The diagram reveals the stages of nitrogen in groundwater along the coast.
The diagram clearly shows that under natural conditions, nitrogen oxides from lightning and plants fix nitrogen. Household gardens and markets replenish nitrogen in the soil through fertilizers and household waste/garbage. Industry contributes to the nitrogen cycle by adding nitrogen through leaks from storage tanks and wastewater ponds. Finally, nitrogen in landfills/wastewater is absorbed by the soil and enriches it.
The diagram further shows that groundwater flows from east to west, passes near the saltwater interface, reaches its destination sea, and is discharged into the sea from the groundwater discharge zone. Ammonia reduction occurs through two processes: first, ammonia is absorbed by soil particles, and second, ammonia degassing. Nitrogen concentrations are highest below landfills, followed by industry, while concentrations are lower near the sea.
Overall, waste disposal supplies/releases maximum nitrogen in groundwater compared to other sources, but the density beneath landfills is higher.