What is a significant cause of soil and water contamination related to human activities?

Intensive farming is a significant cause of soil and water contamination tied to human activities due to several factors related to agricultural practices. In intensive farming systems, the use of large quantities of synthetic fertilizers and pesticides can lead to runoff that contaminates nearby water bodies. This runoff can carry nutrients like nitrogen and phosphorus, which can cause problems such as algal blooms and eutrophication in aquatic environments.

Additionally, intensive farming often involves the cultivation of monocultures, which can reduce soil health and biodiversity. The heavy machinery and tilling practices commonly employed can further disturb the soil structure, increasing the potential for erosion and runoff. This can lead not only to soil degradation but also to the leaching of contaminated materials into groundwater, posing risks to water quality.

In contrast, natural wildlife migration, periodic flooding, and soil erosion control do not have the same direct, pervasive impact on contamination. Wildlife migration is a natural process, while periodic flooding, although it can cause localized contamination, is typically an environmental event, not a result of human practices. Soil erosion control is a management practice aimed at reducing soil loss and protecting water quality, thereby mitigating contamination risks rather than contributing to them.