Assessing lead sources in fishes of the northeast Pacific Ocean (original) (raw)
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Environmental Science & Technology, 2017
We report the continued lead (Pb) contamination of the Northwest Pacific Ocean in 2002 and present the first comprehensive Pb isotope dataset for that region. In the upper ocean, a Pb concentration maxima (64-113 pmol kg-1) extended throughout the entire North Pacific Subtropical Gyre (NPSG). We determined most of the Pb in this feature was from industrial emissions by many nations in the 1980s and 1990s, with the largest contributions from leaded gasoline emissions. In contrast, the deep water (> 1000 m) Pb concentrations were lower (6-37 pmol kg-1), and constituted a mix of background (natural) Pb and anthropogenic Pb inputs from preceding decades. Deep water below the Western Subarctic Gyre (WSAG) contained more industrial Pb than below the NPSG, which was attributed to a calculated 60-fold greater flux of particulate Pb to abyssal waters near the Asian continent. Assuming Pb isotope compositions in the North Pacific Ocean were homogenous prior to large-scale 20 th century anthropogenic inputs, this evidence suggests a relatively faster change in Pb isotope ratios of North Pacific deep water below the WSAG versus the NPSG.
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2000
Variations measured in the lead (Pb) stable isotope ratios in otoliths of juvenile tropical reef fish Scarus perspiculatus, Abudefduf abdominalis and Dascyllus albisella reflect mixing of anthropogenic lead from the Kaneohe Bay watershed and ‘background’ lead characteristic of the adjacent ocean. The otoliths and water samples collected in a transect across the bay demonstrated nearly identical Pb isotopic trends. The Pb isotopic composition of the watershed has a low 206Pb/204Pb signature primarily reflecting past combustion of tetra-ethyl Pb additive in fuels. Ocean water not contaminated by this watershed signature has a different, high 206Pb/204Pb isotopic composition, similar to previously measured Asian anthropogenic aerosols and natural eolian dusts, where the anthropogenic signal dominates. Where a history of past anthropogenic Pb contamination exists, it may be possible to use the ratios of Pb stable isotopes in fish otoliths to reconstruct the nursery grounds of fish.
Environmental Science & Technology, 2011
Recent trends of atmospheric lead deposition to the North Pacific were investigated with analyses of lead in aerosols and surface waters collected on the fourth Intergovernmental Oceanographic Commission Contaminant Baseline Survey from May to June, 2002. Lead concentrations of the aerosols varied by 2 orders of magnitude (0.1À26.4 pmol/m 3 ) due in part to variations in dust deposition during the cruise. The ranges in lead aerosol enrichment factors relative to iron (1À119) and aluminum (3À168) were similar, evidencing the transport of Asian industrial lead aerosols across the North Pacific. The oceanic deposition of some of those aerosols was substantiated by the gradient of lead concentrations of North Pacific waters, which varied 3-fold (32.7À103.5 pmol/ kg), were highest along with the Asian margin of the basin, and decreased eastward. The hypothesized predominance of Asian industrial lead inputs to the North Pacific was further corroborated by the lead isotopic composition of ocean surface waters ( 206 Pb/ 207 Pb = 1.157À1.169; 208 Pb/ 206 Pb = 2.093À2.118), which fell within the range of isotopic ratios reported in Asian aerosols that are primarily attributed to Chinese industrial lead emissions. 9875 dx.doi.org/10.1021/es2020428 |Environ. Sci. Technol. 2011, 45, 9874-9882
Lead and lead isotopes in the North Pacific: mid-depth maxima and deep water anthropogenic source
2007
Lead (Pb) concentrations and isotopic ratio in seawater samples that were collected in a section from 7 °S to 30 °N along 158 °W in the central Pacific ocean were determined using Mg(OH)2 coprecipitation ICPMS. Surface water Pb concentrations decrease by 30-50% since 1980¡¦s, probably due to the phasing-out of leaded gasoline in Japan. There is pronounced mid-depth maxima for Pb at ~ 600 m in subtropical oceans which coincides with salinity minima and the maxima of CFC, tritium Pu, Cs, Co, Bi and Fe, indicating the influence by the advection of the North Pacific intermediate water. 206Pb/207Pb ratios at 30¢XN are relatively constant in the upper 500 m, increase with increasing depth below 500 m and are lower than those for the Pleistocene sediments and Mn nodule, suggesting that anthropogenic Pb may have contaminated some of oldest waters of the world ocean, possibly via Pb regeneration during microbial degradation of sinking organic debris.
Marine Pollution Bulletin, 1998
For seawater, solvent extraction pre-concentration and the use of a micro-concentric nebulizer allowed 1 ml of concentrate to be measured for several minutes to achieve precisions in the range 0.5-1.2% relative standard deviation for 2°Spb/Z°6Pb and 2°Tpb/2°6Pb. The environmental dispersion of trace amounts of anthropogenic Pb produced distinctive Pb isotope ratio changes in seawater and marine sediments in the immediate vicinity of a Pb-Zn concentrate shipping facility. Concentrate was found to have 2°Spb/2°6pb ratios in the range 2.21-2.25, whereas environmental background 2°Spb/z°apb ratios were: filtered (<0.45 om) seawater, 2.13-2.15; unfiltered seawater, 2.06-2.10; sediment, 2.06-2.09. The combined Pb isotope ratio and concentration measurements by ICP-MS have provided a sensitive and cost effective monitoring tool allowing an una~abiguous assessment of the source of Pb.