Trace metal dynamics in fishes from the southwest coast of India

The concentration of Fe, Co, Ni, Cu, Zn, Cd, and Pb in the muscle tissue of marine fishes like Lates calcarifer, Nemipterus japonicus, Caranx melampygus, Rastrelliger kanagurta, and Cyanoglossus macrostomus was estimated from samples collected in the continental shelf waters off Kochi and Mangalore on southwest coast of India. Species-specific and spatially heterogeneous patterns of tissue metals loads were apparent within the pelagic and demersal fish species for the two regions. The concentration ranges of Fe (541.60 to 649.60 ppm), Ni (12.12 to 13.92 ppm), and Cu (3.09 to 3.62 ppm) were higher in the demersal species C. melampygus, whereas Co (9.10 to 11.80 ppm) and Zn (79.30 to 84.30 ppm) were higher in the pelagic species L. calcarifer and Cd (4.35 to 6.38 ppm) were higher in the demersal species N. japonicus, possibly due to enhanced bioavailability of these metals from ecological processes associated with upwelling during the summer monsoon. The fish species showed a great capacity to accumulate metals, with highest bioaccumulation for the essential element iron and lowest bioaccumulation for the non-essential element lead. Among the demersal species, C. melampygus and N. japonicus had high concentration factors for the metals Fe (280,268 to 322,808), Ni (88,252 to 96,891), Cu (2,351 to 2,600), and Cd (29,637 to 32,404). In contrast, the pelagic species L. calcarifer and R. kanagurta had high concentration factors for the metals Zn (40,812 to 46,892), Co (280,285 to 423,037), and Pb (854 to 1,404).     

Response Surface Method Coupled with First-Order Reliability Method Based Methodology for Groundwater Flow and Contaminant Transport Model for the Uranium Tailings Pond Site

Groundwater flow and contaminant transport modelling is carried out to predict the concentrations of radionuclides in groundwater beneath the tailings pond. This is used as a tool for radiological impact assessment studies. The geo-hydrological parameters involved in the modelling exhibit inherent uncertainty associated with their values. This uncertainty may get propagated to the model output, i.e. the dose to the public. The propagation of the uncertainty in the input parameters to the output is modelled using suitable methods of probabilistic analysis. Response surface method coupled with first-order reliability method is used to develop a methodology for estimating the probability that the dose rate value through drinking water pathway at a location around the tailings pond exceeds the WHO guidelines for drinking water, termed as the probability of exceedance of acceptable levels. This method also gives the estimate of sensitivity of the probability of exceedance to the different input parameters. It is observed that the probability of failure decreases as the distance from tailings pond centre is increased and beyond a distance of around 0.5 km from tailings pond centre, the probability reduces to zero. The work also brings out the importance of quantifying the uncertainty in case of actual field problems where there is wide variation in the values of the various parameters within the domain under study.     

Microbial inoculants for small scale composting of putrescible kitchen wastes

This research looked at the need for ligno-cellulolytic inoculants (EM bacteria and Trichoderma sp.) in small to medium scale composting of household wastes. A mixture of household organic waste comprised of kitchen waste, paper, grass clippings and composted material was subjected to various durations of thermo composting followed by vermicomposting with and without microbial inoculants for a total of 28 days. The results revealed that ligno-celluloytic inoculants are not essential to speed up the process of composting for onsite small scale household organic waste treatment as no significant difference was observed between the control and those inoculated with Trichoderma and EM in terms of C:N ratio of the final product. However, it was observed that EM inoculation enhanced reproductive rate of earthworms, and so probably created the best environment for vermicomposting, in all treatment groups.     

Anaerobic ammonia-oxidizing bacteria in tropical bioaugmented zero water exchange aquaculture ponds

Environmental Science and Pollution Research - Bioaugmented zero water exchange aquaculture production systems (ZWEAPS) maintained with minimal or no water exchange prevent the ammonia accumulation...     

Monitoring of heavy metal partitioning in reef corals of Lakshadweep Archipelago, Indian Ocean

This paper focuses on the partitioning of trace metals in five selected coral species from Lakshadweep Archipelago, which remains as one of the least studied areas in the Indian Ocean. Based on the morphological features, selected coral species are classified as massive (Porites andrewsi), ramose or branching (Lobophyllia corymbosa, Acropora formosa and Psammocora contigua) and foliaceous (Montipora digitata). Relating trace metal concentrations with morphological features in skeleton, highest concentrations of all the trace metals (except Zn) were reported for the ramose type corals. In tissue, all the metals (essential as well as non essential) showed highest concentrations within the branching type corals. Irrespective of their growth characteristics/pattern, all species except P. contigua displayed higher concentrations of Pb, Ni, Mn and Cd within their skeleton compared to tissue which may exemplify a regulatory mechanism to avoid the build up of the concentrations of these metals in their bio-part, strikingly toxic metals like Cd and Pb. The concentrations of trace metals in the skeleton and tissues of these coral species were subjected to 3 way ANOVA based on non standardized original data and the results showed significant differences between metals and between species leading to high skeleton/ tissue - species interaction as well as skeleton/tissue - metal interaction. The significant values of student's t calculated are depicted in the form of Trellis diagrams.     

Biodegradability of leathers through anaerobic pathway

Leather processing generates huge amounts of both solid and liquid wastes. The management of solid wastes, especially tanned leather waste, is a challenging problem faced by tanners. Hence, studies on biodegradability of leather become imperative. In this present work, biodegradability of untanned, chrome tanned and vegetable tanned leather under anaerobic conditions has been addressed. Two different sources of anaerobes have been used for this purpose. The effect of detanning as a pretreatment method before subjecting the leather to biodegradation has also been studied. It has been found that vegetable tanned leather leads to more gas production than chrome tanned leather. Mixed anaerobic isolates when employed as an inoculum are able to degrade the soluble organics of vegetable tanned material and thus exhibit an increased level of gas production during the initial days, compared to the results of the treatments that received the anaerobic sludge. With chrome tanned materials, there was not much change in the volume of the gas produced from the two different sources. It has been found that detanning tends to improve the biodegradability of both types of leathers.     

Phosphorus and other soil components in a dairy effluent sprayfield within the central Florida Ridge

There is concern that P from dairy effluent sprayfields will leach into groundwater beneath Suwannee River basins in northern Florida. Our purpose was to describe the effects of dairy effluent irrigation on the movement of soil P and other nutrients within the upper soil profile of a sprayfield over three 12-mo cycles (April 1998-March 2001). Effluent P rates of 70, 110, and 165 kg ha(-1) cycle(-1) were applied to forages that were grown year-round. The soil is a deep, excessively drained sand (thermic, uncoated Typic Quartzipsamment). Mean P concentration in soil water below the rooting zone (152-cm depth) was < or = 0.1 mg L(-1) during 11 3-mo periods. Mehlich-1-extractable (M1) P, Al, and Ca in the topsoil increased over time but did not change in subsoil depths of 25 to 51, 51 to 71, 71 to 97, and 97 to 122 cm. Topsoil Ca increased as effluent rate increased. High Ca levels were found in dairy effluent (avg.: 305 mg L(-1)) and supplemental irrigation water (avg.: 145 mg L(-1)) which likely played a role in retaining P in the topsoil. An effect of effluent rate on P and Al concentrations in the topsoil was not detected, probably due to large and variable quantities present at project initiation. The P retention capacity (i.e., Al plus Fe) increased in the topsoil because Al increased. Dairy effluent contained Al (avg.: 31 mg L(-1)). Phosphorus saturation ratio (PSR) increased over time in the topsoil but not in subsoil layers. Regardless of effluent rate, the P retention capacity and PSR of subsoil, which contained 119 to 229 mg kg(-1) of Al, should be taken into account when assessing the risk of P moving below the rooting zone of most forage crops.     

Geochemical index of trace metals in the surficial sediments from the western continental shelf of India, Arabian Sea

The present study focuses on the determination and abundance of trace metals (viz. Cu, Ni, Zn, Cr, Co, Cd, Mn and Fe) in the surficial sediments of west coast of Arabian Sea along the Indian subcontinent. Sediment samples were collected from three transects along the western continental shelf of Arabian Sea. The enrichment of Fe and Mn in coastal oxic-sediments indicates the precipitation of these redox sensitive elements as Fe- and Mn-hydroxides and oxides, whereas the low Fe and Mn concentrations in the oxygen deficient sediments of deeper stations reflects the dissolution of their hydroxides and oxides. Concentrations of fairly redox insensitive trace metals like Cu, Ni, Zn, Cr and Cd (with the exceptions of Cr) showed higher values at nearshore sediments, then it decreased towards seaward and again showed a slight increase at oxygen minimum stations in all the three transects. This geochemical variability in their distributional characteristics is mainly associated with the extent to which the precipitation or dissolution of Fe- and Mn-oxides/hydroxides occur since the scavenging or releasing effects of Fe- and Mn-oxides/hydroxides act as significant ‘sinks’ or ‘sources’ of heavy metals. The change in wind pattern, coastal upwelling and increased productivity are also the reported factors which influence the biogeochemical cycling of trace metals in the surface sediments of west coast of India. Enrichment factor generally showed a high gradient accumulation from nearshore to shelf.     

The mechanism of nestmate discrimination in the tropical social wasp Ropalidia marginata and its implications for the evolution of sociality

Summary We have demonstrated that females of the primitively eusocial tropical wasp Ropalidia marginata can discriminate nestmates from nonnestmates outside the context of their nests. This was accomplished by recroding all behavioural interactions in a neutral arena and comparing tolerance levels. In order for these wasps to make such a discrimination, however, it was essential that after eclosion both the discriminated and the discriminating animals were exposed to their respective natal nests and nestmates. The results suggest that both recognition labels and templates are acquired by the animals from sources outside their body, perhaps from their nest or nestmates. It is thus unlikely that different genetic lines within a colony can be distinguished. We conclude, therefore, that genetic asymmetries created by haplodiploidy, but often broken down by multiple mating and polygyny, are not restored by preferential altruism towards full rather than half sisters by means of kin recognition. Hence we recommend caution in ascribing the multiple origins of eusociality in the Hymenoptera to haplodiploidy.     

Making decisions on environmental problems

A methodology is presented based on decision analysis for making decisions on environmental problems as required in the environmental impact assessment context. The major issues are identified, and the ability of the methodology to address these issues discussed. Explicit treatment of uncertainty and value tradeoffs, and the ability to consider different points of view are the important features of the methodology. Because of its sound theoretical foundation and its systematic and logical development, the methodology is well suited for documenting and justifying the decision process in public, regulatory, and judicial hearings. Case histories are summarized to illustrate the wide range of applicability of the methodology.