Effects of Untreated Sewage and Fertilisers

Untreated sewage contains a high amount of organic matter, creating an environment for bacteria to thrive. These bacteria can deplete oxygen levels in the water, a condition known as eutrophication, which can eventually lead to the death of aquatic life.
Sewage can escalate the nutrient levels in a water body. Nitrogen and phosphorus from sewage act as nutrients encouraging the growth and reproduction of algae, leading to algal blooms.
Excessive amounts of nitrogen and phosphorus found in untreated sewage alter the nutrient balance in an ecosystem. In high quantities, they degrade water quality, harm water resources, and have detrimental effects on wildlife and public health.
Fertilisers are often used in agriculture to increase the nutrient content of soil, promoting plant growth. However, when released into the water system, whether through surface run-off or leaching, they too can cause eutrophication.
Fertilisers contribute to algal blooms. Like sewage, they contain high levels of nutrients (particularly nitrogen and phosphorous), which stimulate the excessive growth of algae.
After consuming the nutrients released by the fertilisers, these algae die and decompose. The decomposition process is facilitated by bacteria, which use up most of the oxygen available in the water, thus creating a shortage for other aquatic organisms, which can cause a decrease in biodiversity.
Furthermore, this process produces toxins harmful to both aquatic and terrestrial organisms, and even to human health. Some of these toxins, accumulated in shellfish and other seafoods, can poison whoever consumes them.
Both untreated sewage and fertilisers are examples of point source pollution. Appling techniques to handle sewage and rational use of fertilisers can significantly reduce their impact on ecosystems.
It is important to understand these impacts to develop strategies to prevent water pollution, such as appropriate wastewater treatment and responsible agricultural practices. The introduction of more sustainable practices can mitigate the effects on ecosystems and contribute to maintaining biodiversity.