Well,

The most important processes affecting the transfer of pollutants to groundwater:

I. Geochemical processes:

Are all changes that occur in the concentration of pollutants in water before reaching groundwater.

1 - The process of adsorption and removal: One of the most important characteristics of the balance between the number of bonds of materials interacting with the solution through the process of adsorption, increasing the concentration of the solution increases the process of adsorption and decrease causes the removal. The components of clay rock, zeolite, hydroxyl, iron hydrate, manganese, hydroxyl and organic compounds are more affected by adsorption. The adsorption effect of the roots of micro-organic microorganisms plays a key role in adsorption. The process of exchange between solution ions and sediment ions is called ion exchange. Its direction, quantity and velocity are influenced by several factors, the most important of which are the types and characteristics of the rock components, the quality of the ions, the concentration of the dissolved ions and the dissolved ions and the continuous reactions of adsorption and removal. = (Ratio of the speed of groundwater to the speed of contaminants).

2. Solubility and sedimentation process depends on the contaminants' ability to dissolve and break down. The contaminants are divided according to the degree of their dissolution and their reaction in water to: electrolytic contaminants (salts, acids, bases) and non-electrolytic pollutants (polarizing, non-polarizing compounds).

3 - Oxidation -Reduction process: The process of action is: deposition of oxidative ions (at specific pH values) in groundwater where the oxidation and reduction effort changes according to the runways of groundwater and the components of the reservoir rocks. It works on the dissolution of organic matter in oxygen-free reducing ranges and with the presence of iron, manganese and nitrates precipitating heavy metals.

II. Biochemical processes:

 During which the main organic compounds are broken down by bacteria into carbon and hydrogen, to be used as energy in their reactions to form carbon dioxide, carbon dioxide and water.

III. Physical processes include:

1- Dispersion: There are two directions for the dispersion of dissolved pollutants (horizontally and vertically). Contaminated water expands when mixed with pure groundwater due to hydrodynamic dispersion until the concentration of pollutants reaches normal levels. Due to mixing, there is a decrease in the concentration of pollutants over time depending on the runoff .

2 - the process of disability retention:

 In accordance with physical-chemical mechanisms, the movement of dissolved substances in the waterway is hindered. The dissolved material is divided into two categories: a conservative class, soluble substances that do not interact with soil or groundwater, such as chlorine, and are often rapid. An effective class: reactants (chemical and biological) with soil are often slow to move. The mechanism of action for disability is summarized by the successive effect of adsorption and removal, which impede the transfer of pollutants in the waterway, determination of solution, filtration, chemical reaction and biochemical change.

3. The process of filtration: The total physical and chemical activities occurring in soil components to remove large particles by mechanical effort and adsorption of suspended small particles (bacteria, bacteria and iron hydroxyl residues).

4 - Gas transport process:

During the transition from groundwater to the atmosphere, the gases pass through two separate bands separating the unsaturated band from the ground water and the second between the unsaturated band and the atmosphere. The movement and spread of gases in the unsaturated and saturated ranges is affected by the effect of temperature and varying atmospheric pressure, the effect of dispersion, the quantity and effectiveness of oxygen supply from the atmosphere in aerobic or anaerobic conditions in groundwater.

IV. Biophysical processes:

 Germs seep into the groundwater through water recharge and their speed is related to the source of pollution and the nature of the soil above the area of ​​the aquifer where the average time required for the arrival of germs to groundwater between (20-400) days.

Regards

Very good teacher Dr. Hussien.

How can I cite in references?

Best Regards

Well,

Text book, Groundwater Science / Fitts, 2006.

Regards