Tracing the sources of pollutants in Ganga river water using conventional and non-conventional isotope analysis in nitrates
Authors: Maurya Abhayanand Singh 
Published: March 2020

&lt;p&gt;&lt;strong&gt;Tracing the sources of pollutants in Ganga river water using conventional and non-conventional isotope analysis in nitrates&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Abhayanand S. Maurya&lt;sup&gt;1&lt;/sup&gt;, Amzad H. Laskar&lt;sup&gt;2&lt;/sup&gt;, Nityanand S. Maurya&lt;sup&gt;3&lt;/sup&gt;, Mao-Chang Liang&lt;sup&gt;4&lt;/sup&gt;,&lt;/p&gt;&lt;p&gt;&lt;sup&gt;&amp;#160;&lt;/sup&gt;&lt;/p&gt;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt;Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India&lt;/p&gt;&lt;p&gt;&lt;sup&gt;2&lt;/sup&gt;Geosciences Division, Physical Research Laboratory, Ahmedabad 380009, Gujarat, India&lt;/p&gt;&lt;p&gt;&lt;sup&gt;3&lt;/sup&gt;Department of Civil Engineering, National Institute of Technology Patna, India&lt;/p&gt;&lt;p&gt;&lt;sup&gt;4&lt;/sup&gt;Institute of Earth Sciences, Academia Sinica, Taiwan&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Ganga is the largest river in India providing fresh water to ~40 % of India&amp;#8217;s population which is more than any other river in the world. It is also one of the most polluted rivers in the world. Pollution, mainly from human and industrial wastes in the Ganga poses significant threats to human health and environment. This is an attempt to identify and quantify the contribution of different sources in the river water pollution using stable isotopes in nitrate (NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;). We measured non-conventional triple oxygen isotopes (&amp;#8710;&lt;sup&gt;17&lt;/sup&gt;O&lt;sub&gt;NO3&lt;/sub&gt;=&amp;#948;&lt;sup&gt;17&lt;/sup&gt;O&lt;sub&gt;NO3&lt;/sub&gt;-&amp;#955;&amp;#948;&lt;sup&gt;18&lt;/sup&gt;O&lt;sub&gt;NO3&lt;/sub&gt;) along with the conventional isotopes (&amp;#948;&lt;sup&gt;15&lt;/sup&gt;N and &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O) in NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; and concentrations of major ions and metals (both heavy and trace ones) in Ganga river water to understand the sources and contribution from different pollution sectors. We also measured stable water isotopes (&amp;#948;D and &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O) to understand the secondary processes such as in stream evaporation and inflow over the course of the river.&amp;#160; Water samples were collected from multiple locations starting from the clean water in the upstream region to all the way to the estuaries before the onset of monsoon, to best capture anthropogenic signals. &amp;#8710;&lt;sup&gt;17&lt;/sup&gt;O in NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; is used to partition the atmospheric depositions from other sources such as human and industrial wastes and &amp;#948;&lt;sup&gt;15&lt;/sup&gt;N and &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O values are used to partition the contribution of pollutants from different land sources such as municipal wastes and agricultural fertilizers. &amp;#8710;&lt;sup&gt;17&lt;/sup&gt;O in NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;- &lt;/sup&gt;is also used to understand reaction processes which affect the isotopic composition such as nitri&amp;#64257;cation, denitri&amp;#64257;cation, volatilization, assimilation and mineralization as those processes mostly follow mass dependent fractionation without affecting &amp;#8710;&lt;sup&gt;17&lt;/sup&gt;O but influence the conventional isotopic compositions. We will present the results along with some recommendations for reducing the pollution level of the Ganga water.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;