Eko Haryono
Department of Environmental Geography, Faculty of Geography, Universitas Gadjah Mada

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In Situ Bioremediation Strategies for the Recovery of Mercury-contaminated Land in Abandoned Traditional Gold Mines in Indonesia Winardi Winardi; Eko Haryono; Sudrajat Sudrajat; Endang Sutariningsih Soetarto
Biosaintifika: Journal of Biology & Biology Education Vol 12, No 3 (2020): December 2020
Publisher : Department of Biology, Faculty of Mathematics and Sciences, Semarang State University . Ro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/biosaintifika.v12i3.25229

Abstract

Traditional gold mining activities release mercury into the environment, creating a major concern for the Indonesian governments today. In situ bioremediation, which draws on the activities of indigenous soil bacteria for the recovery of mercury-contaminated land, has never been conducted intensively in the country. This research set out to determine the most efficient in situ bioremediation strategy for this purpose. It took place in Mandor Village, Landak Regency, Kalimantan Barat-Indonesia. During the experiment, four groups of sampling plots were made into triplicate and given various treatments: a. nutrient addition, b. aeration, c. pH neutralization, and d. without nutrient addition and aeration as a control. pH neutralization was conducted in all sampling plots by adding lime until soil pH of ±7 was achieved. The experiment was performed during both rainy and dry seasons to determine the influence of seasonal weather. Total mercury levels of each plot were measured on day 0, 30, 60, 90, and 120, and the effects of treatments and time on mercury depletion were analyzed by two-way ANOVA (P0.05), followed by a post hoc test to identify the best treatment and optimum time for in situ bioremediation. The results showed that the best time to conduct this bioremediation was in the rainy season by applying nutrient addition and aeration for 90 days on soils with neutral pH; these stimulations could remove ±89.6% of the mercury. This bioremediation technique is a novel technological approach in land recovery that local governments can adopt to restore soils contaminated with mercury from traditional gold mining.  
Typology of Indonesian Stratovolcanoes: Insights from Geomorphological and Geological aspects Indranova Suhendro; Eko Haryono
Indonesian Journal of Geography Vol 55, No 2 (2023): Indonesian Journal of Geography
Publisher : Faculty of Geography, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijg.74692

Abstract

This study aims to provide the first general typology of Indonesian stratovolcano (number of analyses=154), including various types of rock compositions and diverse volcanic hazards. Several parameters were evaluated, including average radius (r), average slope (S), surface roughness (RMS), rock compositions, mineralogy, and deposit characteristics. Four types were identified as follows: (1) small-least dissected cones, (2) broad-dissected cones, (3) extremely broad-dissected cones with caldera, and (4) residual-highly dissected cones. Type I is typically small (r=2.1 km), steep (S=19.8ᵒ), rough (RMS=88.8), less evolved (predominantly basic to intermediate), having abundant mafic (olivine, clinopyroxene) and minor hydrous (amphibole, biotite) minerals, with rare pumice and lava domes (mostly scoria and lava flows). Type II has moderate values of r, s, and RMS (8.8 km, 15.2ᵒ, and 47.7, respectively) with predominantly intermediate rocks, minor olivine with abundant hydrous minerals, and abundant pumice and lava domes. Type III is typically large (r=18.1 km), gentle (S=9.2ᵒ), smooth (RMS=40.1), producing abundant felsic rocks and felsic minerals (quartz and sanidine), and characterized by the occurrence of thick ignimbrite deposits. Type IV has relatively similar size to type II (r=8.2 km), but the slope is gentler with coarser surface textures (S=10.7ᵒ and RMS=56.8), includes more portion of ultrabasic rocks and mafic minerals, and has no feature of lava domes with common exposure of intrusions (e.g., dyke). We suggest that the evolution from type I to type III corresponds to maturation stage, whereas the formation of type IV represents erosional stage.