Graphene oxide-MnFe2O4 magnetic nanohybrids for efficient removal of lead and arsenic from water.

We show that the hybrids of single-layer graphene oxide with manganese ferrite magnetic nanoparticles have the best adsorption properties for efficient removal of Pb(II), As(III), and As(V) from contaminated water. The nanohybrids prepared by coprecipitation technique were characterized using atomic force and scanning electron microscopies, Fourier transformed infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and surface area measurements. Magnetic character of the nanohybrids was ascertained by a vibrating sample magnetometer. Batch experiments were carried out to quantify the adsorption kinetics and adsorption capacities of the nanohybrids and compared with the bare nanoparticles of MnFe2O4. The adsorption data from our experiments fit the Langmuir isotherm, yielding the maximum adsorption capacity higher than the reported values so far. Temperature-dependent adsorption studies have been done to estimate the free energy and enthalpy of adsorption. Reusability, ease of magnetic separation, high removal efficiency, high surface area, and fast kinetics make these nanohybrids very attractive candidates for low-cost adsorbents for the effective coremoval of heavy metals from contaminated water.

Dose estimates to the public from 210Po ingestion via dietary sources at Kalpakkam (India).

Distribution of one of the natural radionuclides 210Po activity in food of plant origin such as cereals, pulses, vegetables and food of animal origin such fish, crab, prawn, chicken, egg etc. were determined in and around Kalpakkam upto a distance of 32 km radius. The general range of 210Po activity levels in all the dietary components (excluding milk and drinking water which are reported in mBq l(-1)) ranged widely from < or = 10 to 122,641 mBq kg(-1) fresh, the minimum being in vegetables and maximum being in the edible portions (muscle) of crab samples. 210Po levels in drinking water and milk samples ranged between 0.6-2.6 and 8-12 mBq l(-1) respectively. 210Po content in cereals ranged from < or = 32 to 745 mBq kg(-1) and in pulses it was found to vary between < or =32 and 294 mBq kg(-1). The range of 210Po activity in different types of vegetables was found to be < or = 10-653 mBq kg(-1). Among the different varieties of vegetables, 210Po was significantly higher in leafy vegetables (28-653 mBq kg(-1)) as compared to rooty and other types of vegetables which ranged from < or = 10-180 mBq kg(-1). In food of animal origin, the observed minimum activity of 210Po was 8 mBq l(-1) in milk and the maximum observed was 122,641 mBq kg(-1) in the muscles of crab. It was also observed that 210Po activity was found to be in higher levels in the food of aquatic animal origin (1414-122,641 mBq kg(-1)) than in the food of terrestrial animal origin (other than milk) which varied from 41 to 963 mBq kg(-1). It is evident from the present study that the foods of animal origin especially crab, fish and prawn deliver significantly greater dose (93-3364 microSv yr(-1)) to the public compared to foods of plant origin whose mean dose ranged 0.08-128 microSv yr(-1). The study showed evidence to suggest that the total ingestion dose due to 210Po received by the Kalpakkam public through dietary sources is significantly higher than the ingestion dose received due to fallout sources such as 137Cs and 90Sr.

A study of polonium-210 distribution aspects in the riverine ecosystem of Kaveri, Tiruchirappalli, India.

Distribution of a natural radionuclide (210Po) in water, sediment and biota was quantified along a 95 km reach of the Kaveri River, India. It is observed that the soft tissues of animals concentrated a higher level of 210Po than the hard parts like shell and bone. The ranges of 210Po activity in biological samples were 2.32-10.78 Bq kg(-1) wet (aquatic weeds), 18.94-28.55 Bq kg(-1) wet (plankton), 32.51 to 46.17 Bq kg(-1) wet (snail), 57.42 to 105.78 Bq kg(-1) wet (bivalve), 12.13 to 19.10 Bq kg(-1) wet (prawn) and 1.86 to 4.17 Bq kg(-1) wet (fish). The concentration factors (CFs) for the aquatic organisms ranged from 10(3) to 10(4), indicating a high affinity of 210Po for organic moieties. The bivalve mollusc, Lamellidens marginalis, accumulated higher concentrations of 210Po, suggesting that it could serve as a biomonitor of 210Po radionuclide in riverine systems. Further, the levels of 210Po in water, sediment and biological samples from impoundments were higher than those from stations located in the open river. This may be largely due to aerial inputs of the radionuclide, accumulation of radionucliderich silt and organic matter, and increased biological production in the impounded water body.

Studies on some umbelliferous herbs.

Experimental evidences are offered in this article for the popular medicinal use of some umbelliferous herbs.

Studies on some recommended ayurvedic herbs for contact dermatitis.

A number of plant drugs are used in topical application meant for medical and cosmetic purposes. Many of such recommended drugs have been reported to cause contact dermatitis which fact is well supported by clinical studies. To find out the role of these plant drugs in the etiology of contact dermatitis, clinical studies of 34 such herbal drugs were carried out.

Folkloric uses of memecyclon malabaricum (C.B.cl.) cogn.

By personal observation and on consultation with large numbers of local folks with some interest and experiences, local popular healers, ayurvedic physicians the folkloric uses of a popular medicinal plant Memcyclon Malabaricum are discussed here.

Histology of the bark and leaf of a toxic plant holigarna ferruginea march.

The histological features of both the bark and leaf of a poisonous plant H.ferruginea March responsible for contact dermatitis has been reported.

Allergenic agent in contact dermatitis from Holigarna ferruginea.

9 of 10 patients who developed dermatitis following contact with Holigarna ferruginea and 5 of 35 asymptomatic volunteers showed a positive patch test reaction to 2% W/V acetone extract of the plant's resinous exudate. 6 albino rats were sensitized following 3 weekly applications of the same extract. Laccol (3-heptadecadienyl catechol) was identified as the active principle in the exudate.