Overall persistence (P ov ) and long-range transport potential (LRTP) of organic chemicals are environmental hazard metrics calculated with multimedia fate and transport models. Since there are several models of this type, it is important to know whether and how different model designs (model geometry, selection of compartments and processes, process descriptions) affect the results for P ov and LRTP. Using a set of 3175 hypothetical chemicals covering a broad range of partition coefficients and degradation halflives, we systematically analyze the P ov and LRTP results obtained with nine multimedia models. We have developed several methods that make it possible to visualize the model results efficiently and to relate differences in model results to mechanistic differences between models. Rankings of the hypothetical chemicals according to P ov and LRTP are highly correlated among models and are largely determined by the chemical properties. Domains of chemical properties in which model differences lead to different results are identified, and guidance on model selection is provided for model users.

(323 words)36 Rockström et al. (2009aRockström et al. ( , 2009b have warned that humanity must reduce anthropogenic impacts 37 defined by nine planetary boundaries if "unacceptable global change" is to be avoided.

Human adipose samples collected in Tokyo, Japan in 1970 and 2000 were analyzed for the presence of polybrominated dibenzo-p-dioxins (PBDDs), dibenzofurans (PBDFs), and diphenyl ethers (PBDEs), and the concentrations in the two groups were compared. As far as we know, the concentrations of the PBDD/Fs in adipose tissue from the general Japanese population are reported for the first time. Three PBDD/F congeners were found in the following adipose tissues: 2,3,7,8-TeBDD, 2,3,7,8-TeBDF, and 2,3,4,7,8-PeBDF. The median concentrations (ranges) of three PBDD/Fs in 1970 and 2000 were 5.1 (3.4-8.3) and 3.4 (1.9-5.3) pg/g lipid wt (l.w.), respectively. For PBDEs, seven PBDE congeners were determined in the following samples: 2,4,4'-tribromodiphenyl ether (BDE-28), 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), 2,2',4,4',5-pentabromodiphenyl ether (BDE-99), 2,2',4,4',6-pentabromodiphenyl ether (BDE-100), 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE-153), 2,2',4,4',5',6-hexabromodiphenyl ether (BDE-154), and 2,2',3,4,4',5',6-heptabromodiphenyl ether (BDE-183). Median concentrations (ranges) of PBDEs showed a significant increase from 29.2 (6.8-78.4) pg/g l.w. in 1970 to 1288 (466-2,753) pg/g l.w. in 2000. BDE-47, the major congener of PBDEs, was 56.2% and 35.6% of the total in 1970 and 2000, respectively, whereas the BDE-153 was < 1% and 29.7% of the total in 1970 and 2000, respectively. This may indicate that the source of PBDEs had changed during this period. Further analysis of archived human samples from 1970 to 2000 is needed to describe the details of the contamination trends of PBDD/Fs and PBDEs in the Japanese population. Furthermore, PBDD/F monitoring, particularly 2,3,7,8-TeBDD and 2,3,7,8-TeBDF, may give more toxicological information based on TeCDD toxic equivalents (TEQs).