Historical Fluxes of Toxic Trace Elements and Associated Implications in the Salton Sea Basin
Abstract
The Salton Sea is a polymictic, hypersaline lake that is predominantly sustained by wastewater and agricultural runoff from Mexico and the United States. It is a terminal lake that acts as a net sink for toxicants, which in addition to nutrients and increasing salinity, have dramatically transformed the lake over the past century. However, the impacts of these changes on the cycling and bio-accessibility of toxic elements and compounds and their associated human and environmental health implications are not well understood. This project aims to measure and model the fluxes of toxic elements, including selenium, lead, and mercury, in the lake over temporal and spatial scales by using geochemical data from the analysis of sediment cores, a pervasive salt crust, and the water column. The project also aims to elucidate the bio-accessibility and depositional environments of these elements. Preliminary results highlight two different oxygen concentration regimes in the lake: an increasingly anoxic condition in the bottom of the northern lobe and a seasonally variable oxygen deficiency in the bottom of the southern lobe. The deteriorating conditions at the lake could be exacerbated by a receding shoreline, which has already exposed several square kilometres of lake bed and is expected to continue as future inflows are diverted under the Quantification Settlement Agreement. Continued water conservation by Imperial Valley farmers and the increasing reuse of reclaimed water by Mexico are also expected to contribute to reduced inflows to the lake. Therefore, improved understanding of the cycling of toxic elements and their potential remobilization, including via wind entrainment (dust) associated with lake desiccation, will be valuable in protecting human and environmental health within the Salton Sea basin.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.H54E..07O
- Keywords:
-
- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 0461 Metals;
- BIOGEOSCIENCES;
- 1806 Chemistry of fresh water;
- HYDROLOGY;
- 1871 Surface water quality;
- HYDROLOGY