Distribution, speciation and bioavailability of arsenic in a shallow-water submarine hydrothermal system, Tutum Bay, Ambitle Island, PNG

Shallow-water hydrothermal vent systems can introduce large amounts of potentially toxic elements, such as arsenic (As), into coastal marine environments. The first step in understanding and describing the potential impact of these elements throughout hydrothermally influenced coastal ecosystems is to determine the element’s distribution and speciation, which in turn influences the availability of the toxin for biological uptake. Shallow submarine hot springs near Ambitle Island, Papua New Guinea, are discharging as much as 1.5 kg per day of arsenic directly into a coral-reef ecosystem. We have investigated the bioavailability of the As throughout Tutum Bay by studying vent fluid, seawater, pore water, precipitates, and sediments. In addition to measuring As abundance, As speciation (As(III), As(V), and the methylated species DMA and MMA) was determined in various waters. The As concentration for discrete mineral phases in vent precipitates and sediments was determined by sequentially extracting arsenic from the easily extractable, carbonate, Fe-oxyhydroxide or hydrous ferric oxide (HFO), and residual fractions, each of which have a different bioavailability. Diffuse venting seems to play a critical role on the distribution of As throughout Tutum Bay surface sediments, which have a mean As concentration of 527 ppm while excluding the vent precipitates (range=1483 to 52 ppm). Up to 54 ppm As were extracted from the easily extractable fraction of surface sediments (mean=19.7 ppm), using a K2HPO4/KH2PO4 buffer at pH=7.2. Arsenic from this fraction is considered to be the most available for biological processes, and therefore the most dangerous for biota. However, sequential extraction shows that 98.6% of the As in vent precipitates, and a mean of 93.3% in surface sediments (range=88.2% to 96.3%), is coprecipitated with the hydrous ferric oxide (HFO) fraction. Thus, the bulk of the As being discharged into Tutum Bay is scavenged by the HFO, and should remain stable unless the physicochemical conditions surrounding the oxides change. In surface seawaters of Tutum bay, we found as much as four times the average seawater concentration of As (8.4 Ag/L compared to ~2 Ag/L). The abundance of As in seawater just above the sediment/water interface is near normal, although As(III) in both surface and bottom seawater throughout Tutum Bay is substantially enriched compared to average seawater. Hydrothermal venting therefore provides bioavailable As by two major pathways throughout Tutum Bay: 1) easily-exchangeable As from hydrothermally influenced sediments to as far away as 200 m from focused venting, and 2) in surface seawaters, which may allow for biological uptake by phytoplankton and transfer up the food web. D 2005 Elsevier B.V. All rights reserved.

[1]  G. Hall,et al.  The mineralogy of arsenic in uranium mine tailings at the Rabbit Lake In-pit Facility, northern Saskatchewan, Canada , 2001 .

[2]  T. Pichler,et al.  The precipitation of aragonite from shallow-water hydrothermal fluids in a coral reef, Tutum Bay, Ambitle Island, Papua New Guinea , 2004 .

[3]  J. Edmonds,et al.  Transformations of arsenic in the marine environment , 1987, Experientia.

[4]  M. Andreae.  Determination of arsenic species in natural waters. , 1977, Analytical chemistry.

[5]  Philippe Quevauviller,et al.  Methodologies for soil and sediment fractionation studies. , 2007 .

[6]  V. I. Fadeev,et al.  Effect of shallow-water hydrothermal venting on the biota of Matupi Harbour (Rabaul Caldera, New Britain Island, Papua New Guinea) , 1999 .

[7]  H. Dunkelberg,et al.  Comparative and environmental genotoxicity of antimony and arsenic. , 1997, Anticancer research.

[8]  J. Kuever,et al.  Hydrothermal studies in the Aegean Sea , 2000 .

[9]  Prosun Bhattacharya,et al.  Behavior of arsenic and geochemical modeling of arsenic enrichment in aqueous environments , 2004 .

[10]  A. Tessier,et al.  Speciation and adsorption of arsenic on diagenetic iron oxyhydroxides , 1991 .

[11]  D. Young,et al.  Coastal submarine hydrothermal activity off northern Baja California , 1978 .

[12]  P. Quevauviller,et al.  Methodologies in soil and sediment fractionation studies : single and sequential extraction procedures , 2002 .

[13]  G. Stingeder,et al.  Arsenic fractionation in soils using an improved sequential extraction procedure , 2001 .

[14]  J. Clark,et al.  Synopsis of discussion session on physicochemical factors affecting toxicity , 1994 .

[15]  A. Mountouris,et al.  Bioconcentration of heavy metals in aquatic environments: the importance of bioavailability. , 2002, Marine pollution bulletin.

[16]  P. Sedwick,et al.  Chemistry of shallow submarine warm springs in an arc-volcanic setting: Vulcano Island, Aeolian Archipelago, Italy , 1996 .

[17]  Angels Sahuquillo,et al.  Sequential extraction procedures for sediment analysis , 2002 .

[18]  J. Aggett,et al.  The extent of formation of arsenic(III) in sediment interstitial waters and its release to hypolimnetic waters in Lake Ohakuri , 1988 .

[19]  T. Pichler,et al.  Hydrothermal venting within a coral reef ecosystem, Ambitle Island, Papua New Guinea , 1996 .

[20]  G. Cutter.  Kinetic controls on metalloid speciation in seawater , 1992 .

[21]  T. Pichler,et al.  Hydrothermal Effects on Isotope and Trace Element Records in Modern Reef Corals: A Study of Porites lobata from Tutum Bay, Ambitle Island, Papua New Guinea , 2000 .

[22]  G. Bryan,et al.  Bioavailability, accumulation and effects of heavy metals in sediments with special reference to United Kingdom estuaries: a review. , 1992, Environmental pollution.

[23]  H. Harvey,et al.  Metal concentrations in crayfish tissues in relation to lake pH and metal concentrations in water and sediments , 1991 .

[24]  J. Nriagu.  Cycling and characterization , 1994 .

[25]  D. Cronan,et al.  Hydrothermal Metalliferous Sediments and Waters Off the Lesser Antilles , 2001 .

[26]  R. Oremland,et al.  The Ecology of Arsenic , 2003 .

[27]  P. Dando,et al.  Hydrothermalism in the Mediterranean Sea , 1999 .

[28]  Gwendy E.M. Hall,et al.  The chemical composition of shallow-water hydrothermal fluids in Tutum Bay, Ambitle Island, Papua New Guinea and their effect on ambient seawater , 1999 .

[29]  E. Baker,et al.  Hydrothermal plumes along the East Pacific Rise, 8°40′ to 11°50′N: Particle distribution and composition , 1994 .

[30]  D. Cronan,et al.  Arsenic, antimony and bismuth in sediments and waters from the Santorini hydrothermal field, Greece , 1988 .

[31]  A. Tessier,et al.  Sequential extraction procedure for the speciation of particulate trace metals , 1979 .

[32]  Michel Astruc,et al.  Fractionation studies of trace elements in contaminated soils and sediments: a review of sequential extraction procedures , 2002 .

[33]  R. Braman.  Arsenic in the environment , 1975 .

[34]  G. Hall,et al.  Natural Input of Arsenic into a Coral-Reef Ecosystem by Hydrothermal Fluids and Its Removal by Fe(III) Oxyhydroxides , 1999 .

[35]  R. Rosenberg,et al.  Macrobenthic succession in relation to organic enrichment and pollution of the marine environment , 1978 .

[36]  D. Nordstrom,et al.  Preservation of water samples for arsenic(III/V) determinations: an evaluation of the literature and new analytical results , 2004 .

[37]  T. Pichler,et al.  PRECIPITATION OF FE(III) OXYHYDROXIDE DEPOSITS FROM SHALLOW-WATER HYDROTHERMAL FLUIDS IN TUTUM BAY, AMBITLE ISLAND, PAPUA NEW GUINEA , 1999 .

[38]  Daniel B. Parvaz,et al.  Chemical geology. , 1884, Science.

[39]  J. Hamelink,et al.  Bioavailability: Physical, Chemical, and Biological Interactions , 1994 .

[40]  Jung-Suk Lee,et al.  Uptake pathway for Ag bioaccumulation in three benthic invertebrates exposed to contaminated sediments , 2004 .

[41]  S. Maeda.  Biotransformation of Arsenic in Freshwater Organisms , 1998 .

[42]  William R. Cullen,et al.  Arsenic speciation in the environment , 1989 .

[43]  R. Keefer,et al.  Arsenic mobilization and bioavailability in soils. , 1994 .

[44]  K. Mccarthy,et al.  Geochemistry of Champagne Hot Springs shallow hydrothermal vent field and associated sediments, Dominica, Lesser Antilles , 2005 .