Why is over-fertilisation a concern for groundwater contamination?

Over-fertilisation is a concern for groundwater contamination because it can lead to nutrient pollution and harmful algal blooms.

Over-fertilisation occurs when excessive amounts of fertilisers are applied to agricultural fields or gardens. These fertilisers contain nutrients such as nitrogen and phosphorus, which are essential for plant growth. However, when applied in excess, these nutrients can leach into the groundwater, a process known as nutrient pollution. This can have serious implications for both the environment and human health.

Groundwater is a vital resource, providing drinking water for many communities and supporting agriculture and industry. When contaminated with nutrients from over-fertilisation, it can pose a risk to human health. High levels of nitrates in drinking water, for example, can cause methemoglobinemia, a condition that reduces the blood's ability to carry oxygen. This is particularly dangerous for infants and can lead to a condition known as 'blue baby syndrome'.

Nutrient pollution of groundwater can also have significant environmental impacts. When nutrient-rich groundwater flows into rivers, lakes, and oceans, it can stimulate the excessive growth of algae, leading to harmful algal blooms. These blooms can deplete oxygen levels in the water, killing fish and other aquatic life. They can also produce toxins that are harmful to both wildlife and humans.

Furthermore, over-fertilisation can disrupt the balance of nutrients in the soil. This can lead to a decrease in soil fertility over time, as the excessive nutrients can inhibit the growth of certain beneficial soil microorganisms and promote the growth of harmful ones. This can have long-term impacts on agricultural productivity and sustainability.

In conclusion, over-fertilisation is a significant concern for groundwater contamination due to its potential to cause nutrient pollution. This can have serious implications for human health, the environment, and agricultural sustainability. Therefore, it is crucial to manage fertiliser use carefully to protect our groundwater resources.