Levels and trends of PCDD/Fs and PCBs in camel milk (Camelus bactrianus and Camelus dromedarius) from Kazakhstan

To date, despite the fact it represents a very important part of the national dairy production, no data are
available concerning the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated
dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) in camel milk from the Republic of
Kazakhstan. Selected PCDDs, PCDFs, and PCBs were measured in pools of milk from camels (n = 15)
located in various places of Kazakhstan (Almaty, Atyrau, Aralsk, Shymkent) and sampled at two different
seasons for two different species (Camelus bactrianus and Camelus dromedarius). Non-dioxin-like (NDL-
)PCB concentrations (6.3 ± 2.7 ng gÿ1 fat, median 5.1 ng gÿ1 fat, range 0.6–17.4 ng gÿ1 fat) were far below
the maximum value of 40 ng gÿ1 fat proposed by the EU. Dioxin-like (DL-)PCB concentrations
(1.7 ± 0.7 ng gÿ1 fat, median 1.5 ng gÿ1 fat, range 0.3–4.2 ng gÿ1 fat) and the NDL-PCB to DL-PCB ratio
(4.3) were similar to what is reported in EU for cow-based dairy products. PCB 52 and PCB 101 appeared
to be proportionally more present in Kazakh camel milk samples (>60% of the sum of the 6 indicator
NDL-PCBs) than in European cow milk samples (<10% of the sum of the 6 indicator NDL-PCBs), indicating
possible differences in the route of exposure to PCBs in Kazakhstan. PCB 105 and PCB 118 appeared to be
present at higher concentrations in camel milk (>80% of the sum of the 12 DL-PCBs). PCB 105, PCB 118
and PCB 156 were the major congeners for DL-PCBs, accounting for 92% of the sum of concentrations
of DL-PCBs (88% for Belgian cows). In terms of TEQ, PCB 126 and PCB 118 are the major contributors
and represent, respectively, 80% and 14% of the DL-PCB TEQWHO05 concentrations. No significant interracial
or geographical trends were observed for NDL- and DL-PCB profiles. However, concentrations of all
DL-PCBs appeared to be significantly higher for samples collected in Atyrau region. 2,3,7,8-TCDD level
(mean 0.08 ± 0.07 pg gÿ1 fat, median 0.08 pg gÿ1 fat, range 0.00–0.18 pg gÿ1 fat, 60% > LOQs) were very
low for all samples and 2,3,4,7,8-PeCDF was the major contributor (27%) to the PCDD/F TEQWHO05. Considering
the total TEQWHO05 (sum of DL-PCBs and PCDD/Fs), DL-PCB and PCDD/F contributed for 73% and
27%, respectively. A decrease of only 1% of the total TEQ was observed when using the TEFWHO05 scale
instead of the TEFWHO98 scale. Two samples collected in the region of Atyrau exceeded the EU maximum
level value of 6.00 pg TEQWHO98 gÿ1 fat (6.4 pg TEQWHO05 gÿ1 fat and 6.9 pg TEQWHO05 gÿ1 fat). Both samples
exceeded the EU action level for the sum of DL-PCBs. Based on the fact that camel milk is used to
prepare popular traditional fermented drinks like shubat, this suggests that the human exposure in the
Caspian Sea region of Atyrau should be expected to be higher than in the other regions studied here.