Macrobenthic Invertebrate assemblage along gradients of the river Basantar (Jammu, J&K) in response to industrial wastewater

Aquatic ecosystem is one of the most productive ecosystems in the world that inhabits a large proportion of the earth’s biodiversity (McAllister et al., 1997 and Groombridge and Jenkins, 1998). Numerous plants and animals, ranging from microscopic algae to large plants, from protozoan to mammals, exhibit a variety of adaptations which allow them to survive and grow in water (Gopal and Chauhan, 2001). In the past, ‘Water’ the basic amenity for living organisms was pure, virgin, undisturbed, uncontaminated and basically most hospitable for living organisms but the situation is just the reverse today because progress in science and technology is also leading to pollution of environment and serious ecological imbalance which in the long run, may prove disastrous for mankind (Chauhan, 2008), thereby affecting its ecological integrity to a greater extent.

 Macrobenthic invertebrates refer to the organisms that inhabit the bottom substrates (sediments, debris, logs, macrophytes, filamentous algae etc.) of aquatic habitats, for at least part of their life cycle. The density of aquatic macrobenthic invertebrate species and communities is controlled by a variety of environmental factors such as habitat characteristics (Hynes, 1970; Peeters and Gardeniers, 1998), sediment quality (Chapman and Lewis, 1976), sediment grain size (Tolkamp, 1980), and by biological factors such as competition and predation (Kohler, 1992; MacKay, 1992; Macneil et al., 1999; Bhat et al., 2011). Stream flow, nature of substratum and organic pollution generally regulates the species composition and dominance of different taxa in various stretches of rivers (Negi and Singh, 1990; Bhat et al., 2011) and thus, macrobenthic invertebrates constitute the most popular and commonly used group of freshwater organisms in assessing water quality (Rosenberg and Resh, 1993). Benthic invertebrates have been favoured in environmental effects monitoring because they are sessile or limited in their range of movement and therefore cannot avoid pollution (Gaufin, 1973). They are generally abundant and can be found year round so are easily sampled. Since many aquatic species have a life span in water of approximately a year, they provide an indication of water quality conditions over that period. Thus, benthic invertebrate monitoring data provides a link between the effects of human activities on the physical and chemical properties of water and aquatic ecosystem health (Norris and Hawkins, 2000). 

River Basantar (the present study site) is a tributary of river Ravi and is an important water body of Jammu and Kashmir State of India. It flows through the district Samba of Jammu region and is one of the main sources of drinking water for its inhabitants. The establishment of an Industrial Growth Centre with large number of industrial units along the side of this river causes direct discharge of the industrial waste into the river through drainage thereby severely deteriorating the water quality of the river and thus drastically affected the overall ecology of river Basantar. In order to assess the impact of pollution load on the diversity and distribution pattern of macrobenthic invertebrate fauna of river Basantar, a study was carried out for a period of two years i.e. from December, 2009 to November, 2011 at four pre-designated stations of river Basantar viz. St I, II, III and IV (Fig 1). St I lie near the National Highway Bridge and is under continuous stress of anthropogenic influences in the form of Cattle-bathing, washing of vehicles, fishing, drawing of water using electric motor and mining of sand. St II is about 2.2 km downstream from the Station I near Railway Bridge. It receives industrial effluents from industrial drainage. St III lies 1 km downstream from Station II. Sand mining, cattle bathing and drawing of water using electric motor (by Gujjar community residing at the bank of the river) are the common activities at this station. St IV is about 3.5 km downstream from Station III. 

Thus, the present study describes the response of macrobenthic fauna to the industrial pollution with regard to its species composition and distribution in river Basantar so as to utilize the information so generated to devise proper strategies regarding the monitoring and conservation of river Basantar.