To estimate the impact of mercury released from an artisanal small-scale gold mining (ASGM) activities on the ecosystem. Total and organic mercury concentrations in paddy field soil and freshwater snails around an artisanal small-scale gold mining area were investigated. Paddy field soil samples and freshwater snails were collected from ten sites along the Cikaniki River. A site located in a national park, which was approximately 12 km upstream from the ASGM site, was considered the reference site for this study. The organic mercury concentration in soil samples collected at the ASGM site was n.d.–0.018 mg kg−1 and that at the reference site was 0.005–0.008 mg kg−1. The organic mercury concentrations in the freshwater snails collected at the ASGM and reference sites were 0.38 ± 0.21 mg kg−1 (31.0 ± 26.6% of total mercury, n = 38) and 0.056 ± 0.032 mg kg−1 (40.5 ± 11.5% of total mercury, n = 16), respectively. Although the original form of mercury in the mining waste was elemental mercury and/or Hg2+, the mercury form changed to organic mercury in environment and the organic mercury was concentrated two orders of magnitude, even in low-order organisms.

Here we briefly introduce 13 papers that exem-plify the role of Quaternary research in disaster prevention and mitigation from multiple approaches ; this is a compilation from the open symposium “Multiple approach to reduce and mitigate disaster from Quaternary studies” held at Fukuoka University on August 27, 2017. These studies cover a variety of topics, from recent natural disasters, to historical and paleo- disasters that were revealed from historical records, and geo-morphological, stratigraphical, and archaeological investigations, in which we demonstrate the significant contributions from Quaternary research to improving hazard assessment.

The behavior of mercury (Hg) in water, sediments, air, dwarf bamboo leaves, and soils around the fumarolic area of Mt. Myoko, Japan, was investigated. Although some of the hot spring water samples contained over 1 µg/L total-Hg, overall, the total-Hg concentrations in the water samples decreased rapidly as the water flowed into a river. The total-Hg concentrations decreased not only due to simple dilution, but also to co-precipitation of Hg2+ with Fe(OH)3. The highest atmospheric Hg concentration, 91.7 ng/m3, was detected near the fumarole, and the concentrations decreased with distance from the fumarolic area. This tendency was also confirmed in the total-Hg concentrations of plant leaf samples. Total-Hg, methylmercury (MeHg), and ethylmercury (EtHg) concentrations in the soil surface layer (n = 13) ranged from 0.19 to 21.7 mg/kg, 0.3 to 9.3 µg/kg, and undetected to 7.7 µg/kg, respectively. The total-Hg concentrations in the surface layer soil samples decreased with distance from the fumarolic area, while the vertical distribution of total-Hg concentrations in the core and outcrop samples showed no clear trends. However, the MeHg and EtHg concentrations had no relationship with the total-Hg concentrations and were higher in the upper layer soils. The results suggest that MeHg and EtHg not only migrate with other Hg species from the volcanic gases, but are also generated on site. It was also confirmed that EtHg occurs in soil at the same level as MeHg in the study area.

The distributions of the total mercury (T-Hg), methylmercury (MeHg), and ethylmercury (EtHg) concentrations in soil and their relationship to chemical composition of the soil and total organic carbon content (TOC, %) were investigated. Core samples were collected from hill slope on the right and left riverbanks of the Idrija River. Former smelting plant is located on the right bank. The T-Hg average in each of the core samples ranged from 0.25 to 1650 mg kg(-1) .The vertical T-Hg variations in the samples from the left bank showed no significant change with depth. Conversely, the T-Hg varied with depth, with the surface, or layers several centimeters from the surface, tending to show the highest values in the samples from the right bank. Since the right and left bank soils have different chemical compositions, different pathways of mercury delivery into soils were suggested. The MeHg and EtHg concentrations ranged from n.d. (not detected) to 444 mu g kg(-1) and n.d. to 17.4 mu g kg(-1), respectively. The vertical variations of MeHg and EtHg were similar to those of TOC, except for the near-surface layers containing TOC greater than 20%. These results suggest that the decomposition of organic matter is closely related to organic mercury formation. (C) 2017 Elsevier Ltd. All rights reserved.

The distribution of mercury in the soil, sediment and river water around the artisanal small-scale gold mining (ASGM) area along the Cikaniki River, West Java, Indonesia, was investigated. The total mercury concentration (T-Hg) in the forest soil ranged from 0.11 to 7.0 mg kg−1, and the highest value was observed at the ASGM village. In the vertical T-Hg profile around the villages, the highest value was observed at the soil surface, and the concentration decreased with depth. This result suggested that the mercury released by mining activity was dispersed through the atmosphere and deposited on the surface. The total organic carbon content (TOC) showed a similar vertical profile as the T-Hg, and a linear relationship was found between T-Hg and TOC. Mercury deposited on the surface can be absorbed by organic matter. The slope of the line was larger near the ASGM village, implying a higher rate of deposition of mercury. The T-Hg in the sediment ranged from 10 to 70 mg kg−1, decreasing gradually toward the lower reaches of the river. Mining waste can be transported with the river flow and deposited along the river. The distribution of the mining waste can be determined using the mineralogical composition measured by X-ray fluorescence spectrometry.

2011年3月11日の東北地方太平洋沖地震以降，日本各地で地域防災計画や防災教育の見直しが行われている．防災教育は，普段の学校の教育システムの中で無理なく行われることが望ましい．その実施のためには，専門家だけでなく，教員や保護者，さらには地域社会の協力が必要不可欠である．子供たちには，災害への直接的な対処法ではなく，自然現象に対する正確な知識と，各人がそれに基づいて意思決定をできるように教育することが大切である．子供たちが自然の仕組みを理解することは，災害時の対応だけでなく，将来の研究者を育てることにもつながる．

霧島山は，南九州の鹿児島・宮崎の県境に位置する，第四紀の複成火山である．本コースでは，2010年に日本ジオパークネットワークに登録された霧島ジオパークのジオサイトを巡りながら，霧島山の噴火史や2011年1月に始まった新燃岳（しんもえだけ）噴火について紹介する．巡検では，まず，麓から霧島火山全体の地形や生い立ちを学び，その後，高千穂河原（たかちほがわら）や新湯（しんゆ）付近にて，2011年の噴出物や噴火による地形の変化などを観察する．噴出物に覆われた地域の植生回復の様子も見どころのひとつである．

The 850 m diameter crater of the Shinmoedake volcano was filled by andesitic lava after three subplinian eruptions on 26-27 January 2011. We analyzed blocks thrown from the lava-filled crater by subsequent Vulcanian explosions to estimate the lava’s viscosity and evaluate the possibility of drain-back processes in the crater. Petrographic work on the ejecta, including bulk and glass chemistry, phenocryst and microlite modes, and the water content of the glass enabled us to estimate the bulk viscosity of the lava to be 109.8(+15 − 12) Pa s. The conduit radius is constrained to 4.5 to 6 m by the eruption rate of preceding subplinian eruptions (450–740 m3/s dense rock equivalent). We estimate the simple drain-back rate of the lava to be 3 × 10−2 ~ 2 × 10−5 m3/s. At this rate, less than 1 percent of the total amount of the effused lava could drain back within 100 days. Synthetic aperture radar (SAR) observations did not reveal evidence of drain-back after the eruption, possibly because the chamber was sustained, at least in part by repressurization and refilling as observed by global navigation satellite system (GNSS) measurements of the volcano. This study showed that degassing and crystallization of the andesitic magma during emplacement increased magma viscosity by more than five orders of magnitude, prohibiting drain-back of the lava that filled the crater after the emplacement.

Although the mining activity of the Idrija mine in Slovenia ceased in 1995, a large amount of mining dregs containing high concentrations of mercury remains in the area. The mining dregs were transported with river flow and deposition along the Idrija River. To estimate the dispersion and change in the chemical form of mercury, a total of 28 soil core samples were taken around the river. The individual core samples were separated into layers for the analysis of their chemical composition, carbon contents, total mercury (T-Hg) and methylmercury (MeHg) concentrations. The chemical composition measured by X-ray fluorescence spectrometry was useful to estimate the dispersion of tailings: the fluvial terrace soil had a chemical composition similar to that of the tailings and could be distinguished clearly from the forest soil. The highest T-Hg concentration, 1,100 mg kg−1, was observed in the fluvial terrace soil near the mine. Although the concentration decreased gradually along with distance from the mine, concentrations higher than 200 mg kg−1 of T-Hg were still observed in the fluvial terrace soil approximately 20 km downstream from the mine. In the vertical distribution of T-Hg in the hillslope soil, a higher value was observed in the upper layers, which suggests the recent atmospheric deposition of mercury. The concentration of MeHg was the lowest at the riverside and higher in the hillslope soil, which was the opposite of the T-Hg distribution. The total organic carbon content tracked similarly with the distribution of MeHg and a linear relation with a significantly high correlation coefficient was obtained. The distinction may be related to the different dispersion process of mercury, and the organic carbon contents may be an important factor for MeHg formation.

In May 2010, the mid-congress of INQUA, the International Focus Group on Tephrochronology and Volcanism (INTAV) was held in Kirishima City, Kagoshima Prefecture, Japan. The local organizing committee INTAV-J (based on the Japan Association for Quaternary Research) started to plan the conference in 2007. Financial support was provided by Tokyo Geographical Society in addition to INQUA, PAGES, WEST JEC, Asahi Insatsu Co., Ltd and Paleo Labo Co., Ltd.The conference focused on eight scientific themes and calls for papers. We also invited six keynote speakers. A total of 76 participants attended the conference from 11 countries (Australia: two, Canada: four, Germany: one, Indonesia: one, Japan: 42, New Zealand: four, Philippines: one, Russia: one, Sweden: three, UK: 12, USA: five), and 37 persons attended the post-conference excursion (15th, 16th, and 17th). Forty-nine oral presentations and 38 poster presentations were given over three days (10th, 11th and 14th May). On 12th and 13th May, one-day intra-conference field trips were organized for all participants. Papers emerging from the conference will be published in a special issue of Quaternary International, supported by INTAV executives.

The atmospheric concentration of mercury was determined daily for 3 years (July 1999-March 2002) in Kagoshima City to clarify the seasonal variation of mercury levels and the influence of mercury emitted from Sakurajima. The atmospheric mercury was collected on a porous gold collector at Kagoshima University approximately 11 km west of Sakurajima and the amount of mercury was determined by cold vapor atomic absorption spectrometry (CVAAS). A loss of temperature dependency was found for the east wind in 1999. However, in 2001, high temperature dependency was observed for all wind directions with the easing of volcanic activity. Short-term movement in the atmospheric concentration of mercury was also investigated by making measurements every two hours over a three-day period at heights of 3 and 12 m. This operation was carried out about every two months in the year 2001 at Kagoshima University. The atmospheric mercury concentration was higher in the daytime than nighttime showing temperature dependency: the concentration at 3 m (Hg(3m)) ranged from 1.65 to 17.9 ng m-3 (5.96 ± 3.47 ng m-3) in the daytime and 1.50 to 12.8 ng m-3 (4.20 ± 2.33 ng m-3) overnight, while that at 12 m (Hg(12m)) ranged from 1.24 to 29.4 ng m-3 (4.74 ± 3.61 ng m-3) and 1.38 to 14.8 ng m-3 (4.50 ± 2.85 ng m-3), respectively. The variation in Hg(3m) from day to night was considerably larger than that in Hg(12m). As a result, Hg(3m) was higher than Hg(12m) in the daytime and lower in the nighttime. On the other hand, the concentration gradient showed a high degree of dependency on solar radiation. These observations suggested that mercury is emitted from the ground with an increase in solar radiation and rise of the temperature in the daytime and deposits with the fall of temperature at nighttime. The influence of rain and volcanic activity on the periodic variation of mercury is also discussed in detail.