Determination of Lead and Cadmium Concentrations in Lettuce and Spinach Using Atomic Absorption Spectroscopy

Abstract

The levels of lead (Pb) and cadmium (Cd) were determined in vegetables such as Allium`s leaf vegetables that are commonly consumed by human beings, using Atomic Absorption Spectroscopy (AAS) at the Central Laboratory of the University of Baghdad. Because they have high consumption rates and can build up high amounts of heavy metals, lettuce (Lactuca sativa) and spinach (Spinacia oleracea) were selected. Due to variations in soil characteristics and the proximity to possible pollution sources (including traffic, industrial activities and agricultural activities), samples were collected from various parts of Al-Shatrah city. Three consecutive months (three experimental stages) of sampling of leaves, stems and roots was conducted for both plants. The data showed significant differences in the levels of both the elements among the different sampling locations and among the various sections where the plants were sampled.

All the lead readings were above the national average and the highest reading was at City 1 (15 ppm), City 2 (13.4 ppm) and City 3 (12 ppm). Cadmium also was identified in some samples with the highest concentration (0.40 ppm and 0.27 ppm) in City 1 samples. Species dependent variability in the efficiency of heavy metal uptake was noticed, as cadmium content was higher in spinach as compared to lettuce. Various other factors affect the reported level of pollution, including soil properties, temperature, wind characteristics, etc., and anthropogenic factors (chemical fertilizer use, fuel burning and industrial emissions).

The findings highlight the importance of continued environmental surveillance and sustainable agricultural practices to reduce the levels of heavy metals, and to ensure food security and safety, as well as the potential human health risks associated with consumption of contaminated leafy vegetables.