Aquatic BiologyAquatic Biology

AcidificationAcidification

Causes, Causes, Consequences and Consequences and

SolutionsSolutions

Introduction to Introduction to AcidificationAcidification

By Alastair FraterBy Alastair Frater

Introduction to Introduction to AcidificationAcidification

Acidification - definitionAcidification - definition Acidification - basic descriptionAcidification - basic description Social considerationsSocial considerations Legal considerationsLegal considerations

Acidification - definitionAcidification - definition

Change towards more acidic Change towards more acidic conditions in:conditions in:

Rain and cloud waterRain and cloud water LakesLakes RiversRivers GroundwaterGroundwater SoilsSoils

Acidification - basic Acidification - basic descriptiondescription

Two speeds of acidificationTwo speeds of acidification Slow - due to biological and Slow - due to biological and

geological processesgeological processes Fast - due to climatic fluctuations or Fast - due to climatic fluctuations or

volcanic eruptions; or by human volcanic eruptions; or by human activityactivity

Air pollution - direct and indirectAir pollution - direct and indirect Emissions from industryEmissions from industry

Aquatic environment Aquatic environment acidificationacidification

Three criteria to be metThree criteria to be met 1 - Increase of atmospheric anion 1 - Increase of atmospheric anion

depositiondeposition 2 - Poor anion retention of soils2 - Poor anion retention of soils 3 - Low alkalinity3 - Low alkalinity

Social considerationsSocial considerations

Industries important to society Industries important to society Problems of controlProblems of control Location of sourceLocation of source Location of affected areaLocation of affected area Emission “producer” & “importer” Emission “producer” & “importer”

co-operationco-operation

Legal considerationsLegal considerations

International legal considerations International legal considerations International co-operation on International co-operation on

controlcontrol Complications?Complications?

Causes of Aquatic Causes of Aquatic AcidificationAcidification

William BarkerWilliam Barker

AcidificationAcidification

Domestic and commercial waste Domestic and commercial waste /general pollution/general pollution

Agricultural inputAgricultural input Acid RainAcid Rain

Domestic and commercial Domestic and commercial waste /general pollutionwaste /general pollution Water stores throughout the world are Water stores throughout the world are

subject to stress; because it’s used for subject to stress; because it’s used for water supplies, industry and recreation.water supplies, industry and recreation.

Even though the wastewater's are Even though the wastewater's are treated, large quantities of treated, large quantities of contaminants flow downstream.contaminants flow downstream.

Domestic sewage includes human Domestic sewage includes human wastes and a variety of waste materials wastes and a variety of waste materials that arise from household products.that arise from household products.

Agricultural inputAgricultural input

Plants need nutrients in order to Plants need nutrients in order to complete their life cycles.complete their life cycles.

Fertiliser are used to supplement or Fertiliser are used to supplement or replace, the nutrients supplied by replace, the nutrients supplied by natural processes.natural processes.

These artificial chemicals contain These artificial chemicals contain pollutants that will ultimately change pollutants that will ultimately change the pH of surface water, through the pH of surface water, through runoff.runoff.

Acid RainAcid Rain

Rainwater was once the purest form of water available Rainwater was once the purest form of water available but now is often contaminated by pollutants in the air. but now is often contaminated by pollutants in the air. Acid rain is caused when industrial emissions mix with Acid rain is caused when industrial emissions mix with atmospheric moisture. Pollutants may be carried in atmospheric moisture. Pollutants may be carried in clouds for long distances before falling., which means clouds for long distances before falling., which means that forests and lakes far away from factories may be that forests and lakes far away from factories may be damaged by acid rain. In the near vicinity of the damaged by acid rain. In the near vicinity of the factories, additional damage is caused by the factories, additional damage is caused by the deposition of larger pollutant particles falling to the deposition of larger pollutant particles falling to the ground in dry form. Air pollution has been increasing ground in dry form. Air pollution has been increasing since the Industrial Revolution but only recently have since the Industrial Revolution but only recently have side effects such as acid rain become severe and side effects such as acid rain become severe and widespread enough to evoke international concern.widespread enough to evoke international concern.

Acid RainAcid Rain

Acid RainAcid Rain

Forests, lakes, ponds, and Forests, lakes, ponds, and other terrestrial and aquatic other terrestrial and aquatic environments throughout the environments throughout the world are being severely world are being severely damaged by the effects of damaged by the effects of acid rain. Acid rain is caused acid rain. Acid rain is caused by the combination of sulphur by the combination of sulphur dioxide and nitrogen dioxide and nitrogen compounds with water in the compounds with water in the atmosphere. In addition to atmosphere. In addition to chemically burning the leaves chemically burning the leaves of plants, acid rain poisons of plants, acid rain poisons lake water, killing most, if not lake water, killing most, if not all, the aquatic inhabitants.all, the aquatic inhabitants.

IntroIntro

Direct effects of Sulphuric acid.Direct effects of Sulphuric acid. Indirect effects of Sulphuric acid.Indirect effects of Sulphuric acid. Case Study.Case Study.

Direct EffectsDirect Effects

Sulphuric acid (H2SO4) directly Sulphuric acid (H2SO4) directly interferes with the fish’s ability to interferes with the fish’s ability to take in oxygen , salt and nutrients.take in oxygen , salt and nutrients.

Acid causes mucus to form in the Acid causes mucus to form in the gills and can lead to suffocation.gills and can lead to suffocation.

Salt levels such as Ca²+ cannot be Salt levels such as Ca²+ cannot be maintain and results in failure of maintain and results in failure of reproduction. reproduction.

Eggs become too weak or brittle to Eggs become too weak or brittle to survive.survive.

Ca²+ deficiency also causes weak Ca²+ deficiency also causes weak spines and deformities.spines and deformities.

Crayfish need Ca²+ to maintain Crayfish need Ca²+ to maintain healthy exoskeleton.healthy exoskeleton.

Indirect effectsIndirect effects

Sulphuric acid causes heavy Sulphuric acid causes heavy metals to be released from soils.metals to be released from soils.

Al²+ is released from a harmless Al²+ is released from a harmless compound into soils and eventually compound into soils and eventually into lakes.into lakes.

Al²+ Burns the gills of fish causing Al²+ Burns the gills of fish causing respiratory problems.respiratory problems.

Effect Of Aluminium On Effect Of Aluminium On GillsGills

It also accumulates in the organs It also accumulates in the organs causing damage and eventually death.causing damage and eventually death.

Although many fish can tolerate a pH Although many fish can tolerate a pH of 5.9, this is enough to release Al² of 5.9, this is enough to release Al² from the soil to enter the aquatic from the soil to enter the aquatic environment.environment.

This is further augmented by spring This is further augmented by spring acid shock.acid shock.

Spring Acid ShockSpring Acid Shock

When snow melts in spring a large When snow melts in spring a large quantity of acids and chemicals quantity of acids and chemicals are released into the soils.are released into the soils.

The acids and chemicals will make The acids and chemicals will make their way into lakes.their way into lakes.

This causes a dramatic change in This causes a dramatic change in the pH in lakes.the pH in lakes.

The aquatic water system has no The aquatic water system has no time to adjust to the sudden change.time to adjust to the sudden change.

Springtime is a vulnerable time for Springtime is a vulnerable time for many aquatic species since it is the many aquatic species since it is the time for reproduction.time for reproduction.

This may cause severe deformities or This may cause severe deformities or even annihilate the whole species.even annihilate the whole species.

Case Study - Lake 223Case Study - Lake 223

Since 1976 Lake 223 was monitoredSince 1976 Lake 223 was monitored Over the years man crustaceans died out Over the years man crustaceans died out

due to reproduction failures.due to reproduction failures. At a pH of 5.6 algae growth was At a pH of 5.6 algae growth was

hindered.hindered. Larger fish died due to problems in Larger fish died due to problems in

reproductionreproduction There were more adult fish in the lake There were more adult fish in the lake

than young ones.than young ones.

By 1983 Lake 223 had reached a By 1983 Lake 223 had reached a pH of 5 and the surviving fish were pH of 5 and the surviving fish were thin and deformed and unable to thin and deformed and unable to reproduce.reproduce.

Solutions to acidificationSolutions to acidification

Two ways of attacking acidificationTwo ways of attacking acidification– Stop air pollution at its source and so Stop air pollution at its source and so

reduce acid rain.reduce acid rain.– Combat the effect of acidification.Combat the effect of acidification.

Attacking the SourceAttacking the Source

This involves reducing the This involves reducing the emissions of SOemissions of SO2 2 and NOx gases and NOx gases

E.C. directives such as BATNEEC E.C. directives such as BATNEEC and the Helsinki agreement in and the Helsinki agreement in 1985 1985

Controlling the effects of Controlling the effects of acidificationacidification

This involves increasing a streams This involves increasing a streams or lakes buffering capacity. or lakes buffering capacity. BUT BUT– Only a temporary solutionOnly a temporary solution– Can kill aquatic organismCan kill aquatic organism– How much and where? How much and where?

RecoveryRecovery

If pollution is cut off at its source then lakes If pollution is cut off at its source then lakes and streams will recover firstly chemically and streams will recover firstly chemically and then biologically. However due to the and then biologically. However due to the complexity of natural habitats the time of complexity of natural habitats the time of recovery can vary a huge amount between recovery can vary a huge amount between aquatic environments.aquatic environments.

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