Dispersion of cerussite-rich tailings and plant uptake of heavy metals at historical lead mines near Newtownards,Northern Ireland

Abstract

A legacy from mid-19th Century mining near Newtownards is lead-rich tailings and derived soils containing typically 10% Pb. Lead occurs dominantly as very fine-grained cerussite (PbCO₃) and the tailings are also rich in calcite and dolomite. Rainwash and overland flow has transferred tailings material from the original impoundments into a meadow, forming a depositional ‘plume’ characterised by contrasting soil colour, vegetation species and vigour of growth. Cerussite is dispersed farther than calcite and dolomite. In areas of the plume proximal to the tailings source, the Pb content (dry weight) of dock and plantain is up to 6540μg/g in roots and 1140μg/g Pb in leaves. Plume soils and plants are also enriched in Fe, Mn, Cu, Zn, Cd and Sb. Bracken foliage contains up to 1500μg/g Pb in non-tailings soil and 2800μg/g Pb in tailings-contaminated soil. For most elements analysed, there is a low contrast between bracken plants growing on tailings-contaminated and normal soil. This reflects the low bioavailability of these elements within the carbonate-rich tailings together with absorption thresholds imposed by plant metabolism. Plants growing on tailings-dominated substrates appear to be stressed by low bio-availability of trace elements (e.g. Mn) and nutrients (e.g. P, K), rather than metal toxicity. Metal uptake is higher in healthy, vigorously growing plants that are not rooted in tailings-dominated soil. The bio-availability of lead and other metals increases when: (i) tailings material is mechanically transported and mixed with soil; and (ii) relatively acidic groundwater dissolves tailings and transfers metals in solution into adjacent soil. Remedial action is required to limit further tailings erosion and acidification.

Keywords

CERUSSITE MINE TAILINGS PLANT UPTAKE HEAVY METALS HISTORICAL LEAD MINES

Get full access to this article

View all access options for this article.

References

ALLOWAY

B. J.

(ed): ‘Heavy metals in soils', Glasgow, Blackie, 1990, 1–339.

ASLIBEKIAN

and MOLES

: ‘Environmental risk assessment of metals contaminated soils at Silvermines abandoned mine site, Co Tipperary, Ireland', Environ. Geochem. Health, 2003, 25, 247–266.

DREVER

J. I.

: The geochemistry of natural waters — surface and groundwater environments' (3rd edn), London, Prentice Hall, 1997.

GEE

, RAMSEY

M. H.

and THORNTON

: ‘Buffering from secondary minerals as a migration limiting factor in lead polluted soils at historical smelting sites‘, Appl. Geochem., 2001, 16, 1193–1199.

GRIFFITH

A. E.

and WILSON

H. E.

: ‘Geology of the country around Carrickfergus and Bangor', Memoir of the Geological Survey of Northern Ireland, Sheet 29 (Northern Ireland). British Geological Survey, London: HMSO, 1982, 1–118.

HILLIER

, SUZUKI

and COTTER-HOWELLS

: ‘Quantitative determination of cerussite (lead carbonate) by X-ray powder diffraction and inferences for lead speciation and transport in stream sediments from a former lead mining area in Scotland', Appl Geochem., 2001, 16, 597–608.

KAMBATA-PENDIAS

and PENDIAS

: ‘Trace elements in soils and plants', Boca Raton, FL, CRC Press, 1984, 1–380.

KELLY

S. J.

: ‘Geochemical dispersion and concentration of Pb and Zn in soils of the northern Midlands of Ireland', Unpublished PhD thesis, Queen's University Belfast, 2001, 1–282.

LEVY

D. B.

, BARBARICK

K. A.

, SIEMER

E. G.

and SOMMERS

L. E.

: ‘Distribution and partitioning of trace metals in contaminated soils near Leadville, Colorado‘, 1 Environ. Quality, 1992, 21, 185–195.

10.

MASKALL

J. E.

and THoRmroN

: ‘Chemical partitioning of heavy metals in soils, clays and rocks at historical lead smelting sites', Water Air Soil Pollution, 1998, 108, 391–409.

11.

MERRINGTON

and ALLOWAY

B. J.

: ‘The transfer and fate of Cd, Cu, Pb and Zn from two historic metalliferous mine sites in the UK', Appl Geochem., 1994, 9, 677–687.

12.

MILLER

J. R.

: The role of fluvial geomorphic processes in the dispersal of heavy metals from mine sites', Geochem.Explor., 1997, 58, 101–118.

13.

MOLES

N. R.

and NAWAZ

: ‘Harmotome associated with Tertiary dyke intrusion in mineralised breccia at Newtownards, Northern Ireland', Jr..1. Earth Sc., 1996, 15, 145–153.

14.

SCHOOF

R. A.

, BUTCHER

M. K.

, SELLSTONE

, WAYNE-BALL

, FRICKE

J. R.

, KELLER

.: An assessment of lead absorption from soil affected by smelter emissions', Environ. Geochem. Health, 1995, 17, 189–199.

15.

SMITH

R. A.

, JOHNSTON

T. P.

and LEGG

I. C.

: ‘Geology of the country around Newtownards', Memoir for 1:50, 000 geological sheet 37 & part of 38 (Northern Ireland). British Geological Survey, London: HMSO, 1991, 1–42.

16.

WOODROW

: ‘A history of the Conlig and Whitespots lead mines’, Monograph of the Northern Mine Research Society, British Mining, 1978, 7, 1–52.

17.

XIANGDONG

and THORNTON

: ‘Chemical partitioning of trace and major elements in soils contaminated by mining and smelting activities', Appl Geochem., 2001, 16, 1693–1706.