Current Status of Some Heavy Metals in Intensively Cultivated Lands of Andalusian East Coast

Intensively cultivated lands of the Andalusian east coast (South of Spain) were sampled in 3 areas, with 3 plots and a non-cultivated control plot per area, and at two depths, 0–25 cm and 25–50 cm. In each plot and depth, 3 samples were taken, made up of 5 subsamples. The analysis of elements such as arsenium (As), cadmium (Cd), copper (Cu), mercury (Hg), and lead (Pb) were made by two different digestion methods: 2 hours with acqua regia in an oil bath at 140°C, or 10 minutes with nitric acid in closed recipients inside a microwave oven. Results show differences for most of the elements between areas and between methods, and sometimes between depths. Average values per plot were always below the critical levels accepted for agricultural use. A detailed exam of values for each plot suggests reliability on the determination of As and Cu, in each case. There were few occasional anomalies in the determination of Cd, Hg, and Pb. This could be related either to irregular distributions of the elements in the soil, or to sampling and analytical errors.