Explanation: Swahili developed as a common coastal language as early as the thirteenth century and has been greatly influenced by Arabic. It easily incorporates foreign words (primarily from Arabic, Hindi, Persian, and English) and consequently has been considered the most flexible of all languages in East Africa.
Fertilizers and chemicals are important contaminants of water and enter ground both directly and indirectly. In the case of Karst landscapes, the contaminated water infiltrates into the groundwater through underground streams or percolation.
Oil and gas spills also pose a serious problem for groundwater contamination as they can pollute aquifers near fracking zones and other oil extraction areas.
Animal feces are more of a problem in the modern age due to large-scale commercialized animal farms. Unless the waste from these facilities is controlled, it can runoff into fields and rivers and eventually seep into groundwater reserves.