Environmental assessment of metal exposure to corals living in Castle Harbour, Bermuda N.G. Prouty a, b, ⁎, N.F. Goodkin a, 1 , R. Jones c, d , C.H. Lamborg a , C.D. Storlazzi b , K.A. Hughen a a Marine Chemistry and Geochemistry Department, 266 Woods Hole Rd., Woods Hole Oceanographic Institution, Woods Hole, MA 02543, United States b US Geological Survey, Pacific Coastal and Marine Science Center, 400 Natural Bridges Dr., Santa Cruz, CA 95060, United States c Bermuda Institute of Ocean Sciences, 17 Biological Lane, Ferry Reach, St. George's GE 01, Bermuda d Australian Institute of Marine Science, The UWA Oceans Institute (M096), 35 Stirling Highway, Crawley, WA 6009, Australia abstract article info Article history: Received 10 October 2012 Received in revised form 19 April 2013 Accepted 1 May 2013 Available online 7 May 2013 Keywords: Bermuda Corals Landfill Trace metals Resuspension Sediment Environmental contamination in Castle Harbour, Bermuda, has been linked to the dissolution and leaching of contaminants from the adjacent marine landfill. This study expands the evidence for environmental impact of leachate from the landfill by quantitatively demonstrating elevated metal uptake over the last 30 years in corals growing in Castle Harbour. Coral Pb/Ca, Zn/Ca and Mn/Ca ratios and total Hg concentrations are elevated relative to an adjacent control site in John Smith's Bay. The temporal variability in the Castle Harbour coral records suggests that while the landfill has increased in size over the last 35 years, the dominant input of metals is through periodic leaching of contaminants from the municipal landfill and surrounding sediment. Elevated contaminants in the surrounding sediment suggest that resuspension is an important transport medium for transferring heavy metals to corals. Increased winds, particularly during the 1990s, were accompanied by higher coral metal composition at Castle Harbour. Coupled with wind-induced resuspension, interannual changes in sea level within the Harbour can lead to increased bioavailability of sediment-bound metals and subsequent coral metal assimilation. At John Smith's Bay, large scale convective mixing may be driving interannual metal variabil- ity in the coral record rather than impacts from land-based activities. Results from this study provide important insights into the coupling of natural variability and anthropogenic input of contaminants to the nearshore environment. Published by Elsevier B.V. 1. Introduction Bermuda is a crescent shaped chain of islands located on a sea- mount in the western North Atlantic and supports some of the most northerly reefs in the world (Fig. 1). The islands are densely populated, and in the absence of suitable landfill space, bulk metal waste and municipal solid waste incinerator ash has been dumped in the sea at a ‘foreshore reclamation site’ in an inshore basin, Castle Harbour (CH). The marine landfill (or seafill) has grown to encompass an area of 35 acres in the last 25 years (Jones, 2010). Dominated by metal-bearing fine-grain sediment, resuspension in CH can liberate legacy contaminants. Recent surveys have shown that widespread leaching of different contaminant classes (especially metals) has occurred from the landfill resulting in a pronounced halo of contamination in the surrounding sediment (Jones, 2010). Within the halo there is a small patch containing numerous large brain corals (Diploria labyrinthiformis). Some of these corals are large enough to have established themselves before the marine land filling began and have provided a unique opportunity to investigate the geochemistry of the coral skeletons and provide a high-resolution proxy record of environmental contamination associated with the seafill. Flood et al. (2005) and Jones (2010) provide a detailed historical analysis of widespread anthropogenic influences that have occurred in CH in the last 100 years, including extensive dredging and the commencement of the landfilling processes. Briefly, the dumping started sometime in the early 1970s (although exact dates are uncer- tain), which included the disposal of cars, buses, and mopeds. Prior to the landfill, extensive dredging occurred in CH to create land for an air station during World War II (Tucker, 1983). According to coral surveys in the 1970s, the dredging caused mass mortality of large, old corals in CH (Dodge and Vaisnys, 1977). More recently bulk waste, such as scrap metal, domestic appliances, construction waste (soils, rubble, and plasterboard), electrical goods, PVC plastics, and used tires were added to the waste stream (Fig. 1C). Since the mid 1990s municipal solid waste incinerator ash, generated from combustion of household garbage, was disposed off at the reclamation site, generally after being cement-stabilized into 1 m 3 blocks (Hjelmar, 1996; Jones, 2010). No Marine Chemistry 154 (2013) 55–66 ⁎ Corresponding author at: US Geological Survey, Pacific Coastal and Marine Science Center, 400 Natural Bridges Dr., Santa Cruz, CA 95060, United States. Tel.: +1 831 460 7526. E-mail address: nprouty@usgs.gov (N.G. Prouty). 1 Now at: Earth Observatory of Singapore, Nanyang Technological University, 50 Nanyang Avenue, Block N2-01c-41, Singapore 639798, Singapore. 0304-4203/$ – see front matter. Published by Elsevier B.V. http://dx.doi.org/10.1016/j.marchem.2013.05.002 Contents lists available at SciVerse ScienceDirect Marine Chemistry journal homepage: www.elsevier.com/locate/marchem