ABSTRACT In the present work, an attempt has been made to address the groundwater quality issue of Ajmer-Pushkar railway line region in post-monsoon season. Physico-chemical characterization of groundwater in the study area has been carried out as per national and international standards. The study revealed in groundwater contamination post-monsoon season. Some samples were found to have higher contents of Ca, TDS, Na and F than the limits prescribed by BIS, and WHO. KEYWORDS: Groundwater, physico-chemical parameters, Standard deviation, Pearson's Coefficient of correlation INTRODUCTION Groundwater is fresh and clean in nature. But human activities are constantly adding industrial, domestic and agricultural wastes to groundwater reservoirs at an alarming rate. In comparison with rivers or streams, groundwater tends to move slowly and with very little turbulence. Once contaminants reach groundwater, little dilution or dispersion normally occurs. Groundwater quality may also vary temporarily in pre- and post-monsoon seasons. The pollutants present on surface get dissolved in rainwater and percolate through ground to reach the groundwater table. However, the dissolution and percolation of pollutants depend on many parameters such as solubility and chemical nature of the pollutants, the soil type, i.e., soil texture and its quality as well as the ground cover. The present work investigates seasonal changes in groundwater quality of Ajmer-Pushkar railway line region, which is a part of EIA studies being carried out for the project. It becomes necessary to evaluate the present quality of groundwater because it is a main source of drinking water in the study area and directly affects human health. Present study of groundwater monitoring in pre- and post-monsoon seasons is useful in understanding the nature of pollution and seasonal fluctuations in groundwater quality. STUDY AREA The study area of Ajmer-Pushkar region mainly has two cities Ajmer and Pushkar, both of which are of historic, tourist and religious importance. Ajmer is a big and rapidly growing city. Pushkar is a small town situated 12 km northwest of Ajmer. State Highway no. SH-18 connects Pushkar to Ajmer. The area covered by Ajmer city is 241.50 sq. km. It lies between 26⁰ 20’ N to 26⁰ 33’ N Latitude and 74⁰35’ E to 74⁰43’ E Longitude at an elevation of about 486.0 m above mean sea level (MSL). Pushkar is located at 26⁰ 27’ N Latitude and 74⁰ 37’ E Longitude, at an elevation of 530 m MSL. Pushkar lies on eastern fringe of the ‘Thar Desert’. Location map showing the sampling sites is represented in figure 1. Weber Earth Science & Environmental Engineering http://www.weberpub.org/weseehtm © Author(s) 2015. CC Attribution 3.0 License. STATISTICAL STUDY ON PHYSICO-CHEMICAL PARAMETERS OF GROUNDWATER OF AJMER-PUSHKAR RAILWAY LINE REGION IN POST MONSOON SEASON Sarita Sharma¹, Sudesh Kumar²*, Pradeep Kumar Sharma³, Praveen Mathur¹ ¹ Department of Environmental Studies, Maharshi Dayanand Saraswati University, Ajmer-305009, India. ²* Department of Chemistry, Banasthali University, Rajasthan - 304022 ³ Department of Computer Science, Banasthali University, Rajasthan - 304022 Accepted 26�� January, 2015 Corresponding Author: Sudesh Kumar Department of Chemistry, Banasthali University, Rajasthan - 304022 Email address: sudeshneyol@gmail.com Research Article Volume 1-1 (2015) Figure 1: Location map of sampling sites