Development of Toxicity Index to Evaluate the Level of Water Contamination by Using Cellular Responses

Abstract

Conventional tests in environmental monitoring have been performed by quantifying levels of toxicity of specific substances such as pesticides or drugs, and then comparing with known toxicity thresholds. These tests are conducted using analytical chemistry methods and can only be used for targeted substances, often missing unexpected toxicants. This shortcoming underlines the need for novel tests for rapid assessment of toxicity of environmental sample mixtures, followed by more detailed and expensive laboratory analysis as required. In order to evaluate the level of toxicity in water contamination, a mathematical model to predict the toxicity index is developed based on time-dependent cellular response curves (TCRCs). First, the water sample is diluted to a series of strength (80%, 60%, 40%, 30% 20% and 10%) to get the multiple concentrations. Then, the living cells are exposed to those water samples and the corresponding dynamic cytotoxicity response curves are collected via xCELLigence real-time cellular analyzer for high throughput (RTCA HT) system. A synthetical index, based on the calculation of area under curve (AUC) of the negative control, is proposed to evaluate the level of toxicity in water contamination. The proposed index also takes the variation of biological experiment into consideration. The biological experiment demonstrates the effectiveness of the proposed toxicity index to measure the level of toxicity in water contamination.