**1. Introduction**

Thousands of chemicals are used in industry, agriculture, pharmacy, commerce, and daily life. With that, a large number of chemical compounds enter the environment. Often these are considered with potential harmful effects on environmental media quality and biota safety. Thus, the understanding of them is crucial both for a better management of their use and for the better protection of the environment and living organisms. Monitoring these chemical compounds frequently is time-consuming and requires large financial efforts; one of the most cost-effective as well as time-efficient methods of evaluating their behavior in the environment and living organisms could be the use of predictive numerical models.

on the characteristics of transformation products, these transformation processes could be either of benefit (attenuation processes) or be hazardous (when the resultant transformation products possess more hazardous characteristics than the "parent" compound).

Numerical Modeling of Chemical Compounds' Fate and Kinetics in Living Organisms: An Inverse…

http://dx.doi.org/10.5772/intechopen.76611

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**ii.** *Chemical compounds' transformation in the environment:* Based on chemical compounds' specific physicochemical properties as well of biogeochemical and physicochemical characteristics of the media in which they are discharged (soil, water, air), these chemicals can be distributed across different environmental compartments (soil, surface and/or underground water , air, sediments, etc.) and biota [4]. In almost all cases their accumulation in environmental or biota compartments is characterized by continuous dynamic processes such as volatilization, degradation, precipitation, sorption, and so on, processes that often have the potential to end up in the formation of new chemical compounds called as transformation products of the initial chemical compound (**Figure 1**). Often these compounds could enter in new reaction processes and for other new end products. A schematic diagram of principal processes that could take place in both environment and biota and their interconnection with the "initial" chemical compounds and

Challenges considering potential transformation products are given by their physicochemical properties that in several cases could make them more harmful against environment quality or biota safety than the initial chemical compound. Both processes as well as the resultant transformation products' formation are directly dependent on the environmental conditions

**Figure 1.** A schematic presentation of the main processes involved in chemical compounds and corresponding potential

transformation of products' fate between different environmental compartments and biota.

"resultant" transformation products is presented in **Figure 1**.

as well properties of chemicals.

Experimental data and models for chemical compounds' fate and kinetics in living organisms play a crucial role for assessing the potential human and ecological risks associated with chemical use.

Plants are receptor organisms and could be either direct or indirect vectors for chemical exposure to all other organisms [1]. In the first instance, the generated experimental data considering chemical concentrations in different media of the environment and biota are necessary to improve our understanding on plant-chemical-environment interactions. These, in turn, admit and bring forward the development of better scientific knowledge as well as conceptual and predictive models on chemical partition, fate, and uptake [2]. The strong interconnections between experimental data and model development are continuous and a long-term updated process which is needed to advance our ability to provide reliable quality information that can be used in various environmental protection contexts and regulatory risk assessments [1].

At this moment there are no standard protocols both for chemical compounds' bioaccumulation data generation and for data use for prediction through numerical methods [1, 3]. For the reliable modeling of plant-chemical-environment interactions with the major goal to predict chemical compounds' fates and kinetic in living organisms, it is necessary to understand and keep into account all process, phenomena, and characteristics of both chemicals and receptors (living organisms and the environment) and the interconnected process between them. Inconsistent data collection, inaccurate generation of them, or reporting them with gaps will provide improper and less useful information for their application in assessment and numerical model development.

This chapter is about to find optimal numerical modeling ways considering chemical compounds' fate and kinetics in a living organism, specifically plants. The aim of this study was to propose a numerical procedure which estimates the highest accumulation rate of a chemical compound of interest for a growing living organism and to validate the procedure.
