Water Pollution

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DO THE MATH

Water Quality Indicators

• The measurements that are used to decide if the water quality is in good condition or not.

• Water must meet different requirements for different uses (fishing versus drinking)

– Drinking water must have 0 coliform bacteria colonies, very low turbidity and low nutrient levels

– Water for fishing can have thousands of coliform bacteria colonies and high turbidity, but must have at dissolved oxygen levels of at least 6 ppm to support life.

Temperature

• What is measured – the temperature (oC or oF) of the water body. Should change according to hydrology and season.

• How to measure – use a thermometer

• Desired range – varies depending on location, but should fit the range of tolerance of native species and change seasonally as appropriate to the region

• Impacted by – stream flow and lake depth, thermal pollution from industry or power plants, turbidity level

pH

• What is measured – the concentration of H+ ions. Indicates how acidic or basic the water is.

• How to measure – use a pH probe or litmus paper

• Desired range – most species can survive between 5 and 8

• Impacted by – acid rain, acid mine drainage, buffering capacity, geology of the watershed

• pH = -log[H+]

Nitrate (NO3-)

• What is measured – the concentration (ppm) of nitrate ions. Indicates how nutrient rich the water is.

• How to measure – use a digital probe or a nitrate titration kit

• Desired range – less than 1

ppm

• Impacted by – agricultural runoff, fertilizers, feedlots, sewage treatment plants

Phosphate (PO43-)

• What is measured – the concentration (ppm) of phosphate ions. Indicates how nutrient rich the water is.

• How to measure – use a digital probe or a phosphate test kit

• Desired range – less than 0.1 ppm

• Impacted by – agricultural runoff, fertilizers, detergents

Dissolved Oxygen (DO)

• What is measured – the concentration (ppm or mg/L) of oxygen dissolved in the water. Indicative of the amount of life the water can support.

• How to measure – use a digital probe or a DO test kit

• Desired range – above 6 pmm

• Impacted by – temperature, photosynthesis, nutrient levels, turbidity, organic wastes

Biochemical Oxygen

Demand (BOD5)

• What is measured – the rate of oxygen use. Specifically the amount of oxygen consumed over 5 days. Indicative of the amount of organic matter in the water.

• How to measure – Measure the DO, cover water sample and allow to sit for 5 days. Measure DO again. BOD = DOi-DOf

• Desired range – • pristine rivers <1 mg/L, • polluted river 2mg/L-8 mg/L • sewage effluent <20 mg/L

• Impacted by – respiration, nutrient levels, organic wastes

Fecal Coliform

• What is measured – the number of bacteria colonies present in the sample. Indicates the presence of bacterial pathogens in the water.

• How to measure – place a 1 mL of of water on a agar petri dish. Incubate for 24-48 hours. Count bacteria colonies.

• Desired range – – Drinking water 0/100 mL – swimming <200/100 mL – naturally present in ecosystems

• Impacted by – animal waste, sewage

Turbidity

• What is measured – the amount of light that can pass through water. Indicates the amount of dissolved solids in the water.

• How to measure – Collect a sample and use a turbidity meter, compare to known samples, lower a Secchi disk and record depth at which it can be seen.

• Desired range – Drinking water <1 NTU – Ecosystem < 5 NTU over background

• Impacted by – sediment, flooding, animal waste, sewage, riparian habitat, land disturbances, nutrients

Macroinvertebrates /

Species Diversity

• What is measured – the size, diversity and distribution of organisms in the aquatic habitat

• How to measure –

– Macroinvertebrates – scoop and screen sediment samples to collect organisms. Use keys to identify and count species.

– Species diversity – use sampling techniques to estimate diversity and size of populations

• Desired range – – Want a wide variety of native species – Healthy populations of pollution sensitive species – Low populations of pollutant tolerant species

• Impacted by – all of the previously discussed indicators, but mostly DO

Leeches Pouch Snails

Bad

Good

Tubifex

worms

Midgeflies

larvae

Mayflies Stoneflies

Snipefly

larvae Pond Mussels

Fish Species

Intolerant of Pollution Tolerant of Pollution

Salmon and Trout

Streamline chub

Lamprey

Carp

Creek Chub

Blackstripe Minnow

http://www.epa.gov/bioiweb1/pdf/EPA-260-R-08-016AnIntroductiontoFreshwaterFishesasBiologicalIndicators.pdf

Emerging Contaminants

• http://www.teachersdomain.org/asset/frntc10_vid_water/

• Sources of emerging contaminates – Excess drug concentrations are urinated out and end up in waste

water.

– Improper disposal of medication (i.e. flushing medication down the toilet)

– Excess antibiotics and hormones fed to cattle enter the water cycle via waste lagoons

– Chemicals in everyday products like stabilizers, humectants and fragrances

Types of Water Pollution

Nutrients • Sources - agricultural runoff (fertilizer, feedlots), detergents (P only),

disturbed soil • Effects – Eutrophication nutrients ↑, algae grows, blocks sunlight, dies

and decomposes, O2 ↓ – Dead zones

• Indicators -

– Elevated N and P levels – Decreased DO levels, increased BOD levels – Often observed in conjunction with organic

matter • Reduction - reduce runoff, treat stormwater,

improve farming techniques, use organic fertilizer, avoid detergents with phosphates

Excess nutrients

Lakes – Eutrophication Put in order: a. Decomposers consume lots of

oxygen, reducing DO levels in the lake

b. Fish kills occur c. Algae grows, blocking sunlight d. Plants and other aquatic

producers die due to lack of sunlight and space

e. Algae and other plants die and sink to the bottom of the lake

f. Fertilizer or animal waste runs off into the lake

Ocean – dead zone • http://www.pbslearningmedia.or

g/asset/envh10_vid_deadzone/

Gulf of Mexico Dead Zone

http://www.mnn.com/earth-matters/translating-uncle-sam/stories/what-is-the-gulf-of-mexico-dead-zone

Organic Matter

(also called oxygen demanding waste)

• Sources - agricultural runoff, sewage, paper mills, food processing

• Effects - Organic material must be broken down leading to an increase in biological activity and oxygen demand until waste is broken down.

• Indicators – Slightly elevated N and P levels – Decreased DO levels, increased BOD levels – Possible increase in fecal coliform depending

on source – Increase in turbidity – Loss of sensitive species

• Reduction - reduce runoff, increase riparian habitat, treat sewage, improve farming techniques

Thermal Pollution

• Sources - industry, power plants, reduced water flow, increased sediment

• Effects – increased temperatures reduce the amount of oxygen the water can hold, thus reducing DO levels and causing fish kills

• Indicators – Increased water temperature – Decreased DO – Fish kills

• Reduction - reduce runoff, cool water before

releasing, maintain adequate water flow, maintain healthy riparian zones for shade

Oxygen Sag

Curve

A. Clean Zone – DO high – BOD low

B. Pollution enters stream C. Decomposition Zone

– DECOMPOSITION increases to break down pollution – OXYGEN decreases as it is used up by decomposers

D. Septic zone – dissolved oxygen levels are very low and very few species can survive

E. Recovery Zone – Waste concentrations decrease – DO , BOD

F. Clean Zone • DO is high, BOD is low and normal biodiversity levels are present.

Pathogens

• Sources - human and animal waste (fecal matter) • Effects – diseases in humans and animals: cholera,

typhoid fever, hepatitis, Cryptosporidium, Giardia, E. coli, Guinea worm – Symptoms: nausea, vomiting, diarrhea, dehydration

• Indicators – Presence of fecal coliform bacteria (these are

harmless themselves, but indicate the presence of pathogens)

• Reduction – treat sewage using disinfection, separate drinking and waste water, boil water before drinking, use filters for parasites

• Guinea Worm • Cryptosporidium

Cholera

E. Coli

Rota Virus

Sediment Pollution

• Sources - erosion, runoff from farms, construction, mining, etc

• Effects – clogs waterways, blocks sunlight, may choke fish, increases water temperatures, fish kills

• Indicators – Increased turbidity – Increased temperatures – Possible decrease in DO

• Reduction – protect/replace riparian habitat, minimize erosion, practice soil conservation strategies, maintain wetlands around water bodies

Heavy Metals

• Sources - natural deposits (arsenic, mercury, etc) – mining (all) – coal burning (mercury) – e-waste (cadmium, mercury, lead) – industrial processes like smelting (lead, mercury, arsenic, etc)

• High salinity, low pHs and O2 deficiencies increase metal concentrations in water

• Effects – heavy metals bioaccumulate and biomagnify – Often have the largest impacts at the top of the food chain – Most are toxic at low doses and nuerotoxins

• Indicators - Positive tests for metals • Reduction

– minimize mining and perform effective remediation – burn coal in larger coal plants with advanced air pollution control devices – recycle e-waste – regulate industry and require the use of advanced air pollution control devices

• Arsenic (natural) http://ca.pbslearningmedia.org/res

ource/envh10.sci.life.nathis.arseni

c/in-small-doses-arsenic/

Groundwater Pollution

• Sources - underground storage tanks, older unlined landfills, modern landfill leaks, buried waste, etc

• Effects – aquifer contamination, drinking water contamination, plume movement into surface water

• Indicators – Positive well tests

• Reduction – line landfills and lagoons – bury waste in appropriate hazardous waste

facilities – cleanup superfund and brownfield sites – replace underground storage tanks before

leaks occur.

Groundwater contaminate: MTBE

• Gasoline additive that is a persistent organic compound

• Used to reduce air emissions in places like CA – Adds oxygen to fuel to make it burn cleaner

• As a water pollutant: – Causes odor and taste in water

– Possible carcinogen

– Recommended levels below 40 ppb

• California banned MTBE in 2004 – Large settlement requires gasoline companies to

pay to clean-up wells

Oil Spills

• Sources - 1. natural oil seeps 2. surface runoff 3. transport 4. extraction

• Effects – See case studies • Indicators

– Presence of oil byproducts including benzene, toluene, xylene, napthalene, benzo(a)pyrene

• Reduction – Improve safety standards for extracting and

transporting oil – Perform routine inspections – Require back-up systems and a disaster

management plan in case of unexpected event

– Research oil spill cleanup techniques prior to a spill

Ocean Pollution

• The only substance that is illegal to dump anywhere in the ocean is plastic

• NOAA Ocean Pollution

Acid Rain

• Sources - burning fossil fuels (SOx, NOx), especially coal (SOx) – In the eastern US, most acid rain is caused by SO2 from coal burning – In So. Cal, most acid rain is caused by NOx emissions from cars – NOx + SOX + H2O H2SO4 and HNO3

• Effects – Loss of the most sensitive species first (very young, very old) – Increased leaching of metal from sediment – Loss of biodiversity food web disruption – HNO3 can also cause eutrophication

• Indicators – Normal rain is around 5.5-6.5, acid rain is below 5.5 – Reduced pH in water bodies – Reduced soil pH

• Reduction – Remove SO2 and NOx from emissions before release (install scrubbers

on power plants) – Switching to less polluting alternative fuels – Add lime to aquatic ecosystems to absorb H+ ions (expensive)

Preventing Water Pollution

• Protect wetland and riparian habitat

• Use less chemicals, energy, and manufactured products that contain plastic or metal

• Minimize the use of agricultural chemicals (inorganic fertilizer, pesticide, soil stabilizers, etc)

• Develop effective storm water runoff systems

• Develop and enforce strict safety requirements for oil drilling and transport

• Minimize runoff from all sources

• Treat contaminated water prior to release into the environment (waste water treatment)

Cleaning Up Polluted Water

• Immediately reduce or eliminate pollution discharges into the water body

• Bacteria can be used to clean up organic or oil pollution

• Dredge contaminated soil out of the water body – will temporarily increase water pollution

Waste Water

Treatment Primary Treatment

Type:

Process:

Removes:

Out

Secondary Treatment

Type:

Process:

Removes:

Tertiary Treatment

Type:

Process:

Removes:

IN

Sludge

Contents Treatment Disposal

Water Water

Disinfection Options

• Chlorine – the most common disinfectant – not effective against cryptosporidium – can create dangerous byproducts – must be removed prior to discharge into ecosystems – Residual left in water for residual disinfection (pro/con – depends)

• UV – new technology, very effective, damages DNA – Can catalyze undesirable reactions – Ineffective against adenoviruses – No residual disinfection (for drinking water)

• Ozone – new technology – more expensive – ozone is a regulated air pollutant – No residual disinfection (for drinking water) – Can form unintended byproducts

Problems with Waste Water

Treatment

• Water is often removed from one source and returned to another, this is unsustainable (open loop)

– Better options include pumping the water back into groundwater or sending it directly to the drinking water treatment plant

• Many municipalities only use primary and secondary treatment for residential waste water and may use no treatment for storm water

Water Quality Laws

Clean Water Act

• The Clean Water Act is a 1977 amendment to the Federal Water Pollution Control Act of 1972

– Set the basic structure for regulating discharges of pollutants in the US

– The law gave EPA the authority to set water quality standards for industry and for all contaminants in surface waters

• Designed to protect fishing, swimming and the ecosystem health

Clean Water Act

• Sets up the National Pollutant Discharge Elimination System (NPDES) – Regulates point sources of pollution by requiring a permit to discharge

any pollutant into a navigable waterway.

• Total Maximum Daily Load (TMDL)

– sets daily limits for total pollutant discharges into impaired water bodies (on 303d list)

– Set based on the maximum pollution levels the water body can receive and still meet water quality standards

Safe Drinking Water Act

• The Safe Drinking Water Act (1974) was established to protect the quality of drinking water in the U.S

• This law focuses on all waters actually or potentially designed for drinking use, whether from above ground or underground sources

Safe Drinking Water Act

• The EPA sets Maximum Contaminant Levels (MCLs) for drinking water

• Standards for dozens of contaminants • http://www.epa.gov/safewater/contaminants/index.html#mcls

Pollutant Standard Health Impact

Nitrate 10 mg/L Fertilizers: Blue Baby Syndrome

Lead 0.015 mg/L Lead pipes: Neurotoxin, decreased IQ

Chloramines 4 mg/L Byproduct of chlorine disinfection: eye and nose irritant, stomach discomfort

PCBs 0.0005 mg/L Industrial processes: increased cancer risk, reproductive issues