Source of arsenic pollution in the ground water is

The correct answer is Industrial effluents.

Arsenic is a toxic metalloid, and industrial activities are among the most significant anthropogenic (human-induced) sources of its pollution in groundwater. Various industrial processes, such as mining, metal smelting and refining, coal-combustion in power plants, glass manufacturing, and the production of arsenic-based pesticides, herbicides, and wood preservatives, generate large volumes of wastewater containing arsenic compounds.

When these industrial effluents are discharged untreated or improperly managed, they seep into the soil and leach down through the earth's layers. This process allows the dissolved arsenic to infiltrate the water table, resulting in the contamination of deep and shallow aquifers that serve as sources of groundwater.