Arsenic accumulation in native plants of West Bengal, India: prospects for phytoremediation but concerns with the use of medicinal plants

Arsenic (As) is a widespread environmental and food chain contaminant and class I, non-threshold carcinogen. Plants accumulate As due to ionic mimicry that is of importance as a measure of phytoremediation but of concern due to the use of plants in alternative medicine. The present study investigated As accumulation in native plants including some medicinal plants, from three districts [Chinsurah (Hoogly), Porbosthali (Bardhman), and Birnagar (Nadia)] of West Bengal, India, having a history of As pollution. A site-specific response was observed for Specific Arsenic Uptake (SAU; mg kg(-1) dw) in total number of 13 (8 aquatic and 5 terrestrial) collected plants. SAU was higher in aquatic plants (5-60 mg kg(-1) dw) than in terrestrial species (4-19 mg kg(-1) dw). The level of As was lower in medicinal plants (MPs) than in non-medicinal plants, however it was still beyond the WHO permissible limit (1 mg kg(-1) dw). The concentration of other elements (Cu, Zn, Se, and Pb) was found to be within prescribed limits in medicinal plants (MP). Among the aquatic plants, Marsilea showed the highest SAU (avg. 45 mg kg(-1) dw), however, transfer factor (TF) of As was the maximum in Centella asiatica (MP, avg. 1). Among the terrestrial plants, the maximum SAU and TF were demonstrated by Alternanthera ficoidea (avg. 15) and Phyllanthus amarus (MP, avg. 1.27), respectively. In conclusion, the direct use of MP or their by products for humans should not be practiced without proper regulation. In other way, one fern species (Marsilea) and some aquatic plants (Eichhornia crassipes and Cyperus difformis) might be suitable candidates for As phytoremediation of paddy fields.     

Effect of dust load on the leaf attributes of the tree species growing along the roadside

Dust is considered as one of the most widespread air pollutants. The objective of the study was to analyse the effect of dust load (DL) on the leaf attributes of the four tree species planted along the roadside at a low pollution Banaras Hindu University (BHU) campus and a highly polluted industrial area (Chunar, Mirzapur) of India. The studied leaf attributes were: leaf area, specific leaf area (SLA), relative water content (RWC), leaf nitrogen content (LNC), leaf phosphorus content (LPC), chlorophyll content (Chl), maximum stomatal conductance (Gs_max), maximum photosynthetic rate (A _max) and intrinsic water-use efficiency (WUEi). Results showed significant effect of sites and species for DL and the leaf attributes. Average DL across the four tree species was greater at Chunar, whereas, the average values of leaf attributes were greater at the BHU campus. Maximum DL was observed for Tectona grandis at Chunar site and minimum for Syzygium cumini at BHU campus. Across the two sites, maximum value of SLA, Chl and Gs_max were exhibited by S. cumini, whereas, the greatest value of RWC, LNC, LPC, A _max and WUEi were observed in Anthocephalus cadamba. A. cadamba and S. cumini exhibited 28 and 27 times more dust accumulation, respectively, at the most polluted Chunar site as compared to the BHU campus. They also exhibited less reduction in A _max due to dust deposition as compared to the other two species. Therefore, both these species may be promoted for plantation along the roadside of the sites having greater dust deposition.     

Selected organochlorine pesticides (OCPs) in surface soils from three major states from the northeastern part of India

Eighty-two surface soil samples were collected from forest, grassland, tea estate, wildlife sanctuary, wetland, and roadside areas from the northeastern states of India, viz., Tripura, Manipur, and Assam. Thirteen different organochlorine pesticides (OCPs) were detected from background soils using gas chromatography electron capture detector. Manipur soils were found to be with higher concentration of dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), and endosulfan followed by Tripura and Assam. The spearman correlation coefficient shows significant correlation between HCHs, DDTs, and endosulfan isomers (r ²?>?0.5 and p?<?0.05). Additionally, α-HCH, δ-HCH, o,p′-DDE, and endosulfan-sulfate shows good correlation with total organic carbon in soil (r ²?=?0.5, p?=?0.05), indicating that the soil organic matter could enhance adsorption of these compounds, also demonstrating that the present OCPs in the background soil were from similar source. Further principal component analysis evaluates that most of the higher volatile compounds where clustered together in soil. However, after comparing with different states of Indian soil samples, the concentrations of OCPs in the present study areas are much lower and comparable with background soil across the globe.     

Receptor model-based source apportionment of particulate pollution in Hyderabad, India

Air quality in Hyderabad, India, often exceeds the national ambient air quality standards, especially for particulate matter (PM), which, in 2010, averaged 82.2?±?24.6, 96.2?±?12.1, and 64.3?±?21.2 μg/m³ of PM₁₀, at commercial, industrial, and residential monitoring stations, respectively, exceeding the national ambient standard of 60 μg/m³. In 2005, following an ordinance passed by the Supreme Court of India, a source apportionment study was conducted to quantify source contributions to PM pollution in Hyderabad, using the chemical mass balance (version 8.2) receptor model for 180 ambient samples collected at three stations for PM₁₀ and PM_2.5 size fractions for three seasons. The receptor modeling results indicated that the PM₁₀ pollution is dominated by the direct vehicular exhaust and road dust (more than 60 %). PM_2.5 with higher propensity to enter the human respiratory tracks, has mixed sources of vehicle exhaust, industrial coal combustion, garbage burning, and secondary PM. In order to improve the air quality in the city, these findings demonstrate the need to control emissions from all known sources and particularly focus on the low-hanging fruits like road dust and waste burning, while the technological and institutional advancements in the transport and industrial sectors are bound to enhance efficiencies. Andhra Pradesh Pollution Control Board utilized these results to prepare an air pollution control action plan for the city.     

A comparative study on mesozooplankton abundance and diversity between a protected and an unprotected coastal area of Andaman Islands

The study was carried out to understand the variability in phytoplankton production (Chlorophyll a) and mesozooplankton diversity from two different shallow coastal regions of south Andaman viz. Port Blair Bay (PBB), the only real urban area among the islands and Mahatma Gandhi Marine National Park, a Marine Protected Area (MPA) at Wandoor. Seasonal sampling was carried out during the Northeast monsoon (NEM—November 2005), Intermonsoon (IM—April 2006), and Southwest monsoon (SWM—August 2006). Significant (P?<?0.05) seasonal variation was observed in the environmental variables at both the regions. Higher average chlorophyll a (Chl. a) and mesozooplankton standing stock were observed at PBB compared to MPA, but the seasonal variation observed was marginal at both the study areas. Chl. a showed a steep increasing gradient from outer to the inner regions of the PBB. The number of zooplankton taxa recorded at both areas was quite similar, but marked differences were noticed in their relative contribution to the total abundance. Eventhough the Copepoda dominated at both the areas, the non-copepod taxa differed significantly between the regions. Dominance of carnivores such as siphonophores and chaetognaths were noticed at PBB, while filter feeders such as appendicularians and decapod larvae were more abundant at MPA. A total of 20 and 21 copepod families was recorded from PBB and MPA, respectively. Eleven species of chaetognaths were observed as common at both areas. Larval decapods were found to be predominant at MPA with 20 families; whereas, at PBB, only 12 families were recorded. In the light of the recent reports on various changes occurring in the coastal waters of the Andaman Islands, it is suspected that the difference in Chl. a as well as the mesozooplankton standing stock and community structure observed between the two study areas may be related to the various anthropogenic events influencing the coastal waters.     

Effect of spatial variation on salinity tolerance of macroinvertebrates in Eastern Australia and implications for ecosystem protection trigger values

Salinisation of freshwater has been identified as a serious environmental issue in Australia and around the world. Protective concentrations (trigger values) for salinity can be used to manage salinity impacts, though require locally relevant salinity tolerance information. 72-h acute salinity tolerance values were determined for 102 macroinvertebrates collected from 11 locations in four biologically distinct freshwater bio-regions in Northeast Australia and compared with sensitivities observed in Southeast Australia. The salinity tolerance of individual taxa was consistent across Northeast Australia and between Northeast and Southeast Australia. However, two distinct communities were identified in Northeast Australia using distributions of the acute tolerance values and a calculated index of salinity sensitivity. Salinity trigger values should therefore be representative of local or regionally relevant communities and may be adequately calculated using sensitivity values from throughout Eastern Australia. The results presented provide a basis for assessing salinity risk and determining trigger values for salinity in freshwater ecosystems at local and regional scales in Eastern Australia.     

Biodegradation of catechol (2-hydroxy phenol) bearing wastewater in an UASB reactor

The present study deals with the biodegradation of catechol through co-metabolism with glucose in aqueous solution as primary substrate in an upflow anaerobic sludge blanket (UASB) reactor. Batch studies indicated that the 1000mgl(-1) glucose concentration was sufficient to cometabolize and degrade catechol in an aqueous solution up to a concentration of 1000mgl(-1). The reactor operated at 35+/-2 degrees C, and at a constant hydraulic retention time of 8h with a gradual stepwise increase in catechol concentration from 100 to 1000mgl(-1) along with glucose as a cosubstrate. The results showed that the catechol was successfully mineralized in an UASB reactor in which microbial granulation was achieved with only glucose as the substrate. The reactor showed > or = 95% COD removal efficiency with 500-1000mgl(-1)catechol concentration in the feed and a glucose concentration of 1500mgl(-1) as a cosubstrate. Similar efficiency was obtained at a constant catechol concentration of 1000mgl(-1) with 500-1000mgl(-1) glucose concentration. Once the reactor got acclimatized with catechol, higher concentrations of catechol can be mineralized with a minimum amount of glucose as the cosubstrate without affecting the performance of the UASB reactor.     

Growth performance and biochemical responses of three rice (Oryza sativa L.) cultivars grown in fly-ash amended soil

The disposal of fly-ash (FA) from coal-fired power stations causes significant economic and environmental problems. Use of such contaminated sites for crop production and use of contaminated water for irrigation not only decreases crop productivity but also poses health hazards to humans due to accumulation of toxic metals in edible grains. In the present investigation, three rice cultivars viz., Saryu-52, Sabha-5204, and Pant-4 were grown in garden soil (GS, control) and various amendments (10%, 25%, 50%, 75% and 100%) of FA for a period of 90 days and effect on growth and productivity of plant was evaluated vis-a-vis metal accumulation in the plants. The toxicity of FA at higher concentration (50%) was reflected by the reduction in photosynthetic pigments, protein and growth parameters viz., plant height, root biomass, number of tillers, grain and straw weight. However, at lower concentrations (10-25%), FA enhanced growth of the plants as evident by the increase of studied growth parameters. The cysteine and non-protein thiol (NP-SH) content showed increase in their levels up to 100% FA as compared to control, however, maximum content was found at 25% FA in Saryu-52 and Pant-4 and at 50% FA in Sabha-5204. Accumulation of Fe, Si, Cu, Zn, Mn, Ni, Cd and As was investigated in roots, leaves and seeds of the plants. Fe accumulation was maximum in all the parts of plant followed by Si and both showed more translocation to leaves while Mn, Zn, Cu, Ni and Cd showed lower accumulation and most of the metal was confined to roots in all the three cultivars. As was accumulated only in leaves and was not found to be in detectable levels in roots and seeds. The metal accumulation order in three rice cultivars was Fe > Si > Mn > Zn > Ni > Cu > Cd > As in all the plant parts. The results showed that rice varieties Saryu-52 and Sabha-5204 were more tolerant and could show improved growth and yield in lower FA application doses as compared to Pant-4. Thus, Sabha-5204 and Saryu-52 are found suitable for cultivation in FA amended agricultural soils for better crop yields.     

An innovative technique for lake management with reference to aeration unit installed at lower lake, Bhopal, India

Water is key element in human life. All forms of life upon the earth depend upon water for their mere existence. Life & water may be aptly said to be two facets of the same coin. Most of the water bodies are getting polluted due to domestic waste, sewage, industrial waste and agricultural effluent. The present study is designed to ascertain the effectiveness of artificial aeration cum Ozonizer unit installed at Lower Lake, Bhopal for assessment of water quality. Various physico- chemical parameters like pH, Dissolved oxygen, Biochemical Oxygen demand, Chemical oxygen demand, nitrate, phosphate and bacteriological status were studied to assess the extent of deterioration in water quality of Lower lake and at the same time to assess the performance of the dual aeration system in improvement of water quality.     

Assessment of bioavailable nitrogen and phosphorus content in the sediments of Indian mangroves

Environmental Science and Pollution Research - Efficient nutrient cycling and adequate sediment bioavailable nutrient supply are considered to be the two most important factors regulating the high...