Assessment of environmental and carcinogenic health hazards from heavy metal contamination in sediments of wetlands.

Sediment contamination jeopardizes wetlands by harming aquatic organisms, disrupting food webs, and reducing biodiversity. Carcinogenic substances like heavy metals bioaccumulate in sediments and expose consumers to a greater risk of cancer. This study reports Pb, Cr, Cu, and Zn levels in sediments from eight wetlands in India. The Pb (51.25 ± 4.46 µg/g) and Cr (266 ± 6.95 µg/g) concentrations were highest in Hirakud, Cu (34.27 ± 2.2 µg/g) in Bhadrak, and Zn (55.45 ± 2.93 µg/g) in Koraput. The mean Pb, Cr, and Cu values in sediments exceeded the toxicity reference value. The contamination factor for Cr was the highest of the four metals studied at Hirakud (CF = 7.60) and Talcher (CF = 6.97). Furthermore, high and moderate positive correlations were observed between Cu and Zn (r = 0.77) and Pb and Cr (r = 0.36), respectively, across all sites. Cancer patients were found to be more concentrated in areas with higher concentrations of Pb and Cr, which are more carcinogenic. The link between heavy metals in wetland sediments and human cancer could be used to make policies that limit people's exposure to heavy metals and protect their health.

First record of geophagy in Jungle Babbler (Turdoides striata) prior to egg-laying: an instinct for calcium supplement.

Geophagy has been documented in different animal taxa including Aves and particularly in Passeriformes. However, no geophagic activity has been reported in the genus Turdoides of the family Leiothrichidae belonging to the passerine order. Studies reveal the behaviour of geophagy to be aiding in nutrient supplementation, toxin neutralisation, cytoprotection, gut pH stabilisation and parasite liberation. Here, we provide a record of geophagy in Jungle Babbler Turdoides striata in a peri-urban area of Berhampur city in India. Although this species, being insectivorous, was thought to be feeding on insects, nevertheless, close observations confirmed the activity to be a case of geophagy, which was followed up by nest-building, egg-laying and hatching. The soil samples from the geophagic sites (Ca = 2415 mg/kg) contained 130% more Ca than that of the non-geophagic sites (Ca = 1050 mg/kg). The biochemical requirement of calcium throughout the reproductive phase of Turdoides sp. may corroborate the soil consumption instinct, which was also extrapolated from the reproductive success observed, because the demand for calcium in birds remains high during the egg-laying time. Although the possible explanations for geophagy, reported for the first time in this species, were oriented specifically towards Ca supplement, the present findings provide impetus for furthering research in this domain.

Organochlorine pesticide residues in plants and their possible ecotoxicological and agri food impacts.

Scientific investigations on levels of Organochlorine Pesticide (OCP) residues in plants largely consider the edible parts (crops, vegetables, and fruit plants). Though the non-edible parts of plants are not eaten by human beings directly, these parts are consumed by livestock and other animals, thereby facilitating the flow of chemical residues through the food chain. The objective of the present investigation was to evaluate the concentration of OCP residues in non-edible plant parts to provide insights on their potential ecotoxicological impacts. Eighteen OCP residues were extracted in nine different plant species (banana Musa acuminate, brinjal Solanum melongena, Casuarina equisetifolia, Eucalyptus globulus, lotus Nelumbo nucifera, paddy Oryza sativa, sugarcane Saccharum officinarum, tapioca Manihot esculenta, tomato Lycopersicon esculentum) following QuEChERS method. The concentrations of OCP residues in plant extracts were determined using Gas Chromatography coupled with Mass Spectrometry (GC-MS). The OCP residues, namely: γ-HCH (lindane), heptachlor epoxide isomer, dieldrin, endrin, endrin aldehyde and endrin ketone were found predominantly in seven plant species. Residues of γ-HCH (lindane) were reported in different parts of plant species such as stem (581.14 ng/g in paddy and 585.82 ng/g in tapioca) and leaf (583.3 ng/g in tomato). Seven samples contained residues of heptachlor epoxide isomer (512.53 to 1173.8 ng/g). Dieldrin was found in paddy stem (489.97 ng/g), tapioca stem (490.21 ng/g) and tapioca leaf (490.32 ng/g). The detected OCPs in the present study were 10-50 times higher than the Maximum Residue Limits (MRL, 0.01-0.1 mg/Kg) as prescribed in the Codex Alimentarius of the FAO/WHO. Their elevated concentrations in the plant parts therefore pose risk of contamination to the consumers in the food chain, including human beings those are dependent on the animals as source of protein. The findings of this study are the first report on residue levels of OCPs in non-edible plant parts in the agricultural landscape of Puducherry region, India. Since, this study assumes significance for the strategic location of Oussudu Lake, an interstate lake spread over Puducherry and Tamil Nadu states, regular monitoring of OCP residues in different environmental segments in strategic locations in both the states is suggested, which will help the authorities in devising a comprehensive environmental management plan aiming at the ecosystem at large.

Chelate-assisted phytoaccumulation: growth of Helianthus annuus L., Vigna radiata (L.) R. Wilczek and Pennisetum glaucum (L.) R. Br. in soil spiked with varied concentrations of copper.

Phytoextraction is an economic, environment-friendly and growing technology for clean-up of metal-contaminated soil. Several factors play pivotal role in making phytoextraction a successful technique. Soil fraction is an important parameter that may affect phytoextraction potential. There has been an increased realization on the role of chelates in accelerating metal uptake by plants. Thus, the present study examined the influence of different soil fractions, spiked metal concentrations and chelate dosages on Cu accumulation by Helianthus annuus L. (common sunflower), Vigna radiata (L.) R. Wilczek (mung bean) and Pennisetum glaucum (L.) R. Br. (pearl millet). To mimic the mill tailings of various mined-out sites in India, five soil fractions containing different proportions of garden soil and silica were prepared (S1: 100% soil; S2: 75% soil + 25% silica; S3: 50% soil + 50% silica; S4: 25% soil + 75% silica; and S5: 100% silica) and each fraction was spiked with known Cu (100, 250, 500 and 1000 mg kg-1) concentration. Upon maturity of the plant, EDTA and NTA in different dosages (0.25, 0.5, 1.0 and 2.0 g kg-1) were applied to each pot. Bioconcentration factor (BCF), bioaccumulation coefficient (BAC) and translocation factor (TF) were estimated for each set. The accumulation of Cu by H. annuus, V. radiata and P. glaucum indicated direct relation between soil fractions and harvesting periods. Better plant growth and Cu uptake were observed in pots with silica < 50% of fraction, whereas growth was arrested in pots with silica > 75%. The Cu accumulation varied significantly (p < 0.05) among the species, spiked metal concentration, chelate dosages and plant parts. Best accumulation was reported in pots with 50% soil and 50% silica either under 1.0 g kg-1 EDTA or 2.0 g kg-1 NTA. Irrespective of the combinations of various variables, the harvesting time affected Cu accumulation considerably. Among the species, H. annuus emerged out to be the most efficient for Cu translocation. Apparently, soil amendments facilitated enhanced uptake thereby playing an active role in improving the BAC and TF. Assisted phytoextraction is still a need until full-fledged alternatives are established in the market. The future of chelate-assisted phytoextraction seems to be limited to ex situ condition.

Association of metals with geochemical phases in wetland soils of a Ramsar site in India.

Mobilization of metals in wetland ecosystems is a function of the behaviour of a specific metal species and is dependent largely on the prevailing micro-environmental conditions. Apparently, five different chemical forms of metals are known with varying affinity to binding sites, mobility, bioavailability and toxicity. Quantification of these forms of metals in the soils is imperative in predicting their biogeochemical fate and toxicity. In this context, we examined the association of Cu, Pb and Zn, with various geochemical phases in the soil profile of wetland system of Keoladeo National Park, a Ramsar site in India. The assessment covered the soil profile until 100 cm depth at every 25-cm intervals. Different operationally defined geochemical phases in the soil at different depths were examined during the study for respective metal concentrations. Hydrous oxides of Fe-Mn were the major carrier for all the three metals and the fraction associated with exchangeable phase was the least. The low organic matter content in the soil seems to be influencing the metal association with the organic matter (OM-S) phase, which was also a less preferred carrier for metals. For Cu (5.8-78.4%) and Pb (33.5-88.5%), Fe-Mn hydroxide phase was an important binding site and for Zn (31.02-79.03%), it was the silicate mineral matrix (RES phase). This suggests the importance of micro-environmental conditions in the wetland bed such as redox and pH in mobilization of metals. As metals such as Pb have high eco-toxicological potential, an assessment of fractional concentrations of metals provides insights into their mobility and bioavailability in aquatic ecosystems. This aids wetland managers to develop appropriate strategy to maintain quality of inflow water, the single most crucial factor for a wetland ecosystem, and thus controls the micro-environmental conditions.

Meteorology drives ambient air quality in a valley: a case of Sukinda chromite mine, one among the ten most polluted areas in the world.

The ambient air quality (AAQ) assessment was undertaken in Sukinda Valley, the chromite hub of India. The possible correlations of meteorological variables with different air quality parameters (PM10, PM2.5, SO2, NO2 and CO) were examined. Being the fourth most polluted area in the globe, Sukinda Valley has always been under attention of researchers, for hexavalent chromium contamination of water. The monitoring was carried out from December 2013 through May 2014 at six strategic locations in the residential and commercial areas around the mining cluster of Sukinda Valley considering the guidelines of Central Pollution Control Board (CPCB). In addition, meteorological parameters viz., temperature, relative humidity, wind speed, wind direction and rainfall, were also monitored. The air quality data were subjected to a general linear model (GLM) coupled with one-way analysis of variance (ANOVA) test for testing the significant difference in the concentration of various parameters among seasons and stations. Further, a two-tailed Pearson's correlation test helped in understanding the influence of meteorological parameters on dispersion of pollutants in the area. All the monitored air quality parameters varied significantly among the monitoring stations suggesting (i) the distance of sampling location to the mine site and other allied activities, (ii) landscape features and topography and (iii) meteorological parameters to be the forcing functions. The area was highly polluted with particulate matters, and in most of the cases, the PM level exceeded the National Ambient Air Quality Standards (NAAQS). The meteorological parameters seemed to play a major role in the dispersion of pollutants around the mine clusters. The role of wind direction, wind speed and temperature was apparent in dispersion of the particulate matters from their source of generation to the surrounding residential and commercial areas of the mine.

Spatial variability and temporal changes in the trace metal content of soils: implications for mine restoration plan.

Trace metals in soils may be inherited from the parent materials or added to the system due to anthropogenic activities. In proposed mining areas, trace metals become an integral part of the soil system. Usually, researchers undertake experiments on plant species selection (for the restoration plan) only after the termination of mining activities, i.e. without any pre-mining information about the soil-plant interactions. Though not shown in studies, it is clear that several recovery plans remain unsuccessful while carrying out restoration experiments. Therefore, we hypothesize that to restore the area effectively, it is imperative to consider the pre-mining scenario of metal levels in parent material as well as the vegetation ecology of the region. With these specifics, we examined the concentrations of trace metals in parent soils at three proposed bauxite locations in the Eastern Ghats, India, and compared them at a spatio-temporal scale. Vegetation quantification and other basic soil parameters accounted for establishing the connection between soil and plants. The study recorded significant spatial heterogeneity in trace metal concentrations and the role of vegetation on metal availability. Oxidation reduction potential (ORP), pH and cation exchange capacity (CEC) directly influenced metal content, and Cu and Ni were lithogenic in origin. It implies that for effective restoration plant species varies for each geological location.