Persistent organochlorinated compounds in Norwegian human milk in 1979.

The levels of the persistent organochlorine compounds HCB, sum-DDT (1.1 DDE + 1.1 DDD + DDT), DDE and PCBs were determined in 133 Norwegian human milk samples from 7 cities with various degrees of industrialization. All samples contained organochlorines. No dramatic geographical differences were observed. The average HCB, sum-DDT, DDE and PCB levels in human milk were 2.1 +/-; 1.0, 29.8 +/- 23.5, 25.8 +/- 20.3 and 23.9 +/- 13.7 p.p.b. respectively (126 +/- 128, 1440 +/- 950, 1270 +/- 850 and 1210 +/- 690 p.p.b. respectively in human milk fat) which are among the lowest reported. The present results were compared to Norwegian results from 1970 and 1976. A slight decrease in the average HCB levels was observed from 1976-1979. The average PCB levels which doubled from 1970-1976 showed no or only a slight increase from 1976-1979. The distinct decrease in average sum-DDT levels observed from 1970-1976 continued during the period 1976-1979. The present survey demonstrated that human milk is a good indicator substance in monitoring the environment for contamination by organochlorine compounds. The results were evaluated toxicologically by comparison with maximum residue limits and acceptable daily intakes (FOA/WHO 1978). It was concluded that the present levels of organochlorines in Norwegian human milk did not represent any threat to the infants' health.