Investigation of heavy metal content in the suspended particulate matter and sediments of inner Gokova Bay and creeks

The Bay of Gokova in Southeastern Aegean Sea (Turkey) is important by the potential of agricultural, municipal, and tourism activities. In addition, there is no industrial plant within the area in the Aegean Sea. Kad?n Creek (Azmak) and Ak?ap?nar Creek (Azmak) flowing into the inner Gokova Bay are one of the important factors in determining the character of the inner Gokova Bay. In this study, nine stations were selected in the inner Gokova Bay, Kad?n Creek, and Akcap?nar Creek. The concentrations of Cd, Cu, Fe, Pb, and Zn were measured in suspended particulate matter (SPM) and sediments. The samples of sediments and SPM were collected in between February 2008 and September 2008. The aim of the study is searching the change of concentrations of Cd, Cu, Fe, Pb, and Zn in suspended particulate matter and sediments in the inner Gokova bay, Kad?n Creek, and Ak?ap?nar Creek. It has been identified that the metal concentrations in the creeks are higher than the metal concentrations in the marine environment. It has also been observed that the concentrations of Pb, Cd, and Cu in summer season have been higher than in the winter season, but the concentrations of Fe and Zn have not shown a significant difference between in summer and winter seasons. The obtained results show that the some heavy metals are caused by the agricultural, municipal, and tourism activities operating in the coastal areas and terrestrial environment, and they are transported from the creeks to the Gokova Bay by suspended particulate matter.     

Assessment of bioavailable fraction of POPS in surface water bodies in Johannesburg City,South Africa,using passive samplers: an initial assessment

In this study, the semipermeable membrane device (SPMD) passive samplers were used to determine freely dissolved concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in selected water bodies situated in and around Johannesburg City, South Africa. The devices were deployed for 14 days at each sampling site in spring and summer of 2011. Time weighted average (TWA) concentrations of the water-borne contaminants were calculated from the amounts of analytes accumulated in the passive samplers. In the area of interest, concentrations of analytes in water ranged from 33.5 to 126.8 ng l^?1 for PAHs, from 20.9 to 120.9 pg l^?1 for PCBs and from 0.2 to 36.9 ng l^?1 for OCPs. Chlorinated pesticides were mainly composed of hexachlorocyclohexanes (HCHs) (0.15–36.9 ng l^?1) and dichlorodiphenyltrichloromethane (DDT) with its metabolites (0.03–0.55 ng l^?1). By applying diagnostic ratios of certain PAHs, identification of possible sources of the contaminants in the various sampling sites was performed. These ratios were generally inclined towards pyrogenic sources of pollution by PAHs in all study sites except in the Centurion River (CR), Centurion Lake (CL) and Airport River (AUP) that indicated petrogenic origins. This study highlights further need to map up the temporal and spatial variations of these POPs using passive samplers.     

Effect of humic substances on the Fenton treatment of wastewater at acidic and neutral pH

This paper describes results of treatability studies of the effect of humic substances (humate, HS, at the concentration 500-5000 mg l-1) on the Fenton (Fe2+/H2O2) treatment of industrial wastewater at pH 3.5 and 7.0. Without humate, the removal of all contaminants was significantly higher at pH 3.5 than at pH 7. At pH 7.0, the removal of all compounds in the presence of HS (3000 mg l-1) was comparable to that at pH 3.5 without HS. At pH 3.5, humate had no effect on the removal of arsenic, thiocyanate and cyanide, but the removal of all organic compounds (phenol, 2,4-dimethylphenol, benzene, toluene, o-xylene, m- & p-xylene and dichloromethane) was significantly inhibited. Mechanisms of the processes are discussed. It is suggested that, in the presence of HS, acidification of the treated wastewater may not only be unnecessary but it can even hinder the degradation of organic pollutants.     

Recycling of waste tire by pyrolysis to recover carbon black: an alternative reinforcing filler

Journal of Material Cycles and Waste Management - Thermal pyrolysis of waste tires is an industrially beneficial method for material and energy recovery. Pyrolytic carbon black (CBp) is considered...