air, water and land pollution chapter 1: introduction copyright © 2009 by dbs

Air, Water and Land Pollution

Chapter 1:Introduction

Contents

• What is Pollution Science• The Chemicals of Interest• Units of Concentration• Sources

IntroductionWhat is Pollution Science?

Two key components to the definition of pollution:

1. Pollution involves a change to an environmente.g. addition of man-made chemicals that do not occur naturally*

2. The environment must be perturbed in a harmful way

* This is not to say that naturally occurring chemicals are always good! They may be present at levels over and above what is healthy (criteria 2)

Not all pollutants are chemicals!

What are some other examples?

Here is a hint!

This 1988 thermal image of the Hudson River highlights temperature changes caused by discharge of 2.5 billion gallons of water each day from the Indian Point power plant. The plant sits in the upper right of the photo — hot water in the discharge canal is visible in yellow and red, spreading and cooling across the entire width of the river.

Two additional outflows from the Lovett coal-fired power plant are also clearly visible against the natural temperature of the water, in green and blue.

• Aquatic Life

– Decreased ability of water to hold oxygen

– Increased rate of chemical reactions

– Changes in reproduction, behavior and growth throughout the food chain

– Long-term damage to natural waters

• Temperature is one of the most important factors governing the occurrence and behavior of life

Ecological Effects of Thermal Pollution

Ecological Effects of Thermal Pollution• One famous case is that of Sockeye Salmon - Columbia River

• A series of hydroelectric dams changed it from cool/fast-flowing to warmer/slower moving lakes

• Bacterial diseases drastically reduced the population

• Listed as US endangered species

Total commercial landings of chinook and sockeye salmon in the Columbia River, 1866-1990(from NPPC 1986, ODFW and WDF, 1991)

Environmental Compartments

• Can be subdivided further

• May have interactions between compartments

• Contaminants may behave very differently in each compartment e.g. have different lifetimes (residence times), exchange rates and mobility

• When the flow of a substance into a system is equal to the outflow then the amount of substance will be constant – equilibrium or steady-state

• Average amount of time a substance exists before it is removed is defined as follows:

Residence time (τ) = amount of substance in the ‘reservoir’ (M)

rate of inflow to, or outflow from, reservoir (F)

• Must be distinguished from half-life, residence time is the time taken for the substance to fall to 1/e (~37%) of the initial concentration

• Important for determining whether a substance is widely distributed in the environment c.f. CFC’s and acidic gases

Question

A college has a constant undergraduate enrollment of 5,000 students. No students flunk out or transfer in from other colleges and so the residence time of each student is four years. How many students graduate each year?

Residence time = amount of substance in the ‘reservoir’rate of inflow to, or outflow from, reservoir

4 yrs = 5,000 / rate of outflow

Rate of outflow = graduation rate = 5,000 /4 = 1250 students / yr

In this problem all students have the same residence time. In the case of pollutants residence time is an average of all the molecules and each individual molecule has different residence times

Residence time: For a 1st order reaction:

C = C0e-kt

When t = τ = 1/k

C = C0e-1 = 1 x C0 (where e = 2.718..)

C = 0.37 C0

• Half-life: Time taken for the concentration in the reservoir to fall by 50%

• When C = C0/2

C = C0e-kt

C0/2 = C0e-kt

e-kt = ½

τ1/2 = ln 2 k

• Monitoring:– Chemical analysis

– Biological monitoring

• Pros/cons: Bio-monitoring is not specific to a single substance, chemical monitoring cannot establish an adverse effect only a concentration

• Two methods are complementary

• To understand the behavior of pollutants in the environment and appreciating their effects on the environment and on humans, and to monitor and manage those pollutants

• A grounding in which sciences is required?

IntroductionThe Chemicals of Interest

• Pollution and pollutant

– Preferred by environmentalists and EPA

• Contamination and contaminant

– Preferred by US DOE

• Legal defination specifies concentration and location

Inorganic OrganicRadioactive

Metals Metalloids Non-metals

Toxic Non-Toxic

TransitionMetals

HeavyMetals

Chemical type:

Make connections

Inorganic OrganicRadioactive

Metals Metalloids Non-metals

Toxic Non-Toxic

TransitionMetals

HeavyMetals

Chemical type

3 main categories:

(a) Chemicals of concern because of their human toxicity

(b) Chemicals which cause damage to non-human biota but are not believed to harm humans at current levels of exposure

(c) Chemicals not directly toxic to humans or other biota at current environmental concentrations, but capable of causing environmental damage

3 main categories:

e.g. Pb, Cd, Hg, As have known effects

No known essential role in the human body

Tolerated at low-exposure

Toxic symptoms

Fig. 1:

3 main categories:

essential trace elements behave very differently

Deficiency iflow-exposure

Toxic symptoms

Acceptable range

Body burdens of lead in ancient people uncontaminated by industrial lead (left); typical Americans (middle); people with overt clinical lead poisoning (right). Each dot represents 40 µg of lead.

Source: Patterson et al., 1991; adapted from NRC, 1980.

Case StudyMinamata, 1953

• Minamata Bay, Japan (1953-1960)• Plastic manufacturer (Chisso Corp.), used mercury in the

production of acetaldehyde• Discharged methyl mercury into the bay• Main diet of locals was fish + shellfish

– 5-20 ppm (106 water)• Over 3,000 people suffered (730 deaths):

Minamata disease / Dancing Cat Disease

various deformities, damage to nervous system, retardation or death

• Developing embryos are especially vulnerableWHO limit 0.5 mg kg-1

Minamata 50 mg kg-1

Health EffectsMode of Action

• Hg dissolves neuronshttp://commons.ucalgary.ca/mercury/

• Chromated copper arsenate (CCA) used to protect wood (45% As2O3)

• Concern over leaching of As especially in childrens playgrounds

In 2004 EPA banned CCA from residential use

Source: http://www.sptimes.com/News/031101/State/The_poison_in_your_ba.shtml

• e.g. Fluoride has a narrow window of optimal exposure

• Water is fluorinated to 1 mg L-1

• Half this concentration may result in deficiency syndrome and weakened teeth

• Double this concentration can lead to adverse effects on teeth and bones

• e.g. chemical carcinogens

benzene, polynuclear aromatic hydrocarbons, dioxins, polychlorinated biphenyls

(d) polychlorinated biphenyl

• Dioxins - Agent Orange

Herbicide (defoliant) ~ 10 ppm TCDD dioxin

Used by U.S. military in its Herbicidal Warfare program during Vietnam War.

• Million of gallons used 1962 - 1971 to remove unwanted plant life otherwise provided cover for enemy forces during the Vietnam Conflict

• Veterans and to a greater extent the Vietnamese reported a variety of health problems due to exposure that continues to this day [graphic and disturbing images]

Movies: http://www.pulitzercenter.org/openitem.cfm?id=426

Before……

After spraying AgentOrange……

http://research.yale.edu/ysm/article.jsp?articleID=48Baird and Caan, 2008

GE began using PCBs for a wide range of industrial purposes in the late 1940s. From 1947 to 1977, GE plants north of Albany poured more than 1.3 million pounds of PCBs into the upper Hudson.

200 miles is now designated NPL site

Source: http://www.nrdc.org/water/pollution/hhudson.asp

By the mid-1970s, a growing number of studies had found links to premature births and developmental disorders, and had shown that PCBs caused cancer in lab animals.

Today, the federal government classifies PCBs as probable human carcinogens. They are also associated with reproductive problems, low birth weight, reduced ability to fight infections and learning problems.

Health EffectsEffects in Utero

• Exposure to low levels results in impaired intellectual development

NYT, September 12th 1998

• Polyaromatic Hydrocarbons – PAH’s

• Sources: oil tankers, refineries, offshore drilling, aluminum smelters, creosote (railway ties)

• Typically ng L-1

• Larger PAH’s bioaccumulate

• PAH’s, PCBs and Mirex implicated in devastation of beluga Whales in the St. Lawrence River

3 main categories:

e.g. Copper and zinc are essential trace elements for humans

Toxic to growing plants and there are regulations limiting their addition to soil in materials such as sewage sludge

3 main categories:

e.g. Endocrine disrupting chemicals

hormone mimics which disrupt reproduction and growth in wildlife

Baird and Caan, 2008

3 main categories:

e.g. CFCs

disrupt stratospheric ozone cycles

Turco, 2002

3 main categories:

e.g. Carbon Dioxide - the greenhouse effect

http://services.google.com/earth/kmz/changing_sea_level_n.kmz

IntroductionUnits of Concentration

• When describing environmental processes it is important to know how much of each participating chemical is present

• Confusing to the newcomer

Soilds –

mass analyte/total mass of sample

• mass per unit mass, also known as w/w

e.g. mg Pb / kg soil (mg/kg, mg kg-1)

• Important with soils to note wet or dry weight due to moisture content

Aquatic systems –

mass analyte/total mass of sample

• mass per unit mass, ng kg-1 or μg kg-1

Or more commonly

mass analyte/total volume of sample

• Mass per unit volume, mg L-1 (=ppm) or μg L-1 (=ppb) and ng L-1 (=ppt)

• Unfortunately leads to confusion with units used in atmospheric chemistry which have a different meaning (volume per unit volume v/v instead of w/v)

ppmw vs. ppmv

e.g. 10 mg F per million mg of water = 1 g F per million g of water= 10 tons F per million tons water= 10 mg F per million mg water= 10 ppmw F (or ppm/w)

ppm = mg kg-1 = mg L-1

[since 1000,000 mg water = 1 kg water = 1 L water]= 10 mg F per L water (10 mg/L or 10 mg L-1 F)= 10 ppmv F (or ppm/v)

• ppm, ppb, etc. (assumes pollutant has same density as water, ρ = 1.00 g mL-1)

e.g. show that 1 mg/L = 1 ppm

1 mg/L = 1 ppm

1 μg/L = 1 ppb

1 ng/L = ppt

Conversions:

1 ppb = 1 ppm / 1000

1 ppt = 1 ppb /1000

million per part 1 OH g 10

pollutant g 1 =

OH g 1000

OH L 1

mg 1000

pollutant g 1 OH of /Lpollutant mg 1

Question

Prove that 1 mg L-1 = 1 μg mL-1

1 mg x 1000 μg

mg= 1 μg / mL

L x 1000 mL

Question

0.01 g/L x (1000 mg/g) = 10 mg/L = 10 ppm

10 ppm x 1000 ppb / ppm = 10,000 ppb

M[Pb(NO3)2] = 331.2 g/mol

Example 1: convert 0.100 M lead nitrate to ppm

Example 2: convert 0.01 g lead nitrate dissolved in 1L to ppb

0.100 mols/L = 0.100 mols x (331.2 g/mol) / 1 L

First convert g/L to mg/L (ppm), then ppm to ppb

First convert mol/L to g/L, then to mg/L (ppm)

= 33.1 g / L = 33.1 g/L x 1000 mg/g = 33100 ppm

Atmosphere –

Concentration units for gases• Mass per unit volume, μg m-3 (=ppm) or molecules cm-3

• Not independent of temperature or pressure, volume of air will change, mass of pollutant won’t change

e.g. air containing 1 μg m-3 SO2 at 0 °C will contain less than 1 μg m-3 SO2 if heated to 25 °C

Atmosphere –

Mixing ratios

volume analyte/total volume of sample

• Problem is overcome by expressing concentration of a trace gas as a volume-mixing ratio,e.g. 1 cm3 SO2 dispersed in 1 m3 air = 1 ppmv

• 1 ppmv = 1 molecule in 106 molecules

= 1 mol in 106 mols

= Partial pressure of 10-6 atm.

• Now if T or P changes effects both trace gas and air in which it is contained, volume-mixing ratio does not change

IntroductionUnits of Concentration: Gases

• Conversion (at normal temperature of 20 ºC and 1 atm.) from w/v to v/v:

concentration (ppmv) = concentration (mg m-3) x 24.0Molar mass

Note: At STP of 273 K (0 C) the molar volume is 22.4

• Similarly:

concentration (ppbv) = concentration (μg m-3) x 24.0Molar mass

concentration (pptv) = concentration (ng m-3) x 24.0Molar mass

Question

Convert 800 mg m-3 O3 (w/v) to ppm (v/v) without short-cut

M [O3] = 48 g mol-1

No. moles O3 in 1 m3 air = 800 mg / 48 g mol-1 = 800 x 10-3 g / 48 g mol-1

= 1.67 x 10-2 mol

Volume occupied by 1 mole at 20 °C and 1 atm (SATP)

= 24.0 L = 0.0240 m3

Volume O3 in 1 m3 air

= 1.67 x 10-2 mol x 0.0240 m3 mol-1

= 400 x 10-6 m3 = 400 ppmv

Question

Convert 800 mg m-3 O3 (w/v) to ppm (v/v) with short-cut

concentration (ppmv) = concentration (mg m-3) x 24.0 Molar mass

= 800 mg m-3 O3 x 24.0 = 800 mg m-3 O3 x 0.5 = 400 ppmv48 g mol-1

Question

Express [O3] = 2.0 x 1012 molecules cm-3 as a volume mixing ratio (ppbv)

[O3] = 2 x 1012 molecules cm-3

= 3.3 x 10-12 mols cm-3

= 3.3 x 10-12 mols cm-3 x 48 g/mol = 1.6 x 10-10 g cm-3

= 1.6 x 10-7 mg cm-3 x (1 x 106 cm3 / m3)= 0.16 mg m-3 = 0.16 mg m-3 x 24.0 / 48 g mol-1

= 0.080 ppmv = 0.080 x 1000 ppmv / ppbv = 80 ppbv

[Convert to mg m-3 then use w/v to v/v conversion]

Question

Calculate the pressure of ozone in atm and in ppmv at the tropopause (15 km, 217 K), given [O3] = 1.0 x 1012 molecules cm-3, and p(total) = 0.12 atm

[O3] = 1.0 x 1012 molecules cm-3 x 1000 cm3/1 L x 1 mol/6.022 x 1023 molecules

= 1.7 x 10-9 mol L-1

pV = nRT, p(O3) = (n/V) RT = 1.7 x 10-9 mol L-1 x 0.0821 L atm/mol K x 217 K = 3.0 x 10-8 atm

p(O3) ppmv = (3.0 x 10-8 atm / 0.12 atm ) x 106 ppmv = 0.25 ppmv

IntroductionSources

• Point – well-defined source (e.g. end of a pipe, smokestack, drain)

• Non-point - less well defined, cannot be pinpointed

Arbitrary to some extent – depends on spatial scale

e.g. air - one smoke stack (P) meaningless to analysis of regional air pollution, 100’s of stacks become NP source

e.g. water - one house septic system (P), on a regional scale may be considered NP

Discharge from waste water plant contaminates ground and surface water

Source: USGS

Point and Non-point Sources

Smol, 2008

IntroductionSources

Source General Waste (representative)

Agricultural Field and chemical waste, nutrients, pesticides/herbicides, petroleum fuels, feedlot waste, dairy waste

Chemical Industry Metal products, metal sludges, nonmetal waste, electrical equipment waste, detergents/soaps/cleaners, petroleum, metal plating, film processing, solvents, wastewaters, pesticides, smog precursors (NOX, HC’s)

Mining Industry Mine tailings, Mineral leachate (CN), acid mine drainage, coal, smelting waste, particulates

Energy Industry Petroleum-based waste, solvents, gas and vapor emissions, coal tars, boiler waste, nuclear waste, petroleum stored underground, smog and acid rain precursors ((NOX, HC’s)

Landfills Chemicals

Incinerators Incomplete combustion of feedstock, combustion by-prodcuts, metals, particulates

Medical Industry Biohazards, pharmaceutical waste, solvents

Food Processing Waste food products, rinsing waste, slaughterhouse waste

Domestic Waste Detergents/cleaners, pesticides, fertilizers, compost, paints/solvents, gasoline

Municipal Governments Water and wastewater treatment chemicals, sewage

Federal Givernemnt Weapons-related waste, nuclear waste, petroleum-based waste

Dunnivant and Anders, 2006

IntroductionSources

• Basel Convention: International treaty regulating reporting, disposal and transport of hazardous waste

• Designed to reduce movement of waste

• Nuclear waste not included!

http://www.basel.int/natreporting/index.html

(Data from 2000, metric tons)

Questions

1. Correlate hazardous waste to a country’s development level (economic status).

2. Calculate the import/export ratio (if ratio > 1 the country is a net importer). Are there any net importers?

3. Why are Germany and Japan absent from the list?

4. How does the US hazardous waste amount compare to the rest of the world?

5. Why is the US (40,821,482 tons in 2001) absent?

Questions

1. Which state is the largest producer of hazardous waste?

2. Which has the most hazardous waste generators?

3. Conduct an internet search of a company from any state and determine what are their waste chemicals.

http://www.epa.gov/epaoswer/hazwaste/data/biennialreport/

Large quantity generator

IntroductionSummary

• Pollution is the introduction of contaminants (chemicals, heat, light, noise) into an environment that causes instability, disorder, harm or discomfort to the physical systems or living organisms they are in

• Chemicals

• Units

• Sources

References

• Harrison, R.M. (2006) Introduction to Pollution Science. The Royal Society of Chemistry, London.

• Dunnivant, F.M. and Anders, E. (2006) A Basic Introduction to Pollutant Fate and Transport: An Integrated Approach with Chemistry, Modeling, Risk Assessment, and Environmental Legislation. Wiley-Interscience, New Jersey.

• Smol, J.P. (2008) Pollution of Lakes and Rivers: A Paleoenvironmental Perspective. Wiley-Blackwell.

IntroductionHarrison

• This chapter is available as a publisher’s Adobe PDF file here:

http://academics.rmu.edu/faculty/short/envs4450/textbooks/Harrison-IPS-Chp1.pdf

air, water and land pollution chapter 1: introduction copyright © 2009 by dbs

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