COMPARISON OF DIBENZODIOXIN LEVELS IN BLOOD AND MILK IN AGRICULTURAL-WORKERS AND OTHERS FOLLOWING PENTACHLOROPHENOL EXPOSURE IN CHINA

Substantial amounts of sodium pentachlorophenol (Na-PCP) salts have be en sprayed in certain areas in central China since the 1960s for contr ol of snail-borne schistosomiasis. A sample of Na-PCP used in the area of concern was analyzed and showed 2,3,7,8-substituted dibenzodioxin (PCDD) and dibenzofuran (PCDF) congeners as well as some non-2,3,7,8-s ubstituted congeners. Dibenzodioxin analysis of two pooled blood sampl es from 100 persons living in sprayed areas and a pooled sample from 2 6 individuals who had direct contact with the Na-PCP showed elevations of PCDD/F congeners found in the Na-PCP. Total PCDD/Fs ranged from 63 1 to 1252 parts per trillion (ppt) lipid in the blood of those exposed to Na-PCP, while two general population age-matched pooled blood samp les from 50 persons each had total PCDD/Fs of 147 and 178 ppt. Toxic e quivalents calculated with International Toxic Equivalency Factors (I- TEqs) ranged from 9 to 16.3 ppt in the blood samples from exposed pers ons while the general population blood I-TEqs were 4.8 and 6.4 ppt. A pooled breast milk sample from 50 women living in the sprayed areas wa s compared with a pooled sample from 50 women living in unsprayed area s. Total PCDD/Fs was low in both exposed and general population sample s (134 and 42 ppt lipid, respectively), however, the women living in s prayed areas had considerably higher PCDDs, 129 ppt versus 34 ppt. The mothers exposed to Na-PCP had a I-TEq of 5.4, which was about double that of the mothers from the general population, 2.6 ppt, lipid. Altho ugh human PCDD and PCDF tissue levels in China are low compared with t hose in more industrialized countries, the higher levels in exposed pe rsons are cause for concern.