Wasserversorgung

Groundwater Monitoring

Rahel Oechslin / Andreas Peter

Stadt Zürich

Wasserversorgung

Overview of the presentation

Introduction

Analytical strategy

- Inorganic parameters

- Organic parameters

- Sampling time intervals

Stadt Zürich

Wasserversorgung

City of Zurich

- 450’000 inhabitants

67 municipalities

- 500’000 inhabitants

- 660 km2 supply area

Supply area of Zurich Water Supply

Zurich

Bachs Hoch-

felden Bülach

Rorbas

Uitikon

Killwangen

Embrach

Dättlikon

Pfungen

Wiesen-

dangen

Elsau

Elgg

Schlatt

ZellKyburgTurbenthal

Wila

Sternenberg

WeisslingenWild-

berg

Russikon

Fehraltorf Bauma

PfäffikonHittnau

Bäretswil

Wetzikon

HinwilGossau

Rüti

Dürnten

Bubikon

Egg

Hombrechtikon

Mönch-

altorf

Grüningen

Stäfa

Oetwil a.S.Meilen

Herrliberg

Ober-

EmbrachBrütten

Lindau

WinterthurHöri

Nieder-

weningen

Ober-

weningen

Rümlang

KlotenNürens-

dorf

Lufingen

Bachen-

bülach

Winkel

Bassers-

dorfOpfikon-

Glattbrugg

Wallisellen

Illnau-

Effretikon

Dietli-

kon

Uster

See-

gräben

Volketswil

Wangen-

Brüttisellen

Dübendorf

Greifen

-see

Schwerzen-

bachFällanden

MaurZumikon

Zollikon

Wädenswil

Horgen

Hirzel

Wollerau

Hütten

Schönen-

berg

Menzingen

Baar Neuheim

Thalwil

Kappel a.A.

Hausen

a.A.

Rifferswil

Zug

ChamStein-

hausen

Hünenberg

Masch-

wanden

Knonau

Obfelden

Ottenbach

Mettmen-

stetten

Langnau

a.A.

Aeugst

a.A.

Richters-

wil

Uetikon

a.S.

Affoltern

a.A.

Adliswil

Hedingen

Bon-

stetten

Stallikon

Arni

Jonen

IslisbergUnterlunkhofen

Oberlunkhofen

Zufikon

Berikon

Oberwil-

Lieli

Wettswil

a.A.Aesch

Birmensdorf

Oberglatt

Nieder-

glatt

Eggenwil

WidenRudolfstetten-

Friedlisberg

Urdorf

Schöfflis-

dorf

Neer-

ach

Steinmaur

Dielsdorf

Buchs

Regens-

berg

Schlei-

nikon

Boppelsen

Nieder-

hasli

RegensdorfDän-

ikon

Würenlos

Otelfingen

Hüttikon

Ober-

engstringen

Schlieren

Weiningen

Untereng-

stringen

Gerolds-

wil

Oetwil

a.d.L.

Spreitenbach

Dietikon

Bergdietikon

Dällikon

Küsnacht

Oberrieden

Rüschli-

kon

Kilch-

berg

Männe-

dorf

Erlenbach

Stadt Zürich

Wasserversorgung

Lengg

Lake Water Plant

Sihlbrugg

Spring Water Plant

Moos

Lake Water Plant

Hardhof

Groundwater Plant

Water treatment plants

Stadt Zürich

Wasserversorgung

Quality control in the laboratory

Microbiology (Germs, bacteria)

Limnology (Algae, Plankton)

Chemistry(inorganic compounds, DOC)

Trace compounds(target analysis of organic

compounds and screening

methods)

24 full-time equivalents

>10'000 water samples

> 1'000 analytical parameters

Stadt Zürich

Wasserversorgung

On-line monitoring

Physical-chemical parameters are constantly recorded.

Sensitive organisms, such as Daphnia species, are used as real-time bio-

monitors.

Stadt Zürich

Wasserversorgung

construction : 1934/1973, capacity: 150‘000 m3/day

Hardhof Groundwater Plant

Stadt Zürich

Wasserversorgung

Hardhof Groundwater Plant

Stadt Zürich

Wasserversorgung

Hardhof Groundwater Plant

Stadt Zürich

Wasserversorgung

Sampling sites

Stadt Zürich

Wasserversorgung

Legal requirements

Drinking water is part of the foodstuff regulation. It defines limits

for chemical and microbiological quality parameters

("Höchstwerte").

Stadt Zürich

Wasserversorgung

Drinking water quality:

Metals > LOQ

Element Health risk Analytical

method

Limit value

(µg/L)

LOQ

(µg/L)

Max. conc

(µg/L)

As Black foot disease ICP-MS 10 0.5 0.7

B teratogenic ICP-MS 1000 5 12

U Nephritis ICP-MS 30 0.5 0.6

Stadt Zürich

Wasserversorgung

Occurrence of boron (B)

Stadt Zürich

Wasserversorgung

Element Health risk Analytical

method

Limit value

(µg/L)

LOQ

(µg/L)

Max. conc

(µg/L)

Al Discussed controversially

(Alzheimer’s disease)ICP-MS 200 5 < LOQ

Cd Accumulation in the kidneys, flue-

like symptomsICP-MS 3 0.05 < LOQ

Cr because of Cr(VI) ICP-MS 50 0.5 < LOQ

Cr (VI) Carcinogenic (liver, kidney),

genotoxicityIC-ICP-MS 20 0.05 < LOQ

Cu Gastrointestinal irritation

headache, vomiting, diarrhea)ICP-MS 1000 0.5 < LOQ

Hg Kidney damage, tumors, genotox.

activityAtomic emission

fluorescence

1 0.01 < LOQ

Ni Dermatitis ICP-MS 20 0.5 < LOQ

Pb Neurological effects, renal

function, fertility affectedICP-MS 10 0.5 < LOQ

Sb strong irritating effect on the

gastrointestinal mucosa, cancerICP-MS - 1 < LOQ

Se Gastrointestinal disturbances,

decayed teeth, hair or nail lossICP-MS 10 1 < LOQ

Drinking water quality:

Metals < LOQ (selection)

Stadt Zürich

Wasserversorgung

Drinking water quality:

Anionic species and ammonia

Compound Health risk Analytical

method

Limit value

(µg/L)

LOQ

(µg/L)

Max. conc

(µg/L)

Cyanide Hypoxia Photometry 50 2 < LOQ

Fluoride Dental and skeletal fluorosis IC 1'500 3 80

Ammonia No health risk (but oxidation to

nitrite, nitrate)Photometry 100 3 < LOQ

Nitrite shortness of breath, cyanosis Photometry 100 1 1.6

Chloride Taste IC - 150 11'000

Sulfate Taste (laxative effect ) IC - 240 15'000

Stadt Zürich

Wasserversorgung

Drinking water quality:

Organic compounds

Compound Health risk Analytical

method

Limit value

(µg/L)

LOQ

(µg/L)

Max. conc

(µg/L)

HCFCs, e.g.

Tetrachloroethene

Possible carcinogen, nervous

systemGC/MS 10 0.02 0.40

Benzo[a]pyren Carcinogenic GC/MS 0.01 0.005 <LOQ

PAHs Carcinogenic GC/MS 0.1 0.005 <LOQ

BTEX (Benzene,

Toluene, Ethyl benzene,

Xylene)

Liver, kidney, nervous

system, cancerGC/MS 3 0.02 <LOQ

PCBs Enriched in the fat tissue and

human milk, liver, cancerGC/MS - (US-EPA

0.5 µg/L)

0.005 <LOQ

Hydrocarbon Oil

Index C10-C40

? GC/MS 20 not analyzed by WVZ

Stadt Zürich

Wasserversorgung

Tetrachloroethene

Contamination probably from a nearby industrial site and not from

the waste disposal site

Stadt Zürich

Wasserversorgung

In addition to the chemical monitoring parameters,

microbiological monitoring is essential for drinking

water control.

Monitoring parameters:

• Heterotrophic plate counts (HPC; cfu)

• E.coli (fecal indicator)

• Enterococcus (fecal indicator)

• Total cell counts (flow cytometry)

Drinking water quality:

Microbiological parameters

Stadt Zürich

Wasserversorgung

Sampling intervals:

Groundwater wells: 4 - 12 /y

Groundwater sampling sites: 1 - 2 /y

Online at 14 sampling sites: Electric conductivity (dissolved salts)

Drinking water quality:

Sampling intervals

Groundwater flow rate: 5 - 10 m/d

Stadt Zürich

Wasserversorgung

Drinking water

from the Hardhof

ground water

plant is safe to

drink!