Ac. Gutleb et al., GIANT OTTER (PTERONURA-BRASILIENSIS) AT RISK - TOTAL MERCURY AND METHYLMERCURY LEVELS IN FISH AND OTTER SCATS, PERU, Ambio, 26(8), 1997, pp. 511-514
Mercury and methylmercury levels in fish muscle and seats of the giant
otter (Pteronura brasiliensis) of Manu National Park, Peru, and in on
e gold-mining area in the vicinity of its borders were analyzed. In 68
% of fish muscles, total mercury levels exceeded the proposed maximum
tolerable level of 0.1 mg kg(-1) fresh weight in fish for the European
otter (Lutra lutra), and 17.6% exceeded 0.5 mg kg(-1) fresh weight, t
he most common standard for human consumption. The ratio of methylmerc
ury to total mercury in fish muscle was from 61.3% up to 96.9%, No met
hylmercury and only traces of inorganic mercury could be detected in t
he otter seats. No data for tissue concentrations of the giant otter a
re available at the moment, but as a high percentage of fish levels ex
ceeded the tolerable level, as given for the European otter, a possibl
e risk of mercury intoxication in the giant otter can be postulated, o
n the basis of mercury intoxication in free-living otters in Europe an
d North America described in the past.