Rainwater chemistry and qualityin and around twin cities of hyderabad and secunderabad, Andhra Pradesh, India

The rainwater investigations over the Hyderabad and Secunderabad were carried out to observe the quality of rainwater with regard to influence of marine or non-marine components of atmosphere. 20 rainwater samples from different locations covering an area of 150 Sq.Km. collected and were analyzed for pH, EC, CO₃, HCO₃, SO₄, NO₃ using standard methods, Na, Ca, K and Mg on AAS and trace elements like Pb, Fe, Cr, Cd and As were analyzed on ICP. The concentrations observed maximum for Cl (2.6 ppm) and lowest for Cu (0.0037 ppm) with pH ranging from 6 to 7 and EC from 17 to 53 μMhos/cm. From correlation study and neutralizing factors (NF) calculation for Ca²⁺ and Mg²⁺ it is observed that good correlation exists between H⁺ and SO₄ and H⁺ and NO₃ suggesting strong affinity between the oxides of sulpher, nitrogen and H⁺ ion concentration indicating the influence of non-marine components and neutralizing factors calculations suggests potential acid neutralizing capacity of alkaline elements such as Ca²⁺, K⁺, Mg²⁺, Na⁺ mostly released from granitic soils to atmosphere in the form of dust.