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TitreBenthic foraminiferal morphological abnormalities observed in metal(oid)-contaminated sediments, coastal areas of Notre Dame Bay, Newfoundland
AuteurMiller, A A L; Parsons, M B; Kwong, J Y T; Parrott, D R
SourceGAC-MAC-CSPG-CSSS Halifax 2005, building bridges - across science, through time, around the world: abstracts/AGC-AMC-SCGP-SCSS Halifax 2005, Jeter des ponts entre les disciplines scientifiques, les époques, et unifier le monde : recueil des résumés; AGC-AMC-SCGP-SCSS Reunion conjoint, Receuil des Résumés vol. 30, 2005 p. 131
LiensOnline - En ligne (HTML)
Séries alt.Secteur des sciences de la Terre, Contribution externe 2004360
RéunionGAC/MAC/CSPG/CSSS Joint Annual Meeting; Halifax; CA; mai 15-18, 2005
Documentpublication en série
Formatspdf; html
ProvinceRégion extracotière; Nouvelle-Écosse
Lat/Long OENS -63.0000 -59.0000 44.0000 42.0000
Sujetsanalyses des résidus; carottes; carottes de sédiment marin; Mine Tilt Cove
ProgrammeLes géosciences à l'appui de la gestion des océans
Résumé(disponible en anglais seulement)
A multidisciplinary survey was completed in July 2001 to assess the spatial extent and concentrations of metal(oid)s in submerged tailings
from two abandoned copper mines, which have contaminated coastal areas of Notre Dame Bay, Newfoundland. Geophysical data and
sediment gravity cores and/or grab samples were collected. Dissolved metal(oid) concentrations in sediment pore waters are relatively low, suggesting that the tailings serve as a sink, rather than a source, of metals to overlying waters. Ten samples from each site were analysed for benthic foraminifera, which are known to show morphological abnormalities in the form of distorted chambers, abrupt changes in coiling direction / chamber arrangement, misplaced apertures, and twinning, in response to metal(oid) contamination. In all non-barren samples examined from both sites, deformed specimens were observed. Some species exhibit a predominance of a specific deformity. At the Little Bay Mine, where 30-50% of the 1.8 million tonnes of impounded tailings have flowed into a sheltered estuary since dam failure in 1989, the ranges of As, Cd, Cu, Pb and Zn concentrations (mg/kg) are: 3-52, 0.04-0.92, 13-520, 1-10, and 19-136, respectively.
The foraminifera are variable and diverse. Samples closest to the impoundment have the fewest agglutinated specimens (<10%), and are
dominated by Cribroelphidium excavatum (no deformed specimens); whereas in the outer bay the fauna is >85% agglutinated, dominated by Labrospira crassimargo, Verneulinulla advena, Recurvoides trochamminiforme and Spiroplectammina biformis. All samples
contain deformed specimens, comprising 0.5-8% of the fauna. S. biformis has both the highest number of deformed specimens (0.5-3.5%) and deformed specimens present in the greatest number (7) of samples. At the Tilt Cove Mine, 5-6 million tonnes of tailings were slurried directly into an open-marine, high-energy environment, from 1957-1967. Metal(oid) concentrations here have greater ranges and much
larger maximum values. Arsenic, Cd, Cu, Pb and Zn values (mg/kg) are: 3-310, 0.02-4.5, 8-1600, 2-110, and 28-2900, respectively. Faunas here exhibit lower diversities and all samples are strongly dominated by agglutinated species, mainly V. advena and C. arctica. The inter-sample range of deformed specimens (2.8-5.5%) is less, but higher numbers of species and specimens exhibit deformities per sample. At both sites there is no direct correlation between a specific metal(oid)'s concentration and the number of deformed species or specimens, or type of deformities. In general, the percentage of deformed specimens is highest in the most contaminated sediments.