Zahra Abedi

Bioavailability and Concentration of Heavy Metals in the Sediments and Leaves of Grey Mangrove, Avicennia marina (Forsk.) Vierh, in Sirik Azini Creek, Iran

The concentration and bioavailability of Ni, Cu, Cd, Zn, and Pb in the sediments and leaves of grey mangrove, Avicennia marina, were studied throughout Sirik Azini creek (Iran) with a view to determine heavy metals bioavailability, and two methods were used. Results show that Zn and Ni had the highest concentrations in the sediments, while Cd and Cu were found to have the lowest concentrations in the sediments. Compared to the mean concentrations of heavy metals in sedimentary rock (shales), Zn and Cu showed lower concentration, possibly indicating that the origin of these heavy metals is natural. A geo-accumulation index (Igeo) was used to determine the degree of contamination in the sediments. Igeo values for Zn, Cu, Pb, and Ni showed that there is no pollution from these metals in the study area. As heavy metal concentrations in leaves were higher than the bioavailable fraction of metals in sediments, it follows that bioconcentration factors (leaf/bioavailable sediment) for some metals were higher than 1.

Air Quality Risk Index (AQRI) and its application for a megacity

Abstract Urban air quality is a major concern throughout the world. The concentration of human activities in a relatively small area puts enormous pressure on urban systems and has led to numerous environmental problems which have created major problems for urban air quality management. The complex nature of air pollution, especially with respect to health impacts in urban areas, has prompted attempts to define the so-called indicators that condense and simplify the available monitoring data to make them suitable for public reporting and decision makers. Several concepts and indicators exist to measure and rank urban areas in terms of their infrastructural, socioeconomic and environment-related parameters. In past four decades different indices have been introduced, such as Pollutant Standards Index, Air Quality Index (AQI), Air Quality Health Index and Aggregate Risk Index, but none of them have considered importance of the integrated health, environment and safety factors relevant to the extended risk factors involved, such as diverse economic losses and negative socioeconomic aspects. Therefore an integrated AQI, so-called, Air Quality Risk Index which considers environmental conditions, and economic losses involved were applied for the city of Tehran as a megacity. The results indicated that this index can be applied to define the actual condition(s) of urban air quality and to achieve sustainability and resiliency.