Photocatalytic oxidation of triclosan

In the spring of 2003, there was an outbreak of the severe respiratory syndrome (SARS) in Hong Kong. Health concerns have thus triggered an increased and predominant use of various types of household cleansing agents such as triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol). However, it has been reported recently that triclosan could be photochemically converted to toxic 2,8-dichlorodibenzo-p-dioxin (2,8-Cl(2)DD) in the environment. It is therefore necessary to develop environmentally friendly methods for the treatment of triclosan. To this end, photocatalytic degradation of triclosan in aqueous solution was conducted using TiO(2) (Degussa P25) under irradiation of UV light (lambda < 365 nm). It was found that triclosan could be degraded by this approach. Hydrogen peroxide was added to enhance the degradation process, and the optimal initial hydrogen peroxide concentration for triclosan degradation was 0.005% (w/v). Product identification indicated that triclosan oxidation occurred at its phenol moiety and yielded quinone and hydroquinone intermediates. The formation of a dichlorophenol intermediate in triclosan degradation suggested bond-breaking of the ether linkage occurred during the process. Moreover, no chlorinated dibenzo-p-dioxin congener was detected. These findings confirm that the photocatalytic degradation of triclosan is an environmentally friendly process.     

On-road motor vehicle emissions and fuel consumption in urban driving conditions

This paper reports on the analysis of on-road vehicle speed, emission, and fuel consumption data collected by four instrumented vehicles. Time-, distance-, and fuel-based average fuel consumption, as well as CO, HC, NOx, and soot emission factors, were derived. The influences of instantaneous vehicle speed on emissions and fuel consumption were studied. It was found that the fuel-based emission factors varied much less than the time- and distance-based emission factors as instantaneous speed changed. The trends are similar to the results obtained from laboratory tests. The low driving speed contributed to a significant portion of the total emissions over a trip. Furthermore, the on-road data were analyzed using the modal approach. The four standard driving modes are acceleration, cruising, deceleration, and idling. It was found that the transient driving modes (i.e., acceleration and deceleration) were more polluting than the steady-speed driving modes (i.e., cruising and idling) in terms of g/km and g/sec. These results indicated that the on-road emission measurement is feasible in deriving vehicle emissions and fuel consumption factors in urban driving conditions.     

Fuelwood assessment at the micro-watershed level:a case study in Garhwal Himalaya,India

Biomass,as fuelwood,is one of the major sources of energy in rural areas,especially in the mountainous regions of the world.As the increasing human population exerts more pressure on the forest thereby inducing an adverse effect on the sustainability of the ecosystem,which consequently causes fuelwood crisis at a local level,this crisis is spatio-temporal in nature.Thus,the major objective of this study is to assess the sustainability of fuelwood at different probable scenarios at a micro watershed level.The present study was conducted in the Phakot watershed,the Tehri Garhwal district of central Himalaya in India,during 2006-2008.Based on the vegetation composition in the study area,the net primary productivity(NPP)value of the Oak forest,and mixed oak and sal forests,was used for the quantification of fuelwood availability in evergreen and deciduous forests,respectively.The fuelwood demand was calculated on the basis of seasonal fuelwood consumption values.Nine probable permutations for availability-demand scenarios assuming the existence of high(H),low(L)and average(A)conditions were analyzed for evaluating the stress.The available annual harvestable fuelwood in the watershed is in the minimum and maximum ranges of 2283.28 to 4066.00 tons,respectively,per year whereas it has a demand of 110.76 tons as the minimum to 3659 tons as the maximum annually.This shows that in the current availabilitydemand scenario,the watershed does not have fuelwood crisis in the present situation but needs to maintain the sustainability of the system.Based on our study,it is concluded that,globally,more spatio-temporal study is required to understand the issues at the local level.     

Risk assessment and pathway study of arsenic in industrially contaminated sites of Hyderabad: a case study

Different areas in the industrial region of Patancheru near Hyderabad, Andhra Pradesh (A.P), India are contaminated with high concentration of arsenic, which is attributed to industrial source like veterinary chemicals, pharmaceuticals, pesticide industries, etc. Fourteen villages of this area of Patancheru were assessed for arsenic contamination by collecting samples of water (surface and ground), soil, fodder, milk, and vegetables. The total arsenic content in the whole blood, urine, hair, and nails of the residents showing arsenical skin lesions and other clinical manifestations were also studied. To understand the bioavailability of arsenic in this environment and its possible entry into human food chain, speciation studies of arsenic was carried out and the results are presented in this paper.     

Effect of cadmium on nodulation and N2-fixation of soybean in contaminated soils

The effects of cadmium stress on nodulation, N2-fixation capabilities of the root nodule, the change in ultrastructure of the root nodule, soybean growth, and the distribution of cadmium in plants were studied. The results obtained show that the nodulation of soybean roots was greatly inhibited by the addition of Cd, especially at the addition level of 10 and 20 mg kg(-1) soil. The inhibition of plant growth, especially the root growth, increased as the cadmium concentration increased, with deleterious effects observed for the roots. The weight ratio of soybean root/leaf decreased as the Cd concentration increased, which might explain the reason for nodulation decreases. The results also indicate that N2-fixation of root nodule was stimulated to some extent at the low levels of Cd addition, but decreased sharply with further increase of the Cd concentration. High Cd levels were also associated with changes in the ultrastructure of root nodule, in which the effective N2-fixing area was reduced and the N2-fixing cells in the area also reduced. In addition, the results also reveal that the content of Cd in different parts of the plants was as follows: roots > stems > seeds, indicating that the accumulation of Cd by roots is much larger than that by any other part of the soybean plant, and might cause deleterious effects to root systems.     

Development of plant-friendly vermicompost using novel biotechnological methods

Journal of Material Cycles and Waste Management - For the first time in the world, raw tea waste from tea plants was mineralized by rapid biotechnological methods using beneficial worms, enzymes...     

Diving behaviour of female northern rockhopper penguins, Eudyptes chrysocome moseleyi, during the brooding period at Amsterdam Island (Southern Indian Ocean)

The pattern and characteristics of diving in 14 female northern rockhopper penguins, Eudyptes chrysocome moseleyi, were studied at Amsterdam Island (37°50′S; 77°31′E) during the guard stage, using electronic time–depth recorders. Twenty-nine foraging trips (27 daily foraging trips and two longer trips including one night) with a total of 16 572 dives of ≥3 m were recorded. Females typically left the colony at dawn and returned in the late afternoon, spending an average of 12 h at sea, during which they performed ∼550 dives. They were essentially inshore foragers (mean estimated foraging range 6 km), and mainly preyed upon the pelagic euphausiid Thysanoessa gregaria, fishes and squid being only minor components of the diet. Mean dive depth, dive duration, and post-dive intervals were 18.4 m (max. depth 109 m), 57 s (max. dive duration 168 s), and 21 s (37% of dive duration), respectively. Descent and ascent rates averaged 1.2 and 1.0 ms⁻¹ and were, together with dive duration, significantly correlated with dive depth. Birds spent 18% of their total diving time in dives reaching 15 to 20 m, and the mean maximum diving efficiency (bottom time:dive cycle duration) occurred for dives reaching 15 to 35 m. The most remarkable feature of diving behaviour in northern rockhopper penguins was the high percentage of time spent diving during daily foraging trips (on average, 69% of their time at sea); this was mainly due to a high dive frequency (∼44 dives per hour), which explained the high total vertical distance travelled during one trip (18 km on average). Diving activity at night was greatly reduced, suggesting that, as other penguins, E. chrysocome moseleyi are essentially diurnal, and locate prey using visual cues. Received: 9 December 1998 / Accepted: 3 March 1999     

Phylogenetic relationships of deep-sea mussels of the genus<Emphasis Type="Italic"> Bathymodiolus</Emphasis> (Bivalvia: Mytilidae)

We examined phylogenetic relationships among three Bathymodiolus species in Japanese waters and Bathymodiolus spp. from the Manus Basin by two different approaches. Two-dimensional gel electrophoresis allowed us to compare 263–407 (average=318) proteins, giving comprehensive information on genetic distances among the species. The neighbor-joining tree presented two clusters: (1) B. japonicus and B. platifrons and (2) B. septemdierum and B. sp. Members of the first cluster contain methanotrophic endosymbiotic bacteria and members of the second cluster contain thioautotrophic endosymbionts. DNA sequencing of a fragment (415 bp) of mitochondrial cytochrome c oxidase subunit I (COI) provided a neighbor-joining tree with the same topology as that derived from protein analysis. Inspection of intraspecific variation in COI in B. japonicus and B. platifrons revealed no genetic differentiation between mussel populations of either species from cold-water seeps versus hydrothermal vents, suggesting high adaptability of these Bathymodiolus species to deep-sea chemosynthetic environments. Our results indicated genetic exchanges between mussels from distant localities, suggesting that a limited dispersal capability of the larvae is not the likely factor leading to speciation events in these Bathymodiolus species.Communicated by T. Ikeda, Hakodate