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Page 14 of 20 Andjelkovic et al. J Environ Expo Assess 2024;3:23 https://dx.doi.org/10.20517/jeea.2024.22

[57]
and dioxin-like PCBs between 2002 and 2010 .

In general, a decrease in all POPs included in the Stockholm Convention, except for HBCD, was observed
in the Belgian pooled sample compared to the results from 2006. The sum of PBDE congeners in the Belgian
[15]
samples has decreased from 2.1 ng/g lw in 2006 to 1.1 ng/g lw in the present study. The concentrations of
only two congeners (BDE-17 and BDE-66) increased. These two congeners are, however, less abundant and
may be present in low concentrations.

In a later study from 2012, Croes et al. reported concentrations of α-HBCD (3.2 ng/g lw) and dieldrin
[34]
(7.2 ng/g lw) for rural areas in Flanders (a pooled sample) . The values in the Belgian pooled sample taken
in 2014 were lower. The explanation is that Croes et al. aimed to follow the elevated exposure to POPs in the
Flemish rural area determined in the human biomonitoring campaign of the first generation Environment
[34]
and Health (2002-2006) . The initial study revealed significantly elevated levels of POPs in the cord blood
of newborns, as well as in the blood of adolescents (ages 14-15) and adults (ages 50-65), compared to seven
other regions in Flanders. Additionally, a downward trend was observed in rural areas, consistent with the
overall findings for Belgium. In that first study, significantly high levels of POPs were observed in the cord
blood of newborns and in the blood of adolescents (14-15 years old) and adults (50-65 years old) compared
to 7 other areas in Flanders. Hence, a downward trend was also observed in rural areas, as in the whole of
Belgium.

For the first time, BB-153, PeCB, chlordecone, and short-chain chlorinated paraffins (SCCPs) were
analyzed, but not detected in the national sample. The decreasing trend in concentrations of POPs in
human milk is a major conclusion from this study and confirms the decreasing concentrations of POPs
observed in the previous surveys. On the other hand, the WHO report indicated that POP concentrations
[13]
in certain areas remained elevated, with DDT continuing to represent the largest average proportion,
followed by SCCPs and PCBs.

In the same report, the high levels of the new POPs listed in the Stockholm Convention, such as SCCPs and
PFASs, were reported, pointing to the need for further monitoring. In the national sample, PFAS
compounds (PFOS and PFOA) and related polyfluoroalkyl compounds were also measured. PFOA was not
detected (LOQ = 80 ng/L), while PFOS and PFHxS were measured at low concentrations (64 and 15 ng/L,
respectively).

POP levels-country comparisons
Compared to levels measured in other countries, the indicator PCB value (37 ng/g lw) was higher than that
[41]
in an Israeli national sample (23.9 ng/g lw) , but the p,p’-DDE level in the pooled sample from Israel
(147 ng/g lw) was twice that found in the Belgian sample (74.2 ng/g lw). Likewise, the level of β-HCH for
Israel (10.8 ng/g lw) exceeded the level in the Belgian sample from the present study (4.3 ng/g lw).

Fluorinated compounds found in the present study in the pooled Belgian sample (< 80 ng/L PFOA and
64 ng/L PFOS) were comparable to the concentrations reported in human milk from France (40 ng/L PFOS
[58]
and 41 ng/L PFOA) , Spain (54 ng/L PFOA) , and The Czech Republic (33 ng/L PFOS and 50 ng/L
[59]
PFOA) . No trend could be established since the fluorinated compounds were not determined in the
[60]
Belgian national pooled sample from the year 2006. However, Croes et al. reported higher concentrations of
PFOS (130 pg/mL) and PFOA (80 pg/mL) in human milk samples collected in Flanders (Belgian region)
during 2009-2010 . On average, for the period 2000-2019, WEOG countries showed a gradual downward
[34]
trend for many POPs [14,18,22-24] . This comparative analysis of all surveys shows that next to Belgium, also the