Major Determinants of Water Quality and the Impact or Availability of Water Pollutants Organisms Solubility Oxygen pH Nutrients (N, P) Metals (Hg, Pb, As) Organic Chemicals (PCBs, Dioxins)

Nutrients: Nitrogen and Phosphorus

Both are limiting to primary productivity Excess amounts can severely alter ecosystems Sources: fertilizers, manures, wastewater discharge Availability in the environment is controlled by Oxygen pH Organisms

Nitrogen

Dominant Forms: NH 4 + and NO 3 Forms are controlled by organisms NH 4 + is converted to NO 3 by aerobic bacteria NO 3 is much more mobile in the environment than NH 4 + Forms are controlled by Organisms Oxygen pH

Surface Water and Nitrates

the highest density of point sources in the entire St. Johns River. Within this area, the river receives about 30 percent of its total amount of nitrate and ammonia nitrogen and 33 percent of its phosphate

Large, prolonged high tides can cause water to reverse its flow in the river as far upstream as Lake George. This delays the dispersal of pollutants.

The roughly 30,000 acres of row crop agriculture in this area of the river basin supplies 40 percent of the spring season inorganic nutrients that enter the river between Palatka and Green Cove Springs . Algae typically peak in this area.

Wastewater Treatment Agriculture As the lower St. Johns River widens downstream of Palatka, the speed of water flow decreases, making the river lake-like and making conditions favorable contaminant accumulation.

St. Johns

Slow Flow of contaminants

Lower Suwannee River Watershed • • • • residential and commercial septic systems in rural areas about

300 row crop

and vegetable farms

44 dairies

with more than 25,000 animals

150 poultry operations

with more than 38 million birds Nitrates NO 3 Drinking water standard: 10 ppm

Phosphorus Availability and pH Low pH High pH

Aluminum and Iron phosphates Calcium Phosphates Insoluble solids There is a limited ability of soils to immobilize phosphorus If the capacity is exceeded, phosphorus becomes mobile Mobile phosphorus can contaminate surface and groundwater

Phosphorus loading to S. Florida Ecosystem Kissimmee Basin Dairy/Beef Inputs North and South of Okeechobee Agriculture (EAA)

Everglades Agricultural Area Organic soils possessing high natural fertility Historically flooded

Water restricts the movement of oxygen The diffusion of oxygen through water is about 1000 times slower than diffusion through air Flooded Marsh Under flooded conditions, oxygen levels tend to be low Anaerobic heterotrophs: live in low-oxygen environments

Aquatic Plants and Algae Die Heterotrophic microorganisms decompose tissues Aerobic heterotrophic organisms use oxygen Oxygen becomes depleted in water; it cannot diffuse fast enough to support aerobic heterotrophs Anaerobic heterotrophs become dominant

e Anaerobic respiration is less efficient and produces less energy.

C 6 H 12 O 6 + 6 O 2 → 6CO 2 + 6H 2 O 2880 kJ

C 6 H 12 O 6 + 3 NO 3 + 3H 2 O = 6HCO 3 + 3NH 4 + C 6 H 12 O 6 + 3 SO 4 2 + 3H + = 6HCO 3 + 3HS -

1796 kJ 453 kJ Therefore, anaerobic decomposition is much slower than aerobic decomposition.

Buildup of Organic soils

Organic matter decomposes slowly when submerged in water. (anaerobic decomposition) Soils throughout the glades historically have been submerged. (anaerobic conditions) Led to vast amounts of organic matter accumulation, sometimes >20 ft. thick.

Organic matter continues to accumulate as long as flooded conditions persist.

Drainage Drainage exposes soils to oxygen and decomposition by aerobic heterotrophic organisms which can more efficiently decompose organic matter

EAA

Subsidence of Organic soils

Greater than 10 feet

1912 to 2000

Chemical Pollutants

Heavy Metals and Metalloids

Arsenic

Erosion of natural deposits; pesticide waste, runoff from glass & electronics production wastes, treated lumber, groundwater

Mercury

Erosion of natural deposits; discharge from refineries and factories; runoff from landfills,

coal burning

Lead Corrosion of household plumbing systems; natural deposits, paint, fuels, electronics

Mercury, Arsenic, and Lead

Lead found in blood sample from 1 of 10 Washingtonians Arsenic found in urine samples from 4 of 10 Washingtonians Mercury found in hair samples from 10 of 10 Washingtonians

Lead Mercury Arsenic Common Health Effects

behavioral problems high blood pressure, anemia kidney damage memory and learning difficulties miscarriage, decreased sperm production

reduced IQ

blindness and deafness brain damage digestive problems kidney damage lack of coordination

cognitive degeneration

breathing problems death if exposed to high levels

decreased intelligence

known human carcinogen: lung and skin cancer nausea, diarrhea, vomiting peripheral nervous system problems

Wonderland

Mercury Nitrate Symptoms included tremors, emotional instability, insomnia, dementia and hallucinations

Lead (Plumbum)

Father of all metals -lead pipes -lead acetate

sugar of lead

sweetener for wine Possible cause of the dementia which affected Roman Emperors and Citizens.

Contemporary Sources: Paint, ceramics, glass, soils, pipes, Solder, brass faucets, gasoline

Natural Soil and Water Contaminants

India 21 million backyard tube wells Failure of 246 surface irrigation projects $600 electric pumps (1% of GDP) 95 % water table falling by 20 feet per year What do you do when your water table falls?

Deeper Wells and Fluoride

Naturally occurring element in Granite which dissolves into the groundwater Water near the surface is generally unaffected Lowering water tables = deeper wells Deep groundwater can contain high fluoride levels Fluoride in water can be a cumulative poison

Intentional Fluoridation of Water in the U.S.

Fluoridation became an official policy of the U.S. Public Health Service in 1951.

By 1960 water fluoridation had become widely used in the U.S. reaching about 50 million people. By 2006, 69.2% of the U.S. population on public water systems were receiving fluoridated water.

How does it work?

Tooth enamel is made of a mineral called hydroxyapatite

Ca

5

(PO

4

)

3

OH

Bacteria in the mouth create acids (H + ) Hydroxyapatite is subject to dissolution by acids (H + ) Fluoridation changes the chemical composition of hydroxyapatite to a crystal less subject to acid dissolution

Sodium fluorosilicate (Na 2 SiF 6 ) Sodium fluoride (NaF) NaF Na + + F Ingestion of fluoridated water increases the F concentration in saliva F replaces OH in hydroxyapatite making fluoroapatite

F

-

Ca

5

(PO

4

)

3

OH

Fluoroapatite is less soluble in acid than hydroxyapatite

Fluoride concentrations In U.S. tap water 0.5 – 1.1 mg/L Lower values in warm climates

Dental Fluorosis Fluoride levels > 1.5 mg/L Intake: 1.6 to 6.6 mg/day

Colorado Brown Stain

Permissible fluoride limit in India is 1.2 mg/L Fluoride levels between 5-25 mg/L have been found

Skeletal Fluorosis Fluoride levels > 10 mg/L Intake 9 mg/day to 12 mg/day

Fluorosis has risen from 1 million to 25 million and threatens 60 million people in India.

Soil, Groundwater, and Arsenic

Arsenic is Naturally Occurring occurs primarily in association with sulfur-containing minerals Natural waters, in general, contain low levels of total arsenic Mobilization of arsenic in the environment arises from anthropogenic activities related to mining and ore processing, metallurgy, agriculture, wood preservation, and industry.

Inorganic Forms of Arsenic

AsO 3 -3 Arsenite

Low Oxygen

AsO 4 -3 Arsenate

High Oxygen

Arsenite is more toxic than arsenate, interfering with enzyme activities which catalyze metabolic reactions Arsenite compounds are also more mobile in the environment due to higher solubility compared to arsenate compounds

Both arsenate and arsenite are chronic accumulative toxins

“The World’s Largest Mass Poisoning”

Bangladesh and W. India ranked among the world's 10 poorest countries

Floodplain and Delta of the Ganges and Brahmaputra Rivers.

Floodplain: area paralleling a river that is periodically inundated Deltas are formed from the deposition of sediment carried by the river as the flow leaves the mouth of the river Accumulation of thick muds in the floodplains and deltas Himalayas Ganges-Brahmaputra Delta

Bangladesh Prior to 1970s One of the highest infant mortality rates in the world Principally due to waterborne disease.

Ineffective water and sewage systems Periodic monsoons and floods water-borne pathogens cholera, dysentery Deaths Due to Surface water contamination: 250,000/yr

Deaths Due to Surface water contamination: 250,000/yr The Solution: Tap groundwater resources • easy • inexpensive First 1 million wells were sunk with aid from World Governments UNICEF World Bank

12 million hand-operated tube wells deliver water to over 80% of the rural village population Infant mortality and diarrheal illness reduced by 50%

Wells in Floodplain and Delta Sediments Natural erosion of

arsenic

to water bearing units.

Well depths between 20m and 100 m Water Bearing Muds

WHO/U.S limit: 10 ppb Bangladesh limit: 50 ppb Majority of wells > 50 ppb arsenic Some wells contain 500 - 1000 ppb

Exposure Estimates Above 10 ppb: Above 50 ppb: 57 million people 35 million people Accumulative Toxin

Early Symptoms:

Skin lesions and thickening Strong skin pigmentation

Long-term Exposure

breathing problems death if exposed to high levels lung and skin cancer peripheral nervous system

2003 Studies

83 million people

Bihar: 40% wells contaminated

Red River Delta 11 million people First wells sunk 7 years ago

Mercury Got Fish?

Mercury Advisories 70% of states Where does it come from?

Enters water bodies principally from the atmosphere

Mercury is naturally occurring

(coal, volcanism, rock weathering)

The number 1 anthropogenic source is the combustion of coal 48 tons of elemental mercury to the atmosphere each year.

Mercury The drinking water standard for Mercury is 0.002 mg/L.

blindness, deafness brain damage digestive problems kidney damage lack of coordination cognitive degeneration 1 gram annually Electrical products such as dry-cell batteries,

fluorescent light bulbs

, switches, and other control equipment account for 50% of mercury used.

Fluorescent Lights A typical fluorescent lamp is composed of a phosphor-coated glass tube with electrodes located at either end. The tube contains a small amount of mercury vapor. When a voltage is applied, the electrodes energize the mercury vapor, causing it to emit ultraviolet (UV) energy. The phosphor coating absorbs the UV energy, causing the phosphor to fluoresce and emit visible light. Phosphor Hg gas UV Coating Voltage

Recycling and Handling Each year, an estimated 600 million fluorescent lamps are disposed of in US landfills amounting to 30,000 pounds of mercury waste.

Forms of Mercury

The dominant inorganic forms are Hg o Hg 2+ often occurs as HgCl 2 and Hg in many aqueous environments.

2+ (mercuric chloride) .

Hg 2+ (inorganic) interacts with soil and sediment particles (- charge) becoming part of lake bottom sediments (limits availability)

Interaction with Sediment Particles -

charge

Small organic and Inorganic particles

-

charge

Hg 2+ Hg 2+ Hg 2+

-

charge

Mercury Bound to Sediments Mercury, however, can undergo chemical

Hg 2+

more environmentally dangerous

Hg 2+

sediments Negatively charged particles bind mercury And retain it in bottom sediments.

-

charge

Mercury Methylation

Mercury can be converted to more toxic forms in bottom sediments under anaerobic conditions

Mercury Methylation Methylation: conversion of inorganic forms of mercury, Hg 2+ , to an organic form: methyl mercury under anaerobic conditions Hg 2+

(CH 3 Hg + )

methylmercury Methylmercury is strongly accumulated in the body and is generally more toxic than inorganic Hg

Mercury Methylation

• • • •

Requires 4 elements: anaerobic conditions a carbon source (organic sediments) a source of sulfur (SO 4 sulfur reducing bacteria )

Occurs primarily in bottom sediments as a byproduct of the life processes of anaerobic sulfate-reducing bacteria (SO 4 HS-) that live in high sulfur, low oxygen environments.

to Sulfate Respiration C 6 H 12 O 6 + 3 SO 4 2 + 3H + = 6HCO 3 + 3HS When sulfur accepts electrons it is said to be “reduced”.

Desulfuromonas

,

Pseudomonas

The exact role of sulfate-reducing bacteria In mercury methylation is poorly understood However, bacterial sulfate respiration requires sulfate. The addition of sulfate to water stimulates the metabolic activity of sulfate reducing bacteria and the inadvertent methylation of inorganic mercury Sulfate concentrations in EAA runoff and Lake Okeechobee average more than 50 times background concentrations than in the pristine Everglades Sulfate

Hg 2+ from coal, volcanism, rock weathering, point sources Water Sediments (Bound) Sulfur reducing bacteria, low O 2 methylmercury Aquatic Organisms

Enhanced Risk Methylmercury attaches to proteins in animals (enters food chain) Methylmercury has a half-life in human blood of about 70 days (almost twice as long as inorganic mercury (Hg 2+ ). Methylmercury is strongly accumulated in the body and is generally more toxic than inorganic Hg Bioaccumulation: concentration of a chemical in organisms relative to the amount in water.

Biomagnification: concentration of a chemical in organisms as it moves up the food chain.

Bio-magnification

Bioconcentration and Biomagnification BAF = Chemical Concentration in organism Chemical Concentration in water

Methylmercury

is rapidly taken up but only slowly eliminated from the body by fish and other aquatic organisms, so each step up in the food chain (bio)magnifies the concentration from the step below.

Bioaccumulation factors

(BAF's) of up to

10 million in largemouth bass

have been reported for the Everglades.

Fish-eating birds, otters, alligators, raccoons and panthers can have even higher bioaccumulation factors. Methylmercury in the organs and tissues causes birth defects & disorders of the brain, reproductive system, immune system, kidney, and liver at extremely low levels in food.

Minamata Bay Chisso Corporation, a company located in Kumamoto Japan, dumped an estimated 27 tons of mercury compounds into Minamata Bay Between 1932 and 1968. 1963 plastics, drugs, and perfumes acetaldehyde As of March 2001, 2,265 victims had been officially recognized (1,784 died) and over 10,000 had received compensation from Chisso

Assessing Your Risk http://www.edf.org/page.cfm?tagID=17694 http://www.mercuryfacts.org/fSafeFish.cfm

Nearly all fish and shellfish contain traces of methylmercury.

However, larger fish that have lived longer have the highest levels of methylmercury because they've had more time to accumulate it. These large fish (swordfish, shark, king mackerel and Albacore tuna) pose the greatest risk. Some of the most commonly eaten that are low in mercury are shrimp, canned light tuna, salmon, pollock, and scallops. Fish sticks and "fast-food" are commonly made from fish that are low in mercury.

Next: Other Bioaccumulative Toxins