In the Sarno River plain and along the Cavaiola tributary are many
food producers, chiefly involved in tomato processing and canning.
The Solofrana River valley, with an area of approximately 3000 ha, constitutes
the upper portion of the Sarno plain and its environmental conditions
are largely affected by the presence of about 160 tanning plants
discharging theirwastewaters directly into the flowingwater especially
in the past (Albanese et al., 2013). A prospecting survey was carried out
in 2010 along the main course of both the River Sarno and Solofrana in
order to collect samples of soil, irrigated or potentially flooded by
stream waters, together with edible vegetables grown in situ. In the
presentwork, 36 sampling points (Fig. 1 and Table S1 in supplementary
materials) were selected along the Sarno river (15 sites) and its
tributary the Solofrana (21sites). At each location samples of topsoil
(at an average depth of 0–20 cm from the surface) and bottom soil (at
an average depth of 30–40 cm from the surface) were collected at a
distance ranging between 70 and 550 m from the riverbeds in areas
potentially affected by flooding.Within each sampling site, 10 soil subsamples
were collected at regular points in a cross pattern in order to
obtain a composite soil sample. This guaranteed adequate representation
of each soil. Topsoil samples were collected from the 0–20 cm soil
layer since most of the roots of vegetable crops develop in this soil
layer and PTEs from anthropogenic sources generally accumulate in
this surface soil layer. Simultaneously, from the same soil sampling
sites, five edible parts (shoots) of lettuce plants (Lactuca sativa) at the
normal stage of consumption were harvested and mixed to obtain a
composite plant sample.