Atmospheric CO2 consumption by rock weathering over a five year period in a large non-perennial tropical river basin of southern India

Environmental Science and Pollution Research - Rivers engage in carbon cycle by transporting the dissolved products of weathering of rocks to the oceans, and this process is sensitive to the global...     

Synthetic organic chemicals (flame retardants and pesticides) with neurotoxic potential induced behavioral impairment on zebrafish (Danio rerio): a non-invasive approach for neurotoxicology

Environmental Science and Pollution Research - Behavior responses of organisms can be used as a non-invasive method for neurotoxicology studies since it directly links the nervous system’s...     

Impact of long-term exposure to mosquito coils: residual deposition and dissipation of D-trans-allethrin in a room

A D-trans-allethrin-based mosquito repellent coil formulation was used continuously in a room for 30 d. Two different experiments were conducted and the deposition of residues on different surfaces of the room was determined. Studies were conducted continuously for a period of 30 d in a fully closed room and in another room kept open for 14 h per day. The residues deposited on different surfaces, ceiling, side walls and floor, were measured. The results showed the accumulation of high concentrations of allethrin on all the surfaces of the room when the room was in a fully closed condition. Samples collected from the ceiling showed residues of D-trans-allethrin of 6.34-148.63 microg m(-2) during the 30 d study, the side walls 4.68-170.72 microg m(-2) and the floor 20.00-184.52 microg m(-2) Maximum residues were observed in 30 d samples collected from the ceiling and floor. The residual concentrations were nearly 10 times higher in samples collected from the closed room. Discontinuation of the use of the mosquito repellent after 30 d led to a gradual decrease in the concentrations of residues on all the surfaces. The influence of environmental parameters on the dissipation of residues was also studied.     

Mitigation of yield-scaled greenhouse gas emissions from irrigated rice through Azolla,Blue-green algae,and plant growth–promoting bacteria

Environmental Science and Pollution Research - Irrigated transplanted flooded rice is a major source of methane (CH4) emission. We carried out experiments for 2 years in irrigated flooded rice to...     

Dissipation of sulfosulfuron in water - bioaccumulation of residues in fish - LC-MS/MS-ESI identification and quantification of metabolites

Dissipation study of sulfosulfuron in natural water and its bioaccumulation in fish was conducted at 25+/-2 degrees C and at two different concentration levels 1mgl(-1) and 2mgl(-1). The dissipation data in water showed the DT50 and DT90 values 67-76 and 222-253 days and followed first order kinetics. Bioaccumulation of sulfosulfuron in fish was conducted under static conditions exposing the fish at one-tenth of sub-lethal concentration 9mgl(-1) and at double the concentration 18mgl(-1), for a period of 56 days. On different occasions fish samples were collected and analyzed. A HPLC-RF method was used for the quantification of sulfosulfuron and aminopyrimidine with the limit of quantification 0.001microg ml(-1). Results showed the accumulation of residues of sulfosulfuron in fish over the concentration range 0.009-0.496microg g(-1). Both in water and fish samples, identified the presence of metabolites aminopyrimidine, desmethyl sulfosulfuron, guanidine, sulfonamide, ethyl sulfone and rearranged amine. The formations of these metabolites are confirmed by LC-MS/MS analysis. An LC-MS/MS electro spray ionization technique was used for this purpose. One of the metabolite Aminopyrimidine was identified at higher concentration levels (0.01-0.1microg ml(-1)) when compared with other metabolites. Subsequently dissipation of aminopyrimidine in water and its bioaccumulation was also studied at the concentration level 1mgl(-1) and 2mgl(-1). The calculated DT50 and DT90 values are 66-68 days and 218-226 days, respectively. This followed first order kinetics. Three hundred days after the exposure complete demineralization was observed.     

Human impacts on methane emission from mangrove ecosystems in India

This study deals with the emission of methane in relation to changing environmental conditions and human impact, in three mangrove ecosystems of south India. Time-varying fluxes of methane adopting the close chamber technique were used to estimate CH₄ emission from an unpolluted site (Pichavaram mangroves) and two polluted sites viz. (1) Ennore Creek mangroves (affected by fertilizer effluents and crude oil discharges) and (2) Adyar estuary mangroves (affected by the discharges of organic and industrial wastes), covering monthly and seasonal variations. The results indicate annual average CH₄ emissions of 7.4, 5.02 and 15.4 mg m⁻² h⁻¹ from the sediment–water interface of the Pichavaram, Ennore Creek and Adyar estuary respectively. Emission characteristics obtained at Pichavaram mangroves represent a natural variability with changing physico-chemical factors, whereas the emission characteristics at Ennore Creek and Adyar estuary mangroves show anthropogenic influence. Several environmental factors such as oxygen availability, organic matter, soil physical and chemical properties, in addition to human-mediated interventions have been identified as influencing emission rates in the mangrove ecosystems. Preliminary CH₄ emission estimates for the mangrove ecosystems along the Indian sub- continent and the tropical and subtropical coastline of the world by linear extrapolation based on surface area range from 0.05 to 0.37 and 2.8 to 19.25 Tg CH₄ year⁻¹ respectively. Our results also highlight the impact of human activities on future emission of methane from the mangrove ecosystems. Received: 3 March 1999 / Accepted: 14 September 1999     

Recycling potential of MWCNTs/HDPE nanocomposite filament: 3D printing and mechanical characterization

Journal of Material Cycles and Waste Management - Fused filament fabrication (FFF) based additive manufacturing (AM) process is a widely used and emerging manufacturing process for...     

用Autospec-Ultima NT气相色谱-高分辨质谱分析二噁英及相关的持久性有机污染物

"二噁英"是指一类化学结构和生物特征均有某些相似之处的化合物.这些有毒化合物有几百种,可分为相关的三大类:氯代二苯并-对-二噁英(CDDs),氯代二苯并呋喃(CDFs)和某些多氯代联苯(PCBs).CDDs和CDFs并非与生具有,而是由于人类活动不注意而生成的.天然过程也会产生CDDs和CDFs.     

Electro-dissolution of metal scrap anodes for nickel ion removal from metal finishing effluent

This contribution reports a novel and cost efficient strategy for nickel ion removal from metal finishing effluents by electro-dissolution of scrap aluminium and iron sacrificial anodes. Electro-coagulation of effluent was carried out at 30 mA/cm² current density for 60 min. The nickel ion concentration of electroplating effluent was analysed by Atomic Absorption Spectroscopy. SEM images of iron and aluminium scrap anodes were critically analysed. Parameters such as heavy metal removal, anode dissolution rate with respect to heavy metal removal, reaction kinetics and cost estimation have been elaborately studied. Electro-coagulation at 30 mA/cm² for 60 min using iron and aluminium scrap anodes resulted in 95.9 and 94.1 % nickel ion reduction, respectively, with 0.0094 and 0.0053 g/ppm dissolution rates. The energy consumption for scrap aluminium and iron anodes was 0.0547 kWh/L. Loose internal bonding and spongy surface morphology of used metal scrap render high porosity and active surface area, enhancing reaction rate. Low cost and ready availability of waste scrap makes the process of electro-coagulation economically viable. Thus, the findings from this contribution point decisively at the superiority of waste metal scrap-based anodes for economic and environmentally sustainable heavy metal ion removal from metal finishing effluent.