Lead levels in Chromolaena odorata (Compositae) along rural and urban roads in Akwa Ibom State, Nigeria

ＩｎｔｒｏｄｕｃｔｉｏｎＣｈｒｏｍｏｌａｅｎａｏｄｏｒａｔａ（Ｅｕｐａｔｏｒｉｕｍｏｄｏｒａｔｕｍ），ｃｏｍｍｏｎｌｙｃａｌｌｅｄ“ｓｉａｍｗｅｅｄ”ｗａｓｉｎｔｒｏｄｕｃｅｄｉｎｔｏＮｉｇｅｒｉａａｂｏｕｔ３０ｙｅａｒｓａｇｏ．Ｉｔｉｓａｓｔｒｏｎｇｌｙｓｃｅｎｔｅｄ，ｄｉｆｆｕｓｅ，ａｎｄｒａｐｉｄｌｙｇｒｏｗｉｎｇｈｅｒｂｔｈａｔｃａｎａｔｔａｉｎａｈｅｉｇｈｔｏｆ３－０ｍｅｔｅｒｓｏｒｍｏｒｅ．Ｉｔｉｓｌｏｃａｌｌｙｃａｌｌｅｄ“ｏｗｏｔｏｗｏ”ｂｅｃａｕｓｅａｔｉｔｓｄｅｂｕｔｉｔｗａ…

Lead levels in Chromolaena odorata(compositae) along rural and urban roads in Akwa Ibom State,Nigeria

Concentrations of lead(Pb) were determined in leaf samples of \%Chromolaena adorata\% from a rural road and an urban road in Akwa Ibom State of Nigeria in relation to vehicular traffic density. Mixed results were obtained wich no trend to indict automobile exhaust fumes. Lead was not detected in rain water from these areas and leaf lead levels seemed to relate more to soil lead concentrations. There was no significant difference in mean leaf lead levels between rural and urban leaf samples and between washed and unwashed leaf samples. It was suggested that the lack of concordance between vehicular traffic density and lead levels in leaves along the highways indicates either a low level use of tetraethyl leaded petrol or, a relatively low vehicular traffic density with lead from exhaust fumes not reaching a threshold to affect levels in plants or be detected in the atmosphere. Implications of concentrations obtained in leaves to consumers when compared with international standards were discussed.