an environmental study of contamination by depleted ... · presentation to rsc radiochemistry...

© Nicholas Lloyd 2008

The fate of depleted uranium contamination in the Colonie

environmental case study

Nicholas S. [email protected]

Prof. Randall Parrish UoL, BGS, NIGL

Dr Simon Chenery BGS & Dr Mike Norry UoL

Presentation to RSC Radiochemistry Group, Young Researchers’ Meeting, 16 April 2008(edited to reduce file size)


IntroductionAims:

To determine the fate of depleted uranium particulate in the environment, and to investigate geochemical processes that effect the distribution of uranium.

Using a field study of an area extensively contaminated by depleted uranium particulate.

particulate emitted > 20 years agoof concern to local residentspotential for a health study

Comparable to DU contamination from munitions?


ContentsIntroduction

what is DU?Colonie and National Lead Industriesbackground datafield sampling & analyses

Distribution of contamination

Isotope ratios

Particlesmorphology & mineralogy

Summary


What is depleted uranium (DU)?By-product of the nuclear fuel cycle

depleted in fissile 235Ui.e. 238U / 235U ratio > 137.88

Strong, dense metal: 19 g/cm3

World inventory of c. 1.18 Mtreadily oxidises

Radioactive (α) 14.8 kBq/g

Chemically toxic, & clastogenic ?

Risks to health if internalised

Controversially used in munitionswww.fas.org


ColonieNY, USA


NLI, ColonieFormer brass & babbit metal foundry

1958 – 1984 uranium metals

Manufactured DU articleskinetic penetratorsaircraft counterweightscasks & shieldingprior to 1968 some EU

Scrap DU metal burnt in a furnaceparticulate emissions filtration system from late 1970s

Closed 1984


0.25 km~ 5 tonnes DU in 1 km~ 5 tonnes DU in 1 km2 2 ??

Teledyne Data (1980)

windrose


Central Avenue

CSX Railroad

$190,000,000$190,000,000NLI, ColonieNLI, Colonie

NLI


MC ICP-MS Urine Analyses (NIGL data)Gulf War veterans test negative for DU

NLI workers tested test positive

Some Colonie residents test positive

Parrish et al. 2008Sci. Total Environ. 390

Natural U

Enriched U

Depleted U

mixing line

0

100

200

300

400

500238235

box heights are 2σ

NLI workers with DU

NL worker with EU + DU

Natural

DU

90 %DU

Some residents with minor DU

EU


Field Sampling

sandy soilssandy soils

dustsdusts


Analytical TechniquesICP-QMS (BGS)

HNO3/HF/HClO4/H2O2 total digestconcentrations and isotope ratiosdesolvating nebuliser

XRF (UoL)metal concentrations

ICP-MC-MS (NIGL)high precision isotope ratios+LA for individual particles

SEM-EDX (UoL)particlesqualitative elemental

TEM / XRD / µXAS (UoL, BGS, Diamond)particle mineralogy


Contamination mapping by concentration

1 km1 km

2 km2 km


0

4

8

12

0 20 40 60 80

sample depth (cm)

uran

ium

(m

g/kg

)

Pit 1

Pit 2

Pit 3

Uranium concentration against depth

Pits 1 & 2 – c. ½ km N of NLI

Pit 3 – c. 2 km WNW of NLI


130

230

330

0 20 40 60 80sample depth (cm)

238U

/ 23

5U ra

tio

Pit 1 (near)Pit 2 (near)Pit 3 (far)natural

Isotope ratio against depth23

8 U/ 2

35U

natural137.88


Contamination mapping by isotope ratio

1 km

2 km2 km

NU4 %17 %

56 %

>92 %

DU


100

200

300

400

500

0.0 0.5 1.0 1.5 2.0

1 / U concentration (ppm)

238U

/ 23

5U

238U/235U against 1/U concentration

natural background~ 0.6 - 2 mg/kg (0.8-1.3)

DU

238 U

/ 23

5 U

1 / U concentration (kg/mg)

137.88


0.E+00

1.E-05

2.E-05

3.E-05

4.E-05

5.E-05

0.1% 0.2% 0.3% 0.4% 0.5% 0.6% 0.7% 0.8%

235U / 238U

236U

/ 23

8U

236U/238U against 235U/238U

natural0.72 % 235U

negligible 236UDU0.2 % 235U

32 ppm 236U

235U / 238U

236 U

/ 23

8 U

2 component mixing line


0.E+00

2.E-05

4.E-05

6.E-05

8.E-05

0.0% 0.2% 0.4% 0.6% 0.8%235U / 238U

234 U

/ 23

8 U

234U / 238U against 235U / 238U

DU~ 6 ppm 234U

natural~ 51 - 61 ppm 234U

variable due to α-recoil


0.E+00

2.E-05

4.E-05

6.E-05

0.15% 0.20% 0.25% 0.30% 0.35%235U / 238U

236 U

/ 23

8 U

LA-MC-ICP-MS (NIGL)

MC-ICP-MS (NIGL)

CHEM-LAD-434

LA- MC- ICP-MS of individual grains

cluster

spread


Dry, sheltered environment (dust) Wet, exposed environment (soil)

Some surface pitting Weathered surface, dissolutionWell preserved But bulk is intact after 25 years

Particles


expansion texture ?UO2 U3O8

Mineralogy

uraninite (UO2)cubic crystals


X-ray Absorption SpectroscopyBioaccessibility is governed significantly by oxidation stateU6+ species are much more soluble than U4+ speciesOxidation from UO2 / U3O8 to UO3 is very slowHow oxidised are these ‘old’ particles ?µXANES can tell us valance states at near µm resolution

DiamondDiamondDiamond


XANESJ. Arnason (SUNY at Albany)

U LIII-edge XANES 1st derivative

UO3

UO2

dry dust

wet sediment

Brookhaven NSLS


SummaryMapped the DU contamination footprint using ICP-MS

up to 5.8 km from NLIup to 40 cm depth near NLIdistribution controlled by physical transport

Measured isotope ratiosmixing linesindividual grains

Isolated primary UOx particulates from soils & dustsconsidered mineralogy & oxidationinitial XAS work


Questions & AcknowledgementsProfessor Randall ParrishDr Simon CheneryProfessor Tim BrewerDr Mike NorryDr John ArnasonDr Sarah HainsworthDr Matt HorstwoodDr Jenny BearcockDr John BridgesCCNL members, Betty Dietz & Sharron HerrBritish Geological SurveyNIGLDiamondUniversity of Leicester

an environmental study of contamination by depleted ... · presentation to rsc radiochemistry...

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