Variations of ochratoxin A concentration in the blood of healthy populations in some Croatian cities

The nephrotoxic; mycotoxin ochratoxin A (OTA), a common contaminant of cere als, has been implicated in the etiology of endemic nephropathy. It was als o frequently found in low concentrations in blood of healthy populations in countries where endemic nephropathy is not known. However, data on regiona l and seasonal differences in the frequency and concentration of OTA in hum an blood are scarce. In June, September and December 1997, and March 1998, about 50 human blood samples were collected randomly from blood donors for blood banks in the Coatian cities of Osijek, Rijeka, Split, VaraZdin and Za greb. OTA was measured in the total of 983 samples using an HPLC technique with fluorescent detection. The daily intake of OTA was estimated from the mean concentration found in different cities and at different times of year . Samples containing OTA above the detection limit (0.2 ng/ml of plasma) we re found in populations from all Croatian cities at all collecting periods. The highest frequency (59%) of samples containing OTA above the detection limit and the highest mean concentration (0.39 ng/ml) were found in June. B oth the frequency and the mean concentration were lowest in all samples in December (36% and 0.19 ng OTA/ml, respectively). Osijek was the city with t he highest frequency of OTA-positive samples (81%) and the highest mean OTA concentration (0.56 ng/ml). The total mean concentration of OTA in blood o f healthy population in Croatia is lower (0.30 ng/ ml) than the mean concen tration in European countries as a whole (0.90 ng/ml). The estimated daily intake, calculated from the mean concentration in all blood samples, is 0.4 0 ng OTA/kg body weight, which is much lower than that proposed by World He alth Organization as the tolerable daily intake (16.0 ng/kg body weight). H ealthy populations of Croatia are exposed to low, but seasonally and region ally variable amounts of OTA.