COMPARATIVE TEST ON SOIL SAMPLING - Welcome to …€¦ ·  · 2015-05-05VolatileorganicVolatile organic carbons (C5-C10, BTEX) 3. 1 1 ... uncertainties of field investigation! ...

CCOMPARATIVEOMPARATIVE TESTTEST ONON SOILSOILCCOMPARATIVEOMPARATIVE TESTTEST ONON SOILSOILSAMPLINGSAMPLING

AT A CLOSED FUEL STATION

Katarina Björklöfmicrobiologist & soil researcher

Finnish Environment Institute (SYKE)Reference Laboratory

Aim for this comparison was to 11 Aim for this comparison was to

● Compare sampling procedures of contaminated soil b i i d li

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between participated sampling teams ● Evaluate if the sampling design and procedure affected the

conclusion on the need for remediation

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● Demonstrate the use of quality procedures in sampling

● Expert planning group with different background

Setup of the comparison● Expert planning group with different background● In autumn 2008 during two weeks● Participants: nine sampling teams from different p p g

organizations (participation fee: 1000 euro)● Funded partly by Ministry of the Environment (40 %)

O f t SOILI● One reference team, SOILI

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The site11 The site21

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● Gasoline station

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(before 1990)● Area = 0.5 ha

C t i t● Contaminants detected by SOILI○ Hydrocarbons y

(C10-C21, C22-C40)

○ Volatile organic○ Volatile organic carbons (C5-C10, BTEX)

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Organization of field work● Not an authentic situation

○ Time limit 4,5 h.

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○ Detailed plan was required in advance based on history due to practical and financial reasons.

○ Amounts of samples to the lab limited (max 15)

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○ Amounts of samples to the lab limited (max 15).● Deviations due to other reasons than sampling planning

and procedures minimized:○ Same drilling equipment.○ All samples transported and stored by the organizersstored by the organizers.○ VOC samples fixed with

methanol on site.○ Samples analyzed at same

laboratory.● Sampling practices were also● Sampling practices were also

documented by the organizer. 4

T2

Slide 4

T2 Esitys tallennetaan muotoon PowerPoint-esitys (*.pptx). Tällöin kaikki esityksessä käytetyt ominaisuudet toimivat ongelmitta.

Voit poistaa tämän kommentin klikkaamalla hiiren oikeaa korvaa "Poista kommenti"Tekijä, 20/05/2011

11 Observations from field work● Experienced personnel most important factor for

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Observations from field work

valid sampling!○ Certification of sampling personnel

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● Big differences in homogenization procedures and storage of samplesstorage of samples

● Use of field instruments ○ Calibration? ○ Interpretation?

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11Quality of homogenization was

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determined by split samples

● One sample was divided into 2 subsamples and both were analyzed in the laboratory.

● Sampling teams with good homogenization practices had

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● Sampling teams with good homogenization practices had less than 10 % difference in concentrations between the subsamples

● The difference between hydrocarbon concentrations (C10-C21) in subsamples was up to 30 %.

● Careful mixing during field work increases the representability. S lit li d i iSplit sampling design i quality assurance tool

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11Heterogeneity of the site was

● Two sampling holes were drilled less than 0,5 m from each

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determined by repeated samplingp g ,

other.● Mean difference in hydrocarbon concentrations (C10-C21)

was 80 % (range 2% 177%)

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was 80 % (range 2% - 177%). ○ This is natural heterogeneity of the site which affect

uncertainties of field investigation!

● Large heterogeneity on site more samples are needed tomore samples are needed to reduce uncertainty of field investigation.

● Estimation of uncertainties should be estimated for every site specific investigation! g

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Maximum concentrations of PHCs found 11

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● Maximum conc. f d i d

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jö found varied between 1 600 –15 000 mg/kg O l f

12000

14000

mg/

kg)

C10-C21C22-C40

● Only four groups detected hazardous waste concentrations ( )

8000

10000

entr

atio

n (m

concentrations ( )○ Affects costs!

● Max conc. did NOT 4000

6000

Max

. Con

ce

correspond to amount of samples investigated or use

f fi ld i t t

0

2000

N8 N3 N9 N2 SOILI N4 N6 N5 N1 N7M

of field instruments. Sampling team

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Determination of volatile organic 11

compounds (VOC) on the site21/1

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● * Samples kept in cold by sampling team.

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30

35

te V

OC

● Higher awareness of how to handle VOC compounds 20

25

/kg)

of s

epar

atun

ds

is needed (mixing, storing, fixing).

10

15

etra

tions

(mg/

com

pou

5

10

Max

. con

cne

0N6* N3* N7* N1 N5 N4 N2 N9 N8

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Estimation of soil to be remediated11

● All teams agreed,

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g ,that the site had to be restored.

● The estimated

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1500

1400

1600

ved

(t)

The estimated amount of soil to be remediated varied 10 times (range 1000

1200

be re

mov

( g140 -1 500 t soil).

● Most estimations were close to 415

468 480 480 500

780

600

800

f soi

l to

bexcecuted.

140

250300

415

200

400A

mou

nt o

f

0A

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Conclusions11

● Difficult to estimate performances of separate teams, because the matrix was very heterogeneous. The results of the SOILI team were not necessarily better than the others

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the SOILI team were not necessarily better than the others.

BUT

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● Comparison tests = good means to increase the awareness of quality issues in this field

● The results were presented at an open seminar with more than 60 participants interesting discussions!p p g

● Sufficient education and training of the sampling personnel is required. Guidelines are in preparation.D f lit t l ( t bilit● Demo: use of quality assurance tools (representability, uncertainties) increases the transparency of sampling procedures (e.g. split sampling taken into use!)

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11 Acknowledgement to group of 21

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Acknowledgement to group of experts:

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● Proficiency test providers○ I. Mäkinen & K. Korhonen,

SYKESYKE● Problem holders:

○ H. Westerholm, Neste Oil Oy○ S Nikunen SOILI –○ S. Nikunen, SOILI –

programme (Finnish Petroleum Federation)

● Legislators○ O. Pyy, SYKE

● Soil researchers○ K. Jørgensen & K. Björklöf,

SYKESYKE

Thank you for your attention!!12

11Need for restoration of contaminated soil is determined on site ● Level of contamination and the remediation need to be

d i ifi ll b i i f h h d d

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soil is determined on site

assessed site specifically by estimation of the hazard and damage of the contaminant on human health and on the environment.

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● Threshold value PHC = 300 mg/kg (C10-C21) and 600 mg/kg (C21-C40)

● Quality of sampling procedures difficult to measure and performance of the sampling team may affect the outcome of the assessment?

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