[Environmental micropollutants in livestock products from Susa Valley, Piedmont]. / La contaminazione ambientale da microinquinanti degli allevamenti della Val di Susa.

OBJECTIVE: to describe the contamination due to dioxins and dioxin-like PCBs of cattle dairy and meat products in cattle herds from Susa Valley (Piedmont) since the second half of 2004. DESIGN: descriptive study based on a biomonitoring campaign on bovine bulk milk and muscle. SETTING AND PARTICIPANTS: the official samplings have been carried out between 2004 and 2010: the dataset refers to 99 mass milk samples and 24 muscle samples from 51 cattle herds based in 23 municipalities of the valley. MAIN OUTCOME MEASURES: counts and frequencies of samples exceeding either the maximum levels or the action levels set by the European legislation; moreover relative distributions of congeners (profiles) were considered. RESULTS: DL-PCBs showed median concentration values double when compared with dioxins values and a couple of congeners (2,3,4,7,8-PeCDF, 118 DL-PCB) were particularly abundant. More than 60% of both the milk samples and herds exceeded the action levels with the involvement of 10 municipalities most of which located nearby a local steel smelter. The DL-PCB values in milk were associated with the distance of each herd from the steel plant. However, the temporal trend highlights a clear decrease of the contamination over the 2004-2010 period, when the plant was renewed and the production levels where negatively impacted by the global economical crisis. CONCLUSION: the findings of the monitoring activity allowed the understanding of the origin and the spatio-temporal evolution of the contamination: this knowledge may be helpful in orienting future controls and the risk mitigation strategies.

Data on milk dioxin contamination linked with the location of fodder croplands allow to hypothesize the origin of the pollution source in an Italian valley.

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) have similar toxic, endocrine-disrupting, and carcinogenic activity. They are classified as persistent organic pollutants accumulating in the environment and the tissues of living organisms. High concentrations of PCDD/F and dl-PCB have been detected in bovine milk collected in a Piedmont valley (Northwestern Italy) since 2004. This geographic study describes the local distribution of pollution from PCDD/Fs and dl-PCBs. Since their presence in animal products could be traced back to the ingestion of contaminated fodder, dioxin levels in cow milk were related to the distribution of fodder cropland parcels. Specifically, the aim of the study was to determine, through an exploratory approach, whether the contamination was consistent with one common point source of contamination or different scattered sources. Data for PCDD/F and dl-PCB concentrations in the bulk milk from 27 herds, sampled over a 4-year period (2004-2007), were matched to the georeferenced land parcels the dairy farmers used for growing fodder. Isopleth maps of dioxin concentrations were estimated with ordinary kriging. The highest level of pollution for both PCDD/Fs and dl-PCBs was geographically juxtaposed: in both instances, the location of the local steel plant was within this extremely highly polluted area. The study results support the hypothesis for one common point source of contamination in the valley. The exploratory spatial analysis applied in this research may provide a valuable, novel approach to straightforward identification of a highly likely source of dioxin contamination of dairy products (even in the absence of top soil contamination data).