Many water sources and beaches do not meet the laid down quality standards because of the elevated levels of fecal pollution. Microbial tracking employs DNA-based technology to aid in the identification of the source of contamination.
Effects of fecal pollution
It is imperative to maintain good quality and safety of water systems that are used for recreational or drinking purposes. Contamination of the water is risky to human health, and it mostly leads to considerable economic losses. These losses are related to the closure of beaches or the areas where shellfish harvesting is done.
The Proper understanding of the actual origin of the fecal pollution is vital in the assessment of the health risks as well as the actions that need to be taken so as to remedy the situation. For many years, alternative and traditional methods have been used to predict the origin of fecal contamination. These methods faced some challenges because most of the organisms that caused water contamination were not limited to humans. Most of the organisms were even found in the intestines of animals. There was the need, therefore, for developing a technique that could define the precise source of these microbial organisms. Microbial Source Tracking (MST) comprises a set of methods that determine the host that is responsible for fecal pollution.
Application of Microbial Tracking
According to Washington’s Department of Ecology, the application of this method in risk assessment, beach monitoring, and total maximum daily load assessment provides a unique tool that is useful in identification of the source of the pollution. The identification allows for the suitable action to be taken.
Fecal pollution may originate from non-point and point sources. The point sources include sewage, stormwater, and effluent from wastewater treatment plants. Non-point sources include wildlife or agriculture runoffs and leaking septic systems. If it is concluded that the main contributor of the pollution is human, the most probable cause is compromised sewage or septic systems. If the contributor is cattle, nearby farms would be the main suspect.
Quantitative Polymerase chain reaction (qPCR) is one of the methods that were developed to detect fecal contamination of surface waters. According to Microbial Insights, PCR is a molecular process that involves the amplification of a particular gene thus allowing the detection and the quantification of the targeted DNA marker. The marker is usually in a mixture of non- target DNA sequences. The target DNA is obtained directly from environmental samples. Therefore, it is not necessary to cultivate the indicator organism. This eliminates the culture bias while at the same time providing a detection that is rapid and sensitive.