Urban hydrogeology and improved management of contaminated

highly productive alluvial aquifers

Joerg Prestor, Brigita Jamnik, Mitja Janža, Nina Mali Geological survey of Slovenia

Final conference MAGPlan

CLEAN GROUNDWATER FOR STUTTGART

„Haus der Wirtschaft“, Stuttgart 3. 7. 2015

City of Ljubljana - vision of development

GREEN WEDGES between

Three of GREEN WEDGES are also groundwater resources

STAR-LIKE settlement

Ljubljansko polje and Barje aquifers

Dolomite Sandstone,… Limestone Clay, silt,… Gravel/sand

Ljubljansko polje is alluvial aquifer, dominantly from sandy gravel sediments.

Ljubljansko Barje is dominantly agricultural.

¾ of Ljubljansko polje aquifer area are urbanized and agricultural.

Groundwater is 4 – 30 m bellow the surface. It is recharged from precipitation and from

Sava river.

Although the atrazine was used more than 20 years ago, we still detected high desethylatrazine conc.

Ljubljansko Barje is confined alluvial aquifer, covered by silty and clayey sediments.

Groundwater is just bellow or even above the surface. It is recharged from precipitation and

deep flows from wider mountainous hinterland built up of limestone and dolomite rocks.

4 10.7.2015

Geological model

Numerical hydrological model

From geostatistical model to numerical hydrogeological model

Gravel and sand Silt clay gravel Silt clay Conglomerate

Typical spatial distribution pattern of hydraulic conductivities (K m/s) in the aquifer

Vertical plane (e.g. in three cross-sections)

Horizontal plane (e.g. 280 m a.s.l.)

High velocities of goundwater flow

TCE pollution in 2004 was detected in VD Hrastje-1a well. In the period 2005-2008 the concentration of TCE decrees and it was on the end of 2008 under 1μg/l (Bračič-Železnik, 2009).

TCE pollution has caused many problems to Ljubljana waterworks. It was indispensable to provide some avdanced tools and to become capable for measures and interventions.

TOOLS - Decision Support System

1. Register and evaluation of active and potential sources of pollution + viewer

2. Free accessible viewer of hydrogeological and chemical data

3. DSS-1 for remediation of illegal landfills

4. DSS-2 for improvement of chemical status of the aquifer (cost & benefit)

5. DSS-3 for emergency water managem.

Control and early warning system

Significant contaminants and their origin Name CAS Origin/use

nitrate - mixed (agriculture/municipal wastewater/industrial)

chromium (VI) - industrial / metal plating tetrachloroethene 127-18-4 industrial / degreasing trichloroethene 79-01-6 industrial / degreasing atrazine 1912-24-9 agricultural / herbicide desethylatrazine 6190-65-4 degradation product of atrazine metazachlor 67129-08-2 agricultural / herbicide dechlorometazachlor* - degradation product of metazachlor 2,6-dichlorobenzamide 2008-58-4 degradation product of pesticide

dichlobenyl carbamazepine 298-46-4 drug /municipal wastewater 2-methyl-2H-

benzotriazole*

16584-00-2 ?

2,4-dimethyl-2H-

benzotriazole*

- ?

*compounds were discovered during period of INCOME project (Auersperger, 2012). .

Pollution of groundwater by urban contaminants

1. The current contamination pattern of the groundwater indicates a diffuse pollution of the aquifer with chlorinated solvents in low concentrations (Schüth et al., 2014).

2. This group of contaminants, they are prone to spread by atmospheric processes and can then be washed out and infiltrated into the subsurface by precipitation (Schüth et al., 2014).

3. Significant and sustained longterm trends are rarely observed for volatile halogenated aliphatic hydrocarbons – LHCH (Kranjc, 2011).

4. The pollution of groundwater by urban contaminants is originating also from the sewage system (Urbanc et al., 2012).

Increasing trends (NaCl)

• 116 monitoring points, (24000 analysis, 81 parameters…).

Mo

nit

ori

ng

po

int

tetr

ach

loro

e

than

e

Al

AO

X

AT

Cu

Ca

Cr

6+

Cr-

filt

.

Fe-

filt

.

flu

ori

de

HC

O3

K

Cl

con

du

ctiv

ity

(20

oC

) co

nd

uct

ivit

y

(25

oC

) K

PK

byK

Mn

O4

ESA

me

taza

chlo

r

Mg

Na N

NO

3-N

o

glj.

ksl

.

Pro

sta

ort

ho

ph

osp

hat

e

pe

stic

ide

s -

tota

l

stro

nti

um

SO4

TOC

1 ● ● ● ●

2 ●

3 ● ● ● ● ●

4 ●

5 ●

6 ● ● ● ●

7 ● ● ●

8 ● ● ● ● ●

12 ●

13 ●

14 ●

16 ●

21 ●

22 ● ● ●

25 ● ● ● ● ● ● ●

29 ● ● ● ● ●

30 ●

31 ● ●

32 ● ● ● ●

35 ● ● ●

36 ● ● ● ● ●

37 ● ●

39 ● ●

41 ● ● ● ● ●

42 ● ● ● ●

43 ● ● ● ● ● ● ● ●

44 ● ● ● ● ●

46 ● ●

47 ● ● ● ● ● ●

48 ● ●

53 ● ●

59 ● ● ●

60 ● ● ●

62 ●

63 ● ● ●

68 ● ● ● ●

Significant regional decreasing trends (AT, SO42-)

1996 partial restriction

2003 total restriction

ATRAZIN:

SO2 concentration in the air of Ljubljana city

SULPHATE

Model of environmental pressures and impacts

mg NO3/l – average concentration in observation wells (inverse distance interpolation)

Janža, M

(Prestor et al., 2012)

Model of environmental pressures and impacts

QCČN WWTP Ljubljana = 926 l/s Qi (losses from sewage) = 194 l/s

mg NO3/l – calculated concentrations in the groundwater – from the sewage exfiltration

mg NO3/l – calculated concentrations in the groundwater – from the N surpluses in the agriculture

Average nitrate concentration in groundwater 17,61 mg/l from sewage system 7,03 mg/l from agriculture 10,58 mg/l.

38

25 20 18 15 10 7,3 7 7 0

10203040

2005 2015 2025 2035 2045 2055

mg

/l N

O3

(Prestor et al., 2012)

Model of environmental pressures and impacts

kg/year

Measured at

WWPT

Ljubljana

kg/year

Calculated

by the

model

House-

holds

Industry

by

monitoring

obligation

Urban

areas /

traffic

Unknown

sources

Ntot 1.191.824 1.121.246 87,7% 3,0% 3,4% 5,9%

Ptot 186.026 189.889 92,9% 7,7% 1,5% -2,1%

TOC 2.551.195 3.325.322 109,0% 13,8% 7,6% -30,3 %

Estimation of shares of the main polutants in the sewage system (inflow to the WWPT Ljubljana)

Significant polutants in the waste water from sewage

Industry - by

monitoring

obligation Urban areas, traffic

Households +

other sources

*Phenols 1,9% 13,6% 84,4% *Zn 6,7% 17,8% 75,5% *Cu 8,7% 49,2% 42,2% *Cl

- 4,1% 43,7% 52,2% *AOX 12,9% 115,1% Triklorometan 3,9% 96,1% Ni 4,4% 15,9% 79,7% Cd 0,1% 49,7% 50,2% Cr tot 12,2% 56,9% 30,9% Pb 8,6% 78,2% 13,1% Hg 0,4% 169,7% PAH 0,0% 103,1%

Estimation of shares of sources (inflow to WWPT Ljubljana).

µg Cr(VI)/l – calculated concentrations from sewage system losses in comparisson with the results from observation wells

Input from the losses along sewage system – from known industrial sites that report Cr(VI) emissions

Comparison of organic compound, identified by GC-MS qualitative method showed, that the same compound are mostly present in aquifer like before year 2009.

New coming pollutants

Prevailing contaminants are pesticides, but some other contaminants could become relevant, mostly drugs and benzotriazoles.

ORGANIC POLLUTANTS

Challenges

Determination of organic pollutants

Setting of standards

Development of strategies to reduce inputs into the aquatic environment

Development of new methods for observing

How to determine emerging contaminants in water To identify pollutants

To identify the possible source of these pollutants

Development of analytical methods to the lowest levels

Determination the presence in the environment

FURTHER CHALLENGES AND ACTIONS

• Setting specific objectives – – nitrates, chromium, organic polutants

• Gradually & progressively decreasing pressures – Yearly / Till 2020 / Till 2050

• Cooperation of sectors: Spatial planning & Water management

– implement the measures to progressively reduce pollution of groundwater

Thank you for your attention!

www.geo-zs.si

• Auersperger, P. 2012. Project INCOME. Action A.2.8: The hydrochemical analysis - sampling and performing. Final report. • Bračič-Železnik, B., 2009. Projekt INCOME. Report on groundwater chemical status: Local monitoring data. • Jamnik, B., Smrekar, A., Janža, M., 2014. Skrb za pitno vodo. Geografija Slovenije 31. GIAM ZRC SAZU. Ljubljana. (http://giam.zrc-

sazu.si/sites/default/files/gs31.pdf) • Janža, M. 2014: A decision support system for emergency response to groundwater resource pollution in an urban area (Ljubljana,

Slovenia). Environ Earth Sci 73:3763–3774. doi: 10.1007/s12665-014-3662-2 • Kranjc, M., 2011. Project INCOME. Action A.2.3 Data from national monitoring. Technical report January – March 2011. • Prestor, J., Pestotnik, S., Meglič, P., Janža, M., 2012. Project INCOME. A.3.3. Model of environmental pressures and impacts (Final

report) • Schüth, C., Piepenbrink, M., Cosma, C., Janža, M. 2014:. Prstni odtisi onesnaževal z uporabo stabilnih izotopov in večnivojskim

vzorčenjem s pasivnimi vzorčevalniki (Contaminant fingerprinting methods). In Jamnik, B. et al. Skrb za pitno vodo, (Geografija Slovenije, 31). Ljubljana. Založba ZRC, 2014, str. 54-59.

• Urbanc, J., Jamnik, B., Janža, M., Cerar, S., Prestor, J., 2012. Project INCOME. A 4.1. Pollution Source Localization. Final report.

• http://www.life-income.si • http://ppmol.org/urbanizem5/submain2.php?get=122 • http://www.geopedia.si/?params=T105_L5833_F1345#T105_F5833:1307_x461982.5_y100811.5_s17_b4 • Program varstva okolja Mestne občine Ljubljana, http://www.ljubljana.si/si/zivljenje-v-ljubljani/okolje-prostor-bivanje/program-varstva-

okolja/ • Skupna izhodišča in cilji projekta Vizija 2025 in SPR MOL: RAZVOJ LJUBLJANE. Dopolnjujoče prepletanje dejavnosti, prestrukturiranje

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