Heavy metals concentration in edible fishes from coastal region of Kalpakkam, southeastern part of India

Concentrations of Cu, Mn, Zn, Fe, Cr, and Pb were estimated using ICP-MS in nine commercially important and locally consumed fish species (Sarda orientalis, Scomberomorus commerson, Rastrelliger kanagurta, Sardinella longiceps, Paraplagusia bilineata, Cynoglossus lida, Cynoglossus macrostomus, Lepturacanthus savala, and Siganus javus) collected from coastal waters of Kalpakkam, eastern part of India. Their concentration (μg g(-1)) in the examined fish species ranged as follows: Cu (0.8-6.5), Zn (14.3-27.9), Mn (0.5-8.8), Fe (17.6-117.0), Cr (0.24-1.78), and Pb (0.18-2.29). Concentrations of most of the metals in the fish species studied were found to be safe for human consumption barring Mn.     

Variations of physicochemical properties in Kalpakkam coastal waters, east coast of India, during southwest to northeast monsoon transition period

A significant variation in physicochemical properties of the Kalpakkam coastal waters, eastern part of India, was observed during the event of southwest to northeast monsoon transition. Increase in nitrate, total nitrogen, and silicate concentrations were noticed during post-transition period. Ammonia concentration was at peak during transition period as compared to pre- and post-transition periods. Hypo-saline condition (~23 psu) was observed during post-transition as the surface water salinity decreased by ~10 psu from the pre-transitional values. Turbidity, suspended particulate matter, phosphate and total phosphorous values decreased marginally, coinciding with northward to southward current reversal. A drastic decrease (eightfold) in chlorophyll-a concentration was observed in the coastal water during post-transition period.     

Spatio-temporal variation in physicochemical properties of coastal waters off Kalpakkam, southeast coast of India, during summer, pre-monsoon and post-monsoon period

Seasonal observations on water-quality parameters and chlorophyll-a in the coastal waters off Kalpakkam, southeast coast of India, was carried out covering an area of about 30 km(2) to find out the variations in physicochemical properties during a monsoonal cycle of the year. Most of the parameters exhibited a significant spatial and seasonal variation. It revealed that the coastal water was significantly influenced by freshwater input from the nearby backwaters during North-east monsoon and post-monsoon periods. A marginal increase in pH from coast towards offshore was noticed during the observation. Relatively low salinity values were observed during pre and post monsoon when compared to summer. Bottom water was found to be highly turbid during summer and pre-monsoon conditions when compared to surface. This could be attributed to the strong northerly wind and northward current prior to the onset of southwest monsoon. N, P and Si based nutrients are relatively high in their concentration in the bottom water. Nitrate was significantly high during post-monsoon and contributed greatly towards total nitrogen as evident from the statistical correlation. Ammonia concentration was relatively high in the bottom samples during all the seasons except on a few occasions during post-monsoon. In general, phosphate and total phosphorous values remained low and particularly so in the surface water. Higher silicate concentration was observed in the bottom water, and there was a reducing trend towards offshore. High chlorophyll-a values were observed during summer and surface water was found to have higher pigment concentrations as compared to the bottom. Results show that phosphate acts as the limiting factor for phytoplankton production particularly during post-monsoon period whereas; none of the nutrients were found to be limiting the phytoplankton growth during other seasons.     

Seasonal variation in physicochemical properties of coastal waters of Kalpakkam, east coast of India with special emphasis on nutrients

A study pertaining to the seasonal variation in physicochemical properties of the coastal waters was carried out at Kalpakkam coast for a period of 1 year (February 2006 to January 2007). It revealed that the coastal water was significantly influenced by freshwater input during North East (NE) monsoon and post-monsoon periods. Concentration of all the nutrients and dissolved oxygen (DO) was relatively high during the NE monsoon, whereas, salinity and chlorophyll-a (chl-a) were at their minimum level during this period. Phytoplankton production peak was observed in summer during which a typical marine condition prevailed. The present observed values of nitrate, phosphate, silicate, and turbidity are significantly high (five to ten times) compared to that of the pre-Tsunami period from this coast. Relatively low DO and chl-a concentration was noticed during the post-Tsunami period. A notable feature of this study is that though nutrient concentration in the coastal waters during post-Tsunami period has increased significantly, turbidity, the most single dominating factor, was found to adversely affect the phytoplankton production during post-Tsunami period as reflected by relatively low chl-a concentration. Thus, the post-Tsunami period may result in a change in coastal biodiversity pattern concomitant with change in coastal water quality.     

Step-up multiple regression model to compute Chlorophyll a in the coastal waters off Cochin, southwest coast of India

The interaction effects of abiotic processes in the production of phytoplankton in a coastal marine region off Cochin are evaluated using multiple regression models. The study shows that chlorophyll production is not limited by nutrients, but their physiological regulations (responses to nutrients, pH, temperature and salinity) are mainly responsible for the increased biological production. The model explaining 77% of variability for chlorophyll a production is indicative of preconditioning of the coastal waters. The phytoplankton production is found to be sensitive to the environment, which varies seasonally. Further, the study suggests that supply of organic matter and grazing of zooplankton (not included) would improve the model efficiency. Despite this, the good agreement in the computed and measured chlorophyll a values shows that step-up multiple regression model is a useful tool to understand the influence of environmental variables on the production of phytoplankton in these coastal waters.     

Heavy metals concentration in soils of southeastern part of Ranga Reddy district, Andhra Pradesh, India

There is a growing concern over the potential accumulation of heavy metals in soils owing to rapid industrial and urban development and increasing reliance on agrochemicals in the last several decades. These metals can infiltrate through the soil thereby causing groundwater pollution. Surface soil samples (5 to 15 cm) collected from southeastern part of Ranga Reddy district were analyzed for 14 heavy metals (As, Ba, Co, Cr, Cu, Mo, Ni, Pb, Rb, Sr, V, Y, Zn and Zr) using Philips PW 2440 X-ray fluorescence spectrometer. Results for heavy and trace elements are reported for the first time in soils for this region. The contamination of the soils was assessed on the basis of enrichment factor (EF), geoaccumulation index (I (geo)), contamination factor and degree of contamination. The results reveal that variations in heavy element concentrations in the soil analyzed have both geogenic and anthropogenic contribution, due to the long period of constant human activities in the study area. The concentration of the metals Ba, Rb, Sr, V, Y and Zr were interpreted to be mainly inherited from parent materials (rocks) and the As, Co, Cr, Cu, Mo, Ni, Pb and Zn concentrations show contribution from geogenic and anthropogenic sources. The major element variations in soils are determined by the composition of the parent material predominantly involving granites.     

Phosphorus speciation in the marine sediment of Kalpakkam coast,southeast coast of India

A study was carried out at Kalpakkam coast to find out the distribution of various fractions of phosphorus (P) in the marine sediment during pre-northeast monsoon period. Samples were collected from ten locations covering ~80 km² of the inner-shelf region. Sedimentary parameters such as sand, silt, clay, and organic carbon percentage were analyzed in order to find out their relation with various P fractions. The sediment was found to be predominantly sandy in nature with low silt and clay content. Among all the fractions (loosely bound (LoP), calcium bound (CaP), iron bound (FeP), aluminum bound (AlP), and organic (OP)), CaP fraction constituted the largest portion (68.7 %) followed by organic fraction (16.3 %). The bioavailable P fractions ranged from 5 to 44 % of the total P (TP) content. Relatively high LoP content was observed at the offshore locations with comparatively high mud percentage as compared with the near-shore locations. As FeP and AlP concentrations were directly proportional to the amount of fine-grain sediment, the low levels of these fractions found in this coastal area were therefore attributed to the sandy nature of the sediments. The order of abundance of the major forms of P in the surface sediments of Kalpakkam coast was as follows: CaP?>?OP?>?LoP?>?AlP?>?FeP.     

Quantifying landscape pattern and connectivity in a Mediterranean coastal settlement: the case of the Urla district,Turkey

This study was aimed at analyzing and interpreting changes in landscape pattern and connectivity in the Urla district, Turkey using core landscape metrics based on a 42-year data derived from 1963 CORONA and 2005 ASTER satellite images and ten 1/25,000 topographical maps (1963–2005). The district represents a distinctive example of re-emerged suburbanization in the Izmir metropolitan area. In order to explore landscape characteristics of the study area, nine landscape composition and configuration metrics were chosen as follows: class area, percentage of landscape, number of patches, patch density, largest patch index, landscape shape index, mean patch size, perimeter area fractal dimension, and connectance index. The landscape configurations in the Urla district changed significantly by 2005 in that the process of (sub-)urbanization in the study area evolved from a rural, monocentric urban typology to a more suburban, polycentric morphology. Agricultural, maquis-phrygana, and forest areas decreased, while the built-up, olive plantation and phrygana areas increased. There was nearly a fivefold increase in the built-up areas during the study period, and the connectivity of the natural landscape declined. To prevent further fragmentation, it is important to keep the existing natural land cover types and agricultural areas intact. More importantly, a sustainable development scenario is required that contains a green infrastructure, or an ecological network planning for conservation and rehabilitation of the vital natural resources in the study area.     

Monitoring of ocean surface algal blooms in coastal and oceanic waters around India

The National Aeronautics and Space Administration’s (NASA) sensor MODIS-Aqua provides an important tool for reliable observations of the changing ocean surface algal bloom paradigms in coastal and oceanic waters around India. A time series of the MODIS-Aqua-derived OSABI (ocean surface algal bloom index) and its seasonal composite images report new information and comprehensive pictures of these blooms and their evolution stages in a wide variety of events occurred at different times of the years from 2003 to 2011, providing the first large area survey of such phenomena around India. For most of the years, the results show a strong seasonal pattern of surface algal blooms elucidated by certain physical and meteorological conditions. The extent of these blooms reaches a maximum in winter (November–February) and a minimum in summer (June–September), especially in the northern Arabian Sea. Their spatial distribution and retention period are also significantly increased in the recent years. The increased spatial distribution and intensity of these blooms in the northern Arabian Sea in winter are likely caused by enhanced cooling, increased convective mixing, favorable winds, and atmospheric deposition of the mineral aerosols (from surrounding deserts) of the post-southwest monsoon period. The southward Oman coastal current and southwestward winds become apparently responsible for their extension up to the central Arabian Sea. Strong upwelling along this coast further triggers their initiation and growth. Though there is a warming condition associated with increased sea surface height anomalies along the coasts of India and Sri Lanka in winter, surface algal bloom patches are still persistent along these coasts due to northeast monsoonal winds, enhanced precipitation, and subsequent nutrient enrichment in these areas. The occurrence of the surface algal blooms in the northern Bay of Bengal coincides with a region of the well-known Ganges–Brahmaputra Estuarine Frontal (GBEF) system, which increases supply of nutrients in addition to the land-derived inputs triggering surface algal blooms in this region. Low density (initiation stage) of such blooms observed in clear oceanic waters southeast and northeast of Sri Lanka may be caused by the vertical mixing processes (strong monsoonal winds) and the occurrence of Indian Ocean Dipole events. Findings based on the analyses of time series satellite data indicate that the new information on surface algal blooms will have important bearing on regional fisheries, ecosystem and environmental studies, and implications of climate change scenarios.     

Phytoplankton community structure in relation to environmental factors from the New Mangalore Port waters along the southwest coast of India

Seasonal and spatial phytoplankton distribution in relation to environmental factors was investigated in New Mangalore Port, a major port along the west coast of India. A well-mixed water column characterized the non-monsoon seasons, whereas it was weakly stratified during monsoon. Water quality index (TRIX) scores indicated good water quality except during pre-monsoon (inner zone surface) and monsoon (near bottom waters). Surface abundance of tychopelagic diatoms (Paralia sulcata, Melosira nummuloides, Cylindrotheca closterium, and Nitzschia sigma) was higher during non-monsoon seasons. Certain centric diatoms, e.g., Leptocylindrus danicus, P. sulcata, and Rhizosolenia imbricata, dominated during pre-monsoon (inner zone) and positively correlated with TRIX. High Skeletonema costatum and dinoflagellate abundance during the monsoon season coincided with high nutrient concentrations. Five potential toxic and fourteen harmful/bloom forming algal species were encountered at abundances below the level that can be considered as harmful to the ecosystem. In addition to a baseline database, this study highlights the potential use of certain diatom species as indicators of hydrography and water quality for monitoring dynamic coastal marine ecosystems.     

Monsoon-induced changes in the size-fractionated phytoplankton biomass and production rate in the estuarine and coastal waters of southwest coast of India

Changes in the autotrophic pico- (0.2–2 μm), nano- (2–20 μm), and microplankton (>20 μm) biomass (chlorophyll a) and primary production were measured in the estuarine and coastal waters off Cochin, southwest coast of India during the onset and establishment of a monsoon. During this period, the estuary was dominated by nutrient-rich freshwater, whereas the coastal waters were characterized with higher salinity values (>30 psu) and less nutrients. The average surface chlorophyll a concentrations and primary production rates were higher in the estuary (average 13.7 mg m^???3 and 432 mgC m^???3 day^???1) as compared to the coastal waters (5.3 mg m^???3 and 224 mgC m^???3 day^???1). The nanoplankton community formed the major fraction of chlorophyll a and primary production, both in the estuary (average 85 ± SD 8.3% and 81.2 ± SD 3.2%) and the coastal waters (average 73.2 ± SD 17.2% and 81.9 ± 15.7%). Nanoplankton had the maximum photosynthetic efficiency in the coastal waters (average 4.8 ± SD 3.9 mgC mgChl a m^???3 h^???1), whereas in the estuary, the microplankton had higher photosynthetic efficiency (average 7.4 ± 7 mgC mgChl a m^???3 h^???1). The heavy cloud cover and increased water column turbidity not only limit the growth of large-sized phytoplankton in the Cochin estuary and coastal waters but also support the proliferation of nanoplankton community during the monsoon season, even though large variation in nanoplankton chlorophyll a and production exists between these two areas.     

Changes in the abundance and composition of zooplankton from the ports of Mumbai, India

Zooplankton abundance, biomass, and composition from the ports of Mumbai, India, were studied by selecting 14 stations in and around the area during three different periods between 2001 and 2002 (Nov 01, Apr 02, and Oct 02). The results are compared with the records available since the 1940s. Copepod species such as Canthocalanus sp., Paracalanus arabiensis, Cosmocalanus sp., Euterpina acutifrons, Nannocalanus minor, and Tortanus sp. which were not reported in the earlier studies were observed during the present investigation. Purely herbivorous forms like Nannocalanus minor, Paracalanus sp., and Temora discaudata were in reduced abundance during Apr 02 sampling which was coupled with reduction in the diatom population. Whereas increased abundance of some carnivorous and omnivorous forms during Apr 02 sampling can be related to the changes in the food web dynamics.     

Dispersion pattern of petroleum hydrocarbon in coastal water of Bay of Bengal along Odisha and West Bengal,India using geospatial approach

Petroleum hydrocarbon (PHC) concentration was monitored in water of estuaries, ports, and coastal transects up to 10-km distance in East Coast of India once in every year during 2002–2009. The highest concentration was observed at Haldia port (1.60–20.11 μg/l) due to the impact of hydrocarbon discharges from nearby oil refinery, petrochemical industries, handling of crude oils, etc. The concentration of PHC exhibited relatively higher values during low tide than the high tide in all the four estuaries indicating riverine inputs and land-based discharges, which contribute substantial amounts of PHC to the coastal water. Hoogly estuary recorded higher values of PHC (1.17–18.50 μg/l) due to the influence of industrial wastes, land runoff, and port activities. The spatial distribution of PHC estimated by the kriging method showed a variation in concentration of PHC over the whole region. To discriminate the dispersion pattern of PHC, principal component analysis (PCA) was performed using a correlation matrix.     

Arsenic content in ground and canal waters of Punjab, North-West India

Groundwater is the primary source of drinking water for more than 95% of the population in Punjab. The world health organization and US Environment Protection Agency recently established a new maximum contaminant level of 10 ppb for arsenic in drinking water. The arsenic concentration of deep water tube wells located in Amritsar city used for domestic supply for urban population ranged from 3.8 to 19.1 ppb with mean value of 9.8 ppb. Arsenic content in hand pump water varied from 9 to 85 ppb with a mean value of 29.5 ppb. According to the safe limit of As, 54% and 97%, water samples collected from deep water tube wells and hand pumps, respectively, were not fit for human consumption. Arsenic content in canal water varied from 0.3 to 8.8 ppb with a mean value of 2.89 ppb. Canal water has got higher oxidation potential followed by deep tube well and hand pump water. The present study suggests the regular monitoring of arsenic content in deep tube well and shallow hand pump waters by water testing laboratories. The consumption of water having elevated concentration of As above the safe limit must be discouraged. In south-western districts of Punjab, it recommends the use of canal water for drinking purposes and domestic use by rural and urban populations than ground water sources.     

Distribution of HCH and DDT in the coastal marine environment of Mumbai,India

Organochlorine pesticides (OCPs) in sediment, water and biota samples from the coastal marine environment of Mumbai were analysed to elucidate their distribution in various environmental compartments. HCH isomers, dichlorodiphenyltrichloroethane (DDT) and its metabolites were the predominantly identified compounds in all the samples. High ratios of DDT to dichlorodiphenyldichloroethylene (DDE) were found in seawater samples. This indicates the presence of a significant source of DDT in this region. In sediment samples, the gamma-isomer contributed almost 55% to the total HCH, indicating a high affinity of the gamma-isomer towards the sediment. The levels of organochlorines in fish obtained from this region were found to be lower than the levels of organochlorines in fish in temperate regions.     

Characterization of groundwater quality in three settlement areas of Enugu metropolis, southeastern Nigeria, using multivariate analysis

Groundwater quality of Enugu metropolis comprising Achara Layout, Abakpa, and Emene settlement areas has been studied and characterized using multivariate statistical techniques. Three principal components (PCs) which explain 77.93 and 88.17 % were extracted at Achara Layout and Abakpa, respectively, while two PCs which explain 83.13 % were extracted at Emene. PC 1 of all the three areas reflects weathering of the host rock minerals and constitutes the dominant controlling process for all the areas. PC 2 of the three areas and PC 3 of Achara Layout and Abakpa can be attributed to both weathering/leaching of feldspathic minerals of host rocks (giving rise to alkaline earth metals in the groundwater) and anthropogenic activities. Cluster analysis defined groups of groundwater samples with similar hydrochemical characteristics. Two groups in Achara Layout and Emene fell into the high pollution loading class, while only one group in Abakpa fell into this class. The variation in the groundwater quality within each of the three areas may be explained in terms of groundwater flow directions, land use, and well depths. Discriminant analysis showed that the discriminating parameters of the groundwater quality of Achara Layout, Abakpa, and Emene are total dissolved solids, Na and Mg, and Cl, respectively. This study has revealed that the groundwater quality of the areas is controlled by both geogenic and anthropogenic processes and activities. The generated groundwater quality spatial variation models for each area will serve as a tool in the planning and development of groundwater in that region.     

Chemical characterization of precipitation at a coastal site in Trombay, Mumbai, India

Precipitation is the best scavenger for the particulates and dissolved gaseous pollutants present in the atmosphere. The chemical composition of precipitation is dominated by a number of in-cloud and below-cloud scavenging processes. The present study is aimed at analyzing the chemical composition of rainwater in the relatively less industrialized part of Mumbai. The pH of rainwater in this region ranges from 4.8 to 6.4. The percentage contributions of ions were calculated and the major contributing ions were calcium (28%), chloride (23%), sodium (18%), sulfate (14%), magnesium (11%), ammonium (4%), potassium (1%), and nitrate (1%). The correlation coefficient is highest for Na and Cl (r ²?=?0.99), giving a clear indication of contribution from sea salt. Sulfate and nitrate ions also show a very good correlation (r ²?=?0.90), which may be due to their coemission from fossil fuel combustion. Acidification caused by these ions is neutralized by Ca, Mg, and NH₄ ions. The neutralization effect due to these ions is validated by calculating the neutralization factor (NF). The NF values are in the order Ca > Mg > NH₄. The major source contributors for the ions in precipitation are sea salt (Na, Cl, and K) and fossil fuel combustion (SO₄ and NO₃). These assumptions are supported by the values of wet-only ratio, enrichment factor, and percent sea salt fraction.