An environmental epidemiological study based on the stream sediment geochemistry of the Salerno province (Campania region, Southern Italy).
The comparison of environmental and epidemiological data of the Salerno provincial territory highlighted the existence of spatial correlations between geochemical anomalies and the higher SIRs of some cancer types.
The most contaminated areas of the province resulted to be the north-western sector of the territory (Agro Nocerino-Sarnese), belonging to the physiographic unit of the Sarno River plain, and some municipalities in the western sector of the Cilento and across the Vallo di Diano. Conversely, the internal and hilly sector of the Cilento and the Mt Alburno and Picentini Mts. areas are generally characterized by the lowest concentration of all the considered toxic elements well in range with the regional geochemical backgrounds as demonstrated also by the distribution map of the CDs. As a matter of the fact, this latter individuated the municipalities of Castel San Giorgio, Nocera Inferiore, Nocera Superiore, Mercato San Severino, Pagani, Roccapiemonte, San Valentino Torio, Scafati in the Sarno River Plain and the municipalities of Orria and Salento in the Cilento as characterized by a contamination degree ranging from moderate to high against the rest of the province generally low contaminated.
The observation of epidemiological data under a geochemical/environmental perspective highlighted how in correspondence with the areas markedly contaminated by heavy metals, there is a good spatial correlation between the incidence of some cancer types and the distribution patterns of contaminants. Specifically, in the Sarno River plain, where heavy metals and, specially, Cr are strongly concentrated in sediments, cancer of lungs, liver and prostate always show values of SIRs generally higher than the most of the remaining provincial territory. In addition, the distribution of lung cancer shows a noticeable spatial correlation also with the distribution of natural radioactivity across the study area suggesting the possibility of a dependence of the incidence of this cancer on the release of Rn into the environment from the volcanoclastic sediments widely spread across the Sarno River plain and its surroundings.
Furthermore, the present study also demonstrated that, when the evidence of a spatial correlation between elemental distribution and pathologies become weaker, a comprehensive analysis including information about geology, pedology, existing potential contamination sources (road network, potentially contaminated sites, soil use) and other territorial and cultural features (life style, eating habits, etc.) can support the interpretation process highlighting unconsidered factors enhancing or reducing the cancer risk (e.g.: the sun exposure for the skin melanoma in the coastal areas and the low fat food for breast cancer in the internal sectors of the Cilento area).
In conclusion, in general accordance with Albanese et al. (2008), we reinforced the belief that a crossover approach in environmental epidemiology, even if a causal relationship between epidemiological and environmental variables cannot be proved, can lead to the creation of a knowledge base relevant to local authorities for the planning of environmental restoration measures to preserve ecosystems and, as a consequence, the public health.