More probable is bird transport, either externally, by accidental attachment of the seeds to feathers, or internally, by the swallowing of fruit and subsequent excretion of the seeds.
The excretion of methyl mercury becomes very difficult because of high enterohepatic circulation and reabsorption by proximal convoluted tubule.
由于甲基汞在体内的肠肝循环和肾脏近曲小管对甲基汞的重吸收效率高，使甲基汞的体外排泄十分困难。
3
Chronic exposure to Cd mainly causes the renal proximal tubule damage, which represents that the excretion of proteinuria, glucosuria and aminoaciduria.