Environmental contaminants,sources and their remediation

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Environmental contaminants, Environmental contaminants, sources and their remediation.sources and their remediation.

Zia-Ur-Rahman. Zia-Ur-Rahman. 2010-ag-2600 2010-ag-2600

Environment:Environment:Word environment is actually derived from the Word environment is actually derived from the

French word “environner” which means a circle French word “environner” which means a circle or around. So;or around. So;

All the biotic and a-biotic factors around us and All the biotic and a-biotic factors around us and their interactions are environment.their interactions are environment.

Contaminant:Contaminant:

Any type of substance when cross its Any type of substance when cross its specific limits become dangerous for specific limits become dangerous for human and other organisms.human and other organisms.

E.g Pb, Hg, As,gasse, petroleum,micro-E.g Pb, Hg, As,gasse, petroleum,micro-organisms etc.organisms etc.

Types of contaminants:Types of contaminants:

Contaminant.

Chemical basis. General basis. Specified basis.

1:Chemical Basis.1:Chemical Basis.

There are 2 types of contaminants on the There are 2 types of contaminants on the basis of chemical behaviors;basis of chemical behaviors;

Organic contaminants.Organic contaminants. In-organic contaminants.In-organic contaminants.

Organic contaminants:Organic contaminants:Compounds having (C,H,O) As their necessary Compounds having (C,H,O) As their necessary

part are called organic compounds and those part are called organic compounds and those organic compouds which cause contamination organic compouds which cause contamination are known as organic contaminants.are known as organic contaminants.

e.g fuels,solvents,pesticides etc.e.g fuels,solvents,pesticides etc.

In-organic contaminants:In-organic contaminants:Compounds having origin other than organic are Compounds having origin other than organic are

in-organic compounds and contamination in-organic compounds and contamination causing compounds related to this group are causing compounds related to this group are called in-organic contaminants.called in-organic contaminants.

e.g Heavy metals,nitrates and asbestos etc.e.g Heavy metals,nitrates and asbestos etc.

2:General Basis.2:General Basis.

There are 2 types of contaminants while There are 2 types of contaminants while classifying on general basis;classifying on general basis;

Point source.Point source. Non-point source.Non-point source.

Point source:Point source:We know about the source of contaminants i.e We know about the source of contaminants i.e

from where they are coming.from where they are coming.

Non-point source:Non-point source:We do not know about the sources of these We do not know about the sources of these

contaminants i.e from where these contaminants i.e from where these contaminants are coming.contaminants are coming.

3:Specifical Basis.3:Specifical Basis.Contaminants are classified into 2 categories on Contaminants are classified into 2 categories on

the basis of specifical sources as;the basis of specifical sources as; Natural contaminants.Natural contaminants. Anthropogenic contaminants. Anthropogenic contaminants.

Natural contaminants:Natural contaminants:Contaminants which are not produced from Contaminants which are not produced from

human activity and are completely natural.human activity and are completely natural.e.g micro-organisms(viruses,bacteria ctc),cd,pb e.g micro-organisms(viruses,bacteria ctc),cd,pb

etc.etc.

Anthropogenic contaminants:Anthropogenic contaminants:Contaminants which are generated and spread Contaminants which are generated and spread

through human activities i.e;through human activities i.e; Industrial activities(Heavy metals)Industrial activities(Heavy metals) Agriculture(Pesticides,pb,As, as toxic agent).Agriculture(Pesticides,pb,As, as toxic agent).

REMEDIATION MEASURES.REMEDIATION MEASURES.(Thermal soil remediation plant.)(Thermal soil remediation plant.)

REMEDIATION MEASURES.REMEDIATION MEASURES.

There are three types of remediation There are three types of remediation measures used;measures used;

Criteria based approach.Criteria based approach. Modified criteria approach.Modified criteria approach. Risk based approach.Risk based approach.

Criteria based approach:Criteria based approach:

Under this approach,the remediation criteria Under this approach,the remediation criteria selected for a site is adopted as the selected for a site is adopted as the remediation measure.remediation measure.

This method is most applicable where site This method is most applicable where site conditions,receptors,and exposure conditions,receptors,and exposure pathways are similar with those which are pathways are similar with those which are assumed when developing criteria.assumed when developing criteria.

Modified criteria approach:Modified criteria approach:

In some conditions,remediation criteria may In some conditions,remediation criteria may be modified within specific limits.be modified within specific limits.

This method applied when land This method applied when land use,receptors and exposure pathays differ use,receptors and exposure pathays differ only slightly from those assumed in the only slightly from those assumed in the development of criteria.development of criteria.

Risk based approach:Risk based approach:

In some circumstances,criteria based In some circumstances,criteria based approach is not be suitable for a approach is not be suitable for a site(pathways of exposure,target site(pathways of exposure,target chemicals,receptors and other site chemicals,receptors and other site characteristics differ from those used to characteristics differ from those used to develop criteria based approaches) and develop criteria based approaches) and risk assesment procedure may be risk assesment procedure may be required in the development of site required in the development of site specific remediation measures.specific remediation measures.

Thank you……!Thank you……!