|Studies on Lead Pollution in Some Part of Sylhet Town (2000)|
|MA Salam Biswas, M. Ahmed, et al.; p. 29-36, Bangladesh Environment 2000, A compilation of Papers of the International Conference on Bangladesh Environment –2000 (ICBEN-2000), BAPA.|
The exhaust gases and particulate releasing from industries and vehicles may pollute the air. In our previous projects we studied some gaseous pollutants of air. This project has been created to bring the facts of Sylhet's environment into light by measuring the extent of air pollution of this area with respect to lead. The major uses of lead are in electrical batteries, cable sheaths, radiation shields, paints and gasoline as tetraethyl lead additive (anti-knocking agent). The presence of lead in vehicle exhausts originating from the tetraethyl lead mixed in gasoline is a well-established phenomenon. The use of tetraethyl lead in gasoline is playing prominent role in lead pollution near roadside environment of this area. The other uses are not very significant. The objective has been attained by taking leaves of roadside plants and air as sample from nine different places particularly vehicle concentrated area of Sylhet town. Lead on the surfaces of leaves was extracted as dithizone complex into ethylene chloride at pH above 9.0. The intensity of the colour of the complex was measured spectrophotometrically at about 510 nm and compared with a calibration curve to calculate the amount of lead. Musking agents were used to eliminate most interference like tin, bismuth and other metals. Using available sample collectors collected air samples and the amount of lead was determined by spectrophotometric method. In absence of previous data, it has not been possible to indicate the trend in the build up of lead concentration on the roadside biomass. However, if no step is taken for introduction of lead free motor fuel and if the present rate in the increase of motor vehicular traffic continues then serious health hazard may occur due to lead pollution in the habitat in the vicinity of the motor highways and busy city roads.