Use of a Bayesian isotope mixing model to estimate proportional contributions of multiple nitrate sources in surface water

To identify different NO3- sources in surface water and to estimate their proportional contribution to the nitrate mixture in surface water, a dual isotope and a Bayesian isotope mixing model have been applied for six different surface waters affected by agriculture, greenhouses in an agricultural area, and households. Annual mean delta15N-NO3- were between 8.0 and 19.4 pro mille, while annual mean delta18O-NO3- were given by 4.5-30.7pro mille. SIAR was used to estimate the proportional contribution of five potential NO3- sources (NO3- in precipitation, NO3- fertilizer, NH4+ in fertilizer and rain, soil N, and manure and sewage). SIAR showed that “manure and sewage” contributed highest, “soil N”, “NO3- fertilizer” and “NH4+ in fertilizer and rain” contributed middle, and “NO3- in precipitation” contributed least. The SIAR output can be considered as a “fingerprint” for the NO3- source contributions. However, the wide range of isotope values observed in surface water and of the NO3- sources limit its applicability.

XUE Dongmei;  DE BAETS Bernard;  VAN CLEEMPUT Oswald;  HENNESSY Carmel;  BERGLUND Michael;  BOECKX Pascal; 

2012-11-08

ELSEVIER SCI LTD

JRC59713

0269-7491,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC59713,   

10.1016/j.envpol.2011.09.033,