Environmental Health Environmental Health Chapter 3Chapter 3

Lesson 3.3 Lesson 3.3

Biodiversity and Environmental HealthBiodiversity and Environmental Health

PA Academic Standards for PA Academic Standards for Environment & EcologyEnvironment & Ecology

Standard 4.3.10.CStandard 4.3.10.C Explain biological diversity as an indicator of Explain biological diversity as an indicator of

a healthy environment.a healthy environment.• Explain species diversity.Explain species diversity.• Analyze the effects of species extinction on the Analyze the effects of species extinction on the

health of an ecosystem. health of an ecosystem.

Learning ObjectivesLearning Objectives

Students will define and explain biological Students will define and explain biological diversity.diversity.

Students will hypothesize the effects of species Students will hypothesize the effects of species extinction on health of an ecosystem extinction on health of an ecosystem

Biodiversity and Biodiversity and Environmental HealthEnvironmental Health

How can we use a measure of biodiversity to How can we use a measure of biodiversity to determine the health of an ecosystem?determine the health of an ecosystem?

Let’s see what Bill Nye, the Science Guy, has to say …

BiodiversityBiodiversity DefinitionDefinition: : variety of living organisms on earth

Biodiversity varies by Biodiversity varies by habitat The overall The overall health of an ecosystem is directly related to its of an ecosystem is directly related to its

biodiversitybiodiversity When in When in equilibrium, the number of species is balanced by , the number of species is balanced by

the resources in a systemthe resources in a system When ecosystems are When ecosystems are stressed, the organisms and , the organisms and

resources in a system are no longer in equilibriumresources in a system are no longer in equilibrium

BiodiversityBiodiversity

BiomonitoringBiomonitoring DefinitionDefinition: biological approach to monitoring an ecosystem’s : biological approach to monitoring an ecosystem’s

health. health. Using living organisms to gauge environmental health.

Ecosystem monitoring incorporates sampling & analyzing Ecosystem monitoring incorporates sampling & analyzing biological factorsbiological factors

Certain types of organisms occur within a Certain types of organisms occur within a limited range of of conditionsconditions

Example: ability to tolerate fluctuations in precipitation and Example: ability to tolerate fluctuations in precipitation and temperature in seasonal climatestemperature in seasonal climates

When conditions change, the When conditions change, the distribution and and number of of organisms in an affected site will also changeorganisms in an affected site will also change

These changes are the premise of biomonitoringThese changes are the premise of biomonitoring

BiomonitoringBiomonitoring How can we use biomonitoring in aquatic How can we use biomonitoring in aquatic

systems?systems?• Aquatic systems generally contain populations of

bottom-dwelling invertebrate species• If most systems have bottom-dwelling invertebrate

communities, then biomonitoring always works for a comparison of data within systems, as well as between unrelated systems

Benthic Macroinvertebrates

Why use bottom-dwelling invertebrates? They are present in nearly all aquatic

ecosystems Easy to collect and identify Limited mobility

Inability to avoid poor water quality conditions Sensitive to a wide range of environmental

conditions

Invertebrate Sampling ChartInvertebrate Sampling Chart

Bottom-dwelling Invertebrates: Bottom-dwelling Invertebrates: Field StudiesField Studies

Invertebrates are collected by nets and screening devices Invertebrates are collected by nets and screening devices using a variety of sampling techniquesusing a variety of sampling techniques

Identification of specimensIdentification of specimens Data collectionData collection

• The number and type of organisms is recordedThe number and type of organisms is recorded Data AnalysisData Analysis

• Charts have been developed to use a scoring table that Charts have been developed to use a scoring table that assigns a value to the level of tolerance an organism assigns a value to the level of tolerance an organism exhibitsexhibits

• The data is “scored” using these tablesThe data is “scored” using these tables ConclusionConclusion

• Data is reviewed, compared, repeated, and an overall tally Data is reviewed, compared, repeated, and an overall tally of indicators determines the overall health of the systemof indicators determines the overall health of the system

Humans and Species ExtinctionHumans and Species Extinction

Biomonitoring studies have shown that the health Biomonitoring studies have shown that the health of ecosystems statewide and nationally, have of ecosystems statewide and nationally, have improved since monitoring programs begansince monitoring programs began

Despite this accomplishment, ecologists estimate Despite this accomplishment, ecologists estimate that the current rate of extinction of species is that the current rate of extinction of species is 10,000 10,000 times faster than normal extinction ratestimes faster than normal extinction rates

Habitat lossHabitat loss is the most common reason for this is the most common reason for this increased rateincreased rate

Habitat AlternationsHabitat Alternations

Main causes of habitat destruction includeMain causes of habitat destruction include Sprawl Pollution Logging and mining Fire suppression

SprawlSprawl Problem: urban sprawl is the result of unplanned Problem: urban sprawl is the result of unplanned

development around urban areasdevelopment around urban areas Problem: major cause of habitat loss from the removal of Problem: major cause of habitat loss from the removal of

trees to clear properties, drainage and filling of wetlands, trees to clear properties, drainage and filling of wetlands, and increased amounts of impervious surfacesand increased amounts of impervious surfaces

Realistic Solution: Realistic Solution:

Smart DesignSmart Design

Smart Design BasicsSmart Design Basics Aims to reduce the amount of Aims to reduce the amount of sprawlsprawl and associated pollution and associated pollution Aims to increase the amount and affordability of mass Aims to increase the amount and affordability of mass transit transit

systemssystems Aims to provide alternatives to nonrenewable Aims to provide alternatives to nonrenewable fuel fuel

consumptionconsumption Aims to provide ecological ways of incorporated the needs of a Aims to provide ecological ways of incorporated the needs of a

growing population with the need for access to urban areasgrowing population with the need for access to urban areas

PollutionPollution Problem: results in the contamination of all forms of Problem: results in the contamination of all forms of

medium: air, water, and soilsmedium: air, water, and soils Problem: results in habitat Problem: results in habitat degradationdegradation and habitat and habitat lossloss Case Study: Case Study: DDTDDT in Pennsylvania in Pennsylvania

DDTDDT What is DDT?What is DDT? How is DDT linked to habitat loss and decreases in How is DDT linked to habitat loss and decreases in

overall habitat quality in Pennsylvania?overall habitat quality in Pennsylvania? What has been done to address the concerns What has been done to address the concerns

associated with the use of DDT in Pennsylvania?associated with the use of DDT in Pennsylvania?

DDT: DDT: DichlorodiphenyltrichloroethaneDichlorodiphenyltrichloroethane

What is it?What is it?• Chlorinated organic Chlorinated organic pesticide.pesticide.• Problem: Accumulates in Problem: Accumulates in fatfat..• Problem: Attacks Problem: Attacks nervousnervous system. system. • Problem: Affects Problem: Affects non-targetednon-targeted species species..

Uses of DDTUses of DDTHistoricalHistorical

• Agricultural productionAgricultural production• Limits crop lossesLimits crop losses

• ForestryForestry• Limits insect damageLimits insect damage

• Public healthPublic health• Malaria and Mosquito controlMalaria and Mosquito control

CurrentCurrent• Malaria control in “hot spots”Malaria control in “hot spots”

USDA 1947

Widespread Use of DDTWidespread Use of DDT

Current Status of DDTCurrent Status of DDT Banned in US in Banned in US in 19721972 Most other nations have banned DDTMost other nations have banned DDT

• ~19 countries still have exemption for its use~19 countries still have exemption for its use

Primarily used to control the spread of diseases by mosquitoes

Migration of DDT particleMigration of DDT particle

BioaccumulationBioaccumulation(Biological Magnification)(Biological Magnification)

DefinitionDefinition: : the accumulation of potentially harmful the accumulation of potentially harmful chemicals in organism higher in a food chainchemicals in organism higher in a food chain

DDT and Food websDDT and Food webs

Concept of Half-lifeConcept of Half-life

Half-life is the amount of time it takes for half of Half-life is the amount of time it takes for half of the chemical substance to degradethe chemical substance to degrade

The half life of DDT is 12-15 years. Let’s assume The half life of DDT is 12-15 years. Let’s assume that the half-life is a constant 15 years.that the half-life is a constant 15 years.

If we apply 100 pounds of DDT today, how much If we apply 100 pounds of DDT today, how much DDT will be left after 5 half-life's?DDT will be left after 5 half-life's?

Half-life of DDTHalf-life of DDT

One Half-LifeOne Half-Life

(15 years)(15 years)

Two Half-LivesTwo Half-Lives

(30 years)(30 years)

Three Half-LivesThree Half-Lives

(45 years)(45 years)

Four Half-LivesFour Half-Lives

(60 years)(60 years)

Five Half-LivesFive Half-Lives

(75 years)(75 years)

50% degraded50% degraded

50 lbs.50 lbs.

75% degraded75% degraded

25 lbs.25 lbs.

88% degraded88% degraded

12 lbs.12 lbs.

94% degraded94% degraded

6 lbs.6 lbs.

97% degraded97% degraded

3 lbs.3 lbs.

Weighing in on DDT use…Weighing in on DDT use…

ProPro• Toxic to wide range of Toxic to wide range of

insect pests insect pests • Appeared to have low Appeared to have low

toxicity to mammals toxicity to mammals and birdsand birds

• Persistent - does not Persistent - does not have to be reappliedhave to be reapplied

• Insoluble - doesn’t get Insoluble - doesn’t get washed off by rainswashed off by rains

• Inexpensive and easy to Inexpensive and easy to applyapply

ConCon• Toxic to a wide range Toxic to a wide range

of insect pestsof insect pests• Toxic to mammals and Toxic to mammals and

birds even in very low birds even in very low concentrationsconcentrations

• Persistent – does not Persistent – does not have to be reappliedhave to be reapplied

• Insoluble – doesn’t get Insoluble – doesn’t get washed off by washed off by precipitationprecipitation

Silent SpringSilent Spring When?When?

• 19621962 Who?Who?

• Rachel CarsonRachel Carson• Biologist and Biologist and

naturalistnaturalist• Noticed a “silent Noticed a “silent

spring”spring” What?What?

• Silent SpringSilent Spring; response ; response to massive use of to massive use of pesticides and pesticides and subsequent wildlife subsequent wildlife mortalitymortality

DDT Affects Non-Target DDT Affects Non-Target SpeciesSpecies

Reproductive failure in birdsReproductive failure in birds• Thinning of eggshells.Thinning of eggshells.• Modification of parental behavior.Modification of parental behavior.• High mortality of embryos and fledglings.High mortality of embryos and fledglings.

Pennsylvania Example: Pennsylvania Example: Peregrine Falcon PopulationsPeregrine Falcon Populations

Rosalie Edge – Hawk Mountain

Value of Raptors

What do we know about What do we know about Latin America?Latin America?

Latin America: Latin America: The DDT ConnectionThe DDT Connection

Falcons and other migratory birds can travel as Falcons and other migratory birds can travel as far as Latin America during period of migrationfar as Latin America during period of migration

Latin America still uses DDT as a means of Latin America still uses DDT as a means of mosquito and pest controlmosquito and pest control

Falcons traveling to these regions are coming in Falcons traveling to these regions are coming in contact with DDT; exposure to DDT occurs while contact with DDT; exposure to DDT occurs while falcons are in Latin Americafalcons are in Latin America

Logging and Mining: ProblemsLogging and Mining: Problems

Logging and mining have destroyed many habitats Logging and mining have destroyed many habitats statewidestatewide

Timber extraction increases erosion and sediments in Timber extraction increases erosion and sediments in waterwayswaterways

Acid mine drainage acidifies waterwaysAcid mine drainage acidifies waterways

Logging and Mining: Logging and Mining: Realistic SolutionsRealistic Solutions

Minimize and prevent further destructionMinimize and prevent further destruction Create and enforce regulations that oversee land Create and enforce regulations that oversee land

use for these practicesuse for these practices Restore and replace destroyed habitats for wildlife Restore and replace destroyed habitats for wildlife

and recreational useand recreational use

RECLAMATION

Fire Suppression: Fire Suppression: ProblemsProblems Interrupts natural processes of ecological successionInterrupts natural processes of ecological succession Disturbs the cycles of organisms which depend on periodic Disturbs the cycles of organisms which depend on periodic

firesfires Native plants vulnerable to competitors better adapted to Native plants vulnerable to competitors better adapted to

survive firessurvive fires

What we want...             What we have.

Fire Suppression: Realistic Solution

Allow controlled fires to prepare land for ecological succession to occurAllow controlled fires to prepare land for ecological succession to occur