Analysis of organochlorine pesticides in human milk: preliminary results

doi:10.1016/S0378-3782(01)00221-3

Early Human Development

Volume 65, Supplement 2, November 2001, Pages S183-S190

https://doi.org/10.1016/S0378-3782(01)00221-3 Get rights and content

Abstract

In the face of evidence of human milk contamination by organochlorine pesticides, an analysis was performed on samples of milk obtained from healthy lactating women in the provinces of Granada and Almeria in Southern Spain. The samples were obtained by the Neonate Section of the Department of Pediatrics of Granada University Hospital (Neonatology Division) and by the Neonatal Service of Poniente Hospital in El Ejido, Almerı́a. A liquid–liquid extraction procedure was performed. The cleaning of the sample before gas chromatography–mass spectrometry (GC–MS) used silica Sep-Pak. Among other pesticides, aldrin, dieldrin, DDT and its metabolites, lindane, methoxychlor and endosulfan were identified. The presence of these products was confirmed by mass spectrometry. The identification and quantification of these organochlorine molecules is important because they have estrogenic effects.

Introduction

Organochlorine pesticides, polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) are widely distributed halogenate aromatic compounds which persistently contaminate the environment.

Dieldrin, lindane, toxaphene, endosulfan, and metabolites of endosulfan were recently shown to have estrogenic hormonal activity. [1], [2]. Humans, as part of the food chain, are constantly exposed to these products through the consumption of animals, fish and vegetables. Over 90% of human exposure is through food and liquid intake.

Lipophilic xenobiotics are habitually eliminated in the fatty fraction of milk. In women, there is a strong correlation between the concentrations of organochlorine pesticides in their adipose tissue at the end of the pregnancy and those in the fatty fraction of their milk [3]. The mean fat content of human milk is 3.5 g% [4], more than enough for milk to be considered a vehicle for toxins during breast-feeding. Many researchers have assessed the concentrations of organochlorine pesticides in this setting as an index of human contamination. In the USA, studies have shown rising concentrations of dieldrin, aldrin and lindane, but falling concentrations of the now restricted hexachlorobenzene and DDT [5]. Many different countries, such as Norway, France, Jordan, Russia, Kenya, and Sweden regularly report the presence of DDT, DDE and PCBs in the milk of breast-feeding mothers [6], [7], [8], [9], [10], [11], [12].

To summarize, organochlorine pesticides, PCBs, and dioxins are found in samples of human milk worldwide, in both rural and urban areas and in countries at all stages of development [13].

The present work describes the preliminary results of our analysis of the milk of lactating mothers who live in an area of intensive agriculture (El Ejido, Almerı́a) or an urban zone (Granada), both in southern Spain.

Section snippets

Methods

(1) Gas chromatography. The chromatograph apparatus used was a Varian-3350 ECD Electron Capture Detector (⁶³Ni) (GC–ECD) with Millenium Chromatography Manager Software. The carrier and auxiliary gas was nitrogen, at a flow rate of 30 and 40 ml/min, respectively.

(2) Gas chromatography–mass spectrum. A Saturn 2000 ion trap mass spectrometer from Varian Instruments (Sunnyvale, CA, USA) was used. The integrated gas chromatograph was fitted with an autosampler (Model 8200), a split/split-less

Sample selection

Selection of the study population: healthy breast-feeding volunteers aged from 17 to 35 years were selected at random from two distinct geographical settings: one an area of intensive agriculture, El Ejido in Almeria (recruitment site, Hospital del Poniente), and the other, a city, Granada (Clinico University Hospital). All of the women gave their written informed consent and the study was approved by the ethical committee of each hospital.

The milk samples were drawn during three periods: 1–7

Sample preparation and analysis

1.
Four to eight tubes of milk sampled from each woman were mixed in a glass jar by shaking.
2.
To this mixture of 4–8 ml of milk, half of the same volume of methanol was added and the solution was shaken for 5 min; 0.1 g of sodium oxalate was then added and shaken.
3.
The extraction was performed using 10 ml ethyl ether/hexane (1:1 v/v).
4.
The extract was centrifuged for 15 min at 3000 rpm.
5.
The organic phase was obtained and the extraction procedure was repeated twice more.
6.
The three organic residues were

Clean-up

The organic extract obtained from any of the extractions were purified with the use of silica Sep-Pak after the prior treatment of the cartridge with 2 ml hexane. The extract was eluted with 10 ml hexane and then with 10 ml hexane:methanol:isopropanol (45:40:15; v/v/v). Both eluates were collected and dried in a stream of nitrogen.

The dry residue was dissolved in 1 ml hexane, labeled with the p-p′ dichlorobenzophenone internal standard and analyzed with GC–ECD. The results were confirmed with

Results

The results for the two study populations are shown in Table 1, Table 2, Table 3. The colostrum, transition milk and mature milk samples all contained significant amounts of organochlorine pesticides.

Discussion

Our study clearly shows that human milk is an elimination route for xenobiotics and a contamination source for the breast-feeding baby. Most of the samples contained p,p′DDD, o,p′DDT and p,p′DDT, while p,p′DDE was detected in 100% and hexachlorobenzene (HCB) in 94–100% of the samples. Other pesticides and their derivatives were also widely found. The concentration of organochlorine molecules in milk mainly depends on their accumulation in the maternal fatty tissue and their subsequent

Acknowledgements

We thank Richard Davies for his editorial assistance. This research was supported by grant from the EU Commission QLRT-1999-01422.

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Analysis of organochlorine pesticides in human milk: preliminary results

Abstract

Introduction

Section snippets

Methods

Sample selection

Sample preparation and analysis

Clean-up

Results

Discussion

Acknowledgements

Public Health

Sci. Total Environ.

The pesticides endosulfan, toxaphene, and dieldrin have estrogenic effects on human estrogen sensitive cells

Environ. Health Perspect.

Inadvertent exposure to xenoestrogens in children

Toxicol. Ind. Health

Pregnancy-related changes in fat mass and total DDT in breast milk and maternal adipose tissue

Ann. Nutr. Metab.

Milk lipids: A. Human milk lipids

Organochlorine pesticide residue levels in human milk: Western Australia 1979–1980

Arch. Environ. Health

Polichlorinated biphenyls and organochlorine pesticides in milk of Norwegian women during lactation

Arch. Environ. Contam. Toxicol.

Storage of organochlorine pesticides in human adipose tissues of Jordanian males and females

Chemosphere

Organochlorine pesticide and PCB congener content of French human milk

Bull. Environ. Contam. Toxicol.

Analysis of breast milk to assess exposure to chlorinated contaminants in Kazakstan: high levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in agricultural villages of southern Kazakstan

Environ. Health Perspect.