Toxicity prediction: An application of alternative testing and computational toxicology in contaminated groundwater sites in Taiwan.

Groundwater contamination remains a global threat due to its toxic effects to humans and the environment. The remediation of contaminated groundwater sites can be costly, thus, identifying the priority areas of concern is important to reduce money spent on resources. In this study, we aimed to identify and rank the priority groundwater sites in a contaminated petrochemical district by combining alternative, non-animal approaches - chemical analysis, cell-based high throughput screening (HTS), and Toxicological Priority Index (ToxPi) computational toxicology tool. Groundwater samples collected from ten different sites in a contaminated district showed pollutant levels below the detection limit, however, hepatotoxic bioactivity was demonstrated in human hepatoma HepaRG cells. Integrating the pollutants information (i.e., pollutant characteristics and concentration data) with the bioactivity data of the groundwater samples, an evidence-based ranking of the groundwater sites for future remediation was established using ToxPi analysis. The currently presented combinatorial approach of screening groundwater sites for remediation purposes can further be refined by including relevant parameters, which can boost the utility of this approach for groundwater screening and future remediation.

Food safety and bioavailability evaluations of four vegetables grown in the highly arsenic-contaminated soils on the Guandu Plain of northern Taiwan.

Arsenic contamination in a large area of agricultural fields on the Guandu Plain of northern Taiwan was confirmed in a survey conducted in 2006, but research concerning the relationship between bioavailable As concentrations in contaminated soils and crop production in Taiwan is not available. Pot experiments were conducted to examine the growth and accumulation of As in four vegetable crops grown in As-contaminated soils and to assess As intake through consumption. The phytotoxic effects of As in soils were not shown in the pot experiments in which vegetable crops were grown in soils contaminated with different As levels in situ collected from Guandu Plain (120-460 mg/kg) or artificially spiked As-contaminated soils (50-170 mg/kg). Experimental results showed that the bioavailable As extracted with 0.5M NaHCO3 from soils can be used to estimate As concentrations in vegetables. The As concentrations in the vegetables were compared with data shown in the literature and As limits calculated from drinking water standards and the provisional tolerance weekly intake (PTWI) of inorganic As established by the Food and Agriculture Organization of the United Nations/World Health Organization (FAO/WHO). Although the As levels in the vegetables were not high and the bioavailability of As in the soils was quite low, long-term consumption may result in higher As intake in the human body.

Baseline concentrations of ten metals in the freshwater sediments of a watershed in Taiwan.

Freshwater sediments and water samples were quarterly collected at different sampling stations from August 1996 to April 1998 in the Fei-Tsui reservoir watershed (FTRW) of northern Taiwan. The sediment and soil samples were digested using mixture of inorganic acids to analyze the total concentration of ten metals. The baseline concentrations of ten metals in the sediments of FTRW were calculated from the geometric mean (GM) values and the geometric standard deviation (GSD). The baseline concentrations of 10 metals in the 239 sediments of this watershed are listed as followings (mg/kg, only % for Fe): As 1.80-51.5, Cd 0.04-7.54, Cr 5.25-273, Cu 2.65-91.7, Hg 0.03-0.26, Mn 18.6-2310, Ni 3.95-167, Pb 1.10-75.4, Zn 6.46-327, and Fe 0.47-9.63%. However, the GMs of 10 metal concentrations in the sediments were lower than the regulated threshold concentrations in Taiwan rural soils. Highly correlations among different metals in the sediments of FTRW indicate that very similar sediments of formation process control the metal content associated with the parent materials. Inadequate land use results in As, Cr, Mn, and Ni accumulated in the sediment to show potentially contamination risk in the study area associated with accelerated erosion and runoff.