On the relationship between regional and local species richness: a test of saturation theory

What are the local community consequences of changes in regional species richness and composition? To answer this question we followed the assembly of microarthropod communities in defaunated areas of moss, embedded in a larger moss "region." Regions were created by combining moss from spatially distinct sites, resulting in regional species pools that differed in both microarthropod richness and composition, but not area. Regional effects were less important than seasonality for local richness. Initial differences in regional richness had no direct effect on local species richness at any time along a successional gradient of 0.5-16 months. The structure of the regional pool affected both local richness and local composition, but these effects were seasonally dependent. Local species richness differed substantially between dates along the successional gradient and continued to increase 16 months after assembly began. To the best of our knowledge, this is the first critical test of saturation theory that experimentally manipulates regional richness. Further, our results failed to support the most important mechanisms proposed to explain the local richness-regional richness relationship. The results demonstrate that complicated interactions between assembly time, seasonality, and regional species pools contribute to structuring local species richness and composition in this community.     

Preliminary estimates of performance and cost of mercury control technology applications on electric utility boilers.

Under the Clean Air Act Amendments of 1990, the U.S. Environmental Protection Agency (EPA) determined that regulation of mercury emissions from coal-fired power plants is appropriate and necessary. To aid in this determination, preliminary estimates of the performance and cost of powdered activated carbon (PAC) injection-based mercury control technologies were developed. This paper presents these estimates and develops projections of costs for future applications. Cost estimates were developed using PAC to achieve a minimum of 80% mercury removal at plants using electrostatic precipitators and a minimum of 90% removal at plants using fabric filters. These estimates ranged from 0.305 to 3.783 mills/kWh. However, the higher costs were associated with a minority of plants using hot-side electrostatic precipitators (HESPs). If these costs are excluded, the estimates range from 0.305 to 1.915 mills/kWh. Cost projections developed using a composite lime-PAC sorbent for mercury removal ranged from 0.183 to 2.270 mills/kWh, with the higher costs being associated with a minority of plants that used HESPs.     

Up to 399 mV bioelectricity generated by a rice paddy-planted microbial fuel cell assisted with a blue-green algal cathode

Environmental Chemistry Letters - Microbial fuel cells are used as an alternative source of energy and for microbial degradation of waste and pollutants. Different types of microbial fuel cells...     

Effects of deltamethrin on serum calcium and corpuscles of Stannius of freshwater catfish,Heteropneustes fossilis

Adult male deer mice were exposed every other day for a period of 11 days to either 7,12-dimethylbenzanthracene (DMBA; CAS# 57-97-6) or benzo[b]fluoranthene (BbF; CAS# 205-99-2) (0, 0.3, 1, 3, 10, or 30?mg?kg^?1). Immune endpoints assessed were lymphocyte proliferation, macrophage pinocytosis, and the antibody plaque-forming cell (PFC) response. Cytochrome P450 (CYP450) activity was assessed using ethoxyresorufin-O-deethylase (EROD) and pentoxyresorufin-O-deethylase (PROD). Macrophage pinocytosis was not altered by either compound. Both T- and B-cell proliferations were significantly increased by DMBA at 0.3 or 1?mg?kg^?1 and by BbF at 10 or 30?mg?kg^?1, but decreased by DMBA at 30?mg?kg^?1. Sheep red blood cell (SRBC)-specific-IgM production, as measured by the PFC response, was the most striking adverse immune effect observed and was significantly suppressed compared to control at all treatment concentrations for both compounds. EROD activity was markedly induced by DMBA at 30?mg?kg^?1, while BbF produced induction at 1, 10, or 30?mg?kg^?1. No marked effect on PROD activity was noted following DMBA treatment, but BbF-induced PROD activity at 1, 10, or 30?mg?kg^?1. Unexpectedly, four of six mice in the 30?mg DMBA?kg^?1 group did not survive to the end of the experiment, and one animal died in both the 3 and 10?mg?kg^?1 treatments. The calculated LD₅₀ was 20.8?mg DMBA?kg^?1. The PFC response in deer mice was a more sensitive endpoint than CYP450 activity, suggesting that utilization of CYP450 endpoints in risk assessment without assessment of immune function, specifically antibody production, might possibly underestimate the risk to wild rodents environmentally exposed to polycyclic aromatic hydrocarbons.     

EDTA and citric acid mediated phytoextraction of Zn, Cu, Pb and Cd through marigold (Tagetes erecta)

Phytoextraction is an emerging cost-effective solution for remediation of contaminated soils which involves the removal of toxins, especially heavy metals and metalloids, by the roots of the plants with subsequent transport to aerial plant organs. The aim of the present investigation is to study the effects of EDTA and citric acid on accumulation potential of marigold (Tagetes erecta) to Zn, Cu, Pb, and Cd and also to evaluate the impacts of these chelators (EDTA and citric acid) in combination with all the four heavy metals on the growth of marigold. The plants were grown in pots and treated with Zn (7.3 mg l(-1)), Cu (7.5 mg I(-1)), Pb (3.7 mg l(-1)) and Cd (0.2 mg l(-1)) alone and in combination with different doses of EDTA i.e., 10, 20 and 30 mg l(-1). All the three doses of EDTA i.e., 10, 20 and 30 mg l(-1) significantly increased the accumulation of Zn, Cu, Pb and Cd by roots, stems and leaves as compared to control treatments. The 30 mg l(-1) concentration of citric acid showed reduced accumulation of these metals by root, stem and leaves as compared to lower doses i.e., 10 and 20 mg l(-1). Among the four heavy metals, Zn accumulated in the great amount (526.34 mg kg(-1) DW) followed by Cu (443.14 mg kg(-1) DW), Pb (393.16 mg kg(-1) DW) and Cd (333.62 mg kg(-1) DW) in leaves with 30 mg l(-1) EDTA treatment. The highest concentration of EDTA and citric acid (30 mg l(-1)) caused significant reduction in growth of marigold in terms of plant height, fresh weight of plant, total chlorophyll, carbohydrate content and protein content. Thus EDTA and citric acid efficiently increased the phytoextractability of marigold which can be used to remediate the soil contaminated with these metals.     

Toxicological evaluation of bacterial decolourised anaerobically treated distillery effluent with common duckweed (Lemna minor)

Duckweed (Lemna minor) a small vascular plant, grows rapidly, is sensitive to a wide variety of toxicants and is easy to culture. A method is described that measures duckweed frond growth, chlorophyll, protein and biomass content as indicator of growth inhibition. The physico-chemical analysis of anaerobically treated distillery effluent revealed high BOD (28,000 mg/l), COD (52,400 mg/l) and dark brown colour (180,000 Co. Pt.). This effluent showed high toxicity to Lemna minor after 96 h of exposure in laboratory condition. EC50 of the fronds for chlorophyll, protein and biomass was found to be 25%, however, the bacterial decolourised effluent showed reduction of BOD (87.50%), COD (84.50%) and colour (76%). Further the toxicity evaluation with Lemna minor showed toxicity reduction up to 63% for all tested parameters. The EC50 noted for chlorophyll, protein and biomass was 100% concentration of decolourised effluent.     

Effect of Aegle marmelos and Hibiscus rosa sinensis leaf extract on glucose tolerance in glucose induced hyperglycemic rats (Charles foster)

In an effort to test the hypoglycemic activity of Aegle marmelos and Hibiscus rosa sinensis in glucose induced hyperglycemic rats, their alcoholic leaf extracts were studied. Both the groups of animals receiving either. A. marmelos or H. rosa sinensis leaf extract for seven consecutive days, at an oral dose equivalent to 250 mg kg-1 showed significant improvements in their ability to utilize the external glucose load. Average blood glucose lowering caused by A. marmelos and H. rosa sinensis was 67% and 39% respectively, which shows that former significantly (p < 0.001) improves the glucose tolerance curve. The magnitude of this effect showed time related variation with both the plants. Efficacy of A. marmelos and H. rosa sinensis was 71% and 41% of glybenclamide, respectively. These data throw some light on the possible mechanism of hypoglycemic activity of both the plants. The mechanism of action could be speculated partly to increased utilization of glucose, either by direct stimulation of glucose uptake or via the mediation of enhanced insulin secretion.     

An international study: Effect of farm manure on the release of phosphorus from fly ash

Fly ash is abundantly produced from thermal power plants and is considered a hazardous waste. However, in recent years, fly ash has been widely utilized in the agricultural sector as a soil modifier. It is particularly important for wasteland/mine spoil reclamation due to its ability to provide a source of plant nutrients and improve physicochemical properties of soil. Although fly ash itself contains many plant nutrients, most nutrients, including phosphorus (P), are in a bound form not easily available to plants. This study analyzed the effect of farm manure on the solubility of P from fly ash. Incubation studies were conducted to determine the effect of farm manure on P solubilization to use as a potential option for remediation. © 2007 Wiley Periodicals, Inc.     

Prenatal exposure to environmental pro-oxidants induces mitochondria-mediated epigenetic changes: a cross-sectional pilot study

Mitochondria play a central role in maintaining cellular and metabolic homeostasis during vital development cycles of foetal growth. Optimal mitochondrial functions are important not only to sustain adequate energy production but also for regulated epigenetic programming. However, these organelles are subtle targets of environmental exposures, and any perturbance in the defined mitochondrial machinery during the developmental stage can lead to the re-programming of the foetal epigenetic landscape. As these modifications can be transferred to subsequent generations, we herein performed a cross-sectional study to have an in-depth understanding of this intricate phenomenon. The study was conducted with two arms: whereas the first group consisted of in utero pro-oxidant exposed individuals and the second group included controls. Our results showed higher levels of oxidative mtDNA damage and associated integrated stress response among the exposed individuals. These disturbances were found to be closely related to the observed discrepancies in mitochondrial biogenesis. The exposed group showed mtDNA hypermethylation and changes in allied mitochondrial functioning. Altered expression of mitomiRs and their respective target genes in the exposed group indicated the possibilities of a disturbed mitochondrial-nuclear cross talk. This was further confirmed by the modified activity of the mitochondrial stress regulators and pro-inflammatory mediators among the exposed group. Importantly, the disturbed DNMT functioning, hypermethylation of nuclear DNA, and higher degree of post-translational histone modifications established the existence of aberrant epigenetic modifications in the exposed individuals. Overall, our results demonstrate the first molecular insights of in utero pro-oxidant exposure associated changes in the mitochondrial-epigenetic axis. Although, our study might not cement an exposure-response relationship for any particular environmental pro-oxidant, but suffice to establish a dogma of mito-epigenetic reprogramming at intrauterine milieu with chronic illness, a hitherto unreported interaction.

Graphical abstract

     

Environmental issues for sustainable development

Environmental Science and Pollution Research -