జర్నల్ ఆఫ్ పొల్యూషన్

Particulate matter 2.5 has been identified as an important contributor to the toxicity of air pollutions. Roadways are one of the major sources in an urban area. To protect the public health from the PM2.5 pollutions, an effective monitoring system is required. Various methodology and technologies have been developed and designed to measure the PM2.5 concentrations, which however also exist some limitations that are not easily overcome. This study is intended to propose a method to estimate and monitor the PM2.5 concentrations in a region within a transportation network. A case study was conducted to the Port of Houston region where there are three ambient air quality monitoring stations. The PM2.5 concentration pattern and its associated health risk were characterized to develop lookup tables of PM2.5 concentration factors. Results showed that the majority of the average daily PM2.5 concentrations in the Port of Houston region are lower than 10 μg/m3, indicating the lowest PM-caused health risk. No significant difference in the trends of the PM2.5 emission patterns collected from the three stations was observed. Two lookup tables of generalized PM2.5 concentration factors were developed to estimate the average daily concentration in a specific time of a year in the region, which could be easily applied to a similar region for PM2.5 monitoring.

The aim of this study was to investigate the ability of Calotropis procera L., as a biomonitoring technique for airborne Vanadium (V) and Nickel (Ni) pollution distribution at four different areas in and around Jeddah city, Saudi Arabia. Concentrations of V and Ni varied significantly between sites. The maximum concentrations of V were 68.06, 40.91 and 25.04 mg kg-1 for soil samples, unwashed plant samples (UWS) and washed plant samples (WS), respectively in the industrial area. However, Ni concentrations were 42.73, 39.09 and 22.40 mg kg-1 for the same samples, respectively in the roadside area. The results indicated that V concentrations were at the order of: roadside > industrial area > residential area. This was not the case with Ni as the order industrial > roadside area > residential area. There was a significant correlation between the V and Ni concentrations in soil and plant samples. The study also showed that the concentrations of V and Ni on the unwashed leaves were higher than those on the washed leaves and this magnified the effect of airborne fall dust on the ambient air quality in Jeddah City. Based on the results of this study, it was recommended that the Calotropis procera plant can be used as a biological technique for the airborne heavy metals bio monitoring, especially in the arid land region countries.

Chemical characteristics of aerosols were elucidated through studying concentrations of total suspended particulate matter (TSP) and their elemental composition at industrial, urban and residential sites in Western coast of Saudi Arabia. The average concentration of total particulates were 225, 121 and 98 μg m-3 at industrial, urban and residential sites, respectively. The present study showed that the concentrations of measured heavy metals were in the order of Residential˂Urban˂Industrial. Moreover, EFs of most of elements collected from an industrial site were the highest.Principle component analysis (PCA) indicated that the major source of Al, Ca, Mg, Fe, Mn and K is road dust (vehicular emissions); Cu is vehicular abrasion; Zn and V is residual oil combustion and Ni is metal plating.

The present study was carried out to evaluate the concentrations of some trace metals in the water of Lake Mariut and their accumulation in tissues of the green alga (Cladophora herpestica). Sampling of water and algae were carried out at four different sites throughout the period from July to Sept 2017. The water of the collected samples was mostly alkaline (7.91-8.51) and showed a wide range of variation in Biological Oxygen Demand "BOD" (5.11-18.92 mg L-1), Chemical Oxygen Demand "COD" (21.36 - 81.36 mg L-1) and Electric conductance "EC" (918 -1827 μS Cm-1) Concentrations of heavy metals in algae were higher compared to their levels in water samples. The concentrations of the selected trace metals were ranged between 11.19 μg L-1 for Pb in water samples collected from site 1 to 271.36 mg Kg-1 for Cd in algae collected from site 3. The concentrations of trace metals exceeded the Egyptian Standards limits. The results showed that the water quality is unacceptable and should be improved for human consumption. Moreover, the study indicated that the high concentrations of trace metals in algal tissues demonstrated the utility of using Cladophora herpestica as a biomonitor of heavy metal contamination and bioavailability. The study included some recommendations aiming at improving both water quality and ecosystem of the lake.

We examined bioaccumulation of Cu, Cr and Ni and their effects on oxidative stress parameters in the green alga Ulva lactuca to determine at a Jeddah City, in order to determine their bioindicators potential.Concentrations of the selected elements (Cu, Ni and Cr) in algal tissues were 16, 24 and 11-fold higher than that in water.Algae collected from seawater had 40% lower total chlorophyll content when compared with controlled algae. On the other hand, lipid peroxidation and H2O2 content were increased in algae collected from seawater by 2-fold each when compared with controlled algae. Antioxidant enzymes showed difference in response, while SOD and POX were increased by 51 and 35%, respectively, CAT showed a decrease by 37% when compared with controlled algae. Our data prove that the toxicity levels of environmentally monitored or exposed heavy metals in algae can be simply and accurately estimated by measuring total Chl content, lipid peroxidation product MDA of samples, and non-enzymatic and enzymatic defense systems.