Risk assessment of groundwater environmental contamination: a case study of a karst site for the construction of a fossil power plant

Abstract

This paper presents a demonstration of an integrated risk assessment and site investigation for groundwater contamination through a case study, in which the geologic and hydrogeological feature of the site and the blueprint of the fossil power plant (FPP) were closely analyzed. Predictions for groundwater contamination in case of accidents were performed by groundwater modeling system (GMS) and modular three-dimensional multispecies transport model (MT3DMS). Results indicate that the studied site area presents a semi-isolated hydrogeological unit with multiplicity in stratum lithology, the main aquifers at the site are consisted of the filled karst development layer with a thickness between 6.0 and 40.0 m. The poor permeability of the vadose zone at the FPP significantly restricted the infiltration of contaminants through the vadose zone to the subsurface. The limited influence of rarely isotropic porous karstified carbonate rocks on the groundwater flow system premised the simulate scenarios of plume migration. Analysis of the present groundwater chemistry manifested that that the groundwater at the site and the local area are of the HCO-Ca, HCO, and SO-Ca types. A few of the water samples were contaminated by coliform bacteria and ammonia nitrogen as a result of the local cultivation. Prediction results indicate that the impact of normal construction and operation processes on the groundwater environment is negligible. However, groundwater may be partly contaminated within a certain period in the area of leakage from the diesel tanks, the industrial wastewater pool, and the cooling tower water tank in case of accidents. On a positive note, none of the plumes would reach the local sensitive areas for groundwater using. Finally, an anti-seepage scheme and a monitoring program are proposed to safeguard the groundwater protection. The integrated method of the site investigation and risk assessment used in this case study can facilitate the protection of groundwater for the construction of large-scale industrial project.

Soil properties and environmental risk assessment of soils in the surrounding area of Hulene-B waste dump, Maputo (Mozambique)

“…The method applies eighth variables to assess risk index: (a) volume of deposited waste; (b) leachate drainage; (b) type of waste; (d) waste physical condition; (e) waste biodegradability; (f) monitoring system; (g) waste compaction; and (h) final coating (Chaudhary et al 2021;Liu et al 2019;Nadiri et al 2017). Risk factor (Ri) and risk weight parameter (Wi) for each of the eight variables are described in Table 1.…”

Groundwater flow velocities in karst aquifers; importance of spatial observation scale and hydraulic testing for contaminant transport prediction

“…A range of pollutants can reach the saturated part of karst aquifers in all the regions which are devolved to industry and agriculture across the world. These contaminants include nitrate, sulphate, chloride, toxic organic compounds released by mineral fertilizers and pesticides, and pathogens (Tratner et al 1997;Drew 2008;Reimann and Hill 2009;Göppert and Goldscheider 2011;Gregory et al 2014;Reh et al 2014;Palmucci et al 2016;Liu et al 2019;Medici et al 2019cMedici et al , 2020Rusi et al 2018;Ducci et al 2019;Parker et al 2019;Ren et al 2019). Fast transport of such pollutants typically occurs through bedding plane discontinuities, joints, and fault-related fractures rather than via porous matrix in lithified carbonate rocks (Berkowitz 2002;West and Odling 2007;Medici et al 2016, Jones et al 2017Maldaner et al 2018;Berlin et al 2020;Hu et al 2020).…”

Application of Geophysical and Hydrogeochemical Methods to the Protection of Drinking Groundwater in Karst Regions

“…However, the high heterogeneity of carbonate rocks in karst areas greatly increases the difficulty of pollution prevention and control [4]. Additionally, the strong hydraulic alternation conditions make this kind of water more susceptible to pollution and rapid migration, thereby posing health risks to the supply objects [5,6]. In view of the concealment of groundwater contamination and difficulty in remediation [7], prevention measures should be taken as the main means for groundwater protection when conducting industrial development, especially in karst areas [8][9][10].…”