Development of a purpose built landfill system for the control of methane emissions from municipal solid waste

In the present paper, a new system of purpose built landfill (PBLF) has been proposed for the control of methane emissions from municipal solid waste (MSW), by considering all favourable conditions for improved methane generation in tropical climates. Based on certain theoretical considerations multivariate functional models (MFMs) are developed to estimate methane mitigation and energy generating potential of the proposed system. Comparison was made between the existing waste management system and proposed PBLF system. It has been found that the proposed methodology not only controlled methane emissions to the atmosphere but also could yield considerable energy in terms of landfill gas (LFG). Economic feasibility of the proposed system has been tested by comparing unit cost of waste disposal in conventional as well as PBLF systems. In a case study of MSW management in Mumbai (INDIA), it was found that the unit cost of waste disposal with PBLF system is seven times lesser than that of the conventional waste management system. The proposed system showed promising energy generation potential with production of methane worth of Rs. 244 millions/y ($5.2 million/y). Thus, the new waste management methodology could give an adaptable solution for the conflict between development, environmental degradation and natural resources depletion.     

Toxicity of a rice field herbicide in a nitrogen fixing alga,Cylindrospermum sp

Supplementation of paraquat into the culture medium proved to be highly toxic for a blue-green alga Cylindrospermum sp. A concentration of 15 microg/ml proved algicidal for the test alga. Various concentrations (0.5 microg/ml - 15 microg/ml) of the herbicide affected the growth and reduced chlorophyll and phycocyanin contents of the alga. In addition, it inhibited differentiation of heterocysts and akinetes. The inhibition of algal growth was found to be partially relieved on addition of 500 microg/ml of glucose.     

Impact of cadmium on food utilization of the Indian major carp,Catla catla (Ham)

Catla catla, under the sublethal stress of cadmium exhibited depletion in food utilization parameters and it was concentration dependent. Heavy metal intoxication was found to exhibit reduction in biomass.     

Season-dependent mineral accumulation in fruits of Okra (Abelmoschus esculentus) and Tomato (Lycopersicon esculentum)

Season-dependent mineral accumulation was recorded in fruits of Okra and Tomato. The highest concentration was in summer in Okra and in winter in Tomato. Lowest concentrations were in winter in Okra and rainy in Tomato. Both crop plants indicated that the mineral contents were in the order of P > K > Ca > Mg > Na > Fe which also signify their relative functional importance in growth and metabolism.     

Vitellogenin induction in Cyprinus carpio treated with 17beta-estradiol and 4-nonylphenol

The aim of the present study was to demonstrate induction ofvitellogenin in the common carp (Cyprinus carpio) as abiomarker for monitoring freshwater ecosystems. Sexually undifferentiated specimens of common carp were treated experimentally with 17-estradiol and increasing doses of 4-nonylphenol and levels of plasma Vtg were measured in orderto: 1) validate an ELISA assay for plasma Vtg in the common carpusing the polyclonal rabbit anti-salmon Vtg antibody AA1 (Biosense, Norway); 2) check the sensitivity of carp juvenilesin producing Vtg in response to estrogen stimulation. The grouptreated with 17-estradiol showed high induction (156%)with respect to controls, also groups treated with 4-nonylphenolshowed induction of Vtg. The group treated with 100 mg kg^-1b.wt showed an induction of 61%. A statistically significantcorrelation was found between dose and response. This preliminary study demonstrate a response to the ELISA assay for Vtg in the common carp using rabbit anti-salmon antibody AA1. With further evidence the tested biomarker might be proposed for large scale monitoring of estrogenic effects caused by pollution in urban and industrial effluents.     

Effect of fertilisation on the potassium and radiocaesium distribution in tree stands (Pinus sylvestris L.) and peat on a pine mire

This paper compares the effects of single and repeated fertilisation on the contents of potassium, 134Cs and 137Cs in different Scots pine compartments at different levels above ground and in the peat profile 9 years after the Chernobyl disaster. The material was collected from a ditch spacing and fertilisation experiment in Finland. Above a needle potassium concentration of 3.0 mg g(-1) in composed crown samples, 137Cs and 134Cs concentrations remained at about the same level but below that the values were higher on average. This potassium value corresponded to the potassium concentrations of 3.5-3.6 mg g(-1) in the current-year needles of two topmost whorls. The result indicates an enhanced radiocaesium uptake by pine trees under severe potassium deficiency. Fertilisation with potassium-containing fertilisers decreased the caesium uptake considerably. The inhibiting effect of fertilisation on caesium uptake by trees seemed to be fairly long lasting. Fertilisation had sped up the penetration of caesium downwards in the peat profile and its moving out of the active circulation of elements between soil and plants.     

A non-policing honey bee colony (Apis mellifera capensis)

In the Cape honey bee Apis mellifera capensis, workers lay female eggs without mating by thelytokous parthenogenesis. As a result, workers are as related to worker-laid eggs as they are to queen-laid eggs and therefore worker policing is expected to be lower, or even absent. This was tested by transferring worker- and queen-laid eggs into three queenright A. m. capensis discriminator colonies and monitoring their removal. Our results show that worker policing is variable in A. m. capensis and that in one colony worker-laid eggs were not removed. This is the first report of a non-policing queenright honey bee colony. DNA microsatellite and morphometric analysis suggests that the racial composition of the three discriminator colonies was different. The variation in policing rates could be explained by differences in degrees of hybridisation between A. m. capensis and A. m. scutellata, although a larger survey is needed to confirm this.     

Theoretical study of the dechlorination reaction pathways of octachlorodibenzo-p-dioxin

The dechlorination reaction pathways of 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin (OCDD) by the hydrogen atom are investigated by the density-functional theory B3PW91 method. The dechlorination reactions have large exothermicity and small activation energies. The activation energies (approximately 5 kcal/mol) of the sigma-complex formation due to the hydrogen addition are lower than those (approximately 9 kcal/mol) of the direct chlorine abstraction. It is suggested that the sigma-complex plays an important role in the reactions, although it has scarcely been shown in previous studies of the dechlorination of dioxins. The sigma-complex formation is favored at low temperatures and the chlorine abstraction is favored at high temperatures. Furthermore, it is found that the lateral positions have a marginal preference over the longitudinal positions. The dechlorination of OCDD by the hydrogen atom is thus not likely to result in a dominant formation of the laterally substituted toxic congeners.     

Comparison of dioxin and furan TEQ determination in contaminated soil using chemical,micro-EROD,and immunoassay analysis

High resolution mass spectrometry gas chromatography (GC/MS) is the standard method for dioxin and furan analysis in environmental matrices. Considered as very accurate, this method is however time consuming and expensive. Methods based on biological interactions have the necessary sensitivity but began only recently to be investigated in the context of environmental applications. We have compared dioxin and furan toxicity levels (expressed as toxic equivalent quantities (TEQs)) in soil samples by three analytical approaches: the micro-ethoxyresorufin-o-deethylase (EROD) bioassay (a receptor-based method), an immunoassay (antibody-based method) and GC/MS analysis (used as a reference) using a shortened extraction-purification method. Both biological methods were sensitive to interferences from compounds co-extracted from samples. Most samples were underestimated by the immunoassay and, at a greater extent, overestimated by the EROD bioassay. The average accuracy of TEQ estimation (86 +/- 45% of values established by GC/MS) and the absence of false-negatives showed by the immunoassay suggest the usefulness of this method for semi-quantitative, preliminary characterization of potentially contaminated sites.     

Methods for collecting time/activity pattern information related to exposure to combustion products

Focus groups, surveys and questionnaires, diaries and observations can be used to gather information about people's exposure to a wide range of combustion products. Information about locations and durations of exposure, and sources of exposure can be obtained with these instruments. The types of instruments used must be fine tuned to meet the design characteristics of the community in which the study will be conducted.