Abstract
Sixteen metals, both total and acid-leached, and their binding formations were quantified for the sediment column of the seasonally anoxic Great Ghost Lake. Since marked variation in the content of organic matter plays a major role in regulating the distribution of metals in sediments, this study provided insight into the relationship between organic matter and metals in a naturally anoxic water environment. Metals, Al, Cs, Mg, Rb and V, had significant negative correlations with total carbon content (TC) and occurred less often in mobile fractions. These findings indicate that these metals came from lithogenic sources and did not change much during early diagenesis. As a result, signals of these elements, whose origins can be traced back to long-range transport dust, were better preserved. Acid-leached contents of Cs, Mg and Rb also had negative correlations with TC, while both total and acid-leached As and Cd had good positive correlations with TC. Large portions of both As and Cd, were observed in mobile fractions (especially As) and came from organic sources and/or were incorporated into organic matter during early diagenesis (especially Cd). Long-term variations in redox conditions of the lake were induced by climate changes and might have influenced distributions of Sr and redox-sensitive Mn and V in mobile fractions. In addition to natural processes, enrichment of Pb and Cd near the core top was from anthropogenic aeolian sources. Finally, recent aeolian fluxes of Al, As, Ba, Br, Ca, Cd, Ce, Cl, Cr, Cs, Cu, Er, Eu, Fe, Ga, Gd, K, La, Lu, Mg, Mn, Na, Nd, Ni, Pb, Rb, Si, Sm, Sr, Ti, Tm, V, Yb, Zn and Zr were estimated and large amounts of micronutrient Fe (~6O μg cm^(-2) yr^(-1)), of aeolian origin, was also noted.
Highlights
The variable water chemistry in lakes favors the study of geochemistry of an aquatic environment
Since the content of inorganic carbon was usually very small, the total carbon content (TC) measured was nearly equal to the total organic carbon (TOC)
Kuivila and Murray (1984) and Birch et al (1996) showed that total organic carbon decreases with depth as a result of decomposition and remineralization of buried organic matter
Summary
The variable water chemistry in lakes favors the study of geochemistry of an aquatic environment. Anthropogenic activity, such as the burning of fossil fuels, garbage and leaded gasoline, has significantly increased the flux of certain elements into the atmosphere (Li 1981; Patterson and Settle 1987; Nriagu 1989; Hsu et al 2004) This aeolian material has become the principal factor controlling distribution of a number of elements in the lake sediments. Analysis of the distribution and forms of elemental species, as well as relationships among elements and organic carbon, was undertaken in this study to develop a better understanding of (1) the extent to which climate and other factors regulate the distribution of elements in sediments; (2) the relationships between metals and organic matter; and (3) the geochemical and diagenetic processes in a seasonally stratified and anoxic lake sediment column
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
