We present full water depth sections of size‐fractionated (1–51 μm; >51 μm) concentrations of suspended particulate matter and major particle phase composition (particulate organic matter [POM], including its carbon isotopic composition [POC‐δ13C] and C:N ratio, calcium carbonate [CaCO3], opal, lithogenic particles, and iron and manganese [oxyhydr]oxides) from the U.S. GEOTRACES Arctic Cruise (GN01) in the western Arctic in 2015. Whereas biogenic particles (POM and opal) dominate the upper 1,000 m, lithogenic particles are the most abundant particle type at depth. Minor phases such as manganese (Mn) oxides are higher in GN01 than in any other U.S. GEOTRACES cruises so far. Extremely depleted POC‐δ13C, as low as ~ −32‰, is ubiquitous at the surface of the western Arctic Ocean as a result of different growth rates of phytoplankton. Moderate penetration of depleted POC‐δ13C to depth indicates active sinking of large particles in the central basin. Lateral transport from the Chukchi shelf is also of significance in the western Arctic, as is evident from increases in biogenic silica to POC ratios and Mn oxide concentrations in the halocline, as well as lithogenic element contents in the deep waters. Our study supports previous suggestions of the near absence of CaCO3in the Arctic Basin. This study presents the first data set of concentration and composition of suspended particles in the western Arctic Ocean and sheds new light on the vertical and lateral processes that govern particle distribution in this enclosed ocean basin.
Total iron and total lead concentrations were correlated in water that had stagnated in laboratory‐scale experiments with sections of 10 harvested lead service lines (LSLs) from Providence, Rhode Island. One of these sections had much greater lead release and pH decrease during stagnation, and the inner surface of this service line had a thick coating of iron oxide scale. The iron‐rich scale was composed of coarse‐grained iron oxides (lepidocrocite and magnetite) covered with a thin lead‐bearing layer (hydrocerussite). Complementary batch experiments with pure iron oxides found that their surfaces accelerated the oxidation of Pb(II) from hydrocerussite, which produced PbO2(s)and decreased the pH. While the findings presented are for LSLs from Providence, the co‐occurrence of iron oxides and lead corrosion products is widespread. The results highlight the importance of considering iron corrosion when evaluating processes that control lead concentrations in tap water.
more » « less- NSF-PAR ID:
- 10187551
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- AWWA Water Science
- Volume:
- 2
- Issue:
- 4
- ISSN:
- 2577-8161
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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