Dioxin Like Compounds Bulk Deposition on Corn (Zea mais) and Alfa Alfa (Medicago sativa): Modelled Levels on Derived Silage and Hay and Their Relevance for Dairy Production

• Published in: Clean : soil, air, water Vol. 41; no. 2; pp. 113 - 118
• Main Authors: Brambilla, Gianfranco, De Filippis, Stefania Paola, Esposito, Vittorio, Settimo, Gaetano
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.02.2013; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: Air deposition; Deposition; Dioxins; Food management; Forage; Milk; Nutrition
• ISSN: 1863-0650; 1863-0669
• DOI: 10.1002/clen.201100566

Dioxin‐like compounds from regular, occasional or fugitive airborne sources of emission may fall out on fodders close to be harvested for silage and hay production. In this way, a prolonged long‐term intake of contaminated forages in dairy animals may be envisaged, able to determine a rise of the background contamination in milk. We simulated different risk scenarios taking into account the inventoried bulk dry depositions in rural areas of the aforesaid contaminants, silage and hay biomass production per hectare, forages regimen in dairy animals, and the congeners carry‐over rate (COR) from forages to milk. Considering atmospheric depositions >10 pg I‐TE m−2 day−1 and accounting for a 30% COR, dairy milk could rise up to the PCDD/F level of 3 pg WHO1998‐TE g−1 fat. The modelling indicates that in rural areas bulk emissions should be selectively minimised, accounting for the calendar of the different agricultural practices, because of their potential impact on the fodders. Since environmental factors play a non‐negligible role in food production, a stronger harmonisation between I‐TE and WHO1998–2005‐TE scales with respect to dioxin‐like polychlorobiphenyl congeners inclusion is envisaged. This will allow the prevention of the human indirect exposure to such contaminants when released in the air. From the results of this study it can be concluded that for mais silage and alfa alfa hay production, air deposition may play a major role with respect to top soil contamination in determining a rise of PCDD, PCDF and DL‐PCB background levels in dairy milk, due to plant density and height of their epigeal parts. The use of a ‘corn watch’ approach, where mais leaves may act as ‘bio‐deposimeter’ may be envisaged also in terms of food and feed control, at farm level.