Differentiating Wild and Apiary Honey by Elemental Profiling: a Case Study from Mangroves of Indian Sundarban.

Honey is a natural substance produced by honeybees from the nectar or secretion of flowering plants. Along with the botanical and geographical origin, several environmental factors also play a major role in determining the characteristics of honey. The aim of this study is to determine and compare the elemental concentration of various macro and trace elements in apiary and wild honeys collected from different parts of Indian Sundarbans. The elemental analysis was performed in inductively coupled plasma optical emission spectroscopy preceded by microwave digestion method. The concentrations of 19 elements (Ag, Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Se and Zn) were investigated from thirteen locations of Indian Sundarbans. This comparative study shows in wild honey samples, the concentration of K was highest followed by Ca, Mg and Na and Zn was lowest among all. In contrast, in apiary honey samples, Ca had maximum concentration followed by K, Mg and Na and Ag had minimum among all. The elemental concentration in honey from apiary was either equal or higher than their wild counterpart. The results of the factor analysis of PCA algorithm for wild and apiary honey samples were highly variable which implies that the elements are not coming from the same origin. The concentration of element was found to be highly variable across sites and across sources of honey samples.

Assessment of role of rhizosphere process in bioaccumulation of heavy metals in fine nutritive roots of riparian mangrove species in river Hooghly: Implications to global anthropogenic environmental changes.

Biota of coastal estuarine habitats of tropics and subtropics are extremely vulnerable. In the study, we have investigated the role of rhizosphere process in bio-accumulation of heavy metals in fine nutritive roots of riparian mangroves at eleven sampling locations of river Hooghly. The rhizospheric sediment of river Hooghly was accumulating HMs due to the presence of organic content and anthropogenic inputs. The mean EF (2.03-8.3), Igeo (-2.27-0.71), and CF (0.62-2.53) values signifies the enrichment of HMs in sediment fine fraction (<62.5 µm) whereas, the mean PLI (0.83 to 1.18) indicates gradual environmental degradation of river Hooghly. Low BCF observed in the river Hooghly might be due to barrier to hypodermal structures and/or any prevailing mechanism of saturation of HMs. However, BCF > 1 for Al, Cu, Cr, Mn, and Zn, signifies the phyto-remediation potential of riparian mangroves to mitigate amplified global anthropogenic environmental changes.

Understanding potentially toxic metal (PTM) induced biotic response in two riparian mangrove species Sonneratia caseolaris and Avicennia officinalis along river Hooghly, India: Implications for sustainable sediment quality management.

Elevated human-induced activities have prompted significant uncontrolled release of potentially toxic metals (PTM) to the undisturbed ecosystem throughout the globe. Riparian mangrove vegetations act as a natural purifier of wastewaters and assist in maintaining a healthy ecosystem. We have investigated the elevated PTM-induced stress and biotic response of two riparian mangrove species e.g. Sonneratia caseolaris and Avicennia officinalis by river Hooghly. The increased PTM concentrations were observed throughout the river bank; with the maximum pollution load at Chemaguri (S9). Except Co, Cr and Pb, higher enrichment factor (1.97-8.89) and contamination factor (0.64-2.88) values were observed for Cd, Cu, Fe, Zn. Mn, and Ni. Geo-accumulation index (-2.2 - 0.92) values indicates natural geogenic accumulation of Cu in the riparian mangrove sediment. Thus, sediment quality indices suggest except Cu, enrichment of all studied PTMs was sourced from anthropogenic activities. The sediment of the region when compared with consensus-based sediment quality guidelines shows considerable ecotoxicological risks and threat towards human health considering Ni accumulation. The highest potential ecological risk index value was observed in Chemaguri (S9). The biotic response of riparian mangroves was characterized by reduced photosyhthetic pigments (Chlorophyll a and Chlorophyll b) and increased activity of antioxidative stress enzymes (POD, CAT and SOD). Significant statistical relationship between antioxidative enzyme activity, photosynthetic pigments and bioaccumulated PTMs reflects active functioning of detoxification mechanism in the riparian mangrove species.

A preliminary study on upstream migration of mangroves in response to changing environment along River Hooghly, India.

Environmental changes and anthropogenic activities can be linked to altered distribution and abundance of species. However, the ecological impacts of change in the microenvironment have not been well documented. Herein, we have identified the distribution of mangroves and associated species and characterized surface sediment and water samples along the banks of River Hooghly. The application of Combined Mangrove Recognition Index (CMRI) and its validation with the available ground data on satellite image of 2015 indicates that some mangrove species have reclaimed the upper course of the river, which was earlier absent before 1995. This study is the first report on the upstream migration of mangrove species such as Sonneratia caseolaris, Sonneratia apetala, Derris trifoliata, Hibiscus tiliaceus, and Thespesia populnea in River Hooghly. The changes in pollution load, varied sedimentation pattern, high chemical oxygen demand, mean sea-level rise, and anthropogenic activity might have played a significant role in the upstream migration of mangroves.

Elemental geochemistry in acid sulphate soils - A case study from reclaimed islands of Indian Sundarban.

Sundarban along with its networks of rivers, creeks and magnificent mangroves form a unique ecosystem. Acid sulphate soils have developed in this ecosystem under anoxic reducing conditions. In the present study, we have investigated the distribution of acid sulphate soils along with its elemental characterization and possible sources in four reclaimed islands of Indian Sundarban like Maushuni (I1), Canning (I2), Bally (I3) and Kumirmari (I4). Elements show moderate to strong correlation with each other (P < 0.01; P < 0.05). Except Si, Ca and Pb, a higher enrichment factor was observed for K, Cr, Mn, Fe, Ni, Cu and Zn. Geo-accumulation index values of all sampling locations reveal that Cr, Fe, Cu and Zn are in Igeo class 1. The pollution load index value of the reclaimed islands of Indian Sundarban varies between 1.31 and 1.48. The observation of this study could help to strategize policies to mitigate and manage acid sulphate soils in Indian Sundarban.

Sediment quality, elemental bioaccumulation and antimicrobial properties of mangroves of Indian Sundarban.

Mangroves have wide applications in traditional medicines due to their several therapeutic properties. Potentially toxic elements (PTEs), in mangrove habitats, need serious concern because of their toxicity, bioaccumulation capacity and ecotoxicological risks. In the current study, we aimed to examine sediment quality and bioaccumulation of PTEs in a mangrove-dominated habitat of Sundarban, India, and their relation with antimicrobial property of ten mangrove species of the region. Antimicrobial activity of different solvent fractions of mangrove leaves was assessed against seven microorganisms. The highest antimicrobial activity was detected in ethyl acetate and acetone-extracted fractions of Avicennia alba. Various sediment quality indices revealed progressively deteriorating nature of surface sediment having moderate contamination, however, low ecotoxicological risk. The accumulation factors (AF) for different PTEs indicate a gradual metal bioaccumulation in leaf tissue. Antimicrobial activities indicated both positive and negative correlations with manganese (Mn), copper (Cu), iron (Fe) and zinc (Zn) concentrations of mangrove species. Concentration of Mn showed a significant correlation with almost all the fractions, whereas Cu had correlation with ethyl acetate, acetone and methanol fractions (P < 0.05). The AF of Mn and Cu exhibited correlation with antimicrobial activities of acetone and methanol fractions, whereas Fe and Zn had correlation with hexane and ethyl acetate fractions. Overall, Mn, Fe, Cu and Zn concentrations of Acanthus ilicifolius and Avicennia alba leaves and in the surface sediments demonstrated the strongest association (P < 0.05) with their antimicrobial activity as also depicted in correlation and cluster analysis studies. Thus, this study will help to establish a link between the PTEs in mangrove ecosystem with their bioactivity.

Assessing the potential ecological risk of Co, Cr, Cu, Fe and Zn in the sediments of Hooghly-Matla estuarine system, India.

Hooghly-Matla estuarine system along with the Sundarbans mangroves forms one of the most diverse and vulnerable ecosystems in the world. We have investigated the distribution of Co, Cr, Cu, Fe and Zn along with sediment properties at six locations [Shamshernagar (S1), Kumirmari (S2 and S3), Petuaghat (S4), Tapoban (S5) and Chemaguri (S6)] in the Hooghly estuary and reclaimed islands of the Sundarbans for assessing the degree of contamination and potential ecological risks. Enrichment factor values (0.9-21.6) show enrichment of Co, Cu and Zn in the intertidal sediments considering all sampling locations and depth profiles. Geo-accumulation index values irrespective of sampling locations and depth revealed that Co and Cu are under class II and class III level indicating a moderate contamination of sediments. The pollution load index was higher than unity (1.6-2.1), and Co and Cu were the major contributors to the sediment pollution followed by Zn, Cr and Fe with the minimum values at S1 and the maximum values at S5. The sediments of the Hooghly-Matla estuarine region (S4, S5 and S6) showed considerable ecological risks, when compared with effect range low/effect range median and threshold effect level/probable effect level values. The variation in the distribution of the studied elements may be due to variation in discharge pattern and exposure to industrial effluent and domestic sewage, storm water and agricultural run-off and fluvial dynamics of the region. The study illuminates the necessity for the proper management of vulnerable coastal estuarine ecosystem by stringent pollution control measures along with regular monitoring and checking program.

Assessment of potentially toxic metal (PTM) pollution in mangrove habitats using biochemical markers: A case study on Avicennia officinalis L. in and around Sundarban, India.

Spatial distribution of potentially toxic metals (PTMs) and their accumulation in mangrove Avicennia officinalis L. were studied along 8 locations in and around Sundarban mangrove wetland, India. Among 8 locations, S3 (Chemaguri) and S5 (Ghushighata) showed higher concentration of PTMs (Cd, Cr, Cu, Ni, Pb, Zn) characterized by higher enrichment factors (3.45-10.03), geo-accumulation indices (0.04-1.22), contamination factors (1.14-3.51) and pollution load indices (1.3-1.45) indicating progressive deterioration of estuarine quality and considerable ecotoxicological risk. Metal concentration in A. officinalis leaves showed significant correlation with sediment metals implying elevated level of bioaccumulation. Significant statistical correlation between photosynthetic pigments (Chlorophyll a, Chlorophyll b), antioxidant response (free radical scavenging and reducing ability) and stress enzymatic activity (Peroxidase, Catalase, Super-oxide dismutase) of A. officinalis with increasing metal concentration in the contaminated locations reflects active detoxification mechanism of the plant. The study indicates the potentiality of biomonitoring metal pollution using studied biochemical markers in mangrove habitats.

Micro-spatial variation of elemental distribution in estuarine sediment and their accumulation in mangroves of Indian Sundarban.

This work describes the micro-spatial variation of elemental distribution in estuarine sediment and bioaccumulation of those elements in different mangrove species of the Indian Sundarbans. The potential ecological risk due to such elemental load on this mangrove-dominated habitat is also discussed. The concentrations of elements in mangrove leaves and sediments were determined using energy-dispersive X-ray fluorescence spectroscopy. Sediment quality and potential ecological risks were assessed from the calculated indices. Our data reflects higher concentration of elements, e.g., Al, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, and Pb, in the sediment, as compared to that reported by earlier workers. Biological concentration factors for K, Ca, Mn, Fe, Cu, and Zn in different mangroves indicated gradual elemental bioaccumulation in leaf tissues (0.002-1.442). Significant variation was observed for elements, e.g., Ni, Mn, and Ca, in the sediments of all the sites, whereas in the plants, significant variation was found for P, S, Cl, K, Ca, Mn, Fe, Cu, and Zn. This was mostly due to the differences in uptake and accumulation potential of the plants. Various sediment quality indices suggested the surface sediments to be moderately contaminated and suffering from progressive deterioration. Cu, Cr, Zn, Mn, and Ni showed higher enrichment factors (0.658-1.469), contamination factors (1.02-2.7), and geo-accumulation index (0.043-0.846) values. The potential ecological risk index values considering Cu, Cr, Pb, and Zn were found to be within "low ecological risk" category (20.04-24.01). However, Cr and Ni in the Sundarban mangroves exceeded the effect range low and probable effect level limits. Strong correlation of Zn with Fe and K was observed, reflecting their similar transportation and accumulation process in both sediment and plant systems. The plant-sediment elemental correlation was found to be highly non-linear, suggesting role of some physiological and edaphic factors in the accumulation process. Overall, the study of micro-spatial distribution of elements can act as a useful tool for determining health of estuarine ecosystem.

Vertical and horizontal variation of elemental contamination in sediments of Hooghly Estuary, India.

Hooghly Estuary along with the Sunderban mangroves forms one of the most diverse ecosystems in the world. We investigated the vertical and horizontal distribution of elements at nine sampling locations in this estuary for assessing the degree of elemental contamination. The elemental concentrations were analyzed by an Energy Dispersive X-ray Flurosence spectrometer (EDXRF). A higher enrichment factor (EF) value of trace elements (V, Cr, Mn, Fe, Ni, Cu and Zn) is evident considering all the sampling locations. Geo-accumulation index (Igeo) values of all the sampling locations and core depth reveals Cr and Cu are under Igeo Class I level of contamination. The value of the pollution load index (PLI) varies between 0.94-1.65 with maximum at Chemaguri and minimum at Haldi Estuary and Petuaghat. The overall variation in elemental concentration may be due to differential discharge pattern of storm water and agricultural run-off, industrial effluent and domestic sewage.

Application of isolated bacterial consortium in UMBR for detoxification of textile effluent: comparative analysis of resultant oxidative stress and genotoxicity in catfish (Heteropneustes fossilis) exposed to raw and treated effluents.

A bacterial consortium isolated from activated sludge was identified to be Bacillus sp., Pseudomonas sp., Shigella sp. and E. coli. and was found capable of 98.62 % decolourization of highly toxic textile effluent, when applied in an ultrafiltration (UF) membrane bioreactor (UMBR). Ceramic capillary UF membranes prepared over low cost support proved to be highly efficient in adverse experimental conditions. The UMBR permeate and untreated textile effluent (40 % (v/v)) was then used to treat Heteropneustes fossilis for a comparative assessment of their toxicity. Micronucleus count in peripheral blood erythrocytes and comet assay carried out in liver and gill cells showed significantly lower nuclear and tissue specific DNA damage respectively in organisms exposed to membrane permeate and was further supported by considerably lower oxidative stress response enzyme activities in comparison to raw effluent treated individuals. The results indicate efficient detoxification of textile effluent by the UMBR treatment using the isolated bacterial consortium.