Transcript Measuring Water Pollution

Measuring Water Pollution
A Quick Overview
How do you measure the
quality of a moving, ever
changing fluid medium?
Two Basic Approaches:

TECHNOLOGYBASED LIMITS: Use
a certain treatment
technology (BPT,
BAT, MACT, BPJ) to
achieve a given
quality of effluent

WATER QUALITYBASED LIMITS:
Quantitative
relationship between
inputs and quality
(LD50, NOEL)-dose/response risk
assessment,
hydrology, mass
balance
The “Conventional” Pollutant
Measures:
Oxygen (BOD, COD, DO)
 Solids content (TSS, Conductivity,
Secchi disk, settleable solids)
 Nutrients (phosphorus, nitrogen)
/Algae/Eutrophication
 Acidity (pH)
 Bacteria (e.g., fecal coliform)
 Temperature

Oxidizing (Oxygen-Using)
Reactions
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Fire
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Metabolism of
humans and animals
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Fate of pollutants in
water
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C in fuel combines
with atmospheric O2
carbon-bearing
organic compounds
oxidized to
CO2,water, energy
pollutants are
oxidized, depleting
O2 in water
Measures of oxygen in water:
Dissolved oxygen (DO)--time and space
variables, dilution
 Biological oxygen demand, five days
(BOD5)
 Chemical oxygen demand (COD)
 Sediment oxygen demand (SOD)
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Oxygen and other pollutants
may vary according to:
Fluctuations in inputs (lagged)
 Time of day (day-night)
 Time of year (summer-winter)
 Water temperature (thermal
stratification)
 Stream flow

– Which in turn varies with land
clearance/impervious cover, storm events,
seasonal variations, channel structure, etc.
Effects of sediment loading
Destruction of spawning beds
 Adsorption and transport of other
pollutants
 Reduced light penetration, aquatic
vegetation
 Greater nutrients loadings, oxygen
demand
 Interference with navigation, flood
control, recreation, industry

Effects of nutrient loadings
(N, P measured by
Chlorophyll a, Secchi, algal
species)
Algae blooms
 DO changes, fish kills
 Shift of trophic status toward eutrophic
 Drinking water impairment (direct and
indirect)
 Aesthetics (color, clarity, smell)
 Uptake and release of toxics

Effects of acidification
(measured in pH--log scale)
Direct kill of living things
 Shift toward acid-tolerant species
 Mobilization (dilution, desorption) of
metals and other toxics

What about toxics?
Impacts of toxics
Acute mortality (instant death)
 Chronic illnesses (e.g., cancer)
 Reproductive and developmental
toxicity (“hormone mimics”)
 Persistence over space (toxaphene) and
time (PCBs); or transformation (DDT to
DDE, PCB dechlorination, methyl
mercury)
 Storage in reservoirs (sediment sinks)
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Some approaches to
toxics parameters
Chemical levels (water, sediment)
 Ability to support designated uses
 Ability to support beneficial uses
 Fish advisories
 Historical baselines
 Background levels
 “Narrative criteria” (no toxics in toxic
amounts)
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Indices
Bring diverse measurements
together into a single-number
value
Ecosystem approaches
Look at interactions of living and
nonliving parts of the ecosystem
(what’s an ecosystem?)
 Try to identify stresses and responses
 Holistically integrate physical, biological,
and social aspects of the area in
question

“Social Indicators”
Stewardship
 Sustainability
 Stakeholder Involvement
 Etc., etc. (what is the good society?)
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