The budget and geochemistry of arsenic in a continental shelf environment |
| |
Authors: | Dennis G Waslenchuk |
| |
Institution: | Skidaway Institute of Oceanography, Savannah, Ga. 31406 U.S.A. |
| |
Abstract: | The concentrations of arsenic species in continental-shelf waters of the southeastern U.S. are controlled mainly by simple physical mixing of shelf waters and Gulf Stream intrusions. The biota mediate redox reactions which result in a disequilibrium of arsenic species; up to 20% of the total arsenic (averaging 1.1 μg/l) occurs as unstable arsenite As (III)] and dimethylarsenic, the remainder consists of thermodynamically favored arsenate As (V)]. Uptake of arsenic by the biota has a minor effect on arsenic distribution in offshore waters, producing a deep-water arsenate maximum, and minima for arsenite and dimethylarsenic. Riverine and atmospheric arsenic inputs to the shelf waters are relatively insignificant. Southeastern rivers contain only about 0.3 μg/l dissolved arsenic, and the atmosphere adjacent to continental shelf waters contains about 1.7 ng/m3 of As (V), exclusively associated with the particulate fraction. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|