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Ecological impacts of large-scale disposal of mining waste in the deep sea.

Hughes DJ, Shimmield TM, Black KD, Howe JA - Sci Rep (2015)

Bottom Line: At Lihir, where DSTP has operated continuously since 1996, abundance of sediment infauna was substantially reduced across the sampled depth range (800-2020 m), accompanied by changes in higher-taxon community structure, in comparison with unimpacted reference stations.At Misima, where DSTP took place for 15 years, ending in 2004, effects on community composition persisted 3.5 years after its conclusion.Active tailings deposition has severe impacts on deep-sea infaunal communities and these impacts are detectable at a coarse level of taxonomic resolution.

View Article: PubMed Central - PubMed

Affiliation: Scottish Association for Marine Science, Oban, Argyll PA37 1QA, United Kingdom.

ABSTRACT
Deep-Sea Tailings Placement (DSTP) from terrestrial mines is one of several large-scale industrial activities now taking place in the deep sea. The scale and persistence of its impacts on seabed biota are unknown. We sampled around the Lihir and Misima island mines in Papua New Guinea to measure the impacts of ongoing DSTP and assess the state of benthic infaunal communities after its conclusion. At Lihir, where DSTP has operated continuously since 1996, abundance of sediment infauna was substantially reduced across the sampled depth range (800-2020 m), accompanied by changes in higher-taxon community structure, in comparison with unimpacted reference stations. At Misima, where DSTP took place for 15 years, ending in 2004, effects on community composition persisted 3.5 years after its conclusion. Active tailings deposition has severe impacts on deep-sea infaunal communities and these impacts are detectable at a coarse level of taxonomic resolution.

No MeSH data available.


Study areas, Papua New Guinea(a) Locations of Lihir and Misima islands. Map modified from original on Wikimedia Commons, source www.demis.nl. (b) Benthic sampling stations off Lihir (L1-L6) and (c) Misima (M1-M6). Tailings outfalls are indicated by solid squares on island coastlines. Detailed bathymetric charts are not available for the Lihir and Misima areas, and (b) and (c) show only general trends using data from the General Bathymetric Chart of the Oceans (GEBCO, www.gebco.net).
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f1: Study areas, Papua New Guinea(a) Locations of Lihir and Misima islands. Map modified from original on Wikimedia Commons, source www.demis.nl. (b) Benthic sampling stations off Lihir (L1-L6) and (c) Misima (M1-M6). Tailings outfalls are indicated by solid squares on island coastlines. Detailed bathymetric charts are not available for the Lihir and Misima areas, and (b) and (c) show only general trends using data from the General Bathymetric Chart of the Oceans (GEBCO, www.gebco.net).

Mentions: In November 2007, we sampled the sediments around two island mines in eastern PNG (Fig. 1a) to quantify the benthic impacts of ongoing DSTP and assess community states following its conclusion. The Lihir gold mine discharges ~100,000 ML tailings slurry year−1 (containing ~2.5 Mt solids) from an outfall at 128 m depth on the east coast of the island1213 (Fig. 1b). Mining began in 1996, with a projected duration of 44 years. Tailings consist of 93% silt particulates, with residual particulate and dissolved metals (including zinc, copper, arsenic, cadmium, mercury and lead)12 and process chemicals. There are no published data for trace metal content in tailings-affected sediments off Lihir, but dispersal models ground-truthed by sediment sampling indicate a depositional “footprint” extending across a broad plain up to 20 km east of the outfall and to depths of at least 2000 m19. The gold/silver mine on Misima Island discharged a total of ~90 Mt tailings from 1989 until the end of operations in May 2004. The outfall was located at 112 m depth on a very steep (>450) submarine slope leading into the 1500 m deep Bwagaoia Basin (Fig. 1c). Seismic profiling indicates a tailings layer tens of metres thick in places and covering approximately 20 km2 of the basin floor20. Unlike Lihir, the main deposition zone at Misima is confined by seafloor topography but this does not exclude the possibility of wider dispersal by resuspension. No information is available on trace metal content of the tailings discharged at Misima.


Ecological impacts of large-scale disposal of mining waste in the deep sea.

Hughes DJ, Shimmield TM, Black KD, Howe JA - Sci Rep (2015)

Study areas, Papua New Guinea(a) Locations of Lihir and Misima islands. Map modified from original on Wikimedia Commons, source www.demis.nl. (b) Benthic sampling stations off Lihir (L1-L6) and (c) Misima (M1-M6). Tailings outfalls are indicated by solid squares on island coastlines. Detailed bathymetric charts are not available for the Lihir and Misima areas, and (b) and (c) show only general trends using data from the General Bathymetric Chart of the Oceans (GEBCO, www.gebco.net).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC4419517&req=5

f1: Study areas, Papua New Guinea(a) Locations of Lihir and Misima islands. Map modified from original on Wikimedia Commons, source www.demis.nl. (b) Benthic sampling stations off Lihir (L1-L6) and (c) Misima (M1-M6). Tailings outfalls are indicated by solid squares on island coastlines. Detailed bathymetric charts are not available for the Lihir and Misima areas, and (b) and (c) show only general trends using data from the General Bathymetric Chart of the Oceans (GEBCO, www.gebco.net).
Mentions: In November 2007, we sampled the sediments around two island mines in eastern PNG (Fig. 1a) to quantify the benthic impacts of ongoing DSTP and assess community states following its conclusion. The Lihir gold mine discharges ~100,000 ML tailings slurry year−1 (containing ~2.5 Mt solids) from an outfall at 128 m depth on the east coast of the island1213 (Fig. 1b). Mining began in 1996, with a projected duration of 44 years. Tailings consist of 93% silt particulates, with residual particulate and dissolved metals (including zinc, copper, arsenic, cadmium, mercury and lead)12 and process chemicals. There are no published data for trace metal content in tailings-affected sediments off Lihir, but dispersal models ground-truthed by sediment sampling indicate a depositional “footprint” extending across a broad plain up to 20 km east of the outfall and to depths of at least 2000 m19. The gold/silver mine on Misima Island discharged a total of ~90 Mt tailings from 1989 until the end of operations in May 2004. The outfall was located at 112 m depth on a very steep (>450) submarine slope leading into the 1500 m deep Bwagaoia Basin (Fig. 1c). Seismic profiling indicates a tailings layer tens of metres thick in places and covering approximately 20 km2 of the basin floor20. Unlike Lihir, the main deposition zone at Misima is confined by seafloor topography but this does not exclude the possibility of wider dispersal by resuspension. No information is available on trace metal content of the tailings discharged at Misima.

Bottom Line: At Lihir, where DSTP has operated continuously since 1996, abundance of sediment infauna was substantially reduced across the sampled depth range (800-2020 m), accompanied by changes in higher-taxon community structure, in comparison with unimpacted reference stations.At Misima, where DSTP took place for 15 years, ending in 2004, effects on community composition persisted 3.5 years after its conclusion.Active tailings deposition has severe impacts on deep-sea infaunal communities and these impacts are detectable at a coarse level of taxonomic resolution.

View Article: PubMed Central - PubMed

Affiliation: Scottish Association for Marine Science, Oban, Argyll PA37 1QA, United Kingdom.

ABSTRACT
Deep-Sea Tailings Placement (DSTP) from terrestrial mines is one of several large-scale industrial activities now taking place in the deep sea. The scale and persistence of its impacts on seabed biota are unknown. We sampled around the Lihir and Misima island mines in Papua New Guinea to measure the impacts of ongoing DSTP and assess the state of benthic infaunal communities after its conclusion. At Lihir, where DSTP has operated continuously since 1996, abundance of sediment infauna was substantially reduced across the sampled depth range (800-2020 m), accompanied by changes in higher-taxon community structure, in comparison with unimpacted reference stations. At Misima, where DSTP took place for 15 years, ending in 2004, effects on community composition persisted 3.5 years after its conclusion. Active tailings deposition has severe impacts on deep-sea infaunal communities and these impacts are detectable at a coarse level of taxonomic resolution.

No MeSH data available.