Water Resources

The Hydrologic Cycle

• Water occurs as a solid, liquid and gas

• Amount of water is fixed

• The places where water resides are called Reservoirs

• Water constantly moves from one reservoir to another

The Hydrologic Cycle: Pathways

• Evaporation

• Evapotranspiration

• Condensation

• Precipitation

• Runoff

• Infiltration/Percolation

RESERVOIRSComparison of the amount of water supply held in each of the major reservoirsIf the total earth’s water supply was a 55 gallon drum

Groundwater• What happens to precipitation once it

reaches the ground– infiltration– percolation

• Water filling pore space, cracks & crevices in rocks- Porosity

• Aquifer- Geologic unit that can store, transmit and yield appreciable amounts of water

Porosity and Permeability• Porosity

– % of rock or sediment that is open (void spaces)

– ability to hold water

• Permeability- ability to transmit water

Movement of ground water • Moves in response to differences in water

pressure & elevation

• Velocity influenced by– Slope of water table– Permeability

Groundwater Movement• Darcy’s Law

– Q= KA (h1-h2)/(l)

– Where Q is discharge; A= BxW– K is hydraulic conductivity

– (h1-h2)/(l) is hydraulic gradient

Cone of Depression

After pumping in a well stops, the water level slowly recovers its previous level and the cone of depression disappears

Water Use:Trends in population and freshwater withdrawals

by source, 1950-2000.

Trends in total water withdrawals by water-use category, 1950-2000

Water Pollution

Water Pollution

• Degradation of water quality– Biological– Chemical– Physical– Based on the intended use of the water

• Attainment vs. non-attainment

Clean Water Act Sec.304(a)(1) :•

The Administrator, after consultation with appropriate Federal and State agencies and other interested persons, shall develop and publish, within one year after the date of enactment of this title (and from time to time thereafter revise) criteria for water quality accurately reflecting the latest scientific knowledge

• (A) on the kind and extent of all identifiable effects on health and welfare including, but not limited to, plankton, fish, shellfish, wildlife, plant life, shorelines, beaches, esthetics, and recreation which may be expected from the presence of pollutants in any body of water, including ground water;

• (B) on the concentration and dispersal of pollutants, or their byproducts, through biological, physical, and chemical processes; and

• (C) on the effects of pollutants on biological community diversity, productivity, and stability, including information on the factors affecting rates of eutrophication and rates of organic and inorganic sedimentation for varying types of receiving waters.

Common Sources of Groundwater Pollution/Contamination

• Leaks from storage tanks and pipes• Leaks from waste disposal sites (landfills)• Seepage from septic systems• Accidental spills• Agricultural activities• Intrusion of salt water• Mine spoils and tailings• Irrigation• Injection wells• Acid mine drainage• Runoff- urban, industrial, agricultural

Water Pollutants• Biological Oxygen Demand• Pathogenic Organisms• Nutrients• Oil• Chemicals• Heavy Metals• Radioactive materials• Sediments• Thermal Pollution

Pollution and Environmental Health

World Health Organization(WHO); World Resources Institute(WRI); United States

Environmental Protection Agency (USEPA); United States Geological Survey(USGS);

Botkin & Keller

Contamination, Pollution and Toxicity

• Any material that is above background level in the environment (introduced)

• Any material that is above background level in the environment and that causes a deleterious effect on humans and ecosystems

Units of Measurement

• Depending on whether it is found in water, soil or air

• Reported as percent (%), ppm, ppb, ppt (parts per million, billion or trillion)– 0.01% = 100ppm = mg/kg or mg/L– Milligram (mg) (1/1,000 g)– Microgram (g) (1/1,000,000g)

• Reported as either volume, mass or weight

There are two very distinctquestion sets

• Will a given material harm the environment?

• Will a given material harm us?

Factors Influencing Toxicity

• Additive 2 + 2 = 4

• Synergistic 2 + 2 = 10

• Antagonism 2 +2 = 0

Spectrum of Toxic DoseAgent LD50 (mg/kg)

Ethanol 10,000

NaCl 4,000

Ferrous Sulfate 1,500

DDT 100

Strychnine sulfate 2

Nicotine 1

Tetrodotoxin 0.1

Dioxin (TCDD) 0.001

Botulinus 0.00001

What determines the impactof Exposure?

• Length of, period of, time• Concentration - dose• Recurrence – is contact repeated• Frequency of recurrence – daily/yearly• Life cycle sensitivity differences - infant/adult• Physical condition of victim – robust/sickly• Presence of other hazards - synergism

Point vs. Non-Point Sources

• As authorized by the Clean Water Act, the National Pollutant Discharge Elimination System (NPDES) permit program controls water pollution by regulating point sources that discharge pollutants into waters of the United States

• Point sources are discrete conveyances such as pipes or man-made ditches

• Industrial, municipal, and other facilities must obtain permits if their discharges go directly to surface waters

• In most cases, the NPDES permit program is administered by authorized states

Point vs. Non-Point Sources• Non-point source (NPS) pollution, unlike

pollution from industrial and sewage treatment plants, comes from many diffuse sources

• NPS pollution is caused by rainfall or snowmelt moving over and through the ground

• As the runoff moves, it picks up and carries away natural and human-made pollutants, finally depositing them into lakes, rivers, wetlands, coastal waters, and groundwater

Non-Point Source Pollutants• Excess fertilizers, herbicides, and insecticides

from agricultural lands and residential areas• Oil, grease, and toxic chemicals from urban runoff

and energy production• Sediment from improperly managed construction

sites, crop and forest lands, and eroding streambanks

• Salt from irrigation practices and acid drainage from abandoned mines

• Bacteria and nutrients from livestock, pet wastes, and faulty septic systems

• Atmospheric deposition are also sources of non-point source pollution

Federal Water Legislation• Refuse Act 1899• Federal Water and Pollution Control Act

1956• Fish and Wildlife Coordination Act 1958• National Environmental Policy Act 1969• Water Quality Improvement Act 1970• Federal Water Pollution Control Act

(Clean Water Act) 1972

Water Quality Standards

• Under §303(c) of the Clean Water Act a water quality standard is described as comprising: (1) the designated beneficial uses (aquatic life, wildlife, recreation, fishing, agriculture, water supply, etc.) of a water body and (2) the criteria (numeric and narrative) necessary to protect these uses. States and Tribes are required by CWA §303(c)(2)(B) to adopt criteria for CWA §307(a) toxic pollutants for which EPA has published CWA §304(a) criteria, and/or recommendations and methodology based on the latest science.

Federal Water Legislation

• Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) 1980

• Hazardous and Solid Waste Amendments to the Resource Conservation and Recovery Act (RCRA) 1984

• Water Quality Act 1987• Safe Drinking Water Act 1996

Water Quality Standards

• Maximum Contaminant Level- MCLs– Based on toxicity

– Usually lethal dose (LD50) for some target organism or toxic dose (TD50)

• Maximum Contaminant Level Goal-MCLGs

Primary Drinking Water StandardsContaminant MCL (mg/L) Problems

Arsenic 0.05 Highly toxic

Lead 0.015 Highly toxic

Mercury 0.002 Kidney, Nervous System

Fluoride 4 Skeletal Damage

Asbestos 7 million fibers/L >10m Benign Tumors

Lindane 0.004 Kidney, Nervous System, Liver

2,4D 0.07 Kidney, Nervous System, Liver

Benzene 0.005 Cancer

Trichloroethylene 0.005 Probable Cancer

Vinyl Chloride 0.002 Cancer risk

Fecal Coliform 1 cell/100ml Pathogen

Categories of Pollutants

• Biological- Infectious Agents

• Heavy Metals

• Organic compounds

• Particulates

• Radiation

• Thermal

Biological Hazards• Of all the environmental hazards humans

encounter, the most formidable adversaries remain the microorganisms -- viruses, bacteria, protozoa, and parasitic worms

• Up to 17 million deaths per year are attributable to these infectious and parasitic agents, almost all in the developing world, along with hundreds of millions of cases of illnesses

Why consider infectious diseases "environmental" in

origin?• Cholera and other diarrheal diseases are

associated with inadequate access to clean water and sanitation and poor hygiene

• Diarrhea is spread by both bacteria and viruses through contaminated food or water, and these disease-causing agents represent one of the most widespread health problems in the world

• Diarrhea killed roughly 2.5 million people in 1996, according to World Health Organization, most of whom were children under age 5

Inadequate Water Supplies

• Creates conditions rife for transmitting diarrhea

• An estimated 2.9 billion people lack access to adequate sanitation

• Roughly 1.4 billion people do not have access to safe drinking water

• This situation has persisted despite investments of more than US$100 billion during the International Water and Sanitation Decade

Infectious Agents

• In 1993, the United States experienced the largest outbreak of diarrhea in recent history

• Affecting more than 400,000 people• The municipal water supply of Milwaukee,

Wisconsin, was contaminated by Cryptosporidium parvum from farm animal wastes

• This protozoan parasite has been wreaking havoc in countries across Europe as well, raising new concerns about the safety of drinking water in some of the world's most affluent countries.

Chemical Hazards in the Environment

• Exposure to chemical agents in the environment -- in air, water, food, and soil -- has been implicated in numerous adverse effects, from cancer to lung disease to brain damage to birth defects

• Some evidence is ironclad; some is suggestive at best

Heavy Metals

• Metals with high atomic mass• Arsenic, Cadmium, Chromium, Lead,

Mercury, Nickel, Platinum, Selenium, Silver, Vanadium (others)

• Used in industrial processes and by-products of mining, smelting, fossil fuel burning, etc.

• Can have direct physiological effect or can Concentrate in fatty tissue (bioaccumulation)

Ducktown, TN- Burra Burra Mine

Copper mining and smelting in the Copper Basin of the SE US

Mercury• Mercury has been well known as an environmental

pollutant for several decades • As early as the 1950’s it was established that emissions of

mercury to the environment could have serious effects on human health

• Inorganic mercury (Hg2+) will undergo bacterial activity and be converted to the more toxic methyl mercury ([CH3Hg]+)

• Early studies demonstrated that fish and other wildlife from various ecosystems commonly attain mercury levels of toxicological concern when directly affected by mercury-containing emissions from human-related activities

• Human health concerns arise when fish and wildlife from these ecosystems are consumed by humans (Minamata, Japan)

• In the U.S. widespread mercury contamination in streams, wet-lands, reservoirs, and lakes

• To date, 33 states have issued fish consumption advisories because of mercury contamination

• These continental to global scale occurrences of mercury contamination cannot be linked to individual emissions of mercury, but instead are due to widespread air pollution

• When scientists measure mercury levels in air and surface water, however, the observed levels are extraordinarily low

Why do fish from some remote areas have elevated mercury concentrations, when contamination levels in the environment are so low?

• Mercury biomagnifies from the bottom to the top of the food chain • Even at very low input rates to aquatic ecosystems that are

remote from point sources, biomagnification effects can result in mercury levels of toxicological concern

• The bioaccumulation effect is generally compounded the longer an organism lives, so that larger predatory game fish will likely have the highest mercury levels

• Adding to this problem is the fact that mercury concentrates in the muscle tissue of fish

• Unlike organic contaminants (PCBs and dioxins) which concentrate in the skin and fat, mercury cannot be filleted or cooked out of consumable game fish

Synthetic Organic Chemicals

• Carbon based molecular structure• Often contain reactive chlorine• Manufactured as pesticides, herbicides,

insecticides or as insulator oil (PCB)• 20 million produced and about 100,000

produced commercially• Persistent in the environment• Soluble in fat and accumulate in tissue

Synthetic Organic Chemicals

• "Over increasingly large areas of the United States spring now comes unheralded by the return of birds, and the early mornings are strangely silent where once they were filled with the beauty of bird song.“

• Rachael Carson, Silent Spring 1962

DDT• Dichloro-diphenyltrichloroethane• World Health Organization

credits DDT with reducing disease

• 1945-1960, used to control agricultural pests as well as disease-carrying insects (Malaria)– Venezuela

• 1943 -8,171,115 cases• 1958 –800 cases

– Taiwan• 1945- 1,000,000 cases• 1969- 9 cases

Jones Beach on Long Island, NY

Cancer

• Cancers may take 10 to 40 years to develop, and many factors may contribute to the appearance of the disease in a particular person

• Accordingly, chemical risks tend to be described in terms of the numbers of people exposed -- for instance, 1.4 billion urban dwellers exposed to air quality that exceeds health guidelines, as WHO estimates

Thermal Pollution• Release of heat into atmosphere or water

ways– Acute (i.e. fires from agricultural burning)– Chronic (i.e. hot water releases from electric

power plants)• Change biological and physico-chemical

composition of streams

Toxicity Testing

• Despite widespread public concern over chemical safety, toxicity testing remains inadequate

• For the vast majority of chemicals in widespread use, no toxicity testing results are available in the public record

Hazards• Of the other potential effects of chemical hazards, such as infertility,

birth defects, immune system impairment, or brain damage, even less is known.

• In the United States, for instance, the chief agency for chemical evaluation spent nearly US$29 million on testing chemicals for cancer in 1991, but just about $6 million for both genetic and reproductive effects

• Testing for other health concerns, such as immune system effects or endocrine disruption, lags even further behind

• United States provides an apt example: according to a recent study, 86 percent of chemicals in widespread use have not been tested for immunotoxicity, and 67 percent have not been tested for neurotoxicity

• This focus on cancer means that other important and preventable risks may be overlooked

Remediation of Groundwater

• Extraction Wells– “Pump and Treat” by filtration, oxidation or air

stripping

• Vapor Extraction• Bioremediation

– Injection of nutrients and oxygen to encourage microorganism growth

• Permeable Treatment Beds

CHEMICAL TREATMENT

Other Methods of Remediation

• Natural attenuation. – Natural attenuation defines the natural

occurring processes in the subsurface environment such as dilution, volatilization, biodegradation, adsorption and chemical reactions with subsurface compounds that contain the spread of pollution and reduce the concentration and amount of pollutants at polluted sites.