Occurrence of aflatoxins in export-quality Pakistani rice.

A survey was conducted to assess the extent of aflatoxin B1, B2, G1 and G2 contamination of export-quality rice. Five hundred and nineteen batches of rice (including white, brown and sella rice) from various exporters were analysed for aflatoxins using Mycosep column clean-up and quantification with high-performance liquid chromatography, during the year 2010. Mean concentrations for aflatoxin B1 (AFB1) and aflatoxin B2 (AFB2) were 0.56 µg kg(-1) and 0.03 µg kg(-1) for brown rice, 0.49 µg kg(-1) and 0.03 µg kg(-1) for white rice and 0.73 µg kg(-1) and 0.02 µg kg(-1) for sella rice, with an overall positive (≥ the limit of detection of 0.1 µg kg(-1) for AFB1 and AFG1; and 0.05 µg kg(-1) for AFB2 and AFG2) incidence of 49%. Out of all analysed samples, only 1.9% was found positive for aflatoxin G1. Highly contaminated samples were found in the month of August, with findings for aflatoxin B1 (AFB1) and aflatoxin B2 (AFB2) of 16.65 µg kg(-1) and 2.64 µg kg(-1), respectively. During the whole year, monitoring aflatoxin concentrations exhibited a distinct variation according to the climatic conditions, with relatively high levels during March, July and August, which could be related to favourable environmental conditions.

Potato peels as solid waste for the removal of heavy metal copper(II) from waste water/industrial effluent.

A new sorbent potato peels, which are normally discarded as solid waste for removing toxic metal ion Cu(II) from water/industrial waste water have been studied. Potato peels charcoal (PPC) was investigated as an adsorbent of Cu(II) from aqueous solutions. Kinetic and isotherm studies were carried out by studying the effects of various parameters such as temperature, pH and solid liquid ratios. The optimum pH value for Cu(II) adsorption onto potato peels charcoal (PPC) was found to be 6.0. The thermodynamic parameters such as standard Gibb's free energy (Delta G degrees ), standard enthalpy (Delta H degrees ) and standard entropy (DeltaS degrees ) were evaluated by applying the Van't Hoff equation. The thermodynamics of Cu(II) adsorption onto PPC indicates its spontaneous and exothermic nature. The equilibrium data at different temperatures were analyzed by Langmuir and Freundlich isotherms.