Snowball: Treasure -vad har vi lärt oss?

TREASURETREASURE

Fiberbank Workshop, SGU, October 6-7 2016, [email protected]

An August morning, near Kramfors in Ångermanälven (Photo taken by I. Snowball, 2015)

vad har vi lärt oss?

TREASURE (2015TREASURE (2015--2017)2017)Sanering av starkt förorenade sediment längs norra Östersjökusten förhållbar utveckling och levande kust och skärgård*

6 komponenter

TREASURE är ett pågående projekt finansierat av forskningsrådet Formas inom initiativet

TUFFO*, som är en samverkan med Statens Geotekniska Institut (SGI) och Naturvårdsverket.

1. Koordination2. Fältarbete3. Geoteknisk4. Kemisk/biologisk5. Riskbedömning6. Utvärdering av

sanering

*Teknikutveckling & Forskning inom Förorenade Områden

TREASURE’s study sites

“Väja”

2015

”Sandviken”

1928

2015

”Sandviken”

TREASURE’s study sites

”Väja”

”Kramfors” (not studied in detail)

Images by Jim Hedfors, SGI, based on SGU data.

TREASURE methodsTREASURE methods

Geotechnical

FF-CPTu (free-fall dynamic cone penetrator)

Unique to MARUM. Measures geotechnical properties in site, rapidly. Identification of layers in situ.

Combined with hydro-acoustic surveys and groundtruthing obtained from cores of sediment to estimatevolumes of ”fiberbanks”.

Hydro-acoustic, FF-CPTu and coring methods

Practical limitations

SGU Corer (6 m)MARUM

FF-CPTu

Core &

CPTu data

Sub-seafloor

hydro-acoustic signalBad Good

Bad

Good

Geotechnical result:

SomeSome resultsresults….….

The The modelmodel is is wrongwrong, , butbut modelsmodels areare not not realityreality

Slope failure can occur under this fiberbank. It has happenedbefore.

’model’

Is Is FluMuFluMu the future for inthe future for in--situ work?situ work?

FluMu….. A device specifically for soft, ”fluid” sediments:

Planned trials in 2017

FluMu (short for Fluid Mud FluMu (short for Fluid Mud

penetrometer) is a lightweight

probe with a very sensitive tip

designed to identify subtle

changes in strength and density

at the interface between

sediment and water.

Rapidly deployed, even from

small boats.A. Kopf, MARUM

50 cm

Benthic lander +

benthic flux chambers

Passive

samplers in

water

Ocean Surveyor (SGU)

FLUXES OF METALS

Benthic lander

(Gothenburg University: M.

Kononets, P. Hall)

FLUXES OF ORGANIC POLLUTANTS

Benthic flux chambers (NGI)

+ passive samplers in the water column

Benthic lander +

benthic flux chambersResults under scrutiny

Realtime observations help…

Idea: bacteria are naturally detoxifying the fiberbanks

(Catherine Paul, Lund University)

We know there are genes that allow bacteria to transform chemicals found in the fiber banks

We look to see if these bacteria are in the fiberbank

The fiberbanks are rich in bacteria*

We find nahAC – a gene from bacteria that can detoxify napthlene (mothballs)

It is only present in the fiberbanks and fiber rich sediments, not the other bacteria are in the fiberbank

sediments and surroundings

We search specifically for those genes to see the potential for natural remediation...

...like police when they look for the DNA at a crime scene.

fiber rich sediments, not the other surroundings

*hence the production of ”gas”

(what do these gases contain?)

TREASURETREASURESanering av starkt förorenade sediment längs norra Östersjökusten förhållbar utveckling och levande kust och skärgård

Large volumes

Q (Sandviken): 250 000 m3 fiberbankarea 48 000 m2

R (Väja): 200 000 m3 fiberbankarea 94 000 m2

Fiberbank = source. Does not include fiber-rich sediments.

The latter cover much larger areas, including the areas where benthic fauna live.

Oskarshamn: 500 000 m3 to be dredged*500 million SEK*

Removal cost: a comparison

Q & R: 450 000 m3 fiberbankTREASURE 383 million SEK** (Norwegian rule of thumb)

* Hav & Vatten, 3, 2015.

** Based on SGI / SAO, 2016 in preparation (Appendix B)

“Dredge and Disposal” cost of 850 SEK / m3

Just 2 of 26 identifiedfiberbanks in

Västernorrland


What have we learnt so far?

1. Due to their low density, high organic and gas content,

anthropogenic ”fiberbanks” are atypical and challenging

to physically characterize.

Always put the camera downbefore doing anything else!

to physically characterize.

2. Sites studied are biochemically very active: the

microbial induced production of gas (~methane,

hydrogen sulphide) is ”enormous”. E.g. Väja’s fiberbank

is internally dynamic because gas movement re-

suspends contaminated fibers and moves pore-waters.

3. Fauna living in nearby fiber-rich sediments are

bioaccumulating the persistant organic pollutants

(POPs), including the ”legacy” banned substances.

TREASURE progress


2016+

2017 +++


I. Snowball (UU), H. Löfröth (SGI), L. Zillén (SGU), S. Josefsson (SGU),G. Göransson (SGI), P. Frogner-Kockum (SGI), A. Svensson (SGU),

M. Holmen (SGI), M. O’Regan (SU), K. Wiberg, SLU), A. Apler (SGU/UU).Missing: C. Paul (LU), A. Kopf MARUM).

Science

Snowball: Treasure -vad har vi lärt oss?