Tiêu chuẩn iso 18400 204 2017

This document does not giveguidanc on: — risk ev luation an charact erization; — sele tion an design of prot ective measur s; — the verif ication of prot ective measur s, although the si

Soil quality — Sampling —

Part 204:

Qu lité du sol — Éch ntillo n ge —

Partie 2 4 : Lignes directrices p ur l’éch ntillo n ge de s g z de sol

Fir t edition

2 17-0

Refer ence n mb r

ISO 1 40 -2 4:2 17(E)

COPYRIGHT PROTECTED DOCUMENT

© ISO 2017, P blshed in Sw itz rlan

A ll rig hts r eserved Unles otherw ise spe ified, nopar of this p blc tion ma y be r epr od c d or utilz d otherw ise in an form

or b an me ns, ele tr onic or me hanic l, inclu in p oto opying , or postin on the internet or an intranet , w ithout prior

written permis ion Permis ion c n be req esed from either ISO at the ad r es below or ISO’s member bod y in the c u try of

F reword v

Introduction vi

1 Sc ope 1

2 Nor mati ve r eferenc es 2

3 Terms an definitions 2

4 Prelminar y items to be c onsider ed 5

5 Basic pr inciples 6

5.1 Physical an chemical principles 6

5.1.1 Pe manent gases 6

5.1.2 Volatie or ganic compou ds 7

5.2 Envir onmental con itions 7

5.3 Soi gas d ynamics 9

5.4 Identifying the sour ce of soi gas 9

6 Req irements for samplng plan 10

6.1 General considerations for samplng plan 1

6.1.1 Obje tives an g eneral r ecommendations 1

6.1.2 Initial ex lor ations (ield scr eening ) 1

6.1.3 K nown contamination c ntre 1

6.1.4 Dete mination of the contamination hot sp t (ar eas showing highes conc ntrations) an gas monitoring wels location 1

6.1.5 Dete mination of horizontal and ve tical dis ribution of VOCs 1

6.1.6 Obse v tion of sp tial distribution of V Cs in the course of time 1

6.1.7 Ev luation of soi gases contribution to ambient , indo r an / r outdo r air 1

6.2 Wor king r ang es of measur ement methods 1

6.3 Monitoring wel o tions 14

6.4 Sampl ng plan 1

6.4.1 Horizontal location of samplng devic s 1

6.4.2 Monitoring depths 1

6.4.3 Timing an fr eq ency of monitoring

1 6.4.4 Sample v lumes an samplng r ates 2

7 Co str uctio of mo itor ing instal atio s 21 7.1 General 2

7.1.1 E vir onmental conditions 2

7.1.2 Ins rument 2

7.2 Soi gas samplng devic s 2

7.2.1 Pas ive soi gas samplng 2

7.2.2 Sub-sla 2

7.2.3 Driven pr obes 2

7.2.4 Gas-monitoring stan pipe in a b r ehole 2

8 S mpl ng 26 8.1 Gene ic consideration 2

8.2 Pr eparation of the monitoring instalations 2

8.2.1 Pr ep ration of the samplng point 2

8.2.2 Leakag e tes 2

8.2.3 P r g e 2

8.3 A ctive samplng 3

8.3.1 General 3

8.3.2 Sor bent tubes or fite s 3

8.3.3 Sample containe s — Samplng b g s 34

8.3.4 Sp r g ing 3

8.3.5 Sample containe s — Pres uriz d containe s 3

8.4 Pas ive samplng 3

8.5 Sampl ng for on-site measur ement 3

9 Identification, packag ing and transpor t of samples for labor atory anal ysis 37 9.1 Identification 3

9.2 Packag ing an transp rt 3

10 S mpl n report .37 11 Qual ty as uranc e 38 1 1 General 3

1 2 Q ualty contr ol samples 3

1 2.1 General 3

1 2.2 Bln r eplcate samples 40

1 2.3 Splt samples 40

1 2.4 Trip blan s 40

1 2.5 Field blan s 40

1 2.6 Othe q alty contr ol samples 40

1 2.7 Ev luation of q alty contr ol sample r esult 40

1 2.8 Chain ofcus ody 41

1 2.9 E uipment 41

1 3 Inte fer enc s 42

1 3.1 General 42

1 3.2 L r g e sample v lume 42

1 3.3 C hesive sois 42

1 3.4 Soi mois ur e 42

1 3.5 L w ambient temperatur es 42

1 3.6 Heter og eneous s ratig raphy 42

1 3.7 S ep g e front

42 1 3.8 Per ched wate ta le horizon 43

1 3.9 C ntamination 43

1 3.1 Br eakthr oug h 43

1 4 Inte pr etation of soi gasanalyses for V Cs 43

A nne x A (informative)Standar d eq ipment and instr uments used for soi gas samplng for VOCs 44

A nne x B (informative)Por table eq ipment to me sur e gases

46 A nne x C (informative) E uipment to me sure flow rates and bor ehole pr es ure 48

A nne x D (informative) Example of samplng she t 50

Biblog raph y 52

ISO (he Int ernational Org nization for Stan ardization) is a worldwide fede ation of national s an ards

b dies (ISO membe b dies) The work of pr p ring Int ernational Standards is normaly car ied out

through ISO t ech ical committ ees Each membe b dy int er st ed in a subje t for w hich a t ech ical

committ ee has be n es a l shed has the right t o be r pr sent ed on that committ ee Int ernational

org nizations, g ove nmental an non-g ove nmental, in laison with ISO, also take part in the work

ISO cola orat es closely with the Int ernational Ele trot ech ical C mmis ion (IEC) on al matt ers of

ele trot ech ical s an ardization

The proc d r s used t o develo this document an those int en ed for it furthe maint enanc ar

desc ibed in the ISO/IEC Dir ctives, Part 1 In p rticular the dife ent a pro al c it eria ne ded for the

dife ent ty es of ISO document should be not ed This document was draft ed in ac ordanc with the

edit orial rules of the ISO/IEC Dir ctives, Part 2 ( e www iso org dir ctives)

A tt ention is drawn t o the p s ibi ity that ome of the element of this document ma be the subje t of

p t ent right ISO shal not be held r sponsible for identifying any or al such pat ent right Detais of

any p t ent right identif ied d ring the develo ment of the document wi be in the Introd ction an / r

on the ISO ls of p t ent de larations r c ived ( e www iso org p t ent )

Any trade name used in this document is information given for the convenienc of use s an does not

cons itut e an en orsement

For an ex lanation on the meaning of ISO spe ific terms an ex r s ions r lated to conformity as es ment,

as wel as information a out ISO’s adhe enc to the Wor ld Trade Org nization (WTO) principles in the

Te h ical Bar ie s to Trade (TBT) se the folowing URL: www iso org / iso/ for word html

This document was pr p r d b Te h ical C mmitt ee ISO/TC 1 0, S i q alt y, Subcommitt ee SC 2,

S mpln

This firs edition of ISO 1 400- 204 canc ls an r plac s ISO 1 3 1-7 :2 0 , w hich has be n t ech icaly

an s ructural y r vised TheISO 1 40 se ies is b sed on a mod lar s ructur an can ot be comp r d

t o ISO 1 3 1-7clause b clause

A l s of al p rt in theISO 1 40 se ies can be fou d on the ISO websit e

This document is one of a group of Int ernational Stan ards t o be used in conju ction with each othe

w he e ne es ary The ISO 1 40 se ies deals with sampl ng proc d r s for the v rious purposes of soi

inves ig tion The roles /positions of the in ivid al s an ards within the t otal inves ig tion pro ramme

ar shown in Figur 1 The s at ed soi g s an lan fil-g s measur ment do not give any q antitative

s at ement of thet otal q antity of mat erial det ect ed in soi g s or soi The measur ment r sult can be

influenc d b , e.g t empe atur , h midity, air pr s ur , minimum extraction depth, et c

The g ene al t erminolo y used is in ac ordanc with that es a lshed in ISO/TC 1 0 an , mor

p rticularly, with thev ca ulary given in ISO 1 0 4

To ic, asphy iating an ex losive soi g ses can ent er buidings an othe bui t develo ment on

an below grou d an v riously p se pot ential risks t o oc up nt an use s an t o the s ructur s

themselves

Such g ses might be pr sent in the grou d natural y, or be pr sent as a r sult of contamination of the

grou d, or arise from buried wast es In ad ition t o the main comp nent foun in air (nitrog en an

o y g en), soi g scan contain v latie org nic comp u ds (VOCs), inorg nic v pours (e.g me cury) an a

wide rang e of othe g ses (e.g methane, carb n dio ide, carb n mono ide, hydrog en sulf ide, ammonia,

helum, neon, arg on, x enon, radon, et c )

These g ses can ha e seve al origins such as: lan f il ed wast es; contaminat ed soi s on a brownf ield

sit e; plume of contaminat ed groun wat er; spi or leakag e of chemicals prod ct , leaks of mains g s

(natural g s); sewe g s, et c

In orde to complet e an as es ment of the risks p sed b the pr senc of pe manent an othe soi g ses

lke VOCs, it is ne es ary to u de s an an characteriz the pot ential sour es of g s in an arou d a site

Guidanc on ins al ations for soi g s sampl ng (eq ipment an ins rument , methods of samplng,

r q ir ment of controls, et c ) an othe r lev nt information (e.g on environmental con itions) ar

pro ided in this document

Figure 1 — Links betwe n the es ential elements of an investig tio programme

NOTE 1 T e n mb r in cir les in Figure 1 def ine the key elements (1 t o 7)of the investig tion pro ramme

NOTE 2 Figure 1 displays a g neric proces which can b amen ed when neces ary

Soil quality — Sampling —

This document contains guidanc on soi g s sampl ng using

— active sampl ng (adsorbent , filt ers, air containe s), an

— pas ive sampl ng

a pled at pe manent or t emp rary monit oring wels or othe ins alations in sois or un e neath

bui dings ( ub-sla )

It pro ides guidanc on:

— develo ment of a samplng plan;

— cons ruction of monit oring ins alations;

— transp rt, p cka ing an st orag e soi g s samples;

— q alty as uranc

This document also givesb sic information a out

— soi g s dynamics, an

— identif ication of soi g s sour es

r lev nt t o pe manent or t emp rary bor holes in soi s or u de neath buidings ( ub-slab)

The comp u ds co e ed b this document ar :

— volatie org nic comp u ds (VOCs);

— inorg nic volatie comp u ds (e.g me cury, HCN);

— pe manent g ses ( i.e CO

2, N

2, O

2, CH

4)

This document does not giveguidanc on:

— risk ev luation an charact erization;

— sele tion an design of prot ective measur s;

— the verif ication of prot ective measur s, although the sit e inves ig tion methodolo ies desc ibed

can beused w hen a pro riat e;

— the samplng of atmosphe ic or in o r g ses;

— the measur ment of g ses from the soi ent ering int o the atmosphe e;

— monit oring an samplng for radon

2 Normati ve referenc es

The folowing document ar r fe r d t o in the t ext in such a wa that some or al of their cont ent

cons itut es r q ir ment of this document F or dat ed r fe enc s, only the edition cit ed a ples F or

un at ed r fe enc s, the lat es edition of the r fe enc d document ( inclu ing any amendment ) a ples

ISO 1 0 4, S i q alt y — Voc ab lar y

ISO 1 40 -1 7, S i q alt y — S mpln — Part 107: R ec ordin a d r p rtin

3 Terms and definitions

F or thepurposes of this document, the t erms an definitions given in ISO 1 0 4 an the folowing a ply

ISO an IEC maintain t erminolo ical data ases for use in s an ardization at the folowing ad r s es:

— IECEle tro edia: a aia le at ht p:/ www ele tro edia org

— ISO Onlnebrow sing plat orm:a ai a le at ht p:/ www iso org o p

3.1

active soi g s sampl ng

samplng b extracting a c rtain volume of soi g s

3.2

bre kthrough

det ection of an adsorbent control se tion of one or mor comp u ds ha ing a mas gr at er than 5 % of

the mas q antif ied on the measuring se tion

3.3

de d v lume

v lume w hich is pr sent betwe n the suction o ening of the soi g s pro e an the sampl ng vial,

inclu ing the v lume of the samplng vial or of the adsorption tube

direct me suring metho

method of analy sis w he e the soi g s sample (alq ot) is dir ctly introd c d int o a suita le eq ipment

without f irs being conc ntrat ed an subje t ed t o analy sis

3.6

direct-re ding detecting tube

glas tube f il ed with r ag ent w hich, aft er drawing through c rtain g seous comp un s, show

conc ntration-depen ent chromo horic r actions and w hich ar th s used for q altative an

semi-q antitative analy ses as wel

Not e 1t o entry: It is important that at ention b paid t o c os -sensitivities

3.7

g s migratio

mo ement of g s from the sour e through the groun t o the adjoining s rata or t o emit t o atmosphe e

Not e 1t o entry: Ex mples of sour es inclu e e.g wastes within a lan f il or spil of hydrocarb ns

g s mo itoring wel

s an pipe suita ly ins aled inside a bor hole from w hich g s samples can be taken t o measur soi g s

conc ntrations an t o monit or chang es in composition of soi g s or soi g s migratio (3.7)

mixtur of pe manent g ses (main comp nent ), dominat ed b methane an carb n dio ide, formed b

the de omp sition of degrada lewast es within lan f il sit es

Note 1t o entry: It can also inclu e a larg n mb r of V Cs ( race components)

3.12.1

lowe ex losive l mit

LE

lowes pe c ntag e (v lume fraction) of a mixtur of flamma le g s with air w hich wi l pro a at e an

ex losion in a conf ined sp c at 2 °Can atmosphe ic pr s ur

3.12.2

upper explosive lmit

UE

up e mos pe c ntag e (volume fraction) of a mixtur of flamma le g s with air w hich wi l pro a at e

an ex losion in a con ned sp c at 2 °Can atmosphe ic pr s ur

metho by adsorptio

method in w hich subs anc s t o be det ermined ar conc ntrat ed adsorptively on an adsorbent,

subseq ently desorbed an analy sed

Note 1t o entry: T e adsorb nt can b e.g activat ed char o l or XAD-4 resin

3.1

mo itoring instalatio

pe manent or t emp rary devic used for soi g s sampl ng

E AMP E Sub-sla , soilg s pro e

pas ive soi g s sampl ng

samplng b sed on the adsorption of g ses of the grou d on an adsorbent plac d in the grou d, without

E AMP E Gas lik e mine an lan f il g ses

Not e 1 to entry: Permanent g s can also b def ined as “element or compou d that is a g s at al ambient

t emperatures likely to b encou tered on the surface of the e rth ” ; se ISO 1 074:2 1 , 3.6.1

3.20

soi g s

g s an v p ur in the p r spac s of soi s

3.21

soi g s mo itoring device

b r hole f inished with suita le mat erial for s a i isation of the bor hole wal an / r for lmiting the

samplng ar a

Not e 1 t o entry: Depen ing on the ty e an sta ility of f it ing, a distinction is made b tween temporary (for single

or short-term repe ted soil sampling) an stationary an semipermanent or permanent soil g s monit oring

points (for long -t erm o servation)

3.22

soi g s pro e

soi g s samplng pro e

pro e, g ene aly a tube, w hich is ins aled dir ctly int o soi (one-s ag e soi g s samplng), or in a b r hole

( wo-s ag e soi g s sampl ng) t o take soi g s samples

Not e 1 to entry: B ap lying a ne ative pres ure to the u per en of the soil g s pro e (he d), the soil g s at

the lower en (ip) is drawn through the suction opening(s) an transfer ed t o a g s col ecting eq ipment an

online me surement eq ipment (direct me suring method) or to an a sorb nt (concentration method), which

are instal ed either in or at the he d of the soil g s pro e or subseq ently used

3.23

soi g s sample v lume

v lume of soi g s taken t o form the sample

3.24

co tinuo s soi g s samplng

samplng from a monit oring wel o e a controled long er pe iod of time (mos ly seve al hours up t o

day s) t o o se ve the v riations o e time of the g s conc ntrations an of the pr s ur dis ribution in

two-stag e soi g s sampl ng

samplng done f irs ly through ins alation of a b r hole with the aid of a dri lng ins rument or b smal

b ring, and se on ly b samplng of soi g s from a soi g s pro e ins aled in the b r hole

v latie org nic compo nd

VOC

org nic comp u d that is v latie un e normal environmental/ tmosphe ic con itions, although it can

be fou d in the grou d in the sold, l q id an dis olved phase form aswel as in g seousphase

Note 1 to entry: V C can also b def ined as “org nic compou d” which is liq id at ro m temperature (2 °C),

which g neraly has a b iling point b low 1 0 °C se ISO 1 074:2 1 , 6.1.24

Note 2 t o entry: Ex mples inclu e single-ring aromatic hydrocarb ns an other low b iling halo enated

hydrocarb ns, which are used as solvents or fuels, an some de radation prod cts

4 Prel minar y items to be considered

Soi v p ur monit oring is a fast er an chea e method t o det ect contamination of VOCs in sois an / r

in grou dwat er an for ma ping the plumes than soi b r holes an / r the ins al ation of groun wat er

monit oring wel s The method pe mit es a l shment of a much dense network of soi g s monit oring

p int than is usual y p s ible for grou dwat er monit oring wel s an soi b r holes

The choic of samplng t ech iq e should be consist ent with the r q ir ment of the inves ig tion

( inclu ing subseq ent analytical proc d r s, conc ptual sit e model, inves ig tion o je tives, et c )

Conside ation should also be given t o the natur of groun u de inves ig tion, as wel as the natur

an dis ribution of contamination, the g eolo y and the hydrog eolo y Eve y efort should be made t o

a oid c os -contamination and c eation ofpr fe ential pathway s t o a oid contamination of u de lying

aq ife s

Befor intrusive works begin, a compr hensive che k should be made of the groun t o ensur that

no se vic s or s ructur s ar at risk an no hazards ar pr sent (for mor information on samplng

t ech iq es an safety, se ISO 1 40 -1 2 an ISO 1 40 -1 3)

When samplng soi g s close t o the surfac , the efe t of ambient air penetration ne ds t o be conside ed

The sampl ng depth is det ermined b the pr senc of impe mea le co e o e the grou d surfac , the

soi ty e (p rosity, cla cont ent, et c )an the depth of bedrock

NOTE 1 A preliminary con ition for soil g s sampling an monit oring is the prior recording of the g eolo ical

soil prof iles/pedolo ical layer For some sites, this can b done whilst taking soil samples from b rings

Cold con itions make soi g s sampl ng diff icult in many way s Grou d fros gr atly lmit the mo i ty

of g s in soi and should be conside ed in plan ing an car ying out sampl ng aswel as in int erpr ting

the measur ment r sult Wat er saturation (t otal or p rtial) of unsaturat ed la e (e.g aft er rainfal)

can signif icantly r d c the soi g s emis ion rat es, lmit soi g s mo i ity, and lead t o high levels of

h midity can seve ely r d c the adsorption ca acity of some sorbent

The main pro lem with soi g s sampl ng below the froz n groun is the los of air-filed porosity d e t o

the high mois ur cont ent in the zone betwe n froz n an unfroz n p rt of the grou d Conseq ently,

the samples should be taken from gr at er depths (but compatible with inves ig tion o je tives)

Al buidings cons ruct ed on u froz n grou d act as pathway s or b r ie s for upwards soi g s

migration L wer pr s ur s an dife enc s in conc ntration in the buidings can also as is g ses t o

penetrat e the b sement of buidings

NOTE 2 Causes of diferentialpres ure efects inclu e the rise of warm air within buildings an the operation

of air -con itioning systems Gas can enter through:

— c acks an openings in conc ete grou d sla s such as c acks d e to shrin a e;

— construction joints/ penings, e.g at wal/ fou dation int erface with grou d sla ;

— c acks in wals b low grou d level present d e for e ample t o shrin a e or movement;

— g ps an openings in suspen ed conc ete or timb r flo r ;

— g ps arou d service pipes an d cts;

— cavity wal s;

— stair ases, elevat or shaf

Gas migration int o othe s ructur s also ne ds t o be conside ed, espe ial y below groun s ructur s

such as man oles, culve t , l f pit , mine shaf s, ac es t o un e grou d se vic s, et c

This document spe ificaly deals with the sampl ng of soi g s R elat ed exhaus or int erfe enc sour es

in ambient air ( in us rial or mor g ene al y anthro og enic activities)ar not conside ed a art from the

cons itution of a field blank

Pr s ur efe t caused b the rise of warm air within bui dings can as is the entry of g ses int o

bui dings

Some org nic p lutant in the g s phase in soi an subsoi can pr sent t oxicolo ical risks ofv rying

severity Due t o thisp s ibi ity, pe son el should be pro ided with a pro riat e g s det ection eq ipment

an should be eq ip ed, ac ording t o the p t ential t oxicity (as umed or measur d), with suita le

pe sonnel prot ective eq ipment (P E)

Ce tain org nic fumes (as wel as methane, for ex mple) can form ex losive mixtur s with air

(ex losivity l mit an self-ignition t empe atur s should be taken int o ac ou t) It is the efor

a pro riat e t o use ele trical eq ipment an t ools w hich ar suita le for use in ex losive atmosphe es

Health an safety is ues should be conside ed at al times Training should be given t o ensur that

pe sonnel u de s and the ne es ary pr cautions (for mor information on safety, se ISO 1 40 -1 3)

5 Basic principles

5.1 Physical and chemical pr inciples

5.1.1 P ermanent gases

Pot ential y hazardous pe manent g ses ( e 3.1 ) such as methane an carb n dio ide oc ur mos

commonly in “lan fil g s” an “ mine g ses”

Whe eve biodegrada le mat erial is pr sent in lan fil sit es or within the soi matrix of the grou d

beneath a brownf ield sit e, mic o ial activity wi l prod c methane an / r carbon dio ide Theseg ses

can simiarly be prod c d in aluvial dep sit an b degrading natural org nic mat erial L n fil g s

consis s primari y of methane an carb n dio ide (at a ratio of a pro imat ely 6 :40) Depen ing on

mic o ial activity, this ratio can chang e A n mbe of ad itional trac g ses can be pr sent

Mine g s, also caled co l mine methane (CMM), is a set of v rious v p urs prod c d d ring mine

o e ations It is a mix of methane (es ential y, mor than 9 % ) an carb n dio ide (nearly 1 % )

Some minor g ses ar also pr sent: carb n mono ide (prod ct of incomplet e combus ion of carb n),

hydrog en sulf ide an nitrog en

Ab n oned mine methane (AMM) r fe s t o mine g s aft er ex loitation, w hich is tra ped in the forme

g le ies, b ost ed and pro eled t o the surfac throughout the flo ding of the mine It usualy contains

les methane an mor air than CMM (5 % t o 6 % of methane, depen ing on the seal ng of the mining

v ids an forme works)

Pe manent g ses can also originat e from co l dep sit , peat, natural dep sit (e.g chalk an aluvial

dep sit ), from leaks of mains g s (natural g s) an from sewe g s Information on t ech iq es for

identifying the origin of g s can be fou d in 5.4

Methane is ex losive at conc ntrations of betwe n 5 % an 1 % (v lume fraction) in air; below 5 %

[the lowe ex losive lmit (LEL)] the e is insuff icient g s t o sup ort combus ion an a o e 1 % [the

up e ex losive l mit (UEL)] the e is insuff icient o y g en t o sup ort combus ion These b th ex losive

l mit ar chang ed b the pr senc of othe g ses(e.g carb n dio ide)

Carb n dio ide is an asphy iant and also t oxic It can ca use adve se health efe t in conc ntrations

gr at er than a out 0,5 % (v lume fraction)

The LEL of a mixtur of ex losive g s is eq al t o the lowes LEL among the comp nent of the g seous

mixtur In the same wa , the UEL of a mixtur of ex losive g s is eq al t o the highes UEL among

the comp nent of the g seous mixtur Th s, othe alkanes conc ntration (ethane, nota ly) should be

conside ed in the calculation of LEL UEL

L n f il g s is usualy saturat ed with mois ur an is cor osive It can cause veg etation t o die b ck d e

t o the elmination of o yg en from the plant’s ro t zone or t o the pr senc of phyt ot oxic comp u ds It

density depen s up n the ratio of carb n dio ide t o methane:the highe the ratio of carb n dio ide, the

gr at er the density

Gas pr s ur within the subsurfac is depen ent on the g s g ene ation rat e, the atmosphe ic pr s ur ,

the pe mea i ty of the wast e mas an the sur ou ding s rata, chang es in the level of leachat e or

grou dwat er within the sit e an the t empe atur

Depen ing up n sit e engine ring an local g eolo y, g s can migrat e conside a le dis anc s and can

pr sent a hazard t o nearb develo ment

In the p rticular case of mine g s, the c s ation of wat er pumping leads t o a rise in wat er ta le

levels w hich inc eases the g s pr s ur in mine v ids, and conseq ently inc eases the pro a i ty of

surfac g s emis ions, through the groun or forme mine works It is, the efor , imp rtant t o g in an

un e s an ing of g s conc ntrations an flow rat es t o es a l sh the p t ential for g s migration of-sit e

or atmosphe ic emis ions Usualy, de ompr s ion b r holes ar dri led t o a oid this phenomenon

They ar g ood monit oring and sampl ng p int t o monit or mine g s composition, pr s ur , flow an

wat er level

5.1.2 Volatie or ganic c ompo nds

Depen ing on the pr s ur an t empe atur con itions, V Cs ent er int o soi por spac as eithe a

lq id or a g seous phase They ar pr sent in soi as g seous and l q id phases, dis olved in soi wat er,

adsorbed on sold (org nic an inorg nic) soi p rticles or enclosed in ca i lary ca ities

Dynamic dis ribution eq i briums ar es a l shed ac ording t o the pr v i ing con itions an b u d

forms of the p lutant Owing t o the dive sity of the p s ible subs anc dis ributions an the

time-dependent efe t on the eq i ibrium, each det ermination of the contaminant conc ntration can pro ide

only a “ point-in-time” desc iption of the s atus Eve y int erfe enc , with the soi an / r grou dwat er,

afe t the dis ribution eq i brium in a dife ent wa , w hich is diff icult t o as es

A saturation eq i brium between the lq id and g seous phases is es a lshed in the contaminat ed

zone indepen ent of the amou t of subs anc pr sent A soi g s saturation conc ntration of a V C

develo s in the immediat e sur oun ings of the p lut ed ar a, ir espe tive of w hethe it is a ve y smal

dro of the subs anc or a larg e dep sit The conc ntrationsmeasur d in the soi g s should not be used

as an in ex of the actual amount ofsubs anc pr sent in the soi V Cs dispe se in soi g s b conve tion

( i.e in the dir ction of the pr s ur gradient) an difusively ( i.e in the dir ction of the conc ntration

gradient) VOCs in the soi can be transp rt ed as flowing non-aq eous-phase lq ids (NAPLs an / r

DNAPLs), or t og ethe with anothe flowing lq id phase (e.g grou dwat er, or dis olved in mine al oi),

from w hich they can be trans e r d b ck int o the soi g s

5.2 En vir onmental c onditions

It is imp rtant that atmosphe ic conditions, befor an d ring the sampl ng, be r corded It wi l

g ene aly be suff icient t o r cord the conditions a out a we k prior t o samplng, but rainfal up t o a

couple of we ks befor ma afe t soi g s sampl ng, depen ing on, e.g t empe atur , soi ty e an

samplng depth L cal clmatic con itions at the time of monit oring should also be r corded This

information can helpin the int erpr tation of the data The mos important p ramet ers t o r cord ar :

— atmosphe ic pr s ur :

d e t o the pr s ur dife enc betwe n soi p r s an atmosphe e, ra id fal ng atmosphe ic pr s ur

inc eases soi g s emis ion rat es Ra id rising atmosphe ic pr s ur can ha e the o p sit e efe t The

ma nitu e of this efe t depen s up n the soi pe mea i ty an the rat e at w hich the pr s ur chang es

It is also conside ed that atmosphe ic pr s ur u de 1 0 3 h a (depr s ion con ition) wi l inc ease

emis ion rat es;

— rainfal:

a long or a s rong pe iod of rainfal can lead t o ac umulation of soi g s u de the wat er front Gas can

be dis olved in wat er an the samplng, even with pumping devic , wi not be enough t o fr e the g s

The measur ment wi l not also be r pr sentative;

aft er rainfal, a wat er lo ging efe t wi oc ur in the u saturat ed la e an chang e the groun ’ s wat er

saturation, r d c the mo ement an r d c emis ion rat es of soi g s

Othe useful paramet ers ar :

— outdo r t empe atur :

out do r t empe atur ha e a signif icant efe t on ev poration, w hich in turn wi l afe t the inf iltration

an pe colation of wat er an th sthe mo i ity an conc ntration of soi g s;

soi t empe atur also afe t the conc ntration of g ses e.g biolo ical prod ction of CO

2(an

consumption of O

2) through ro t an mic o ial r spiration is highe at highe t empe atur espe ialy

in wel veg etat ed ar as Othe g s prod cing r actions ma also be t empe atur depen en

t empe atur influenc s volati ty of chemicals High t empe atur wi raise the v latie p t ential of

chemicals an inc ease emis ion rat es;

NOTE 1 The temperature in the soil ten s t o remain relatively consistent, u til ne r sub-surface (1,0 m to

1,5 m depen ing on climate an of the soil nature) At this depth, outdo r temperature has low or no influence on

the volatilisation in the subsurface an emis ion of V Cs

— in o r t empe atur :

w hen a bui ding is heat ed, if the in o r t empe atur is highe than out do r t empe atur , a “chimney

efe t” can oc ur, leading t o a r d ction in pr s ur r lative t o atmosphe ic pr s ur out ide an

conseq ently ind c a flow of soi g sint o the bui ding;

— h midity (ambient air an soi g s or sub-sla g s):

h midity can seve ely r d c the adsorption ca acity of some sorbent ;

— win spe d/dir ction:

depending the dir ction an int ensity of the win , it can lead t o a r d ction in pr s ur r lative t o

atmosphe ic pr s ur out ide an conseq ently in uc a flow of soi g s int o the buiding;

win p s ing o e the soi surfac lowe s the g s pr s ur in the up e r aches of the soi c eating

a gradient for g s flow t oward the surfac The ext ent t o w hich this oc urs depen s on a v riety of

fact ors, inclu ing w hethe the surfac is “ ealed”b fr e ing or wat er lo ging;

— wat er ta le depth an any hydrog eolo ical pe turb tion nearb (e.g grou dwat er pumping,

ex ca ation, tide influenc ):

a wat er ta le rising (e.g caused b rainfal , tide efe t), can put he g s un e pr s ur an for e it t o the

surfac ; howeve , it can also block migration p thway s The saturation of supe ficial soi s can r s rict

the venting of soi g s t o atmosphe e Thiscan r sult in v riations in g s pr s ur an conc ntrations;

NOTE 2 Aft er co l e ploitation, g s stil desorbs from sour e rock In the same time, water p mping st ops

an a flo ding oc ur in the remaining mining voids T e rising water ta le involves an overpres ure of co l

g s, which can then migrate to the surface through former mine works or the fractures in the u per g olo ical

formations in uced by the e ploitation T is p enomenon is constrained than s t o decompres ion b reholes,

ofering a control ed pathway to the g s from the de p reservoir t o the atmosp ere

— grou d con itions (e.g dry, wet, froz n) an het erog eneity:

the cla wi l sometimes be ome wet an swel th s r sealng (healng) the c acks but this does not

alway s ha pen depen ing on the cla mine als pr sent an w hethe the c acks be ome f iled with san

or othe detritus This wi lead t o an inc ease in g s emis ions at the surfac In pe iods of wet weathe ,

the cla wi l be ome wet an swel, an c acks wi be sealed This wi l r d c surfac g s emis ions an

can lead t o inc eased g s conc ntrations an inc eased lat eral migration A measur ment of intrinsic

soi pe mea i ity an mois ur cont ent can be helpful in as es ing these efe t ac ording t o the natur

of the soi;

depending up n sit e engine ring an local g eolo y, or met eorolo ical con itions (e.g froz n soi), g s

can migrat e conside a le dis anc s (metr s t o t ens of metr s) within the unsaturat ed zone through

pr fe ential pathway s (anthro ic or naturals) an w hen it ent ers a pe mea le la e that is conf ined b

an o e lying impe mea le la e or pe ched grou dwat er

In g ene al, it can be difficult t o es a lsh the ca use of chang es in conc ntrations an emis ions sinc

they ma be d e t o a combination of the a o e fact ors

Howeve , a q altative ev luation of samplng con itions should be pro ided with jus if ication for

each sampl ng camp ign in orde t o draw a conclusion as t o it l kely r pr sentativenes charact er

(u de es imating, inflating or neutral con itions)

NOTE 3 F or permanent g ses, the main factor is atmosp eric pres ure

5.3 S i gas d ynamic

The migration of v lati e comp u ds in soi g scan be via thr e primary me hanisms:

— difusive flow (mo ement of cons ituent along a conc ntration gradient);

— adve tive flow (mo ement of cons ituent d e t o motion of a transp rting fluid);

— dispe sion (ransp rt r sulting from local v riations in fluid flow, e.g d e t o friction efe t in the

matrix)

Fact ors w hich influenc the migration of VOCs in the u saturat ed zone inclu e the chemical/ hy sical

pro e ties of the VOCs, the g eolo ic con itions (e.g groun pe mea i ity) an chemical/ iolo ical

con itions (e.g w hethe mic o ial degradation is active)

5.4 Identifying the sourc e of soi gas

Identifying the origin of the g s is imp rtant w hen making de isions r g rding it monit oring an

control In a contaminat ed lan cont ext, a sit e hist ory s u y, a pr l minary dia nos ics an a conc ptual

sit e model ar ne es ary t o identify the comp un s lkely pr sent in soi , non-aq eous phase lq ids

on/in/un e groun wat er an / r soi g s Pos ible degradation prod ct should be identified so as t o

be a le t o pro e ly det ermine the impact of the contamination that is being inves ig t ed

The comp sition of a g s ma help identify the sour e The folowing ex mples ar given for pe manent

an land l g s:

— g s from a g eolo ical sour e ma ha e a highe pro ortion of methane than lan f il g s;

— g eolo icaly-de ived g s g ene al y contains up t o 1 % ethane an highe hydrocarb ns, w hie

biog enic methane contains only trac amou t ;

— it ma be p s ible t o dis inguish mains g s from othe g ses if the ex ct comp sition of the local

mains g sis k own

Mains g s ma ha e odour comp u ds such as sulf ides an me ca tans ad ed t o give the g s a

dis inctive odour; it ma also contain long chain hydrocarb ns such as octane an nonane Helum is

oft en r mo ed from mains g s

L n f il g s ma also contain highe than normal conc ntrations ofhighe hydrocarbons if the wast e

contains subs anc s that g ene at e or r lease such g ses an v p urs

Identif ication of dife ent comp nent ma , howeve , be l mit ed as the comp nent ma be afe t ed

b chemical chang es oc ur ing in the groun d ring migration, b solution in grou dwat er an b

adsorption ont o cla s, et c

Ratios of pe manent g ses can be useful t o dis inguish the origin of/ roc s esprod cing g ses such as

Biog enic (formed b mic o iolo ical activity) methane an the mog enic (formed b the mal degradation

of org nic matt er at highe t empe atur s an pr s ur s) methane have dife ent pro ortions of

carb n isot opes carb n 1 an carb n 1 w hich can be measur d t o identify the origin of the g s The

t ech iq e, howeve , r q ir s spe ials la orat ories

In a contaminat ed lan cont ext, volatie comp un s can come from:

— sold or lq id compoun s pr sent in the soi;

— non-aq eous-phase lq ids on or in grou dwat er;

— grou dwat er imp ct ed with dis olved v latie comp un s

In this cont ext, some t ools ma help t o identify the sour e, inclu ing:

— conc ntration gradient s u y in sois, grou dwat er an / r soi g s;

— ratio comparison of dife ent comp un s for multi-comp u ds contamination in sois, groun wat er

an / r soi g s;

— ratio comp rison of a comp u d an it degradation prod ct in sois, groun wat er an / r soi g s;

— isot opic analy ses

Identif ied sour es should be inclu ed in the conc ptual sit e model

6 Requir ements for sampl ng plan

6.1 General c onsiderations for sampl ng plan

6.1.1 Objecti ves and g eneral r ec ommendatio s

6.1.1.1 Objecti ves

The main o je tives of soi g ssampl ng ar asfolow s:

— q altative det ermination of subs anc s pr sent in the u saturat ed soi la e ( invent ory);

— q antitative det ermination of subs anc s pr sent in the u saturat ed soi la e (ev luation);

— det ermination ofspatial and t emp ral v ria i ty of local conc ntrations;

— det ermination of the plac () of input an location of the contamination c ntr s (= ar as of highes

conc ntration measur d/hot sp t);

— det ermination of the horizontal an ve tical dis ribution of conc ntrations;

— ma ping of grou dwat er contamination (polutant plumes);

— o se v tion of sp tial dis ribution o e the time;

— det ermination of soi g ses contribution t o ambient, in o r an / r out do r air in a risk as es ment

cont ext ;

— measur ment t o ev luat e the feasibi ity of r mediation measur s (e.g g s extraction pot ential);

— measur ment t o ev luat e the efe tivenes of r mediation measur s

Develo ment of the inves ig tion s rat eg should inclu e de isionsa out:

— phasing of the inves ig tion;

— the location, p tt ern an n mbe of monit oring p int r q ir d for the sit e as a w hole or for

in ivid al zones;

— thedesign of monit oring wel s or monit oring point inclu ing the r sp nse zone();

— w hat on-sit e measur ment ar t o be made an how these ar t o made (choic of ins rument , et c );

— thefr q ency an timing of monit oring an the pe iod o e w hich monit oring is t o be car ied ou

— thety e an n mbe of samples t o be cole t ed for la orat ory analy sis;

— themethodolo y b w hich samples for la orat ory analy sis should be cole t ed, transp rt ed, st or d

an pr se ved;

— the la orat ory analy ses r q ir ment ; (e.g transport con itions, n mbe of sup ort , ma imum

flow rat e);

— thela orat ory analysis r q ir d;

— any safety measur s ne ded t o prot ect thepe sonnel or the environmen

— w hat q al ty as uranc measur s ar r q ir d

When pr p ring the samplng plan, conside ation should be given t o any plan ed inv sive activity

(ex ca ations, vibrations, et c ) that might c eat e pathway s for g s migration or othe wise afe t

migration p tt erns

6.1.1.2 General r ec ommendations

In ad ition t o g s monit oring, b r holes ar also useful for o taining g eolo ical hydrog eolo ical,

g eot ech ical an contamination information an ar the efor a useful multi-purpose t ool

When monit oring r sult , espe ialy those o tained from s an pipes, ar t o be compar d with one

anothe , the t ech iq es used t o o tain them should be consist ent t o ensur comp ra i ity between

dife ent o e at ors, t echniq es an o e dife ent monit oring pe iods or betwe n dife ent la orat ories

To achieve this, q al ty as uranc measur s as given in Clause 1 should be folowed

Gas conc ntration measur ment ma be taken using p rta le eq ipment ( e An ex B) or samples

ma be taken for of-sit e la orat ory analy sis It is advisa le t o cole t g s samples, t o be submitt ed for

conf irmat ory analy sisin a la orat ory, in orde t o ve ify the on-sit e monit oring r sult

NOTE F or permanent g ses, especial y with an “infrared” method, it is ad isa le to implement a specif ic

methodolo y taking into ac ou t he charact eristic of the g s (det ection of methane b fore carb n dio ide)

If samples can ot be taken ac ording t o the plan (e.g be ause of o s acles on the sit e or in the groun ,

highe grou dwat er level than ex e t ed), this shal be r corded in the samplng r p rt It is wise t o

define c rtain proc d r s for such conting encies (e.g r locat e the sample, lea e it out) In the a senc

of pro e ly document ed proc d r s, sampl ng pe son el can make wrong de isions, r n e ing the

inves ig tion useles

The s rat eg should be spe if ic an should be b sed up n the p rticular con itions on the sit e in

q es ion, as r vealed b the pr lminary inves ig tion an any intrusive inves ig tion car ied out t o

dat e ( e ISO 1 400- 20

1)

) The e is no single s rat eg w hich can be g ene aly a pled The efor , some

ty ical ex mples ar given in the folowing p rt

6.1.2 Initial ex ploratio s ( ield s r eening )

The aim of an initial ex loration is t o det ermine the subs anc s pr sent and/ r their conc ntration

rang e A t this s ag e, data on conc ntrations ar g ene aly not k own, so the e is the risk that the

measuring rang e sele t ed ma be not a pro riat e Det ection lmit can be t oo high, raising the

pos ibi ity of br akthrough, in the case of adsorbent In the case of contaminant pr sent at low

levels, the extraction of larg e v lumes (e.g 2 l t o 1 0 l) alow s g the ing of information on a mor

compr hensive rang e of subs anc s

When efe tively used, sc e ning methods can pro ide a compr hensive o e view of subs anc s pr sent

an th s r sult in conside a le cos sa ing as r g rds the subseq ent detai ed inves ig tion

The use of a phot oionization det ect or (PID ), a multi-g s analyz r (O

2, CO

2, H

2

S, CH

4, CO), without prior

use of a g s chromat ogra h, as wel as dir ct-r ading det ect or tubes, se ve for la our prot ection,

workplac monit oring an for rough ma ping of polutant plumes (e.g for det ermining efe tive

s arting p int for es a l shing grou dwat er or soi g s measuring sit es)

They do not sup ly ex ct conc ntrations of single V Cs but give the rang e of conc ntration pr sent in

soi g ses This pe mit the measur ment proc d r subseq ently used t o be f itt ed t o the conc ntration

levels (e.g lowe the sample v lume) C nside ing the r lative pr cision of f ield eq ipment

(non-q antitative measur ment , v ria i ity of r sult ) and transp rt hazards for this ty e of eq ipment, it

is s rongly r commen ed t o d pl cat e soi g s sampl ng w heneve pos ible

6.1.3 Know n c ontamination c entre

If the contamination c ntr is k own, the ext ent an lmit of the contamination can be inves ig t ed

using p int sc e ning The sc e ning is car ied out on sele t ed prof iles b th horizontaly an ve ticaly

ac ording t o the natur of the sit e an the o je tives Starting with larg e dis anc s between samplng

locations an inc easing sample density st epwise, if a pro riat e, wi l pro ide a cos -efe tive s rat eg

6.1.4 Deter minatio of the c ontamination hot spots (areas showing highest c onc entrations)

and gas mo itoring wels locatio

If the contamination c ntr is not k own or w hen the e is doubt a out he pr senc of contamination,

sc e ning is car ied out using a co rse r gular grid p tt ern Al a ai a le information from hist oric

en uiries or pr vious inves ig tions should be taken int o ac ou t

In this case, l ght t ools and eq ipment ar g ene al y combined with analytical/measur ment methods,

alowing det ection of a wide rang e of conc ntrations A larg e n mbe of measur ment point should be

used t o r d c the risk of not f in ing suspe t ed contamination

Onc a contamination c ntr has be n foun , folow the s rat eg of 6.1.3

1) Un er pr eparation

6.1.5 Determinatio of hor izontal and vertical distributio of VOCs

This is es entialy the same proc s given in 6.1.3 S r ening or cole tion of soi samples for headsp c

ex mination o e horizontal and ve tical prof iles is car ied out t o es a l sh the dis ribution of the

contaminant in the soi g s

Point samplng ( mal samplng v lumes of soi g s taken from def ined samplng depths) along prof iles

can also be used t o det ermine sp tial dis ribution Car shal be taken that ambient con itions ( e 5.2)

an consist ent sampl ng t ech iq es an ins rument ar achieved t o ena le comp ra le measur ment

On-sit e analy sis can help t o minimiz int erfe enc s an can al ow an efe tive int ensif ication of the

samplng p int sc e n

6.1.6 Obser vation of spatial distributio of VOCs in the c our se of time

R epeat ed samplng un e almos the same con itions is p s ible only for homog eneous an wel

def ined grou d con itions The efor , it is useful t o es a lsh pe manent oi g s monit oring devic s for

pe manent contin ous o se v tions

The disadv antage of such monitoring devic s is that they pr sent a lmited pictur of the situation as

r g rds soi g s on the sit e In particular, the geometry an surfac of the monitoring devic , as wel as

the p t ential for g s exchange, ar significantly dife ent from the cor esp n ing pro e ties of soi p r s

Particular att ention shal be paid t o ambient con itions (v riations in t empe atur , h midity, air

pr s ur , wat er cont ent, et c )

6.1.7 E aluatio of soi gases c ontributio to ambient, ind or and/or outdo r air

When a risk as es ment is ne ded in adv nc (for a buiding in cons ruction) or for a buiding that is

not ac es ible, it should be b sed on measur d soi g s conc ntrations, emis ion rat es an ado tion of

suita le models t o pr dict in o r air conc ntrations

When a risk as es ment is ne ded for buidings alr ady exis ing on a sit e, it should pr fe a ly be b sed

on conc ntrations det ermined on the ex osur media (ambient, in o r an / r out do r air) rathe

than on conc ntrations de ived b model ing from soi g s conc ntrations or dir ctly from p l utant

conc ntrations in soi

In in o r air, the e ar some VOCs emitt ed b buiding mat erials an furnitur When in o r air

measur ment is ne ded, it is important t o det ermine the contribution of soi g ses conc ntrations t o

the levels measur d in the ex osur medium (e.g in o r air) in orde t o dife entiat e it from othe

contributions (e.g ambient air p lution, in o r domes ic p lution) In this cont ext, soi g s samplng

should be car ied out u de neath the in o r sampl ng locations (or as close as practica le) at thesame

time an with thesame method as used t o det ermine conc ntrationsin the ex osur medium

6.2 Wor king rang es of me sur ement methods

The aim of sp tialy localzing or del neating soi contamination pro ides for a r lative q antitative

comp ra i ity of the conc ntration v lues det ermined The soi g s conc ntration v lues rang e

ac ording t o the cor esp n ing subs anc an method-spe ific det ection lmit ( eve al mic o rams

) In orde t o co e the w hole conc ntration rang e, samplng

t ech iq es an measuring methods ada t ed t o the r lev nt pro lem should be used

NOTE When using adsorption methods, the capacity of adsorb nts can re dily b ex ce ded T e volumes at

which bre kthrough oc ur difer from chemical t o chemical In the case of high concentrations in soil g s, direct

me surement methods are useful to give the rang of concentration present T is permits the me surement

proced re subseq ently used t o b f it ed to the concentration levels (e.g avoiding bre kthrough by lowering the

sample volume)

6.3 Monitoring wel options

Soi g s can be monit or d and/ r sampled using:

— driven pro es;

— pe manent g s-monit oring wels, p rt or sampl ng pro es;

— mine shafs, de ompr s ion b r holes an g s safety works

Although each t ech iq e has it uses, in situations w he e a detaied, long -t erm u de s an ing of the sit e

is r q ir d, pe manent g s monit oring welsor sampl ng pro es ins aled in b r holes should be used

If g s conc ntration measur ment ar r q ir d at dife ent depths, grouped, nest ed or multi-level

ins al ations should beused

S le tion of the ins al ation() t o be used should take int o ac ount health an safety an p t ential

environmental imp ct , and w he e k own, the g eolo y Some t ech iq es also pr clu e the cole tion of

soi samples for ex mination

Options for sampl ng an measuring soi g s ar l st ed in Ta le 1

Table 1 — Optio s for sampl ng soi g s

Sampl ng t echniques Temp rary

or pe

ma-nent moni

t oring

Desc iption Adv nta es Disadv ntag es

A pas ive

Sampl ng t echniques Temp rary

or pe

ma-nent moni

t oring

Desc iption Adv ntag es Disadv nta es

Driven pro es with lost cone t emporary

Sampl ng t echniques Temp rary

or pe

ma-nent moni

t oring

Desc iption Adv nta es Disadv ntag es

Driven pro es with s re ned part

Gas monitoring wel

(without lushing device)

-ous flight aug er;

sonic driling

Can instal

sev-eral stan pipes

in one b rehole

to me sure at

diferent depths

Can take samples

of strata at

diferent depths

d ring driling

Sampl ng t echniques Temp rary

sampling device

simply con

Diferent re

cha-ble depths, from

Gas pres ure

may not b

NOT 1 Gas monitoring wel made with flushing device is not recommen ed b cause air or water flush can

spre d contamination Air flush can also cause migration of soil g s

NOT 2 Al lubricants used should b such that they wil not interfere with the me surements t o b made, ei

ther whilst the work is in pro res or d ring later monit oring (e.g it might b prefera le t o use veg ta le rather

than mineral oils as lubricants when V Cs are to b monitored) Similarly, care should b taken d ring st ora e

an han ling of lubricants, fuels an hydraulic fluids for dril ings rigs, et c that hey do not le k int o the grou d

6.4 S mpl ng plan

6.4.1 Horizo tal locatio of samplng devic es

The location an design of monit oring wel s or othe chosen t ech iq e should be planned wel in

adv nc , in ac ordanc with:

— theaims of the sit e inves ig tion ( e 6.1);

Table 1 (c ontin ed)

— theconc ptual sit e model, inclu ing:

— the k ow ledg e from hist oric s u y an forme dia nos ics;

— the g eolo ical cont ext (e.g natur of soi , het erog eneities);

— the hydrog eolo ical cont ext (natur of aq ife , flow dir ction and v riations of the wat er ta le

in time);

Geolo ical an hydro eolo ical context should be k own befor soi g s sampl ng in orde

to pr vent implantation of the pro e or w el in grou dwate , or in dife ent an / r un nown

soi lay ers

— the location an n mbe of p t ential on- an of-sit e sour es;

— the natur an beha iour of the contaminant (e.g solubi ity, levels an het erog eneity of

p lution in the u saturat ed zone);

— migration p thway s such as mor pe mea le zones of soi or rock and close t o se vic d ct an

tr nches;

— pe mea i ity of the groun (w hich afe t the zone of influenc of the wel s, espe ialy if the

wels ar con e t ed t og ethe b the same la e , a drain, a drif wa , et c );

— locations of u de groun se vic s, et c

— the locations of exis ing buidings ( inclu ing location, form an depth of foun ations) an othe

s ructur s;

— the locationsof pro osed buidings an se vic s;

— the ext ent of pro osed ex ca ations an othe earthworks;

— thesensitivity of the (pro osed) en use;

— ne d t o as es p t ential of-sit e migration;

— radius of action of monit oring wel;

— dri lng cons raint (e.g ac es , location of u de groun se vic s);

— othe conside ationsinclu ing health an safety

Each sit e pr sent a spe ific combination of these element an the e is no g ene ic sampl ng s rat eg

a plca le t o al sit es

A samplng plan should be drawn up in detai containing al the element l st ed a o e as a pro riat e

with jus if ication of the a pro ch that is t o be ado t ed

Any chang es t o this plan should be not ed with jus if ication

6.4.2 Mo itor ing depths

In ar as w he e contamination is thought t o be seve e, the dri lng of b r holes can prod c pr fe ential

p thway s an as a r sult information should be sought on spe ial s dri ing pr ca utions

The depth from w hich samples ar taken depen s on the o je tives Information on conc ntrations

at dife ent depths is useful, as it alow s for a bett er un e s an ing of the pro ensity for the g s t o

migrat e

Depth of soi g s sampl ng also depends on information r q ir d and on sit e con itions such as

s ructur of the grou d, location of the groun wat er ta le, migrat ory p thway s, et c These con itions

shal be es a l shed prior t o plan ing of soi g s samplng Soi profiles of al of the soi g s samplng

b r s shal be r corded in detai depen ing on the het erog eneity of the groun an the o je tives of the

inves ig tion

The folowing thr e p int should be taken int o ac ount when det ermining monit oring depths:

a) owing t o inc easingly uncontroled influenc of ambient air at shal ow depth the minimum samplng

depth should not be les than a out 1 m below groun surfac ;

If the e is g ood r ason for samplng from close t o the surfac (e.g below sealed sit es), this should

be in icat ed in the sampl ng r p rt ;

F or VOCs, if the sampl ng depth is les than 1 m, in the a senc of seal ng surfac in g ood con ition

(conc et e, asphalt, et c ), the grou d surfac for a out a 5 m diamet er arou d the sampl ng point

should be sealed a ains air entry with a suita le flexible membrane (only ine t mat erials should

be used)

F or sub-sla sampl ng, the sample should che k the sla s at e t o identify al the pr fe ential

pathway s between in o r air an sub-sla air The airtightnes of the samplng p int wi l be

guarant eed with a seal madeof ine t mat erial If the e is any doubt as the lkely airtightnes of the

sla , it ma be sealed (or at leas impro ed) b sealng c acks an supe imp sition of a suita le

flexible membrane

b) samplng p int hould be at leas 1 m a o e the wat er ta le so that the sc e ned se tion is alway s

a o e the groun wat er an ingr s of ca i lary wat er is inhibit ed The efor , this should be taken

int o ac ou t w hen de iding the monit oring depth;

F or a pe manent wel, the b se of the monit oring wel should be set 1 m a o e the highes k own

grou dwat er level

NOT Ma imum sampling depth is limited by the ac es ibility, by the availa ility of t ech iq es t o secure

g s-tightnes of the pro e syst em an limit de d volumes, an by the level of the water saturat ed soil zone

c) thesc e ned p rt (or sampl ng chambe )of the samplng wel should be in a u iq e g eolo ical bed;

it is r commen ed that the length of the sc e ned p rt (or samplng chambe ) of the samplng wel

doesnot ex ce d 0,5 m

If conc ntration gradient ha e t o be inves ig t ed (e.g w hen delneating hot sp t ), multi-depth

samplng ( e 7.2.4) an smal samplng v lume should be pr fe r d In this case, t ech iq es that alow

cole tion of soi g s samples from smal sampl ng volumes ( i.e from holes les than 0,1 m in diamet er)

should beused

F or soi g s sampl ng lnked t o risk as es ment, sampl ng at shalow depths is r commen ed

Multiple wel s formed t o dife ent depths (grouped ins al ation) or nest ed wels (nest ed ins al ation)

ma be used t o monit or g s conc ntrations at dife ent depths Whe e nest ed wels ar used, the

ins al ation should be closely supe vised t o ensur g s-tight seals ar achieved within the b r hole

Monit oring wels should ha e r sp nse zones that int er ept g s in a single sour e or p thwa The

r sp nse zones should not normaly sp n ac os dife ent our es or pathway s

6.4.3 Timing and fr equency of mo itoring

Monit oring should be car ied out s arting from shortly aft er ins alation of the monit oring eq ipment

for a pe iod commensurat e with the o je tives of the inves ig tion

When a monit oring wel is ins aled in a b r hole, sampl ng should not be car ied out for at leas 24 h

aft er formation of the wel t o pe mit set lement of the wel pipe within the b r an t o pe mit the

bent onit e seal t o pro e ly set

Monit oring should be sufficient t o alow pr diction of wors case con itions w hen soi g ses an / r

pe manent g ses emis ions t o atmosphe ic air ar lkely t o be high F or pe manent g ses, monit oring

should be car ied out on t ens of day s d ring a pe iod of low atmosphe ic pr s ur s F or othe soi g ses,

monit oring should be car ied out d ring a pe iod of low atmosphe ic pr s ur s, dry air (no rainfal) or

high out do r t empe atur

Jus if ication should be pro ided for the monit oring pe iod an fr q ency that is ado t ed This should

be b sed on the pr lminary conc ptual sit e model

Fact ors that should be taken int o ac ou t in the de ision proc s inclu e:

— pe iods of rising, fal ing an s a le b rometric pr s ur ;

— rainfal;

— wat er ta le depth an any hydrog eolo ical con itions;

— grou d con itions (e.g dry, wet, froz n);

— thene d t o be a le t o pr dict the natur an timing of wors case con itions

Due t o the v ria i ity of soi g ses o e time, it is r commen ed t o r al z at leas two samplng

camp igns in dife ent environmental con itions(e.g wint er/summe ) ( e 5.2)

NOTE T is recommen ation of two sampling campaigns in diferent en ironmental con itions is a

minimum Due to the level of risk, urg ncy, lack of k owledg of soil g s variations, more freq ent sampling

campaign can b re lized especial y in d namic systems (rapid chang s or evolutions) It is common to have

monthly or thre -monthly sampling campaign

In the case of long monit oring ( eve al day s, seve al weeks, et c ) ad itional fact ors ma be taken int o

ac ou t: risk of degradation, swit chg ear monit oring, r veg etation, ene g consumption, et c

Highe fr q ency monit oring can be a pled depen ing on the o je tives (e.g soi g s inves ig tion

l n ed with risk as es ment) an the ex e t ed v ria i ity of g s emis ions

F or each sampl ng camp ign, an as es ment of the g s emis ion con itions should be car ied out This

as es ment should inclu e conside ation of the environmental con itions ( e 5.2) (e.g g ene aly a

pe iod of high atmosphe ic pr s ur , hea y rain an low t empe atur g ene at es low t o ve y low g ses

emis ions)

6.4.4 S mple v lumes and samplng rates

The flow rat es an samplng volumes depen on the natur of the comp u ds sought, natur of

samplng (e.g adsorbent, pr s uriz d containe ), conc ntration rang e ex e t ed, br akthrough v lumes,

r commen ations from the la orat ory (q antif icationslmit ) or the mat erial sup le , an soi intrinsic

pe mea i ity The o e lying lan use shal not be conside ed

The extraction of soi g s d ring samplng r d c s pr s ur in the p r sp c and henc influenc s

phase an solution eq i ibria To l mit these influenc s, espe ialy w hen taking p int samples, flow

rat es up t o a ma imum 2 l/min ar r commen ed for a monit oring wel F or soi s exhibiting a low g s

pe mea i ity an a smal g s p r volume, even lower flow rat es should be used

When a q altative det ermination of the subs anc s pr sent is r q ir d (e.g d ring pr lminary

inves ig tions), a larg e soi g s v lume should be extract ed This wi l pro ide a mor v lume-r lat ed

dif use sampl ng zone

The incorp ration of atmosphe ic air shal be avoided Ap ro riat e controls ( e leakag e t es in 8.2.2)

ar es ential

F or active sampl ng on sorbent, if an insufficient flow rat e or sampl ng time is used, the e is the p t ential

for an inc eased la orat ory det ection lmit as insufficient sorption of the VOCs t o the sorbent medium

wi oc ur C nve sely, if t oo gr at a flow rat e or sampl ng time is used, the sorbent medium might

be ome saturat ed early in the sample cole tion proc s The efor , the flow rat e an samplng time

depends on sit e con itions, the ex e t ed conc ntrations of VOCs in the soi g s and the det ection l mit

r q ir d Flow rat e is also a function of the g eolo y In tight (e.g cla ey) sois, a lowe flow rat e ne ds

t o be used (comp r d with gran lar soi) t o minimiz the p t ential for VOC desorption ( inc the V C

conc ntration in the soi por ssp c is r q ir d)and atmosphe ic air entrainment int o the sample The

flow rat e is ty ical y betwe n 2 ml/min an 5 0 ml/min but can be highe depen ing on the mas and

natur of the sorbent In indo r air samplng, the d ration of the sampl ng is l nked t o the ex osition of

a p pulation (e.g sample ne ds 8h for workers) That is not the case with soi g s samplng

In the case of point soi g s samplng, a smal v lume is taken within the horizon la e (a out 1 ml)for

a p s ibly non-influenc d det ection of the p r v lume f iled with g s When samplng larg er v lumes

(up t o seve al ltr s), the sampl ng ar a is dif use an it location can ot be det ermined Soi g s

samplng from a b r hole with diamet er gr at er than that of the pro e is caled “int egrating as the g s

might be del ve ed o e it entir length

Ins rument for the measur ment of g s flow rat e ar l st ed in Annex C

7 Construction of monitoring instal ations

7.1.1 Environmental c onditions

The ins al ation of soi g s monit oring wels should be car ied out in b r holes or driven b r holes

Ins alation should not be car ied out in a trial pit with subseq ent b ckf il ing d e t o the dis urb nc

an ae ation of the groun an the u c rtainty of the pe iod ne es ary for original grou d con itions

t o r -es a l sh befor monit oring can contin e

The s rata encount er d should be r corded d ring the ins al ation of wel s w hen the sele t ed method

pe mit this t o be done The desc iptions of the s rata encou t er d should inclu e r fe enc t o the

pr senc of any biodegrada le mat erial or othe mat erial that might give rise t o g s, inclu ing the

pro ortion of such mat erial w hen this is practica le If the method of ins alation does not alow the

s rata t o be r corded, the groun conditions arou d the r sp nse zone should be infe r d from othe

nearb inves ig tion p int , such as othe bor holes

Each part of the sampl ng sy st em w hich is in contact with the soi g ssample should be pro e ly cleaned

betwe n each use

NOTE T e eq ipment of the monit oring wel depen s on diferent factor like conte t, o jectives,

en ironmental con itions, safety con itions like risks of e plosive atmosp ere, etc

7.1.2 Instruments

The s an ard eq ipment for soi g s sampl ng g ene al y inclu es the ins rument given in An ex A

Dife ent ins rument measur dife ent g ses o e dife ent conc ntration rang es, an each has it

own adv ntag es an lmitations It is imp rtant for the o e at or t o o tain a g ood u de s an ing of g s

monit oring eq ipment an w hich ty e should be used in a given situation In Annex B, the o e ational

adv antag es an disadv antag esof seve al porta le ins rument , along with the g ses analy sed, ar given

Porta le ins rument w hich ar t o be used on g s-contaminat ed sit es should be intrinsical y safe; this

is p rticularly so if the ins rument is t o be used within a con ned sp c

7.2 S i gas sampl ng devic es

7.2.1 Pas i ve soi gas samplng

Pas ive soi g s sampl ng can be done b burying a p s ive sample in soi or put ing it in a soi g s

monit oring wel

F or the f irs method, a hole is t o be made t o a depth ada t ed t o the o je tives (e.g for ma ping a

p lution a depth a out 1 m is g ene al y ada t ed) Then the pas ive sample is buried and r co e ed

with the groun extract ed Aft er a pr defined la se oftime (a few day s t o a few we ks), the p s ive

sample is dig up an sent t o la orat ory

F or the se on method, the pas ive sample is set in a soi g s monit oring wel , at the sc e ned part level

The pas ive sample s ar maintained in plac for a d ration ada t ed t o the ex e t ed conc ntration level

7.2.2 Sub-slab

A hole should be dri led (hole diamet er: 0,0 m minimum) t o a depth of 0,1 m t o 0,2 m beneath the

sla , c eating a samplng chambe immediat ely un e neath the sla A sc e ned tube is inse t ed int o

the hole, an a bent onit e seal pro ided at the t op of the sub-sla The tube ( c e ned or not) can be

conne t ed t o a g s det ect or or a sampl ng devic

The s at e of the hards an ing or the sla next t o the sampl ng point should be inspe t ed t o det ermine

w hethe p t ential pr fe ential p thway s such as c acks, et c ar pr sent

If pr fe ential p thwa s ar identif ied near the monit oring wel, they should be sealed with bent onit e

(or othe suita le an ine t mat erial) befor sampl ng begins

Aft er sampl ng, the hole ( if it is not a pe manent ins al ation)shal be sealed car ful y t o a oid c eating

a pr fe ential cir ulation p thwa In sensitive cont ext (housing, scho ls, et c ), the a senc of r sid al

emis ions should be control ed

If the sla is co e ed with a carpet, plas ics mat erial (e.g viny l), or othe flo ring mat erial (e.g l noleum),

this should be car fuly r mo ed from aroun the int en ed samplng point The flo r co e ing should

be r st or d onc sampl ng has be n complet ed

7.2.3 Dr i ven probes

7.2.3.1 General

Driven pro es should not be used w he e the e wi l be significant smearing of the grou d along the pipe

as it is driven in (e.g in ve y high plas icity cla sois) Smearing can be minimiz d b using a drive cone

that hasa larg er diamet er than the pipe

Car should be taken w hen driven pro es ar used on sit es k own or suspe t ed t o be contaminat ed t o

a oid c os contamination w hen the same driven pro eis used seve al times in suc es ion Meticulous

cleaning should be car ied out (without any chemical prod ct) between each use ( e ISO 1 40 -1 2)

7.2.3.2 Dr i ven probes w ith s r eened par t

The driven pro e is made of a metal ic holow tube with:

— a diamet er les than 0,0 m;

— a plain p rt of at leas 1 m;

— a sc e ned p rt of at leas 0,0 m

The tube is driven int o the groun (man aly or with a hydraulc or pneumatic hamme ) t o a minimum

depth of 1 m The t op of the wel should be pro ided with a g s ta and a bent onit e seal should be

pro ided at the t op of the wel

7.2.3.3 Dri ven probes with r etractable nose c one

The driven pro e is made of a metal ic holow tube with:

— a diamet er les than 0,0 m;

— a plain p rt of at leas 1 m;

— a sold an r tracta le nose cone alowing a sampl ng chambe of at leas 0,0 m

The tube is driven int o the groun (man aly or with a hydra ulc or pneumatic hamme ) t o a minimum

depth of 1 m then the tube is p rtialy extract ed t o l be at e thesamplng chambe a o e the nose cone

The t opof the wel should be pro ided with a g s ta an a bent onit e seal should be pro ided at the t op

of the wel

7.2.3.4 Dri ven probes with lost c one

The driven pro e is made of a metal ic holow tube with:

— a sold nose cone;

— a diamet er les than 0,0 m;

— a plain p rt of at leas 1 m

The tube is me hanicaly driven int o the groun (man al y or with a hydraulc or pneumatic hamme )

unti a minimum depth of 1 m then the tube is p rtial y extract ed for 0,0 m t o 0,1 m c eating a

samplng chambe a ove the los cone

The t opof the wel should be pro ided with a g s ta an a bent onit e seal should be pro ided at the t op

of the wel

7.2.4 Gas-mo itor ing standpipe in a bor ehole

Aft er c eating the b r hole using ca le pe cus ion, pe cus ive window or win ow les dri lng rigs,

contin ous flght aug er, sonic dri ing or han aug er t ech iq es, a pr -slott ed pipe should be ins aled

t o the r q ir d depth within the b r hole

The pipe mat erial an it thick es should pro ide sufficient s r ngth and chemical r sis anc for

the pro osed ins alation [high density p lyethy lene (HDP ) is normal y used] The pipe should be

un-slott ed (ful ) at leas within the f irs metr u de the grou d surfac The pipe should comprise

se tions w hich can be fitt ed t og ethe with sc ew thr ads, as this a oids the ne d for org nic comp u ds

an solvent t o seal the lengths t og ethe ( i.e pipes should be joined without using glue or ad esive

ta e be a use such mat erials emit volatie comp u ds that could contaminat e the soi g s samples) The

slott ed se tion should be in the r q ir d r sp nse zone ( e 6.4.2)

A ca should be at the b tt om of the wel’s pipe If the wel does not ext en t o the b se of the bor hole,

the b ckf il below the b se of the wel should be wel compact ed (with bent onit e or c ment bent onit e

grout or pelet seal) immediat ely below themonit oring wel

The ann lus between the out er wal of the b r hole and the slott ed pipe should be f iled in with

non-calcar ous single siz gra el or simi ar ine t mat erial, of a suita le grain siz in r lation t o the siz of

the ann lus an the slot of the pe forat ed sc e ns The an ulus arou d the plain u -slott ed pipe should

be f iled with bent onit e or c ment bent onit e grout The t op of the hole (g ene aly 1 m from the grou d

surfac ) should be sealed with an impe mea le plug (bent onit e grout/ ent onit e c ment, et c ), w hie at

leas the uppe 0,2 m from the grou d surfac should be sealed with conc et e or mortar t o sup ort an

se ur a co e

Bent onit e or c ment bent onit e grout should be plac d so that it forms an efe tive seal It should be

mix ed on the surfac an put in plac