PANJIM: An assessment of antibiotic pollution in Mandovi and Zuaririvers shows that the concentration of antibiotics is much higher than what is considered safe, especially during the monsoon season.
Though, the overall water quality conditions of the two major rivers remain ‘considerably good’ due to annual rains, the bacterial presence during the monsoons is ‘highly’ detrimental to the health of the individuals, if exposed to these microbes.
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The National Institute of Oceanography (NIO) has released its publication on ‘Seasonal variations in the water quality and antibiotic resistance of microbial pollution indicators in the Mandovi and Zuari estuaries’.
The study has been conducted by AshwiniToraskar, CathrineManohar, Charmaine Fernandes, Abigayle Gomes andAjit Antony.
In the present study, changes in the water quality and levels of microbial pollution during the pre-monsoon, monsoon and post-monsoon seasons were determined.
According to the study, the water quality in these habitats is affected by various anthropogenic activities as they are extensively used for transportation, fisheries and various recreational activities.
The water quality index was estimated based on the parameterssuch as temperature, salinity, pH, dissolved oxygen, biochemical oxygen demand and nutrients. The seasonal changes in the microbial pollution load were also assessed based on the abundance of pollution indicator organisms and their resistivity towards multiple antibiotics.
“Results show that the water quality index status was ‘poor’ in the pre-monsoon and post-monsoon season and it was ‘good’ only in the monsoon period. Levels of pollution indicator organisms determined show that the counts were the highest in the pre-monsoon season, which reduced in the monsoon and further declined during the post-monsoon season,” the study revealed.
However, the estimated Multiple Antibiotic Resistance (MAR) index, suggests bacterial isolates in monsoonwater and sediment samples have maximum resistance towards antibiotics, it said.
Bacteria with more than 0.2 MAR index are considered to be highly detrimental to the health of the individuals exposed to these microbes.
“In this study, we have observed that during the monsoon season an isolate with the highest MAR index of 0.94 was obtained,” it said.
“This shows that, though the basic water quality improved during the monsoon possibly due to substantial dilution, the increased terrestrial inputs brought harmful pathogens into these estuarine waters, which may be of potential health risk,” the NIO said.
As a part of recommendation, the NIO has stressed on the need to study the pathogenicity, virulence and antibiotic sensitivity of the Pollution Indicator Organisms (PIOs) present in the habitat.
“Any reduction in the monsoonal rains and an increase in the number of virulent PIOs entering the estuarine habitat can alter the microbial community structure. Hence, adequate treatment of urban runoff and terrestrial inputs into the estuarine regions has to be undertaken,” the NIO suggested.
It also said that understanding the ecological status of the estuarine habitats is important for successful environmental management and sustainable development.
