Trend Analysis of Lead Content in Roadside Plant and Soil Samples in Turkey

Objectives: Lead (Pb) is one of the most common heavy metals which contaminate the environment. People may be exposed to Pb by inhaling the contaminated air droplets and dust particles through drinking water or eating contaminated foods such as vegetables grown in lead-contaminated soils. This study aimed to examine the changes in Pb levels measured in roadside plant and soil samples that have been exposed to heavy traffic for years. Materials and Methods: Sixty-three articles were searched using keywords from different databases. Twenty-five of the scanned articles were found to be relevant for the determined criteria. The Pb levels were evaluated according to the previously measured Pb levels in plant and soil samples collected from the roadside by years. Results: In the data collected from databases over the years, it was observed that there was a decrease in Pb accumulation in both soil and plant samples. Pb levels were higher in industrial cities and metropolitan areas than in rural areas. Conclusion: In ealier studies, Pb levels have often been found to exceed safety limits. This may be due to the Pb added to gasoline in the past, as well as the low sensitivity of analytical methods used for measurement. The decrease over the years has been interpreted as the use of unleaded gasoline after 2004, taking essential measures to improve air quality and at the same time increasing the sensitivity of analytical methods.