Abstract
This paper is a preliminary attempt to assess the composition of pollutants in two different caldera lakes situated in the Indonesian Archipelago: Batur and Bratan. Both lakes are characterized by largely different physico-chemical regimes; Batur Lake is located in an area that is currently volcanically active, unlike Bratan Lake. The latter is much smaller and shallower than Batur Lake. The concentration of pollutants in the Indonesian equatorial lakes is largely unknown, and the impact of both biological and geothermal processes on their distribution requires attention. This study shows that the concentrations of cations (Na+, K+, Mg2+, Ca2+), anions (SO42−, F−, Cl−, Br−) and trace elements (Li, B, Al, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Cd, Sn, Cs, Ba, Pb, U, Be, Ag, Sb, Tl, Bi) differ greatly between both lakes. Most chemical parameters determined in volcanically influenced Batur Lake were tens to hundreds times higher than in Bratan Lake, and in the case of trace metals, the ratios of the two lakes’ concentrations reached several hundreds. This study also compared the composition and concentration levels of organic compounds in both lakes, such as fatty acids, halocarbons and esters. On the other hand, the content of organic chemicals in the lakes also results from biological activity by phytoplankton, zooplankton and bacteria.
Highlights
Volcanic lakes can range in salinity from very low to hyper-acidic-brines
The results of our study on the abundance of major, minor, trace elements and organic compounds in the water from two different caldera lakes indicate that their chemistry is the result of important interactions among water, volcanic gases and the local substratum
The most important feature was the detection of multiple trace elements
Summary
Variations in lake-water chemistry are related to variations in the composition and flux of volcanic fluids and gases entering the lake. They are modified by the dilution and evaporation effects [1]. Caldera lakes are filled volcanic cavities of two different origins, closely corresponding to the prevailing rock types. The explosive eruptions of high-viscosity, silica-rich magma cause the volcanic cone to rupture, leaving a basin for a future lake. This is the usual origin of andesitic-dacitic, rhyolitic, and peralkaline calderas [1]. The basaltic lavas, on the other hand, are characterized by effusive eruptions [2], a caldera can only be formed in them following the collapse of an empty magma chamber [3,4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
