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Title: Levels of lead in urban soils from selected cities in central region of the Philippines

Author
item ONA, LOUELLA - TARLIC, PHILIPPINES
item ALBERTO, ANNIE MELINDA - NUEVA ECIJA, PHILIPPINES
item PRUDENTE, JACQUELINE - LOUSIANA STATE UNIVERSITY
item Sigua, Gilbert

Submitted to: Environmental Science and Pollution Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2006
Publication Date: 6/1/2006
Citation: Ona, L.F., Alberto, A.P., Prudente, J.A., Sigua, G.C. 2006. Levels of lead in urban soils from selected cities in central region of the Philippines. Environmental Science and Pollution Research. 13(3):177-183.

Interpretive Summary: Anthropogenic activities in urban areas concentrate potential toxic materials, such as Pb, that may be inadvertently or deliberately released into the environment. Human exposure to these toxins may inevitably result in adverse effects on health that may be either acute or chronic. Thus, it becomes imperative that concentrations of Pb and other hazardous materials in the environment be adequately examined in order that development of regulations and standards to minimize risk associated with these materials in urban areas is continued. This study was limited to the determination of Pb levels in soils of selected urbanized cities located in central region in the Philippines, namely: Site 1 - Tarlac City in Tarlac; Site 2 - Cabanatuan City in Nueva Ecija; Site 3 - Malolos City in Bulacan; Site 4 - San Fernando City in Pampanga; Site 5 - Balanga City in Bataan; and Site 6 - Olongapo City in Zambales. Soil samples were collected from areas along major thoroughfares regularly traversed by tricycles, passenger jeepneys, cars, vans, trucks, buses, and other motor vehicles. Samples from the selected sampling sites were obtained approximately 2 to 3 meters from the road. This study was conducted from 2003 to 2004. Only one (San Juan in Site 4) of the thirty sampling sites recorded a Pb concentration beyond the World Health Organization permissible limit of 100 mg kg-1. San Juan in Site 4 had a Pb concentration of >250 mg kg-1. On the average, elevated Pb concentration was evident in the soil samples from San Fernando, Olongapo, Malolos, Balanga, and Cabanatuan. The average soil Pb concentrations in these cities exceeded the maximum estimated natural soil Pb concentration of 25 mg kg-1. Average soil Pb concentration in Site 1 (16.8 mg kg-1) was well within the estimated natural concentration range of 5 to 25 mg kg-1. Data gathered from the study areas showed that elevated levels of Pb in soil were due primarily to vehicular emissions and partly to igneous activity.

Technical Abstract: Lead (Pb) is a naturally occurring element that poses environmental hazards when present at elevated concentration. It is being released into the environment because of industrial uses and from the combustion of fossil fuels. Hence, Pb is ubiquitous throughout global ecosystems. The existence of potentially harmful concentrations of Pb in the environment must be given full attention. Emissions from vehicles are major source of environmental contamination by Pb. Thus, it becomes imperative that concentrations of Pb and other hazardous materials in the environment not only in the Philippines, but also in elsewhere in the world be adequately examined in order that development of regulations and standards to minimize risk associated with these materials in urban areas is continued. The objectives of this study were: (1) to determine the levels of Pb in soil from selected urbanized cities in central region of the Philippines; (2) to identify areas with soil Pb concentration values that exceed estimated natural concentrations and allowable limits; and (3) to determine the possible sources that contribute to elevated soil Pb concentration (if any) in the study area. This study was limited to the determination of Pb levels in soils of selected urbanized cities located in central region in the Philippines, namely: Site 1 - Tarlac City in Tarlac; Site 2 - Cabanatuan City in Nueva Ecija; Site 3 - Malolos City in Bulacan; Site 4 - San Fernando City in Pampanga; Site 5 - Balanga City in Bataan; and Site 6 - Olongapo City in Zambales. Soil samples were collected from areas along major thoroughfares regularly traversed by tricycles, passenger jeepneys, cars, vans, trucks, buses, and other motor vehicles. Analysis of soil samples for Pb content showed the presence of Pb in all the soil samples collected from the thirty sampling sites in the six cities at varying concentrations ranging from 4.3 mg kg-1 to >250 mg kg-1. Only one (San Juan in Site 4) of the thirty sampling sites recorded a Pb concentration beyond the WHO permissible limit of 100 mg kg-1. Average soil Pb concentration in Site 1 (16.8 mg kg-1) was well within the estimated natural concentration range of 5 to 25 mg kg-1. Data gathered from the study areas showed that elevated levels of Pb in soil were due primarily to vehicular emissions and partly to igneous activity.