smartd errors

[Paolo Galtieri]

Folks,
   recently I have started seeing these messages in /var/log/messages

Oct 27 10:26:13 jackstraw smartd[1177]: Device: /dev/sde [SAT], 16 
Currently unreadable (pending) sectors
Oct 27 10:26:13 jackstraw smartd[1177]: Device: /dev/sde [SAT], 16 
Offline uncorrectable sectors

which are mounted as follows

/dev/sde1 on /media/NSM/NSM-SENSOR-1 type ext4 
(rw,nosuid,nodev,noexec,noatime,seclabel,data=ordered)
/dev/sde2 on /media/NSM/NSM-SENSOR-2 type ext4 
(rw,nosuid,nodev,noexec,noatime,seclabel,data=ordered)

I have unmounted the filesystems and run fsck on them and fsck reports 
no errors.

[pgaltieri at jackstraw ~]$ sudo fsck /dev/sde2
fsck from util-linux 2.26.2
e2fsck 1.42.12 (29-Aug-2014)
NSM-SENSOR-2: clean, 11/45498368 files, 2905980/181964288 blocks

[pgaltieri at jackstraw ~]$ sudo fsck /dev/sde1
fsck from util-linux 2.26.2
e2fsck 1.42.12 (29-Aug-2014)
NSM-SENSOR-1: clean, 32/46080000 files, 2993510/184320000 blocks

It only reports errors on this drive.

Should I be concerned about what smartd is saying?  How do I, if 
possible, correct this?

Paolo