Behaviour of boron in Mandovi estuary (Goa)

Abstract

Boron in the waters of Mandovi Estuary, Goa, India varied with tides and seasons with concentrations decreasing from mouth towards upstream. Higher concentrations of 0.51-5.83 mg kg1 and 0.03-4.42 mg kg-1 respectively were observed during the pre and postmonsoon season as compared to relatively low levels in monsoon (0.01-2.70 mg kg-1) due to increased suspended sediment loads and high dilution resulting from large quantities of freshwater influx. Addition of boron to the extent of 27.74% during the postmonsoon and removal upto 31.30% in the monsoon were observed. In the postmonsoon months, removal of boron to some extent was observed due to phytoplankton. The pH and dissolved oxygen showed a negative correlation with boron whereas chlorinity and alkalinity gave positive correlations with a linear variation. Though the overall behavioural pattern of boron indicated non-conservative nature, it showed a quasi-conservative character during premonsoon and a non-conservative during rest of the seasons