Thane Creek Research Articles

Distribution, source and potential biological impacts of polycyclic aromatic hydrocarbons in the core sediments of a networked aquatic system in the northwest coast of India – A special focus on Thane Creek Flamingo Sanctuary (Ramsar site)

Mumbai, one of the most industrialised and inhabited cities in the world, has been confronting an exponential increase in pollution brought about by anthropogenic activities throughout its coastal belt over the years. The historical accumulation of 16 polycyclic aromatic hydrocarbons (PAHs) in the sediments of Thane creek, Panvel creek and the Ulhas estuarine river system was examined in light of these circumstances. The present study has found that the PAHs were distributed vertically in the sediments of Thane Creek as 16.53 – 1317.02 ng/g dw and Ulhas Estuary as 105.44 – 1815.20 ng/g dw. Major sources of PAHs pollution to the system like petroleum spillages, biomass burning and vehicular exhaust was discernible based on molecular diagnostic ratio (MDR) and principal component analysis (PCA) tools, signifying petrogenic and pyrogenic origins. Based on the total toxicity equivalence (TEQ) and sediment quality guidelines (SQGs) indices, high or moderate contamination risks have been identified in the lower and middle regions of the Ulhas estuary, as well as in the lower regions of Thane creek. Specifically, high contamination risk of benzo[a]pyrene which has high cancerous potential, was identified in the above sites.

Understanding the bird species assemblages found in and around Thane creek, Maharashtra, India

Understanding the bird species assemblages found in and around Thane creek, Maharashtra, India

Assessment of ingestion dose to the members of public from marine biota

Abstract Natural radioactivity is ubiquitous, while the anthropogenic radioactivity is introduced into the environment due to manmade activities. The members of public (MOP) get exposed to both natural and anthropogenic radioactivity through the various routes of intake. The ingestion dose to MOP from natural (40K, 210Po, 226Ra, and 228Ra) and anthropogenic (90Sr and 137Cs) radionuclide through the consumption of benthic and pelagic marine biota collected from Thane creek, Mumbai was investigated. It was observed that 99.9% of ingestion dose is from natural radionuclide while, the anthropogenic radionuclides are contributing just 0.1%. Hence, the dose from anthropogenic radionuclide’s due to the consumption of marine biota is negligible compared to that from natural radionuclide’s which is also an insignificant contribution in the overall dose exposure to man.

Investigation of teak defoliator, Hyblaea puera (Cramer, 1777) outbreak on mangrove ecosystem in Mumbai metropolitan region using multi-spectral satellite data

The mangrove ecosystem supports biodiversity and ecology and plays a vital role in providing economic security to coastal fishers. A severe outbreak of the moth Hyblaea puera occurred along the Thane creek in Mumbai (Maharashtra, India) between September and October 2019. The ecological interaction of pest species in a mangrove ecosystem is complex and very few detailed studies have been undertaken along the Indian coast. There is evidence that infestation can have a negative impact on the already threatened mangrove ecosystem. This study investigates the mangrove infestation, the influence of the infestation on the Leaf Area Index (LAI), rainfall’s effect on such outbreaks’ occurrence, and spectral reflectance in infested and non-infested mangroves. Sentinel 2 MSI data was processed using the QGIS platform. There were two dominant mangrove species, Avicennia marina and Sonneratia apetala, of which the most affected species was A. marina. The study revealed that 67.90% (50.61 km2) of the mangrove area defoliated due to this outbreak, out of which 30.20% (22.50 km2) was highly defoliated, 37.70% (28.11 km2) was less defoliated, and 32.10% (23.95 km2) was unaffected. LAI is the health indicator of a forest affected by an infestation; it indicates the reduction in canopy cover due to the infestation. The t-test was applied to determine the significance of LAI before and after the infestation along the upper stretch of the creek,t-value was 3.886 (p = 0.0011, p ≤ 0.05 significant). The spectral reflectance analysis showed a reduction in the infested mangrove’s Vegetation Red Edge and Near Infra-Red reflectance. The ANOVA result shows that the three groups, Mangrove Highly Infested, Mangrove Less Infested, and Non-Infested Mangrove, are likely spectrally separable (p = 0.020, p ≤ 0.05). The analysis revealed that rainfall intensity during an Infested year significantly differs from that in a Non-Infested year (p = 0.0067, p ≤ 0.05).

Occurrence of Elysia bangtawaensis Swennen in the mangroves of Anthropogenically polluted Thane creek, the Flamingo Bird Sanctuary, Central West Coast of India

The solar powered Sacoglossanmolluscs, Elysia bangtawaensis Swennen, ranging from 35 mm to 40 mm in length, were located for the first time from two locations in the Thane Creek Flamingo Bird Sanctuary. This is a North-western extension of its reported former range which was Ratnagiri in Maharashtra.

A brief description on spatial variability in nutrient–phytoplankton​ relationship in a shallow tidal creek-Thane Creek, India

Anthropogenic influence on nutrient–phytoplanktonrelationship was studied in Thane Creek. The upper creek was highly loaded with N-forms through anthropogenic inputs. The elevated level of nutrients enhanced the chlorophyll a and phytoplankton density. A huge disparity was observed in the distribution of nitrate in the upper creek which can be linked to the 10 times higher density by Skeletonema costatum. CCA analysis carried out on species–environment​ parameters implied that phytoplankton species which were found in ascendancy (Thalassiosira sp. Skeletonema sp.,>Leptocylindrus sp.,>Plagioselmis sp.,>Chaetoceros sp.,>Cylindrotheca sp.,>Teleaulax sp.,>Alexandrium sp.,>Nitzschia sp.,>Gyrodinium sp.,>Surirella sp.>Guinardia sp., and Pyramimonas sp.) were more correlated to environmental variables like nitrate, ammonia, phosphate and salinity. The correlation between nitrate, ammonia and the phytoplankton showed that they were the essential nutrients responsible for their high density and distribution along the creek.

Species diversity and distribution pattern of avifauna from Thane creek, Maharashtra, India

Bird survey in Thane creek was conducted during winter season in 2015-2016. Total 69 species of birds were encountered belonging to 11 orders and 17 families in the entire creek. As per the IUCN Red list, of the 69 bird species, six near threatened and one vulnerable species were recorded. 60.87 percent birds were migratory winter visitors, 36.23 percent birds were residents and local migrants, and the remaining 2.89 percent birds were residents as well as winter visitors. Scolopacidae family had the highest representation with 14 bird species. Order Phoenicopteriformes had the highest number of individuals (N = 20539) with lesser flamingo contributing 80.22 percent. The Shannon-Weiner diversity indices revealed higher diversity upstream (2.56) followed by midstream (1.78) and downstream (1.12). Similarly, the evenness index showed the species were more evenly distributed upstream (0.219) followed by midstream (0.110) and downstream region (0.060). On the contrary, the dominance was higher downstream (0.501) followed by midstream (0.319) and upstream region (0.124). Order Phoenicopteriformes had the highest percent encounter rate with majority encountered in downstream followed by midstream region and sporadically distributed in the upstream region of the creek. The family with moderate to less number of individuals are majorly encountered in the upstream region of the creek. The birds showed a specific distribution pattern primarily because of food availability and also because of other biotic and abiotic factors.

Multi-decadal changes of mangrove forest and its response to the tidal dynamics of thane creek, Mumbai

Mangroves are one of the world threatened ecosystems, which is protected and categorised under CRZ-I according to the Coastal Regulation Zone (CRZ) notification. The present study marked the decadal (1990–2017, Landsat series) change of mangroves and mapped the species distribution (2017, Sentinel-2) around Thane creek, Mumbai using SMLC with QGIS-SCP software. ADCIRC model was used to simulate the tidal flooding/ebbing towards mangroves, and the model was validated with the in-situ observation of tides and currents. From 1990 to 2017, the mangrove area increased from 79.14 km2 to 154.5 km2 and expanded towards landward and seaward regions. Between 2010 and 2017, there was a fluctuation in the mangrove area with ups and downs in their distribution caused by different climatic conditions and anthropogenic activities. The increase in built-up area was two times than mangrove area increase. The dominance of Avicennia marina species confirms the increased anthropogenic activity along the landward side. To understand the response of mangroves to the tidal dynamics, the model was simulated with two scenarios; with mangroves and without mangroves. In the absence of mangroves (without mangroves), Thane Creek demonstrated a perfect funnelling effect by increased tidal amplification with strong flood currents, resulting in severe coastal inundation and erosion. While with mangroves, tidal currents attenuated 80% of its magnitude and favoured the sediment deposition in mangrove areas, which further enhanced mangrove growth, thereby stabilising the coast. The present study has found that the mangroves in the Thane creek are in the saturation stage and reached the maximum growth towards the landward. The study envisages that the stakeholders should adopt a proper management plan for the restoration of mangroves. The highlight of the present study is the combination of satellite imagery and hydrodynamic modelling. Satellite imagery provides the estimated extent of the mangroves, and this information will be used when simulating the model, which provides maximum inundation and attenuation. The utilisation of LULC classification and ADCIRC model results would be helpful to examine the threatening built-up area due to the tidal inundation. The combination of satellite classification and hydrodynamic model findings will be decisive for management authorities towards the conservation and regeneration activities for a balanced mangrove-creek ecosystem.

Determination of concentrations of some elements in marine consumables from Thane creek area (Mumbai, India) using ED-XRF technique; and risk assessment

ABSTRACT Six marine consumable species, namely, Bombay duck (Harpadon nehereus), Ghol (Protonibea diacanthus), Rawas (Eleutheronema tetradactylum), Prawns (Dendrobranchiata), Surmai (Scomberomorus guttatus), and Bangda fish (Rastrelliger kanagurta) were collected for assessment of minor and trace element contents. EDXRF methods (using secondary targets and filters) were optimised and validated for quantification of V, Cr, Mn, Fe, Ni, Cu, Zn Se, As, Br, Cd, Pb, Sr, K, Ca Na, Mg, and Al in these samples. The levels of each target element were found to be comparable to those reported across the globe. The potential health risk evaluated for selected trace and toxic elements showed no adverse impact on human health (Hazard Index < 1) from exposure to these elements through consumption of these marine species.

Fatty acid signatures of sediment microbial community in the chronically polluted mangrove ecosystem

Phospholipid fatty acid (PLFA) analysis was used to examine variation in the distribution of microbial communities in heavily polluted mangrove sediments of Thane creek, west coast of India. A total of 40 individual PLFAs representing 11 functional groups were identified in the sediment and were mainly dominated by saturated fatty acids (anaerobic prokaryotes) >50%. Significant dominance of PUFA, 16:3 ω6c (34.2%) indicators of micro-eukaryotes, in subsurface depth (p < 0.05) suggests input from the remnants of marine microalgae. Declined mean relative abundance of fungi (<6%) and actinomycetes (<1%) were detected in the sediment indicating their sensitivity to anthropic stressors. Homogenous profile of microbial diversity indicating active bioturbation. Cumulative metabolic stress evident from SAT/MUFA (>1), B/F (>1) and G+/G– (<1) ratio and prolonged hypoxia to be prevalent in the creek during the study. In conclusion, PLFA signatures can thus be used as potential biomarkers of environmental monitoring and proxy for interpreting ecosystem health.

Multivariate assessment of outflow water quality in highly urbanized creek system: implication of natural and anthropogenic processes.

Nutrient source and transport study in tropical creeks adjacent to megacities are sparse on a regional and global scale. High-frequency chemical data collected during 2017-2018 in the Thane creek system, the largest micro-tidal urbanized creek in Asia, were analysed to assess the chemical water quality, with its linkage to different hydrological stages (southwestmonsoon, post- and pre-monsoon) and ongoing anthropogenic activities. Cluster analysis indicates typical zonation between creek outflow and nearshore waters with distinctive physicochemical properties. The creek outflow upholds substantial amounts of nutrient and suspended sediment due to turbid water movement from the ephemeral mudflats and anthropogenic dredging. The year-round hyper-turbid condition in the bottom water triggers the addition of disproportionate nutrients (9% dissolved inorganic nitrogen (DIN) and 14% reactive phosphorous (PO43-) in the outflow region. The DIN and PO43- removal up to 10 and 35%, respectively, occurs in the nearshore region; sedimentation, which acts as a sinking interface for nitrogen and phosphorous, also causes shifting in their limiting conditions. The hyper-turbid condition causes removal of dissolved silicate (DSi) by 5% in the entire region. Ammonium (NH4+)is mainly sourced from the sewage in outflow watersand efficiently mineralized. Chemical indexing of water highlights that the bottom water column remained un-supportive to the balanced ecology. The findings of this study have implications for other tropical creek-estuary concerning management strategies against inadequate flushing. The stalled nutrient export affected balance ecology in tropical Thane creek, which need attention in order toaccurately understand the impact onadjacent marine environment and toform effective mitigation policies.

Estimation of trace and toxic metals in marine biota and associated health risk assessment in Thane Creek, Mumbai, India

Effluents released from various industries and domestic sewage can contaminate the seawater leading to serious impacts on marine biota. The present study aims for the estimation of trace and toxic metals concentrations in different marine biota species collected from the Thane creek area, Mumbai, India. Among different metals analyzed, the highest and the least concentration was observed for Fe (9.0–118.3 mg/kg ww) and As (4.7 × 10 −4 –7.8 × 10 −3 mg/kg ww), respectively in most of the marine biota. The toxic metal concentrations observed in the current study are less than the Food and Agriculture Organization (FAO, 1983/1987), World Health Organization (WHO, 1983/1987) limits given for Hg (2 mg/kg ww), Pb (0.5 mg/kg ww) and As (1 mg/kg ww). In the current study, Fe was found to have the highest bio-concentration factor followed by Cu and Zn. Crab has relatively higher bio-concentration factor for most of the metals (except for Se, Hg) as compared to fish samples analyzed. Se-health benefit values were found to be positive indicating less health effects due to Hg exposure from marine biota. The estimated hazard quotient (HQ) value was observed to be highest for Cu in crabs (5.6E-02). However, the Hazard Index (HI) values of all studied marine biota species are <1, indicating no harmful health effects from the consumption of collected biota species in Thane Creek. • Among the most toxic metals, Pb has the highest concentration followed by Hg. • Se-health benefit value is found to be positive for all analyzed species. • Crab has the highest bioconcentration factor for most of the studied metals. • Hazard quotient values for toxic metals are found to be less than unity.

Distribution of size-fractionated phytoplankton biomass from the anthropogenically stressed tropical creek (Thane creek, India)

Size-based partitioning of phytoplankton biomass is a crucial determinant of the type of food web functioning in an aquatic ecosystem. Seasonal and spatial distribution of total as well as size-fractionated phytoplankton biomass (pico, nano and micro-phytoplankton) from the tropical creek (Thane creek, India), was assessed in response to ambient physicochemical parameters. Nanophytoplankton biomass contributed the significant fraction (69%–97%) of total phytoplankton biomass throughout the creek irrespective of the seasons. The ability of nanophytoplankton to proliferate under low solar insolation helped them in sustaining high biomass in nutrient-rich turbid water. Microphytoplankton, which was the second dominant class, contributed 3%–19% during pre-monsoon, 11%–19% during monsoon and 3%–7% during post-monsoon. High suspended sediment load and mesozooplankton grazing pressure have played an essential role in structuring the microphytoplankton biomass. Competitive disadvantage under high nutrient concentration resulted in low picophytoplankton biomass throughout the creek. The dominance of nanophytoplankton biomass deciphered the prevalence of herbivorous based food web in the Thane creek. The Pearson’s correlation and the canonical correspondence analysis interpreted nutrient enrichment, suspended sediments and temperature played a significant role in determining the size structure of phytoplankton biomass. The eutrophication status of the study area studied using Trophic state index (TRIX). Availability of surplus nutrient during all the seasons could be the main factor behind the eutrophic to hypereutrophic (6.7–8.8) condition of the Thane creek.

Assessment of groundwater quality using GIS in Thane Municipal Corporation, Maharashtra, India

In this paper, the groundwater quality of the Thane Municipal Corporation (TMC) area of Maharashtra state, India was assessed for drinking and industrial purposes as per the standards recommended by WHO (2017) and BIS (2012)). In the February 2019, using Random sampling method 25 water samples were collected from different parts of the TMC area. Using these ground water samples various parameters were analysed such as Power of Hydrogen (pH), Electrical Conductivity (EC), Total Hardness (TH), Calcium (Ca2+), Magnesium (Mg2+), Potassium (K+), Chloride (Cl) and Lithium (Li). The pH and EC were determined by Digital pH meter and conductometer respectively. The Cl− was assessed by non-instrumental experiment (Mohr’s method) and the rest of the parameters were analysed by ELICO CL378 flame photometer. With the help of Geographical Information System (GIS), spatial distributions of groundwater quality parameters were mapped. The results indicated that, the ionic dominance for cations and anions were Cl− > Ca2+ > Mg2+ > K+ > Li+. TH and EC showed higher concentrations near the Thane creek and artificial rills compare to forest and construction zones. This infers that anthropogenic activities have greater influence than the natural process (water–rock interaction). Overall study reveals that water quality is good for industrial use in the zone surrounding to Thane creek but unsuitable for drinking. However, 86% of the samples in the study area showed good to excellent water quality for drinking purposes.

Impact of urbanization on creeks of Mumbai, India: a geospatial assessment approach

Creeks are the inherent coastline feature that connects rivers to the sea and plays an important role in the ecological processes and the material transfer. In the present study, an impact of urbanisation on the creeks of Mumbai, India namely Thane, Malad and Manori creeks, has been addressed. Multi-temporal satellite images of Landsat for the years 1972, 1994 and 2016 are considered to perform the changes in the mudflat and growth of the mangrove, as well as the changes in creeks width apart from the Land use Land cover (LULC). Object-based image analysis using multi-spectral resolution confirmed that there is an overall increase in the spatial extent of mangroves and reduction in the width of all the creeks. Mangroves around Thane creek and Manori creek have increased from 50.7 km2 to 57.6 km2 and 8.4 km2 to 25.2 km2respectively. However, there is a decrease in mangroves around Malad Creek from13.3 km2 to 9.7 km2during 1972 to 2016. The relationship between the creek geometry and LULC was also explored, and it has been revealed that the creek width has reduced due to urbanisation. Life expectancy analysis projected a further reduction in the width of the creeks for the years 2025 and 2050. The study suggests that there must be stringent bye-laws for disposal of sewage into the creeks and development activity near the creek areas. Further, upper stretches of the creeks require cleaning and dredging so that the tidal water will be approached up to the upper portion to maintain the creek ecosystem.

Input reduction and acceleration techniques in a morphodynamic modeling: A case study of Mumbai harbor

Thane creek, which houses two major commercial ports; Mumbai & Jawaharlal Nehru Ports face periodic siltation problems. The maintenance dredging, carried out to keep navigational channel navigable, incurs a high annual cost. In this study, an attempt has been made to simulate the annual morphological changes that occur within Mumbai port limits, using a process-based hydrodynamic and morphological model, developed using Delft3D numerical scheme. The tidal levels and currents of the numerical model are validated with in-situ measurements, carried out at three different locations near the main navigational channel. Adopting the concepts of the morphological tide and acceleration techniques, a total quantity of siltation of more than 3.98 Million m3 is estimated to be deposited annually in the main navigation channel, if no dredging is carried out. The modeling results also revealed that a siltation rate up to 1 m/year is observed in the harbor basin and entrance channel to the docks. It is demonstrated that the developed numerical model can qualitatively capture the morphological trends near Mumbai Port region.

Waterbirds from the mudflats of Thane Creek, Mumbai, Maharashtra, India: a review of distribution records from India

Thane creek is one of the coastal and marine protected sites located in Mumbai which declared as a sanctuary recently in 2015. Creek region provides diverse habitat to birds for feeding, nesting and resting, making it a potential bird watching sight for ornithologists and enthusiasts. This article presents some interesting observations of waterbird species recorded from mudflats of Thane creek near Bhandup Pumping Station, Mumbai and also reviewed their previous records from various states of India.

Environmental distribution and ecotoxicological concerns of phthalic acid esters in creek ecosystem

The long-term ecological risk of synthetic organic contaminants, exclusively endocrine disrupting chemicals (EDCs) such as phthalates has threatened reclaimed seawater quality in marine environment. In this study, environmental distributions of 14 phthalic acid esters (PAEs) in seawater, and biota (fish and crab) across Thane Creek, Mumbai India is reported. Identification and quantifications of phthalates in environmental matrices was carried out using GC-MS technique. Abundance of phthalates in each matrix was discussed and compared with literature value. Total phthalate esters concentrations in seawaters, fish and crab samples were found to be 104.8 ± 37.8 μg L−1, 113 ± 36.4 μg g−1 and 155 ± 38 μg g−1 (dry weight) respectively. Di-n-butylphthalate (DBP) was most abundant compound among analyzed PAEs in all tested aquatic media. In situ bio-concentration factors (BCFs) were calculated for all monitored phthalates in fish and crabs and compared with log Kow values. Risk quotient and estradiol equivalent concentration were also calculated to evaluate ecological risk and estrogenic potential of seawater in terms of DBP and di (2-ethylhexyl) phthalate. The average values of total PAEs daily intake were calculated as 58.1 ± 13.6 and 79.6 ± 19.6 (µg kg–1-bw/day) for fish and crab respectively in an adult population.

Polybrominated diphenyl ethers (PBDEs) in core sediments from creek ecosystem: occurrence, geochronology, and source contribution.

The levels of 15 polybrominated diphenyl ether (PBDE) congeners in grab sediment and sediment cores from the Thane creek were monitored for their spatial and temporal distribution. Total PBDE (ΣPBDE) concentrations in grab sediments were ranging from 15.98 to 132.72ngg-1 dry weight. BDE-209 was the most abundant congener with percentage contribution in the range of 19-35% to total PBDEs. Total PBDE show multimode concentration with depth in sediment, among which mode at a depth of 10cm is predominant. Results of sediment core also indicates PBDEs were enormously used in last two decades in surrounding area. Sedimentation rate at the creek was also evaluated using Pb210 dating technique. Average percentage contribution of commercial penta-BDE (fP), octa-BDE (fO), and deca-BDE (fD) to the profile found in sediments collected across Thane creek were 24 ± 5, 5 ± 1 and 69 ± 7% (p < 0.001) respectively. Levels of all measured PBDEs in sediment met with guideline values except for the penta-BDE (total, BDE-99 and BDE-100) at few locations.

Multi-element detection in sea water using preconcentration procedure and EDXRF technique

A method was optimized for detecting trace elements in sea water using Energy dispersive X-ray fluorescence (EDXRF) technique. Sea water samples were pre-concentrated using ammonium pyrrolidinedithiocarbamate (APDC) as chelating agent and methyl isobutyl ketone (MIBK) as organic phase. The preconcentrated samples were dried to form thin films on mylar substrate and analysed using EDXRF spectrometer. The multi-element standard samples prepared in synthetic sea water were used for EDXRF instrument calibration. The instrument was calibrated for 11 elements namely As, Cd, Co, Cr, Fe, Ga, Pb, Se, Sc, V and Zn using linear regression method for concentration up to 200 ppb. The detection limits achieved for As, Cd, Co, Cr, Fe, Ga, Pb, Se, Sc, V and Zn were 13, 70, 5.1, 36, 15, 36, 23, 11, 20, 13 and 40 ppb respectively. The optimized method was used for determination of elements in sea water collected from the Thane creek, Mumbai, India. The results were checked for accuracy by comparing it with inductively coupled plasma atomic emission spectroscopy (ICP AES) technique. The comparison showed the discrepancy of results to be insignificant at 95% confidence level.