Environmental monitoring

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Environmental monitoring

• Dr. William Stafford
• wstafford_at_uwc.ac.za

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Human health..
Is tightly linked to the Health of the
environment
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Pollution

• Pollution is the introduction into the
  environment of substances or energy liable to
  cause hazards to human health, harm to living
  resources and ecological damage, or interference
  with legitimate uses of the environment.
• The changes that are occurring in the environment
  caused by either natural processes or human
  activities, involve many large parameters and
  range from a slow increase in global temperature
  over years to the rapid accumulation of heavy
  metals and xenobiotics.
• Some of the changes may require careful
  monitoring over long time periods. Some of the
  elements and compounds that accumulate in the
  environment are present in concentrations so low
  that they are close to the limits of detection.

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Causes?

• The first major human influence on the
  environment was perhaps agriculture, and later
  the industrial revolution
• Many countries have a legacy of pollution and
  polluted sites.

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Sources

• The main groups of environmental pollutants which
  can contaminate land, water, and air are
• Inorganic compounds such as metals
• Organic compounds such as sewage, petrochemicals
• Synthetic xenobiotic compounds such as phenol
• Micro-organisms such as pathogens and genetically
  engineered organisms (GMOs).
• The environmental pollutants can originate from
  contaminated sites of defunct industries such as
  gasworks, from existing domestic and industrial
  sources such as sewage and metals from industries
  like electroplating, from accidents, and illegal
  dumping.

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What are dangerous levels?

• The permissible levels and type of environmental
  contaminant are regulated by environmental
  legislation.
• National laws are normally associated with a
  number of acts covering many types of pollutants,
  industries, and conditions (McEldowney and
  McEldowney, 1996).

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Air pollution from coal oil

• Use of coal by South Africa's industrial sector
  is the primary source of the country's air
  pollution- 90 of South Africa's electricity is
  generated from the combustion of coal, which
  contains approximately 1.2 sulfur and up to 45
  ash. Coal combustion can lead to particulate
  matter in the air, as well as contribute to acid
  rain. Despite harmful environmental effects,
  coal-fired power stations are not required to use
  coal scrubbers to remove sulfur, as use of
  clean-coal technology would significantly raise
  the cost of electricity for consumers.
• Vehicular emissions also contribute to air
  pollution in urban centers. The effects of
  pollution caused by use of leaded gasoline use of
  older vehicles and lack of emissions control
  technology has been compounded by the historical
  absence of vehicle emissions legislation.
• South Africa's four oil refineries are another
  major contributor to energy-related air
  pollution. The refineries, located in the
  northern suburbs of Cape Town and in the
  southeastern coastal city of Durban, emit high
  levels of sulfur dioxide and several other
  chemicals known to cause health problems.
  According to UNICEF, in 2000, respiratory
  infections from air pollution were the
  fourth-largest cause of death in children under
  five in South Africa (more than 6,000 deaths per
  year).

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Air pollution-legal status

• Though most townships have high levels of air
  pollution, South Africa has long lacked legally
  binding air pollution regulations on a national
  level, with only non-binding guidelines and no
  enforcement authority.
• In order to address this problem, in April 2003,
  the Department of Environmental Affairs and
  Tourism proposed draft legislation for new
  ambient air quality standards for industries. The
  National Air Quality Management Bill, which
  replaces the outdated 1965 Atmospheric Pollution
  Prevention Act (APPA), aims to control air
  pollution, emission of greenhouse gases, and
  ozone-depleting pollutants by setting permissible
  concentrations of several polluting substances as
  well as total emissions levels.
• Atmospheric emission licenses will be used to
  regulate firm-level emissions. This proposed
  legislation aims to make polluters accountable by
  applying the "polluter-pays" principle,

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Discharge into seas

• Pipelines Over 60 licensed pipelines discharge
  effluent along the South African coast one third
  discharge domestic sewage - about 66 million
  litres per day (66ML/d), half discharge
  industrial wastes and the remainder discharge
  mixed effluent. These pipelines operate via
  exemption permits' administered by the
  Department of Water Affairs, and both the
  effluent and environmental effects are monitored
  and controlled.
• South Africa is especially vulnerable to oil
  spills due to the high volume of oil transported
  around the country's coasts by ships en route
  from the Middle East to Europe and the Americas.
  In June 2000, a tanker sank off of the coast of
  Cape Town, rupturing two fuel tanks. The spill
  threatened the South African penguin population
  and damaged tourist areas including the World
  Heritage site of Robben Island.
• Lastly, small waste coal dumps and other
  hazardous waste from energy-related industries
  cause both pollution and safety problems. Waste
  coal may spontaneously ignite, while runoff from
  mining can contaminate groundwater.

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The fate of pollutants
in the environment depends on the properties of
the compound and the environmental conditions.
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Monitoring

• Monitoring must take into consideration the type
  or types of contaminants present (biological and
  chemical), their availability and the possibility
  of biomagnification and bioaccumulation.
• The environmental monitoring must be able to
  detect with accuracy and consistency pollutants
  present at very low levels.
• A range of chemical analyses is used to determine
  the concentrations and type of pollutants- HPLC,
  GC, NMR, MS ,IR etc..
• This does not determine the real effect on the
  environment as the effects can be modified by
  availability, degradation, and transport of the
  pollutants. An alternative is to use a
  biological system to measure the pollutant..

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Bioindicators, Biomarkers, Test organisms

• The effects of pollutants on whole organisms
  representative of the environment, known as
  bioindicators.
• The effects of pollutants on physiological,
  biochemical, and molecular characteristics of
  organisms in the environment, known as
  biomarkers.
• The effect of the pollutant on test organisms in
  the laboratory.
• Bioindicators and biomarkers have the advantage
  that they measure the action of the pollutants in
  the real and complex environment where there may
  be many and complex interactions at sublethal
  levels.

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BIOINDICATORS

• Bioindicator organisms are those that can be used
  to identify and quantify the effects of
  pollutants on the environment.
• Lichens are a symbiotic relationship between an
  alga and fungus and are particularly sensitive to
  air pollutants and have been used widely used as
  bioindicators of air quality (Conti and
  Cecchetti, 2001)
• Honey bees have been used as a bioindicator for
  the contamination of the atmosphere by heavy
  metals (cadmium, chromium, and lead).
• The filter-feeding mussels are known to
  accumulate heavy metals, making them ideal for
  the monitoring of coastal waters eg.
  Mediterranean mussel Myttlus galloprovincialis
  (Regioli and Principato, 1995).
• Frogs, fish eggs as a measure of water quality

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BIOMARKERS

• Biomarkers can be defined as quantitative
  measures of changes in the biological system in
  response to pollutant exposure.
• Biomarkers can be placed into three groups
  biochemical, immunochemical, and genetic.

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Biochemical biomarkers

• Based on the ability of the pollutant to generate
  a response at the gene level, inducing or
  increasing specific enzymes involved with
  detoxification of contaminants.
• The detoxification of xenobiotics often involves
  one of three detoxification strategies
• cytochrome P450,
• conjugation with glutathione and
• chelation by proteins (Metallothioneines).

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s
EROD, ethoxyresorufin-o-dethylase. AHH, aryl
hydrocarbon hydroxylase. GSH, glutathione.polyaro
matic hydrocarbon.
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Immunochemical biomarkers

• The specific reaction between antigens and
  antibodies can be used to determine the presence
  of xenobiotics in environmental samples.
• Antibodies against PCBs (polychlorinated
  biphenyls), PCDDs (polychlorinated
  dibenzo-p-dioxins), and PCDFs (polychlorinated
  dibenzofurans) have been developed and used in an
  ELISA system to determine PCBs in samples (Hahn,
  2002).

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Genetic biomarkers

• Ames test
• The Ames test was developed to test substances
  for their ability to produce mutations in
  bacteria. The test consists of the treatment of a
  Salmonella typhimurium histidine auxotroph
  (His-). The test compound is added to the
  Salmonella typhimurium His- in an extract of rat
  liver.
• If the compound is a mutagen then mutations will
  cause revertants- colonies will form on a medium
  lacking histidine. The number of colonies will
  give a measure of the mutagenic potential.

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Molecular biology biomarkers

• Another development using genetic manipulation of
  biological material for the estimation of
  toxicity has been the generation of a transgenic
  strain of the nematode Caenorhabditis elegans .
• The lacZ gene from E. coli is fused to the hsp16
  gene.
• When the nematode is stressed the enzyme is
  induced in the worm. The enzyme can be detected
  by the addition of a substrate such as
  o-nitrophenyl-p-galactopyranoside (ONPG), which
  will produce a blue colour when cleaved by the
  enzyme.

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BIOSENSORS

• A biosensor can be defined as a device that
  incorporates a biological sensing element in
  close proximity or integrated with a signal
  transducer in order to quantify a compound or
  conditions.
• Thus the biosensor can give an online, continuous
  determination of the compound present. The
  biological material carrying out the reaction can
  be enzymes, antibodies, hormone receptors,
  proteins, organelles, lectins, DNA, and whole
  cells.
• To function correctly the biological material has
  to be kept in close contact with the transducer
  and this is often achieved by immobilizing the
  biological material.

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Biosensors for environmental monitoring

• The oxygen demand of wastewaters and effluents
  has been determined traditionally by measuring
  the BOD5 value -5 days are required to obtain a
  result. With a BOD biosensor a fast, online
  determination is possible.
• BOD biosensors can be either of the biofilm or
  respirometer type. In a biofilm BOD biosensor a
  microbial film is sandwiched between a porous
  membrane and the oxygen permeable membrane of a
  Clark oxygen electrode- A change in oxygen levels
  in the microbial culture will be proportional to
  the metabolizable content of the material to be
  measured.
• In some cases the electrical signal from the
  oxygen electrode has been replaced by optical
  signals using the luminous bacterium Vibrio
  phosphoreum.

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Pesticide biosensors

• Biosensors that can measure pesticide
  concentrations have been developed using the
  enzyme acetylcholinesterase combined with choline
  oxidase.
• Acetylcholinesterase converts acetylcholine to
  choline and choline oxidase converts the choline
  to betain and hydrogen peroxide.
• The H2O2 can be measured with an oxygen
  electrode. Pesticides inhibit the action of
  acetylcholinesterase and therefore produce a
  reduction in peroxide formation.

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Other biosensors

• The oxidation of phenols to catechols and
  quinones by the enzyme tyrosinase requires
  oxygen. If the enzyme tryosinase is linked to an
  oxygen electrode levels down to about 50 parts
  per billion (ppb) could be detected.
• Metals such as lead and cadmium can be detected
  by their inactivation of oxidases and
  dehydrogenases linked again to an oxygen
  electrode.
• Thus biosensors can provide cheap, reliable, and
  accurate monitoring of the environment which will
  also give real-time analysis.

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• Biotechnology will influence the monitoring of
  the environment in the following areas.
• Microbial diversity. The culture-independent
  study of microbial populations in situ.
• Biomarkers using microorganisms with the
  fluorescent protein (gfp) gene inserted will be
  used to monitor pollution in situ.
• Molecular biology techniques to follow the
  introduction of genetically modified
  micro-organisms released into the environment.
• Biosensors will be able to determine the levels
  of contaminants in the environment and perhaps
  provide real-time online monitoring.