Concentración de metales pesados en leche cruda de vaca en la provincia de León, España

Resumen

It had been determined toxic and essential element concentrations (mercury, arsenic, cadmium, lead, chromium, aluminium, nickel, molybdenum, zinc, iron, manganese and copper) in raw cow milk from several farms of the province of Leon. It was collected between months from June to November of 2007, bulk tank milk (112 samples) and individual cow milk (65 samples) in four geographic zones. Different zones were selected to according of productive and environmental conditions of the province of Leon. Milk samples were kept in sterile propylene tubes and they were processed in the Instrumental Technical Laboratory of University of Leon. Trace element concentrations in milk samples were estimated using the Mass Spectrometry (ICP-MS) and Emission Spectrometry (ICP-AES). The statistical analyses included descriptive and normal distribution tests and one-way analysis of variance, taking in account variables as geographic zone, breed, production system, parity and lactation phase. Mercury, cadmium and arsenic content in all raw milk samples were below of limit of detection. Bulk tank raw milk samples showed a mean concentration of lead (4.34 µg/kg), aluminium (192.16 µg/kg), chromium (69.28 µg/kg), nickel (45.11 µg/kg), molybdenum (45.20 µg/kg), zinc (4860 µg/kg), iron (300 µg/kg), manganese (31.82 µg/kg) and copper (63.51 µg/kg). Individual cow milk samples presented a mean content of lead (5.15 µg/kg), aluminium (257.09 µg/kg), chromium (85.33 µg/kg), nickel (62.16 µg/kg), molybdenum (42.42 µg/kg), zinc (5980 µg/kg), iron (670 µg/kg), manganese (39.92 µg/kg) and copper (62.09 µg/kg). It was registered a wide variation among metal concentrations in all milk samples, with exception of mercury, cadmium and arsenic, according to the variables previously mentioned. From the above, we can confirmed that several heavy metal mean concentration analyzed in raw milk samples were into of data ranges described in the most of another researchs. Therefore raw cow milk from farms of the province of Leon has a very low but non-zero healthy risk for human and animal consumers.