Determination of Lead levels in lettuces harvested in different urban environments

Description

Due to the increasing awareness of the link between diet and health, the demand for healthy foods such as leafy vegetables have increased over the recent decades. Among them, lettuce (Lactuca sativa L.) has been broadly produced and consumed worldwide. Besides this, being Portugal a Mediterranean country, lettuce is included in its diet, providing fiber, vitamins and antioxidants which are vital for human health. However, leafy vegetables contamination by lead (Pb) through the environment is increasing, especially among vegetables grown in urban areas that are normally exposed to higher levels of Pb pollution, particularly by industrial and motor vehicle emissions. This metal can be transported into plant surface and also into the soil. Once in the soil, it can be translocated into the plant’s tissues. Concerning lettuce, because of its efficient uptake of metals by the roots, accumulates metals at high internal levels. Due to this, lettuce is one of the biological species recommended by the OECD (Organisation for Economic Cooperation and Development) for ecotoxicological assessments. With the rapid growth in the number of urban gardens that has occurred in recent years, it is urgent to control the quality of the harvested products. Specially because plants growing in contaminated soils may be vehicles of this metal, by transferring Pb into the human body, which can cause anemia, increase in blood pressure, nephrotoxicity, reduced fertility, nervous system damage and multiple other problems.