Air pollution in the semitropical Saudi urban area

This paper presents the outcome of research conducted in the city of Jeddah, Saudi Arabia. Analysis of recorded meteorological elements shows that the atmosphere of the area favors the accumulation of air pollutants. Dustfall rates were measured at 22 stations in different districts. High rates of dustfall were found in all districts, with maximum recorded values in central urban and industrial districts. Collected samples were analyzed to determine the causes of these excessive precipitations. Suspended particulate matter and other pollutants were found to exceed air quality standards set to meet environmental requirements. Carbon monoxide was found to exceed the air quality standard of 9 μL/L. Concentrations of photochemical oxidants indicated the possibility of Los Angeles-type photochemical smog formation. Geographic distribution of pollutant concentrations and chemical constituents of particulates were found to be influenced by both manmade and natural causes. Results are discussed and several conclusions are given.     

Biosensors for pathogen surveillance

Biologists, chemists, and physicists are collaborating to develop highly sensitive and specific biosensors for pathogen detection in the food, healthcare, and environmental sectors. Those novel biosensors allow quick detection and are thus expected to solve the issues of the emergence of highly virulent or antibiotic-resistant pathogens. This article reviews different types of biosensors used for pathogen detection, classified based on the type of transducer used. Optical biosensors integrate labeled means, e.g., fluorophores, quantum dots, and carbon dots to overcome photobleaching. Surface plasmon resonance is also used for enhanced sensitivity. Mechanical biosensors with piezoelectric crystals and cantilevers are adapted for the detection of food pathogens without sample preparation or labels. Conventional methods using electrodes for the measurement of electrochemical changes with differential pulse voltammetry or impedance spectroscopy are fast and highly sensitive. Immunosensors are developed for pathogen detection at trace levels using sample enrichment, signal amplification, and new visual detection techniques.     

Studies on indoor air quality in Egypt

Indoor air quality was examined for some gaseous pollutants and particulate matters. In a public library, the indoor/outdoor ratio of gaseous pollutants were found to be dependent on their reactivity, also on the outdoor concentrations and weather conditions. This ratio was 0.6 for SO₂,and 1.3 for CO. The indoor/outdoor ratio of carbon monoxide was found to increase at the higher floors of the same building. Concentrations of indoor particulates was found to be influenced by the outdoor concentrations and the particle size. Analysis indicated that indoor suspended dust contained a significant high concentration of lead as compared with outdoor values. Indoor sources were found to pollute the premises of fossil-fuel equipped homes, thus having carbon monoxide concentrations more than the recognized threshold limit value for industry.     

我国环境监测体制改革探讨

本文分析了目前我国环境监测工作中普遍存在的体制不顺、职责不明、行政干预、重复监测、资源浪费、信息混乱等问题,提出监测机构垂直管理,调整监测职能,打破条块分割,整合社会监测资源,引入第三方检测的具体构想。     

Occurrence of pesticides and polychlorinated biphenyls in water of the Nile river at the estuaries of Rosetta and Damiatta branches,north of delta,Egypt

Abstract

A study was conducted from summer 1995 to summer 1997 to assess the seasonal occurrence of pesticide residues and other organic contaminants, polychlorinated biphenyls (PCBs), in water at the estuaries of Rosetta and Damiatta branches of the Nile river. The results indicated that organochlorine compounds (OCs) including HCB, lindane, p,p‘‐DDE, p,p‘DDD, p,p‘‐DDT, aroclor 1254 and aroclor 1260 were present in all the water samples at concentration levels ranging between 0.195–0.240, 0.286–0.352, 0.035–0.067, 0.019–0.033, 0.024–0.031, 0.390–0.70 and 0.166–0.330 μg/l, respectively. The levels of these compounds were higher in water of Damiatta branch than those found in water of Rosetta branch. Aldrin, dieldrin and endrin were not detected in all water samples. Only 4 compounds from 36 organophosphorus insecticides, fungicides and s‐triazine herbicides tested were detected in water samples collected during summer and autumn seasons from Rosetta branch. The concentration levels of these detected compounds, dimethoate, malathion, captan, and ametryne, ranged from 0.011 to 0.340 μg/l, respectively. Similar compounds during the same seasons as found in water of Rosetta branch were also detected in water of Damiatta branch except ametryne. The levels of the detected compounds (dimethoate, malathion and captan) ranged between 0.030 and 0.330 μg/l. The levels of detected organophosphorus insecticides, fungicides and s‐triazine herbicides were in the order: dimethoate > malathion > captan > ametryne.     

Evaluation and assessment of environmental protection alternatives for the Jeddah cement company plant

An environmental impact assessment is conducted by utilizing monitoring, meteorological, and physical modeling data. This information serves as input to a decision analysis of the environmental protection alternatives for the cement plant in Jeddah, Saudi Arabia. Utility theory provides the methodology underlying the Evaluation and Sensivity Analysis Program (ESAP) with which the alternatives are evaluated. Recommendation include: (1) installation of electrostatic precipitators of at least 99% efficiency, (2) institution of a 1.6 km nonresidential zone given the present 60 m chimneys, and (3) substitution of low sulphur fuel for the crude oil now consumed. By illustration this study suggests the general relevance of the ESAP program to environmental assessment and management.     

Nitrogen oxides and photochemical oxidants in Cairo City atmosphere

Concentrations of nitrogen oxides were measured continuously for a period of 12 months in the city of Cairo. Photochemical oxidants were examined and their appearance was found to be highly dependent on the NO_x diurnal cycle and wind speed. Nitrogen oxides were found to exceed 10 times the USA air quality standard. Oxidants concentrations were found to exceed 0.1 ppm, average over 1 h, on 74% of the measured days.     

Lead accumulation in edible portions of crops grown near Egyptian traffic roads

Accumulation of lead in different parts of vegetables growing around six Egyptian traffic roads was investigated. Results of this work showed that leafy vegetables such as lettuce and cabbages accumulated lead up to 78.4 p.p.m. in their edible portions while the least lead accumulators were carrots and radish. The highest concentration of lead found in carrots sampled from locations adjacent to the busiest traffic road was 10.2 p.p.m. with an average concentration of 3.8 p.p.m. Lead concentrations in fruits of pepper and tomato were in the range of 0.7–18.6 p.p.m. depending on several factors such as traffic densities and distances from the road. The average ratio between lead in soil to lead in fruit of tomatoes at the first 10 m from roads was about 15 compared with a ratio of 50 at distances more than 100 m. These findings suggest that lead was accumulated in plants through both foliage and root systems, but lead absorption through foliage is more pronounced at locations close to the emission source of lead vapour and fine particles. The concentration of lead in fruit was dependent on its concentration in the leaf rather than in the roots or soil.