Effects of inorganic mercury on the olfactory pits of zebrafish larvae.

Mercury compounds are highly toxic; due to the rising levels of mercury pollution, both human and environmental exposure to mercury are increasing. Occupational exposure to inhaled mercury can be high, causing adverse effects not only in the lungs, but in the olfactory system as well. Olfaction plays a critical role in the survival of fish and other vertebrates, and impaired olfaction can substantially impact human quality of life. We present a study of the effects of mercury exposure in the olfactory pits of zebrafish larvae using a combination of X-ray fluorescence imaging and immunohistochemistry. We show that mercury accumulates in the sensory cells of the olfactory pits and also that it may also damage primary neurons, such as those that innervate olfactory pits.