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.