ORIGINAL PAPER Influence of natural and anthropogenic factors on the water quality of the coastal waters around the South Andaman in the Bay of Bengal Renjith VishnuRadhan 1,5 • Divya David Thresyamma 2 • Kamal Sarma 3 • Grinson George 3,4 • Prabhakar Shirodkar 1 • Ponnumony Vethamony 1 Received: 17 February 2014 / Accepted: 15 March 2015 Ó Springer Science+Business Media Dordrecht 2015 Abstract During the last decade, the Andaman and Nicobar Islands (ANI) have wit- nessed a marginal population growth with associated variations and degradation in the water quality of the inhabited coastal region. Monthly water quality data collected from six coastal locations in ANI were used to evaluate the anthropogenic influence in an otherwise pristine island environment. Exceptionally low dissolved oxygen (0.7–2.0 mg/ L) at the Phoenix Jetty (PJ) and mangrove site indicates hypoxic conditions. Among the nutrients, nitrate shows high values at PJ due to heavy nutrient loading from domestic sewage. The cluster analysis segregated PJ from the remaining sites, indicating dete- rioration in the water quality. On the other hand, water quality at Sippighat, a low- intensity aquaculture site, does not indicate any deterioration. Apart from the large modulations in the water quality of the study area by the Bay of Bengal waters, the effect of domestic waste discharges significantly affects the coastal waters of Andaman. Though the present water quality at most of the study sites appears acceptable, the increased volume of tourism and allied activities poses a potential threat to the island ecosystem. Electronic supplementary material The online version of this article (doi:10.1007/s11069-015-1715-9) contains supplementary material, which is available to authorized users. & Renjith VishnuRadhan renjitvishnu@gmail.com 1 CSIR - National Institute of Oceanography (CSIR-NIO), Dona Paula, Goa 403 004, India 2 ESSO- National Center for Antarctic and Ocean Research (MoES), Headland Sada, Goa 403804, India 3 Marine Research Laboratory, Division of Fisheries Science, Central Agricultural Research Institute, ICAR, Post Box No. 181, Port Blair 744 101, Andaman and Nicobar Islands, India 4 Fishery Resources Assessment Division, Central Marine Fisheries Research Institute, Ernakulam North P.O., Post Box No. 1603, Kochi 682 018, India 5 School of Civil Engineering Surveying and Construction, University of KwaZulu-Natal, Durban 4041, South Africa 123 Nat Hazards DOI 10.1007/s11069-015-1715-9