Pesticide Residues in Mother’s Milk - Pesticides: Evaluation of Environmental Pollution - page 555

food from animal origin and decrease with the duration of lactation. These two factors
represented respectively the main intake and depuration pathways of OCs. Although DDT
levels in human breast milk from Vietnam are still in the highest range in our world-
wide comparison, it should be noted that their concentrations have declined over the past
10 years (Minh et al. 2004).
All breast milk samples contained an excess of HCH with its isomers, α-HCH, β-HCH,
and γ-HCH. Among them, the average content of γ-HCH (32.3 ng/g lipid) was higher than
that of α-HCH (23.3 ng/g lipid) and β-HCH (22.4 ng/g lipid). The total content of HCHs in
breast milk in their study was higher than that reported by Minh et al. (2004) in Hanoi (with
58 ng/g lipid β-HCH) and in Ho Chi Minh city (13.5 ng/g lipid β-HCH). Table 17.5 shows
that the total content of HCH in breast milk in this study was lower than that in studies
in countries such as China, Japan, and Malaysia. However, the total content of HCHs in
the study was higher than that in studies in Indonesia, Cambodia, and Philippines. The
average concentrations of p,p′-DDE, o,p′-DDT, p,p′-DDT, and DDTs in breast milk were
40.3, 11.4, 35.2, and 86.9 ng/g lipid, respectively. Among them, the content of p,p′-DDE
was higher than that of o,p′-DDT and p,p′-DDT. This result is much lower than that of
Minh et al. (2004) in Hanoi and Ho Chi Minh city (the content of DDTs was 2100 and 2300
ng/g lipid, respectively). However, they were lower than those reported in other studies
in Cambodia (1500 ng/g lipid), The Philippines (190 ng/g lipid), Malaysia (1600 ng/g lipid),
Indonesia (630 ng/g lipid), and Japan (290 ng/g lipid; Si and Gia 2010).
A survey showed that in Malaysia, the residue levels of DDTs, HCHs, CHLs, and HCB
were detected with concentrations of 1600, 230, 23, and 11 ng/g lipid weight, respectively,
due to the widespread use of DDT in both agriculture and malaria control (Sudaryanto
et al. 2005). However, the composition of DDTs were dominated by p,p′-DDE (>95%). In
addition, β-HCH was mostly the only HCH isomer detected whereas α- and γ-HCH were
found in trace quantities. This might be due to the restriction in the usage of technical
HCH or lindane not having been used recently in Malaysia.
The national survey on the levels of persistent OCPs in the breast milk of mothers in
China (Zhou et al. 2011) showed that the levels of DDTs, HCHs, and HCB varied from 527.2,
231.8, and 32.8 ng/g lipid respectively. The mean concentrations of DDTs, HCHs and HCB in
breast milk from rural and urban (539.3 ng/g lipid and 629.2 ng/g lipid; 197.9 ng/g lipid and
265.6 ng/g lipid; and 33.8 ng/g lipid and 32.3 ng/g lipid, respectively. Chlordane and mirex
were present in samples at relatively lower concentrations. In Chinese and Indian human
breast milk samples, notably higher concentrations of HCHs were observed compared with
other Asian countries ( Tables 17.4 and 17.5). It seems that this reflects a huge amount of
usage in the past and/or recent illegal use of technical HCH in these two countries. These
results indicate that relatively high sources of HCHs are still present in the environment of
these countries and that technical HCH may be illegally used for public health purposes in
these two countries exposing residents to HCHs (Tanabe and Kunisue 2007).
Milk samples (115 from Hong Kong and 54 from Guangzhou), in the lactation period
from 3-5 weeks, were analyzed (Wong et al. 2002). The results demonstrated that the mean
levels µg/g of fat of p,p′-DDT (Hong Kong: 0.39; Guangzhou: 0.70), p,p′-DDE (2.48; 2.85),
and β-HCH (0.95; 1.11) were 2-15-fold higher when compared with studies conducted else-
where (i.e., United Kingdom, Germany, Sweden, Spain, and Canada). When compared to
a similar study conducted 10 years ago in Hong Kong (p,p′-DDT 2.17 µg/g of fat, p,p′-DDE
11.67 ng/g of fat, and β-HCH 15.96 ng/g of fat), a considerable reduction in the levels of their
contaminations was observed.
The mean concentrations of DDTs were 1300 ng/g lipid (n = 25) in China and 1200 ng/g
lipid (n = 20) in Vietnam, both of which were 5-7 times higher than values in Korea (180 ng/g