The distribution and accumulation of lead in Wuzhishan pig tissues and organs

The lead distribution and accumulation in tissues of Wuzhishan pig, and also the relationship between the lead content of feeds and pig tissues were studied. Twenty mini pigs were randomly divided into five groups and fed for 100 days on diets with lead contents of 0.046 mg·kg^-1, 6.790 mg·kg^-1, 17.370 mg·kg^-1, 53.600 mg·kg^-1 or 154.000 mg·kg^-1. After slaughter, the lead contents in the heart, liver, kidney, lung, stomach, intestine, colon, ears, tongue, tail, pork loin, pork spareribs, sclerotin, femur marrow, costal bone, and hair were determined. The results showed that lead content in the liver, kidney, sclerotin, femur marrow, costal bone and hair significantly increased with the increase of lead content in feeds, exhibiting a linear positive correlation. It was possible to exceed the national standard in these tissues, even if the feed lead content was lower than the standard. However, lead contents in the heart, lung, stomach, intestine, colon, pork loin, tongue and tail showed no significant correlation with lead contents in the feed. Furthermore, the lead in these parts were lower than the national sanitary standard level even when the pigs were fed on a diet with a lead content that was 30 times more than the national standard (i.e., 154.000 mg·kg^-1). Bone tissues, liver and kidneys had a strong accumulation capacity for lead, while the lead in pork meat, ear, tongue, tail, heart, lung, and the other tissues and organs were lower than the standard limit. This study provides a theoretical basis for setting maximum limit standards for lead in pork products, especially in the edible tissues and organs. The data also should serve as an important reference for further risk assessments of heavy metals in edible livestock tissues and organs.