SAMPLING AND FIELD ANALYSIS - University of Manchester · 2008. 11. 3. · SAMPLING AND FIELD ANALYSIS Workshop – 22/09/08 Nepal – May 2007 Delphine Tisserand –CNRS- LGIT

SAMPLING AND FIELD ANALYSIS

Workshop – 22/09/08

Delphine Tisserand –CNRS- LGITNepal – May 2007

STEP 1 : sampling techniques

1- How to sample water

2- How to sample pore water

3- How to sample water and / or sediment

4- How to sample sediment

5- How to sample soils or plants

STEP 2 : Water : physical and chemical parameters measurements

STEP 3 : Water : How to filter water

STEP 4 : in situ analysis

1- Water : total dissolved iron, sulfide, arsenic, alkalinity

2- Sediment : Acid Volatil Sulfide (AVS)

STEP 5 : Water : conditionning for lab analysis

PLAN

Nepal – May 2007

STEP 1 : HOW TO SAMPLE WATER

NISKIN BOTTLE (UP TO 8L) POLYETHYLENE BOTTLE

DEEP WATER SURFACE WATER

STEP 1 : HOW TO SAMPLE PORE WATER

PEEPERS, 0.45 μm membrane inside

STEP 1 : HOW TO SAMPLE WATER AND/OR SEDIMENT

NEEDLE SAMPLER

DEEP WATER (DRILLING WATER)

NEEDLE SAMPLER

STEP 1 : HOW TO SAMPLE WATER AND/OR SEDIMENT

WATER AND SEDIMENT KEPT UNDER ANOXIC CONDITIONS

STEP 1 : HOW TO SAMPLE SEDIMENT

Polyethylene shovel and plastic bags

Beckman sediment sampler

Deep sediment

STEP 1 : HOW TO SAMPLE SOIL OR PLANTS

SOILS :

HAND AUGER AND PLASTIC BAGS

SOILS AND PLANTS :

POLYETHYLENE SHOVEL AND PLASTIC BAGS OR CARDBOARD BOX



2- How to sample porale water










PLAN

Nepal – May 2007

STEP 2 : WATER

PHYSICAL AND CHEMICAL PARAMETERS MEASUREMENT

1- SURFACE WATER

Measurements : pH (pH or mV)

T (°C)

Conductivity (μS/cm)

Redox (mV)

Dissolved O2 (% or mg/l)

Device : WTW multi 340i

In non filtered water

STEP 2 : WATER

PHYSICAL AND CHEMICAL PARAMETERS MEASUREMENT

1- DEEP WATER

Measurements : pH (pH or mV)

T (°C)

Conductivity (μS/cm)

Redox (mV)

Dissolved O2 (% or mg/l)

Device : YSI sensor 600 XLM

In non filtered water













PLAN

Nepal – May 2007

STEP 3 : WATER

HOW TO FILTER WATER

Polyethylene disposable syringes

Cellulose acetate or polycarbonate 0.22 or 0.45 μm membranes










1- Water : total dissolved sulfide, iron, arsenic, alkalinity



PLAN

Nepal – May 2007

STEP 4 : WATER AND SEDIMENT

IN SITU ANALYSIS

FILTERED WATER : Total dissolved S2-→ immediatly after sampling

Total dissolved Fe2+ → immediatly after sampling

Total dissolved As → within the day after sampling

Total alkalinity → within the day after sampling

SEDIMENT: Acid Volatil Sulfide (AVS, on sediment)

→ immediatly after sampling or sediment kept underN2 atmosphere until analysis

S2-, Fe2+, As, alkalinity, AVS

STEP 4 : WATER IN SITU ANALYSIS

1- Total dissolved sulfide : S2-

Methylene blue

Method : methylene blue / colorimetric method


1-Total dissolved sulfide : S2-

Need to be done immediatly after sampling (no oxidation !)


Analysis time : 10 min

Filtered waters (0.22 μm acetate or polycarbonate membranes)

HACH spectrophotometer DR2010 HACH spectrophotometer DR850OR

From 0.03 to 0.7 mg/l

Volume of sample : 25ml

From 0.03 to ? mg/l


Phenantroline C12H8N2


2- Total dissolved ferrous iron : Fe2+

+ Fe2+

Ferroïne = [Fe(C12H8N2)3]2+

Red-orange complex

Method : phenantroline / colorimetric method


2-Total dissolved ferrous iron : Fe2+

Need to be done immediatly after sampling (no oxidation !)

Method : phenantroline / colorimetric method


Filtered waters (0.22 μm acetate or polycarbonate membranes)





HACH spectrophotometer DR2010 HACH spectrophotometer DR850

OR


3- Total dissolved arsenic : As

Sample + reagent 1 + reagent 2 → AsH3(g)on solid HgBr

Yellow-orange colored strips

20 min

Method : visual test

3-Total dissolved arsenic : As

Need to be done within the day of sampling

Method : visual test (by generation of arsine AsH3)

Device : HACH test kit

Analysis time : 20 min reaction

Filtered waters (0.22μm acetate or polycarbonate membranes)


50 ml sample → from 10 to 500 mg/l9.6 ml sample → from 35 to 4000 mg/l

HCO3- + H+ CO2 + H2O


4- Total alkalinity

= capacity of a water to absorb H+ ions = CO32- + HCO3

-

Need to be done within the day of sampling

Method : acid-base titration (with HCl 0.01M)

Gran method : report mole of H3O+ measured


3- Total alkalinity LOMA

y = 1E-05x - 7E-06R2 = 0,9985

0

1

2

3

4

5

6

V HCL0.01M (ml)0,000E+00

2,000E-06

4,000E-06

6,000E-06

8,000E-06

1,000E-05

1,200E-05

pHmoles H3O+lineaireLinéaire (lineaire)

non linear zone = carbonates protonation

pH

moles H

3O+ m

easured

Volume of sample : from 5ml


Filtered waters (0.22μm acetate membranes)

1- Acid volatil sulfides (AVS)

STEP 4 : SEDIMENT IN SITU ANALYSIS

Acidic solution

Sediment + HCl : degazing 1h30

→ generation of H2S

1

Basic solution

2NaOH + H2S→ 2Na2+ + S2- + H2O + 1/2O2Reagent with dimethyl phenylene diammoniumadded

23

Control : same as 2


STEP 4 : SEDIMENT IN SITU ANALYSIS

1- Acid volatil sulfides (AVS)

Need to be done immediatly after sampling or later if sediment kept under N2 atmosphere


From 2.5 μmol S2-

Weight of sample : 2g recommanded

Analysis time : 2 h 00













CONCLUSIONS

PLAN

Nepal – May 2007

STEP 5 : WATER : CONDITIONNING FOR ANALYSIS IN LGIT

• As speciation (Dowex resin)adsorb AsV (AsO4

3-) species, let AsIII (AsO2-) in solution

30ml sample + 2ml resin : let in contact 15 min and filter

Ref. : Wilkie and Hering, Environ.Sci. Technol. 1998, 32, 657-662.

LGIT : ICP-AES analysis (Perkin Elmer)

• Anions (Cl-, SO42-, NO3

-…in mg/l)Filtered water put in 15 ml polyethylene flask, keep at 4°C

LGIT : Ionic chromatograhy analysis (Dionex)

• Cations (total dissolved metals : Ca2+, Fe, Mg2+, As… in mg/l) :Filtered water put in 30ml polyethylene flask, 0.7 ml concentrated HNO3 added, keep at 4°C

LGIT : ICP-AES analysis (Perkin Elmer)

• Dissolved / Total Organic / Inorganic Carbon (DOC/TOC, DIC/TIC in mg/l) :DOC / TOC : filtered / non filtered water (0.7μm glass fiber filters) put in 60 ml amber glass flask, 0.15ml HCl added, keep at 4°C

DIC / TIC : filtered / non filtered water (0.7μm glass fiber filters) put in 60 ml amber glass flask, keep at4°C.LGIT : TOC VCSN (Shimadzu)

CONCLUSIONS

Materials : - easy to handle

- strong

In situ analysis :

positive points :

- easy to handle

- fast

- mobile

- no need to preserve sample under anoxic conditions

negative points :

- AVS long and delicate (N2 bottle)

THANKS FOR YOUR ATTENTION

Nepal – May 2007

SAMPLING AND FIELD ANALYSIS - University of Manchester · 2008. 11. 3. · SAMPLING AND FIELD ANALYSIS Workshop – 22/09/08 Nepal – May 2007 Delphine Tisserand –CNRS- LGIT

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