातों का हमारे घर में गुजर नहीं हो सकेगा। उ. अमरूद के पेड़ को देखकर सबसे पहले बाबू कन्हैयालाल की बूढ़ी पत्नी ने एक दिन टोका कि पश्चिम की तरफ अगर मकान का मुखड़ा हो और सामने ही अमरूद का पेड़ तो 'राम-राम बड़ा अशुभ होता है और माँ के चेहरे पर थोड़ा-सा भय दिखा पर लेखक को विश्वास था कि इन सब पिछड़े खयालातों का हमारे घर में गुजर नहीं हो सकेगा क्योंकि उसके घर के लोग आधुनिक विचारधारा के थे उसकी माँ सत्याग्रह के दिनों में अजमेर में लम्बा जेल कर चुकी है। पिताजी खुद राजनैतिक सामाजिक उदारता वाले आदमी थे। बुआ ने विवाह नहीं किया था, पढ़ने-लिखने में ही अपनी सम्पूर्ण जिन्दगी लगा दी और समाज कोई चुनौती देने का साहस नहीं कर सका। साथ ही परिवार के सभी लोगों में पिछड़ेपन के प्रति भर्त्सना का भाव था। 2. अमरूद के पेड़ की छाया किस प्रकार लेखक को उनके भाई-बहनों के साथ जोड़ती है ? उ. अमरूद के पेड़ की छाया लेखक को उसके भाई-बहनों के साथ जोड़ती है। वे सभी अमरूद की छाया में बेंत की कुर्सियों पर बैठ चर्चाएँ करते थे जिससे उनके बीच...
Read more