Pollution Assessment of Ennore (India) Creek Using Macrobenthos Usha Natesan1, S Kalaivani1, G Kalpana1,2
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ORIGINAL ARTICLE Pollution assessment of Ennore (India) creek using macrobenthos Usha Natesan1, S Kalaivani1, G Kalpana1,2 Natesan U, Kalaivani S, Kalpana G. Pollution assessment of Ennore density of Polycheates and Molluscs and vice versa during monsoon season. (India) Creek Using Macrobenthos. J Environ Geol. 2017;1(1):9-16. Salinity is also an important factor for macro fauna distribution and growth. Salinity is high during pre-monsoon and summer which resulted in high In the present study, the change in benthic community was identified in the production. From the Abundance and Biomass correlation it is inferred coastal stretch from Ennore to Pulicat, total of 6 stations were identified to that Station 2 and 4 are grossly polluted. Stations 1, 3 and 5 are moderately study benthic community. In order to understand the distribution of the polluted and Station 6 is less polluted. benthic community structure with respect to macro fauna in the Buckingham canal benthic were collected from all the stations during high tide on Spring Key Words: Macrobenthos, PRIMER, Ennore, Biomass, Abundance and tide of each month from September 2004 to December 2005 from bed and bio-env bank. Higher nutrient concentration during summer coincides with high ne of the crucial components to monitor the environmental health of an outlet for the excess water from the Poondi Reservoir. The Ennore Creek Oestuaries is by studying the benthic communities. In order to measure flows west to east, and opens into the Bay of Bengal at Ennore. Buckingham the extent and magnitude of pollution impacts in estuarine environments canal runs parallel to the east coast of India, form Kakinada in the north can be done by studying the community response in Macrobenthic (1-3). till Pondicherry in the south. This canal cuts perpendicularly the Ennore Macro invertebrates include those organisms large enough to be caught with Creek, south to north, and enters the vast Pulicat Lagoon in the north at a net or retained on a sieve with a mesh size of 250-1000 µm (4). These the Kotaikuppam Lock. It then is confluent with the Pulicat Lagoon, for organisms can be benthic, inhabiting substrates like sediments, debris, or about 1 km and then emerges onto the Sriharikota Island at the Moosamani logs, or pelagic, swimming freely in the water column. They play an essential Lock, and runs parallel along the western margin of the Sriharikota Island. role in the aquatic habitat and food web. Apart from fishery resources and Between Ennore and Pulicat, the canal spreads out into vast open stretches periphyton, ecological assessment of aquatic systems using macroinvertebrates of shallow waters. There is a second inlet to the Buckingham Canal around has been one of the frequently used protocols for indication of water quality 21 km from the Ennore Creek, but this tidal inlet is closed permanently in standard water management. due to a natural sand bar formation. The climate at Ennore is tropical with high humidity. The coastal area is normally governed by land and sea Benthic macrofauna is a good indicator of the variability of environmental breezes. The region experiences two distinct monsoons viz., the Southwest conditions. Indeed, temporal variations in benthic communities associated (SW) monsoon from June to September and Northeast (NE) monsoon from with the environmental characteristics of lagoons, have been studied (5-7). October to December. SW monsoon is normally temperate in strength. NE Benthic macrofauna is closely correlated with the ecological conditions monsoon is rather more variable in speed and direction, but the strength prevailing at the sediment-water interface where a multiple effect of organic is moderate, between N and NE for long spells over most of the area when enrichment and pollutant occurs (8). Thus, benthic macrofauna is one of well established. In the present study, the change in benthic community was the best biological tools for reflecting environmental change (9). Ecological identified in the coastal stretch from Ennore to Pulicat, total of 6 stations indicators are a subset of environmental indicators that apply to ecological were identified to study benthic community. In order to understand the processes, commonly used to provide synoptic information about the state distribution of the benthic community structure with respect to macro fauna of ecosystems (10,11). They comprise biological, chemical, or physical in the Buckingham canal benthic were collected from all the stations during measurements, indices or models that attempt to characterize critical high tide on Spring tide of each month from September 2004 to December components of the ecosystem (11-13). Ecological indicators mostly address 2005 from bed and bank. the ecosystem’s structure (e.g., genetic, population, habitat, and landscape MATERIALS AND METHODS pattern) and/or composition (e.g., genes, species, populations, communities, and landscape types) and/or functioning (e.g., genetic, demographic/life Surface sediment samples were collected at six stations in the Buckingham history, ecosystem, and landscape disturbance processes), accounting for Canal with the help of Petersen grab sampler covering an area of 0.1 m2. In a certain aspect or component, for instance nutrient concentration, water order to understand the distribution of the benthic community structure flow, macro invertebrate and/or vertebrate diversity, plant diversity and with respect to macrofacuna in the Buckingham canal, from six stations productivity, erosion symptoms and, on occasion, ecological integrity at a during high tide on Spring tide of each month from September 2004 to system’s level (14-16). December 2005. Samples were collected using a fishing boat. From the 25 km stretch of study area from Ennore Creek to Pulicat mouth, based on the Ecological indicators emerged as powerful tools to measure and synthesize various environmental stresses 6 sampling stations were identified as follows: information from specific biological or habitat components (17,18). Therefore, monitoring programs began to include indicators that measured Station 1 - near Ennore Creek mouth where coolant water from the thermal characteristics of the most valued ecological components and those that were power plant is discharged. most responsive to a diversity of stressors (13). The objectives of the present Station 2 – south of Ennore Creek representing the discharges from various study were to use different biotic indices to assess macro benthic diversity, industries. density and composition, compare different indices and assess the ecological quality status of Ennore Creek. The results are discussed in terms of four Station 3 - in the Buckingham canal 5 km away from Station 2. seasons’ viz., post monsoon, summer, pre monsoon and monsoon. Station 4 - in the Buckingham canal near aquaculture farms and adjacent to STUDY AREA the second inlet. The Ennore creek is located approximately 24 km in the northeastern part of Station 5 – 1 km after the second inlet. Chennai City, Tamil Nadu, India at the coast of Bay of Bengal (Figure 1). The Station 6 – near the Pulicat Lagoon inlet where the environmental stress is Ennore Creek is the estuary or the mouth of the river Kortalliyar, which is comparatively less. 1Centre for Water Resources, Anna University, Chennai, India; 2Department of Applied Geology, University of Madras, Guindy Campus, Chennai, India Correspondence: Kalpana G, Ph.D. Centre for Water Resources, Anna University, Chennai, India. Telephone 91 97890 48136, e-mail [email protected]. Received: August 21, 2017, Accepted: October 03, 2017, Published: October 10, 2017 This open-access article is distributed under the terms of the Creative Commons Attribution Non-Commercial License (CC BY-NC) (http:// OPEN ACCESS creativecommons.org/licenses/by-nc/4.0/), which permits reuse, distribution and reproduction of the article, provided that the original work is properly cited and the reuse is restricted to noncommercial purposes. For commercial reuse, contact [email protected] J Environ Geol Vol 1 No 1 October 2017 9 Natesan et al The larger organisms were handpicked immediately and then sieved through between surface and bottom are less significant. Comparatively low pH at 0.5 mm mesh screen. The labelled container and fixed in 5% formalin. The Stations 2 and 4 may be due to the intense bacterial degradation of organic organisms were stained with Rose Bengal solution (0.1 g in 100 mL of distilled matter and less photosynthetic activity of algae. Low pH values in Station 2 water) for enhanced visibility during identification. The samples were then could be attributed to the increase in Carbon dioxide resulting from a rise preserved in 75% alcohol for further identification. In the macrofauna in temperature due to the coolant water discharge. Higher pH values are three groups viz., polycheates, crustaceans and molluscs were considered for recorded at Stations 1, 3, 5 and 6. The relatively high pH may be attributed to analyses. All the specimens were sorted, enumerated and identified to the the intense photosynthetic activity of algae as evident by high phytoplankton advance level possible with the consultation of available literature (19-24). population and DO. The total biomass of benthic macrofauna collected in the present study was estimated by wet weight method. In molluscs, the shells were sorted to size Temperature (mm-group) and the meat was removed from the shells before weighing. The The surface water temperature in the stations varies from 29.5°C – 39.5°C shells were opened by immersion in boiling water (Table 1). and near bottom samples shows an average 10°C reduction than the surface Statistical analysis waters. Station 1 records remarkably higher temperature with an average increase of 90°C compared to other stations. The consistent high temperature The statistical analysis was done using the PRIMER (Plymouth Routines in at Station 1 is due to the coolant water discharge from NCTPS. The Multivariate Ecological Research) software, which has the scope for analysing recommended temperature for discharge into a water body is 320°C.