ENVIRONMENTAL CHEMISTRY

Agricultural production is vital to increase our global food needs. However, it increasingly relies on artificial fertilisers, more water use, pesticides, herbicides, fungicides, hormones, disinfection of products for consumers, plastic packaging and transport/fuel consumption.  

Excess chemicals are lost by leaching, runoff and volatilisation into the air, resulting in pollution of air, land and water resources.

Toxins are found in food chains impacting human health and that of other organisms and affecting biodiversity. We need to be aware of this and manage our production and lives more sustainability.

What will studying Environmental Chemistry do for you?

• Give you a sound grounding in the complex interactions of chemicals in all aspects of life
• Help you to differentiate between the different types of chemicals and their potential hazards and demystify chemical jargon
• Provide you with guidelines how to better understand, measure and manage chemicals you may use in your workplace
• Introduce you to more sustainable practices 
  
  

What will studying Environmental chemistry teach you?

• To understand how chemicals (both natural and man-made) occur in all facets of the environment
• Up-to-date and demystified information on what types of inorganic and organic pollutants are out there
• About how the chemicals we use - degrade or persist in the environment
• The importance of correct field sampling and testing of soil, water and air to identify useful and harmful chemicals
• How better management of environmental chemicals can contribute toward improved human health and sustainable ecosystems.
• Green chemistry concepts and applications.

Lesson Structure

There are 8 lessons in this course:

1. Introduction to environmental chemistry
   • Introduction to environmental chemistry, scales, extent
   • Environmental chemistry through time
   • Global warming, greenhouse gases and carbon sequestering
   • Environmental chemistry in global systems
   • Basic chemistry concepts; atoms and their components
   • Charges on atoms and bonds
   • Formation of molecules and compounds
   • Elements and their significance in the environment
   • Organic and inorganic compounds and biochemistry
   • Basic chemical reactions; chemical terms and units
2. Organic, inorganic & biological contaminants in the environment
   • Introduction; ecological concepts in the environment
   • Differences between contaminants, pollutants and hazardous chemicals
   • Pollutants in the environment and why they are detrimental
   • Degradation of pollutants, and persistent pollutants, POPs
   • Types of pollutants and their sources
   • Important organic and inorganic pollutants
   • Pricing measures to help control pollution
   • Contaminants in the world’s natural environments (biomes)
3. Air pollution and treatment
   • Introduction
   • Composition of the atmosphere
   • Vertical structure; troposphere, stratosphere, mesosphere, thermosphere, exosphere
   • Purpose of the atmosphere
   • Movement of air/gases around the earth
   • Air pollution and its sources; anthropogenic causes
   • Effects of air pollution; health effects and Air quality Index
   • Climate change, global warming; aerosols;
   • Ozone depletion;
   • Acid rain
   • Reducing carbon dioxide and other greenhouse gas emissions
4. Water pollution and treatment
   • Introduction; properties of water
   • Hydrological cycles
   • Distribution of water on earth
   • Ocean environments –overview; salinity, density, temperature
   • Coastal environments – overview; continental shelves
   • Estuaries- overview; salinity, tides
   • Continental/inland water environments – overview; uses, salinity range; residence times
   • Water chemistry –important reactions
   • Water categories/classifications in relation to use; blue green, black, grey water
   • Salinity comparison
   • Water and impurities/pollutants
   • Water quality standards; physical, chemical (inorganic and organic, oxygen); biological parameters.
   • Water pollution management
   • Methods of water treatment, sieving,/screening; removal colour, hardness, alkalinity; disinfection; iron removal.
5. Soil pollution and treatment
   • Introduction; extent and causes
   • The nature of soil; soil formation
   • Soil properties; components inorganic and organic
   • Soil colloids and their charges
   • Exchange reactions and CEC
   • Humus
   • Important soil chemical reactions; Buffering and liming, nitrogen cycle
   • Soil chemistry and its important in management
   • Salinity and sodicity; nutrient availability and pH
   • Acidification; acid sulphate soils
   • Soil pollution, sources: mines, agriculture, landfill, nuclear waste
   • Methods of soil remediation; fallowing landspreading, bioremediation, thermal remediation, bioventing, air sparging; encapsulation, oxidation
   • Bioremediation – types.
6. Environmental chemistry and human health
   • Introduction; environmental health as policy
   • Specific health risks; heavy metals, endocrine disruptors, cancer
   • Nuclear waste
   • Environmental health levels – scales global to local
   • Environmental health at national, state, and local levels
   • Air pollution; indoor, outdoor
   • Water pollutants, disease transmission; pesticides, metals, fluoridation debate
   • Soil pollutants and health; radon, hazardous waste, compound bans
   • Food chain and biomagnification
   • Chemicals in households
   • Managing human health
   • Biological controls, pitfalls and positives
   • Creating green areas, public awareness
7. Field sampling and testing
   • Introduction, standards in sampling, transport, testing reporting
   • Sampling designs – different types; random, transect, grid, cluster; grab and composite samples
   • Sampling equipment
   • Air sampling; passive, real time sampling monitors, inhalable and respirable dust; dust gauges
   • Soil sampling; spade, augers, cores manual, automatic
   • Agricultural produce sampling and packing
   • Water sampling; grab continuous samplers, Kemmerer samplers
   • Using the correct sample container; important of materials, bottle size; preservatives, storage and transport temperatures; holding times.
   • Chain of custody forms
   • Chemical analysis in the field; portable meters, probes; colourimetric methods
   • Chemical analysis in the laboratory
   • Overview of commonly used laboratory equipment; meters, auto analysers, spectrophotometers-UV, VIS & IR; discrete analysers; ICP-MS; ICP-OES; GC-MS; HPLC
   • Laboratory report
8. Sustainability and Green Chemistry
   • Introduction to sustainable environmental management
   • Environmental assessment -principles
   • Principles of sustainable environmental management
   • Green chemistry in environmental management -12 principles
   • Green chemistry – future of environmental protection
   • Manufacturing processes
   • Limiting exposure
   • Green fire control
   • Greener batteries
   • Environmental building practices
   • Treating contamination or pollution sustainably
   • Urban planning concerns
   • Green engineering; heating and cooling, energy production, lighting, noise control, building size
   • Sustainable transport; biofuels, electric and hybrid cars
   • Barriers to sustainability and green design

Aims

• Describe the nature, importance and scope of environmental chemistry and advance an understanding of basic chemistry including atoms and their components, elements, compounds and chemical reactions.
  • Outline different types of air pollutants and their causes and describe appropriate responses to contain, reduce. eliminate or otherwise deal with such problems.
  • Distinguish between various water pollutants and discuss appropriate alternative responses to contain, reduce. eliminate or otherwise respond to such problems.
  • Describe soil pollutants and compare appropriate alternative responses to contain, reduce. eliminate or otherwise respond to such problems.
  • Explain a range of ways that better management of environmental chemicals can contribute toward improved human health.
  • Explain different techniques that can be utilised for sampling and testing chemicals in the environment.
  • Explain the two broad goals of green chemistry and describe examples of green chemistry used in homes, vehicles; industry and the environment.

What You Will Do

• Describe a global and local example of the importance of environmental chemistry.
• Learn about basic chemical concepts, atoms, molecules, bonds, reactions and understand the information In the Periodic Table of element.
• Discuss the background to historical environmental disasters and hypothesis how they could have been averted or minimised.
• Make observations about hazardous chemicals sold in retail outlets such as hardware stores, swimming pool or spa-shops, farm supply stalls etc. and categorise their properties
• Research air quality in your area - how is it assessed as fit to breathe or not and who reports this?
• List ways in which air quality can be improved in your home or work place.
• Find out about the nitrogen cycle and how it influences air quality.
• Examine standards use for drinking water quality in your region and investigate some water quality parameters of interest to you.
• Investigate water quality variations (seasonal, annual) in a water body such as a dam, lake , river near you and how this affects the surrounding environment.
• Investigate the way waste degrades and chemical processes in a landfill or tip near you.
• Describe ways in which degraded soils contaminate by persistent chemical pollutants can be improved e.g. by bioremediation.
• Identify government policies and procedures relating to drinking water in your region.
• Contact a laboratory and obtain information about sampling, sample containers, testing times and costs.
• Sample soils and test them using a provided soil pH test kit.
• Evaluate soil nutrient availability in relation to the measured soil pH on your samples.
• Research green technology and how it being applied in industry.

Learn to understand Chemical Degradation in the Environment

When pollutants are released in the environment, they can start to decay, breaking down from large complex molecules to smaller, simpler molecules or atoms. Alternatively, they can persist (not broken down).  
Decay occurs through several processes:

• Chemical -breakdown through chemical reactions such as oxidation, hydrolysis, reduction.
• Biological – breakdown usually by microorganisms such as fungi and bacteria, or within cellular structures in higher organisms. Biodegradation is the disintegration of materials by bacteria, fungi, or other biological means.
  
• Photolysis - breakdown by light energy.
  
•  Physical breakdown – compounds are physically broken down e.g. grinding action of particles in running water.
• Radioactive decay – release of radioactive particles such as alpha, beta and gamma rays.
  
  

The decay process is complex and is affected by the:

• chemical structure of the pollutant e.g. C-F bonds in PCFs are hard to break;
• environmental conditions e.g. the presence of oxygen, solvents such as water, other reactants;
• physical conditions e.g. the temperature (reactions are usually faster in hot conditions); presence of UV light
• the size, amount, availability of the pollutant (e.g. adsorbed on soil or freely dissolved in water);
• diversity, amount and type of organisms degrading or absorbing chemicals
  
  

Oxidation is common chemical mechanism that breaks down pollutants i.e. chemicals react with oxygen (O) or another oxidizing chemical such a ozone (O₃₎, hydrogen peroxide (H₂O₂) etc.
An example of oxidation occurs when methane (CH₄) is burnt – it reacts with oxygen (O₂) to form carbon dioxide and water (see the following reaction):
CH₄ +O₂ ---> CO2+ 2H₂O