BIHAREAN BIOLOGIST 8 (1): 24-31 ©Biharean Biologist, Oradea, Romania, 2014 Article No.: 141106 http://biozoojournals.ro/bihbiol/index.html Physico-chemical assessment and ecological impacts on Marsh Crocodiles in protected areas of Nara Thar Desert Khairpur Muhammad Saleem CHANG 1,2,3, ٭, Ghulam Sarwar GACHAL 1 , Ayaz Hussain QADRI 1 , Zohra KAHTOON 2 , Syed Iftikhar Hussain JAFRI 2 , Muhsin Ali KALHORO 3 , Khadim Hussain MEMON 3 and Muhammad Yusuf SHEIKH 1 1. Department of Zoology, University of Sindh, Jamshoro, Sindh, code 76080, Pakistan. 2. Department of Science & Technical Education, University of Sindh, Hyderabad/Jamshoro, Sindh, Pakistan. 3. Institute of Evolution and Marine Biodiversity, College of Fisheries, Ocean University of China, Qingdao, P.R. China. * Corresponding author, M.S. Chang, Mobile: 0333-2643404, 0311-3007570, E-mail: saleem_khan74@yahoo.com Received: 8. January 2014 / Accepted: 19. February 2014 / Available online: 20. February 2014 / Printed: June 2014 Abstract. Limnological studies of Nara Thar Desert Khairpur were carried out bimonthly January to November 2008. In water samples the determination of microbial contamination, detection of pollutant indicator organisms and hazard chemicals were performed. The present study deals with the physico-chemical parameters such as temperature of water and air, electrical conductivity, total dissolved solids, calcium, magnesium, bi carbonate, chloride, sodium, potassium, sulphur, carbonate, biological oxygen demand and dissolved oxygen were performed with the recognized standard method of world health organization. During present study various contaminants were observed below the detection range while other chemicals were found within the normal range. It was witnessed during the water analysis the range of contamination, proximity of pollution sources and water quality of lakes suggest that the crocodilian population is at high risk and in under threatened in the lakes of Nara Thar Desert except in Nara canal. Key words: limnological, contamination, hazard, pollution, chemicals, threatened. Introducation Nara Thar Desert (NTD) Khairpur was declared in 1980 as Wildlife Sanctuary by the Government of Sindh and it was established for the protection and enhancement of wildlife in this protected areas of Sindh. NTD which provides a home to large numbers of migratory birds, mammals, reptiles in- cluding Marsh Crocodiles. In NTD there are more than 200 small, permanent, seasonal, freshwater, brackish, marshy and saline lakes. The Nara Canal twitches from the Sukkur barrage which run more than 200 km, the major source of cultivation and drinking in the large areas of Sukkur, Khair- pur, Sanghar, Umarkot and Mirpurkhas districts. In the last decades, the large numbers of Marsh Crocodile (Crocodylus palustris) and Gavials (Gavialis gangeticus) live co-existed in the Nara Thar Desert but unfortunately due to the increasing human population, hunting pressure and other anthropo- genic activities the unique crocodilian species of Pakistan were extinct now. In aquatic habitat various environmental factors include different physical properties of water such as solubility of gases and solids, light penetration, temperature and salinity of water. Physico-chemical factors such as hardness, phos- phate and nitrates which are very important for the growth of primary productivity in aquatic habitat. Examination of water quality is among frequently conducted for bi monthly interval in NTD. Hence, the present study was based on the assessment of the physico-chemical parameters of NTD. The most important key species of ecosystem and endangered species of reptilian, the Marsh Crocodile is inhabitant in NTD Khairpur (WWF-Pakistan 2007). In aquatic habitat for the biodiversity the availability of pure and safe water is es- sential for the prevention of water borne diseases and their survival in aquatic habitat. The major sources of contamina- tion may be due to rain water or pollution from the adjacent areas of lakes, shallow water tables and due to anthropo- genic activities. The present study on water quality of NTD related with its impacts on crocodilian health was conducted first time in Sindh province. Ecological changes in aquatic habitat depends upon the physico-chemical factors of water bodies. The present study of physico-chemical parameters in NTD provides the information and its influence on health and growth of Marsh Crocodiles. Material and methods Assessment of physico-chemical parameters of lake water in NTD Khairpur was conducted bi-monthly January to November 2008. During the collection of water samples we take from surface water and bottom layers by using Van Dorn plastic bottles (1.5 lit) from the crocodile’s lake bi monthly interval. After collecting the water sam- ples we were kept them in polythene plastic bottles, previously soaked in 10% nitric acid for 24 h and rinsed with ultrapure water obtained from lab water system. When we were reached at the labo- ratory; the collected water samples from different lakes were mixed in acid washed bucket to make one composite sample, rinsed with ultrapure water and kept under °C till for further analysis of water samples. During the examination of water samples the analytical data of water quality was ensured through the careful standardiza- tion and duplicate water samples. Assessment of physico-chemical parameters were carried out by the standard methods of water analysis (APHA 1998). For water sampling we were collected sam- ples from 11:00 am to 5:00 pm at bi monthly intervals from the lakes of NTD Khairpur. For the analysis of physico-chemical properties of lake water such as temperature of water, depth and transparency, the procedure of secchi disk measurement was done during the wa- ter sampling. Assessment of temperature level the mercury ther- mometer was dipped into the water samples to a depth of 15 cm for 2-5 minutes, range of pH was examined with Orion Model 420 A pH meter, EC, TDS and Na was measured with WTW 320 conductivity meter. The alkalinity, hardness, Cl and phosphate were measured with the standard methods of APHA, 1998. For the assessment of Ca, HCO3 and HCO the titration method (2310) was applied. Water analysis of Mg and K we were examined with the Spectrometer. The BOD was examined with the Winkler method and DO was deter- mined with the Oxygen meter (Jenway Model 9071).