SHORT COMMUNICATION: Total and leachable phosphorous in urban street tree leaves

Abstract (Received January 13, 2000; revised May 8, 2000) Leaves of different tree species were leached with distilled water (pH 7.0 ± 0.2) and rain water (pH 5.7 ± 0.3) in laboratory glass cylinders to simulate the release of phosphorous (P) pollutant to urban runoff. An average of 106 ± 52.1 μg g-1 and 143 ± 72.7 μg g-1 (air dried weight) of P were leachable from entire leaves in 2 1/2 hours in distilled water and rain water, respectively; these represented 7.21% and 11.36%, respectively, of the total P in the leaves analyzed. The amount of leachable and total leaf P varied significantly (p < 0.05) among tree species but were not significantly (p < 0.05) affected by tree diameters. Fragmented leaves released more than twice as much phosphorous as intact leaves. These findings point to leaves as a source of urban runoff P. Bull. Chem. Soc. Ethiop. 2000, 14(1), 91-95Bulletin of the Chemical Society of Ethiopia. ISSN: 1011-392

Short communication: Total and leachable phosphorous in urban street tree leaves

Leaves of different tree species were leached with distilled water (pH 7.0 plus or minus 0.2) and rain water (pH 5.7 plus or minus 0.3) in laboratory glass cylinders to simulate the release of phosphorous (P) pollutant to urban runoff. An average of 106 plus or minus 52.1 g g-1 and 143 plus or minus 72.7 g g-1 (air dried weight) of P were leachable from entire leaves in 2_ hours in distilled water and rain water, respectively; these represented 7.21% and 11.36%, respectively, of the total P in the leaves analyzed. The amount of leachable and total leaf P varied significantly (p < 0.05) among tree species but were not significantly (p < 0.05) affected by tree diameters. Fragmented leaves released more than twice as much phosphorous as intact leaves. These findings point to leaves as a source of urban runoff P

Disinfection in Waste Water Treatment

© 2012 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. Despite the treatment processes that a typical wastewater is subjected to, microorganisms present in the wastewater are not effectively removed. These pathogenic organisms play important roles in the spread of waterborne diseases.Important treatment process employed to destroy or inactivate these pathogenic microorganisms is called disinfection. Disinfection is an important application under chemical treatment process ofwastewater, which includes the use of chemical agents, such as compounds of chlorine, and/or nonchemical agents, such as heat, UV light, radiation, and mechanical means

A new method for assessment of sediment-associated contamination risks using multivariate statistical approach

This paper presents the assimilation of heavy metal concentration data from sequential extraction method (SEM) with metal toxicity factors to develop and propose two new sediment quality indices modified hazard quotient (mHQ) and ecological contamination index (ECI), to predict the potential ecological risks associated with sediment contamination. Chemical speciation data of five heavy metals: cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), and lead (Pb) from five coastal aquatic ecosystems of the Equatorial Atlantic Ocean were used in the assessment of the degree of heavy metal contamination. Evaluation based on ECI indicated that sediments of most aquatic ecosystems were considerably to highly contaminated. The results showed that the proposed indices are reliable, precise, and in good agreement with similar existing indices used for evaluating the severity of sediment-associated contamination by heavy metals. The principal component analysis (PCA) and factor analysis indicated that heavy metals in the benthic sediments were mostly from anthropogenic sources. • New indices – modified hazard quotient (mHQ) and ecological contamination index (ECI) - were developed for predicting sediment-associated risk adverse effects. • Newly proposed indices agree closely with the existing pollution indices. • Pollution indices reveal significant anthropogenic contamination by Cd and Pb. Method name: New ecological risk indices, Keywords: Fractionation, Heavy metals, Sediment pollution, Contamination indices, Principal component analysi