Trace elements in the Mississippi River Delta outflow region: Behavior at high discharge

Journal Article · Fri Nov 01 04:00:00 EST 1991 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(91)90486-O· OSTI ID:5140826

Shiller, A M ^[1]; Boyle, E A ^[2]

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1. Univ. of Southern Mississippi, Stennis Space Center (United States)
2. Massachusetts Inst. of Tech., Cambridge (United States)

Samples for dissolved trace element analysis were collected in surface waters of the plume of the Mississippi River during a period of high river discharge. These field data are compared with results of laboratory mixing experiments. The studies show that Cu, Ni, and Mo are largely unreactive in the plume. Surprisingly, Fe also appears to show little reactivity; the pronounced flocculation removal of Fe frequently observed in other estuaries is not seen in this system. This difference may be a consequence of the alkaline nature of the Mississippi which results in low dissolved Fe concentrations in the river (<50 nmol/kg). Zinc, another particle-reactive element, also shows little reactivity. This lack of reactivity for Zn, as well as Cu and Ni, is partly a result of the short residence time of plume waters in shallow areas affected by sedimentary interactions. The chromium distribution shows apparent non-conservative behavior indicative of estuarine removal; however, temporal variations in river concentrations is a more likely explanation for this behavior. For some of the elements, complex distributions occur as a consequence of the interplay of physical-chemical and/or biological processes with the dynamic mixing regime. For Cd, desorption from the suspended load plays a major role in determining the distribution. However, sedimentary input may also play a role in the spatial variability of Cd. For V, biological uptake in the plume exerts a strong influence on its distribution. At the time of this study, uptake was large enough to consume both the river flux of V as well as a substantial amount of vanadium supplied by the ocean.

• OSTI ID: 5140826
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 55:11; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540350 -- Environment
Aquatic-- Site Resource &amp; Use Studies-- (1990-)
58 GEOSCIENCES
580000* -- Geosciences
ACTIVATION ENERGY
CADMIUM
CHEMISTRY
CHROMIUM
COASTAL REGIONS
COPPER
ECOLOGICAL CONCENTRATION
ELEMENTS
ENERGY
METALS
MISSISSIPPI RIVER
MOLYBDENUM
NICKEL
POLLUTION
RIVER DELTAS
RIVERS
STREAMS
SURFACE WATERS
TRACE AMOUNTS
TRANSITION ELEMENTS
VANADIUM
WATER CHEMISTRY
WATER POLLUTION