Assessment of landfill leachate in Nam Son, Hanoi using 3D electrical imaging and self-potential data

Abstract

The main objective of this study was to assess the environmental impact of the Nam Son Landfill on the subsurface geological structure studied using 3D electrical imaging and self-potential investigations. The map of the equipotential was based on self-potential data and was indicative of concentrations of redox-active components, and the map of the electrical conductivity provided information about the mineralization of the groundwater. The electrical conductivity of the subsurface was obtained from 3D-electrical imaging analysis conducted using a Wenner-based array configuration. An inversion of the data was carried out using 3D regularized least-squares optimization methods with robust model constraints. Three profiles of 3D electrical imaging and 180 self-potential data points, scattered within the study area near the disposal site, were implemented. The self-potential method supports the results of the geoelectrical method relating to a contaminated zone in the survey area with a large negative self-potential anomaly of ∼−260 mV with respect to the reference of a contaminant plume. Interpretations of geophysical data showed a low resistivity zone (<10 Ω m), which appeared to be a fully saturated zone with leachate from the Nam Son open dumpsite. The correlation between geophysical investigations and hydrochemical analysis proved to show high conductivity zones related with landfill leachate.

Volatile constituents ofAmomum maximumRoxb andAmomum microcarpumC. F. Liang & D. Fang: two Zingiberaceae grown in Vietnam

“…Amomum maximum is a widely distributed plant of the tropical terrain, which has traditional therapeutic potential and culinary values (Nguyen 2000). An investigation has shown that the extract of A. maximum acts as anthelmintic against the cestode, Raillietina echinobothrida (Chetia et al 2014).…”

“…No record of the composition of its essential oil could be found in the literature. Furthermore, Amomum microcarpum is a plant that can grow up to 2.5 m tall (Nguyen 2000). It has been traditionally used for the treatment of fever and postpartum bath (Lamxay et al 2011;Boer et al 2014).…”

Some notes on section Sinarisaema (Arisaema, Aroideae, Araceae) in Vietnam and a new species of Arisaema from Vietnam

“…The genus Arisaema Mart. includes about 200 species mainly distributed across Eastern Asia from both temperate and tropical regions as far south as Indonesia and west into the Himalayas with some species occurring in the Arabian Gulf, East Africa and North America (Mayo et al 1997;Govaerts et al 2002;Gusman and Gusman 2006;Boyce et al 2012;Nguyen 2017). Following Gusman & Gusman (2006), the genus Arisaema is divided into 14 sections: Anomala, Arisaema, Attenuata, Clavata, Decipientia Flagellarisaema, Frenchetiana, Lobata, Nepenthoidea, Pedatisecta, Sinarisaema, Tenuipistillata and Tortuosa. The species described here belongs to sect.…”

“…Sinarisaema contains 29 species of which three can be found in Vietnam. Currently a total of 26 species of Arisaema belonging to seven sections are now recorded in Vietnam; these are sections: Anomala, Attenuata, Decipientia, Franchetiana, Nepenthoidea, Odorara and Sinarisaema, (Nguyen 1998(Nguyen , 2000(Nguyen , 2002(Nguyen , 2005a(Nguyen , 2005b(Nguyen , 2007(Nguyen , 2017Pham-Hoàng 2000;Nguyen & Boyce 2005;Gusman and Gusman 2006;Nguyen & Vu, 2009;Li et al 2010;Boyce et al 2012;Bruggemen et al 2013;Luu et al 2013Luu et al , 2014Luu et al , 2020Luu et al , 2022Nguyen et al 2014;Hoang et al 2015;Ohi-Tomi et al 2016;Van et al 2016aVan et al , 2016bVan et al , 2017Van 2017;Le et al 2020) with a single representative from sect. Nepenthoidea only very recently added to those recorded in Vietnam with the discovery of a new species in 2022 from Pu Ta Leng Mountain, in Tam Duong District, Lai Chau Province (Luu et al 2022).…”