Effect of cigarette butt on concentration of heavy metals in landfill leachate: health and ecological risk assessment.

Cigarette butt is known as hazardous waste with numerous toxic and carcinogenic pollutants which impose serious concern for both the environment and human. Heavy metals are recognized as the most common pollutant in the cigarette butts. The concentration of some heavy metals (cadmium, chromium, nickel, lead and zinc) in leachate obtained from the pilot landfill with commingled waste and freshly smoked cigarettes butts were analyzed. The results showed that the addition of 0.76% (in weight) freshly smoked cigarette butts in landfilled waste increased total heavy metal concentration by 4.8%, while addition of 1.3% (in weight) freshly smoked cigarette butts leads to increased 3.72% of total heavy metals concentrations. An increased 10.52% and 3.43% health risk values were found from the leachate of the landfill pilot, where 1% freshly smoked cigarette butt and a littered cigarette were added, respectively. Overall, it can be concluded that cigarette butt landfilling is not recommended for management of this type of waste and is necessary to be replaced with less hazardous ways such as recycling.

Insecticidal activity of the essential oil of Perovskia artemisioides Boiss.

This work reports the phytochemical profile and insecticidal properties of Perovskia artemisioides Boiss essential oil (PAEO) collected in Baluchestan, Iran. Totally, twenty-six substances were identified with 1,8-cineole (25.81%), geranyl acetate (13.00%) and linalool (10.21%) as dominant chemical metabolites by GC-MS analysis. PAEO possessed fumigant toxicity against various growth stages of Phthorimaea operculella. P. operculella adults showed considerable sensitivity (LC50 = 0.58 µL/L air) in comparison to eggs (LC50 = 5.87 µL/L air) and neonate larvae (LC50 = 1.23 µL/L air). Finally, molecular docking of major components of PAEO was performed against detoxification enzymes, including cytochrome P450 and glutathione S-transferase activities. Humulene, ß-caryophyllene, and α-cadinol exhibited the most interactions with the P450 and GST. It can be concluded that PAEO has the potential for development into natural insecticides for the control of storage pests.

Preparation, characterization and Cr(VI) adsorption evaluation of NaOH-activated carbon produced from Date Press Cake; an agro-industrial waste.

Date Press Cake (DPC) is an inevitable by-product of date processing industries and may pose environmental problems if not managed properly. In this study, DPC was converted into activated carbon using solid NaOH under various activation conditions. The prepared activated carbon showed high specific surface area (2025.9 m2 g-1) and microporous texture (86.01%). It was successfully applied for the adsorption of Cr(VI) from aqueous solutions with maximum monolayer adsorption capacities as high as 282.8 mg g-1 (pH = 2) and 198.0 mg g-1 (pH = 5). The kinetic and isotherm experimental data of Cr(VI) adsorption onto the activated carbon were best described by Elovich and Redlich-Peterson models, respectively. It was found that the Cr(VI) adsorption onto the DPC-derived activated carbon was predominantly a chemisorption process with limited desorption rates (below 50%). Overall, Date Press Cake could be considered as an abundant and renewable agro-industrial precursor for the production of high quality activated carbon.

Biomagnetic monitoring of heavy metals contamination in deposited atmospheric dust, a case study from Isfahan, Iran.

Tree leaves are considered as one of the best biogenic dust collectors due to their ability to trap and retain particulate matter on their surfaces. In this study, the magnetic susceptibility (MS) and the concentration of selected heavy metals of plane tree (Platanus orientalis L.) leaves and deposited atmospheric dust, sampled by an indirect and a direct method, respectively, were determined to investigate the relationships between leaf magnetic parameters and the concentration of heavy metals in deposited atmospheric dust. The objective was to develop a biomagnetic method as an alternative to the common ones used for determining atmospheric heavy metal contaminations. Plane tree leaves were monthly sampled on the 19th of May to November, 2012 (T1-T7), for seven months from 21 different sites in the city of Isfahan, central Iran. Deposited atmospheric dust samples were also collected using flat glass surfaces from the same sites on the same dates, except for T1. MS (χlf, χhf) values in washed (WL) and unwashed leaves (UL) as well as Cu, Fe, Mn, Ni, Pb, and Zn concentrations in UL and deposited atmospheric dust samples were determined. The results showed that the MS content with a biogenic source was low with almost no significant change during the sampling period, while an increasing trend was observed in the MS content of UL samples due to the deposition of heavy metals and magnetic particles on leaf surfaces throughout the plant growth. The latter type of MS content could be reduced through washing off by rain. Most heavy metals examined, as well as the Tomlinson pollution load index (PLI) in UL, showed statistically significant correlations with MS values. The correlation between heavy metals content in atmospheric dust deposited on glass surfaces and leaf MS values was significant for Cu, Fe, Pb, and Zn. Moreover, the similarity observed between the spatial distribution maps of leaf MS and deposited atmospheric dust PLI provided convincing evidence regarding the suitability of the biomagnetic approach as a relatively rapid and inexpensive method for identifying highly polluted urban areas with selected heavy metals, especially those subjected to anthropogenic and other traffic related sources.