Contamination Of Human Milk Research Articles

A review on the usage of POP pesticides in China, with emphasis on DDT loadings in human milk

This article attempts to review the usage of nine pesticides included in the 12 Stockholm Convention persistent organic pollutants (POPs) in China and to examine the extent of DDT contamination in human milk, focusing on the Chinese populations. By comparing all the data available concerning DDTs in human milk from 19 countries, it is revealed that the Chinese populations exhibit rather high concentrations of DDTs, due to the fact that China has been a major producer and consumer of DDTs in the past, and also uses DDT for vector control, resulting in higher background levels of DDTs in different ecological compartments. The high body loading of DDT in Chinese populations is also related to the high dietary intake due to contamination of food. When comparing the data obtained recently (1998–2002), the coastal populations such as Guangzhou (DDE + DDT 2.13 μg g −1 fat), Hong Kong (2.87 μg g −1 fat) and Dalian (2.13 μg g −1 fat) contain higher concentrations of DDTs which may reflect the dietary difference of consuming more meat and fish, than other Chinese populations (Beijing 1.96 μg g −1 fat; Shenyang 0.87 μg g −1 fat). In general, the rather low ratio of DDE/DDT (e.g., 4.07 for Guangzhou) of the Chinese milk samples reflected the more recent releases of DDT. It is recommended to impose a tighter control on the use of DDT for vector control as well as for agricultural application, conduct regular monitoring of DDT concentrations in different ecological compartments which include air, water, sediment and biota. Human milk is a preferred indicator reflecting human body loadings of POPs including DDTs, as well as the risk which may impose on our next generation. A national wide survey is needed to investigate the intake of POPs, including POP pesticides, due to dietary differences, with a strong focus on the more sensitive populations, e.g., coastal residents who consume a large amount of fish.

Human Breast Milk and Xenoestrogen Exposure: A Possible Impact on Human Health

Human milk is the best natural and optimal food for neonates with several immunologic, developmental and practical advantages throughout childhood. Although the World Health Organization strongly supports breastfeeding, it recognizes the potential health risks posed by the presence of environmental toxicants in breast milk. Contamination of human milk is widespread and due to decades of inadequately controlled pollution by toxicants, persistent pesticides or chemical solvents. These chemicals tend to degrade slowly in the environment, to bioaccumulate in the food chain and to have long half-lives in humans. Many of these environmental pollutants have estrogen-like activities and, thus they are called environmental estrogen disruptors or xenoestrogens. Certain adverse health and reproductive outcomes are attributed to these chemicals in laboratory animals and in wildlife as well as in humans. Here, we review available data from breast milk monitoring studies suggesting the environmental chemicals that may affect child health through breastfeeding.

Scientific advances provide opportunities to improve pediatric environmental health

Scientific advances provide opportunities to improve pediatric environmental health

Persistent organochlorines in human breast milk collected from primiparae in Dalian and Shenyang, China

The present study determined the concentrations of organochlorines (OCs) such as polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), chlordane compounds (CHLs), hexachlorobenzene (HCB) and tris(4-chlorophenyl)methane (TCPMe) in human breast milk collected from primiparae in Dalian and Shenyang, northeastern China during 2002. In addition, dioxins and related compounds in pooled samples of human breast milk from Dalian and Shenyang were also analyzed. OCs were detected in all the human breast milk samples analyzed in this study. The predominant contaminants in human breast milk were HCHs, DDTs and HCB, and the levels were relatively higher than those in other countries. On the other hand, concentrations of dioxins and related compounds, PCBs, and CHLs were relatively low. Concentrations of OCs in human breast milk from Dalian, which is located along the coast of Bo Hai Strait, were significantly higher than those from Shenyang, implying that the residents in Dalian might be mainly exposed to these contaminants from seafood. When the relationship between concentrations of OCs in human breast milk and age of primiparae was examined, no significant correlation was observed. This might be caused by the limited sample numbers and narrow range of mother's age and/or recent ban of DDT and HCH production and use. Significant correlation between concentrations of TCPMe and DDTs in human breast milk suggested that technical DDT might be a source of TCPMe in the Chinese population. When daily intakes of DDTs and HCHs to infants through human breast milk were estimated, human breast milk from Dalian showed significantly higher contribution than Shenyang, implying that infants in Dalian might be at higher risk by these contaminants.

Persistent organochlorines in human breast milk collected from primiparae in Dalian and Shenyang, China

The present study determined the concentrations of organochlorines (OCs) such as polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), chlordane compounds (CHLs), hexachlorobenzene (HCB) and tris(4-chlorophenyl)methane (TCPMe) in human breast milk collected from primiparae in Dalian and Shenyang, northeastern China during 2002. In addition, dioxins and related compounds in pooled samples of human breast milk from Dalian and Shenyang were also analyzed. OCs were detected in all the human breast milk samples analyzed in this study. The predominant contaminants in human breast milk were HCHs, DDTs and HCB, and the levels were relatively higher than those in other countries. On the other hand, concentrations of dioxins and related compounds, PCBs, and CHLs were relatively low. Concentrations of OCs in human breast milk from Dalian, which is located along the coast of Bo Hai Strait, were significantly higher than those from Shenyang, implying that the residents in Dalian might be mainly exposed to these contaminants from seafood. When the relationship between concentrations of OCs in human breast milk and age of primiparae was examined, no significant correlation was observed. This might be caused by the limited sample numbers and narrow range of mother's age and/or recent ban of DDT and HCH production and use. Significant correlation between concentrations of TCPMe and DDTs in human breast milk suggested that technical DDT might be a source of TCPMe in the Chinese population. When daily intakes of DDTs and HCHs to infants through human breast milk were estimated, human breast milk from Dalian showed significantly higher contribution than Shenyang, implying that infants in Dalian might be at higher risk by these contaminants.

Microbiological quality of human milk from a Brazilian milk bank

The objectives of the present study were to determine the prevalence of potentially pathogenic microorganisms that indicate the hygienic and sanitary conditions of human milk samples collected at a Human Milk Bank. Three hundred and thirty eight (338) samples of human milk collected from a milk bank in a maternity in the municipality of Goiânia, in the state of Goias, Brazil were submitted to microbiological analysis. The latter were plated on McConkey agar according to the type of bacteria. Among the total number of samples collected, 194 consisted of raw milk and the remaining 144 were pasteurized milk. The presence of Staphylococcus spp., Streptococcus spp., yeasts and molds, and Enterobacteriaceae was verified in the raw milk samples. Staphylococcus aureus were isolated in 10 (5.2%) samples, Staphylococcus epidermidis in 28 (14.4%) samples, Streptococcus spp. in three (1.6%) samples, yeasts and molds in 43 (22.2%) and Enterobacteriaceae in 49 (25.3%) samples. In a hundred and forty four (144) samples which underwent thermal treatment Staphylococcus aureus was detected in five (3.5%) samples, Staphylococcus epidermidis in 15 (10.4%), Staphylococcus lugdenensis in two (1.4%), Streptococcus spp. in four (2.8%), yeasts and molds in 37 (25.7%), and Enterobacteriaceae in nine (6.3%). Analysis indicated a high degree of contamination in raw human milk, and as for the pasteurized milk, despite elimination of the great majority of potentially pathogenic microorganisms, the percentage of yeasts and molds was higher than in raw milk, demonstrating that a lower degree of initial contamination would be necessary for pasteurization to be an efficient means of microbiological control.

Attenuated growth of breast-fed children exposed to increased concentrations of methylmercury and polychlorinated biphenyls.

Breast-feeding has been linked to slowed postnatal growth. Although the basis for this "weanling's dilemma" is unclear, environmental contaminants in human milk may be of relevance. We studied a Faroese birth cohort of 182 singleton children, born at term in 1994-95. Concentrations of mercury in cord blood and of polychlorinated biphenyls in maternal milk were measured, and duration of breast-feeding was recorded. At 18 months, children who had been exclusively breast-fed for at least 6 months weighed 0.59 kg less [95% confidence interval (CI) = 0.03, 1.16 kg] and were 1.50 cm [95% CI = 0.52, 2.47 cm] shorter than those not breast-fed. However, calculated transfer of contaminants from human milk fully explained the attenuated growth. Irrespective of duration of breast-feeding, a doubling of the mercury concentration in cord blood was associated with a decrease in weight at 18 months by 0.19 kg (95% CI = 0.03, 0.35 kg) and in height by 0.26 cm (95% CI = -0.02, 0.55 cm). Weight and height at 42 months showed the same tendencies, but the main effect occurred before 18 months of age. Thus, in communities with increased contaminant exposures, risks associated with lactational transfer of toxicants to the infant must be considered when judging the benefits of prolonged breast-feeding.

Effects of Aroclors and individual PCB congeners on activation of the human androgen receptor in vitro

To investigate possible interactions between the human androgen receptor and PCBs in vitro, we have used a previously characterized human androgen receptor reporter gene assay in which PC-3 LUC AR+ cells respond to 5α-dihydrotestosterone (DHT, 50 pM) with enhanced luciferase activity. The effects of Aroclors, commercial mixtures of PCBs, or polychlorinated terphenyls (PCTs) (0, 0.1, 1.0, and 10.0 μM) on luciferase activity in PC-3 LUC AR+ cells were determined after exposure for 18 h in the presence and absence of DHT (50 pM). In the absence of DHT, none of the Aroclors induced luciferase activity but, in the presence of DHT (50 pM), Aroclors 1016, 1221, 1232, 1242, 1248, 1254, 1260, 5432, and 5442 acted antagonistically at concentrations that did not affect cell viability. Aroclor 5460 was without effect. Similarly, when PCBs found as human milk contaminants were assessed as individual congeners (each at 1 μM, where no cytotoxic effects were observed), none activated luciferase expression in the absence of DHT but PCBs 49, 66, 74, 105, and 118 completely antagonized the stimulation by DHT (50 pM) and PCBs 138, 153, and 156 were less effective antagonists, reducing the DHT stimulation by about 50%. Thus, 30% (by weight) of the PCBs in human milk are androgen antagonists (PCBs 66, 74, 105, and 118) and a further 25% are partial antagonists (PCBs 138, 153, and 156). A proportionally representative mixture of PCBs that contaminate human milk also caused the DHT-mediated activation of luciferase activity in PC-3 LUC AR+ cells to be reduced by more than 50%.

냉장 및 실온 보존에 따른 모유와 환원조제분유 중의 총균수와 대장균수의 변화

본 연구는 손착유 모유와 breast-pump에 의한 기계착유 모유 중의 총균수와 대장균수를 검사하고 또한 냉장 및 실온 보존에 따른 모유(초유, 성숙유)와 환원조제분유의 저장성을 파악하고자 시험하였다. 시험 결과 breast-pump로 수집한 모유 중의 총균수는 2.02×10⁴ CFU/mL로 손착유에 의한 총균수 1.06×10⁴ CFU/mL보다 약 2배 가량 많이 나타났으며 특히 대장균의 경우, 손착유에 의한 감염율이 12.9%인 반면 breast-pump로 수집한 모유의 감염율은 19.5%로 높게 나타났다. 또한 모유와 환원조제분유를 냉장(4℃) 및 실온(20℃, 30℃) 상태에서 보존하면서 총균수와 대장균수의 변화를 시험한 결과, 4℃에서 대장균수의 변화는 10일 동안 뚜렷한 변화를 보이지 않았으며 총균수는 지속적으로 약간 감소하는 경향을 나타냈다. 20℃에서 총균수의 변화는 모유 성숙유와 모유 초유에서 뚜렷한 증가 추세를 보이지 않았으나 대장균의 경우 지속적인 증가 추세를 보였으며, 특히 환원조제분유에서 대장균수는 12시간 이후 급속히 증가하는 경향을 나타냈다. 30℃에서 총균수의 변화는 모유 성숙유의 경우 12시간 이후 급속히 증가하는 경향을 보였으나 모유 초유의 경우 뚜렷한 증가 추세를 보여주지 않았다. 반면에 환원조제분유는 6시간 이후 급속히 증가하는 추세를 나타냈다.

Chemical contaminants in breast milk and their impacts on children's health: an overview.

Human milk is the best source of nutrition for infants. Breast milk contains the optimal balance of fats, carbohydrates, and proteins for developing babies, and it provides a range of benefits for growth, immunity, and development. Unfortunately, breast milk is not pristine. Contamination of human milk is widespread and is the consequence of decades of inadequately controlled pollution of the environment by toxic chemicals. The finding of toxic chemicals in breast milk raises important issues for pediatric practice, for the practice of public health, and for the environmental health research community. It also illuminates gaps in current knowledge including a) insufficient information on the nature and levels of contaminants in breast milk; b) lack of consistent protocols for collecting and analyzing breast milk samples; c) lack of toxicokinetic data; and d) lack of data on health outcomes that may be produced in infants by exposure to chemicals in breast milk. These gaps in information impede risk assessment and make difficult the formulation of evidence-based health guidance. To address these issues, there is a need for a carefully planned and conducted national breast milk monitoring effort in the United States. Additionally, to assess health outcomes of toxic exposures via breast milk, it will be necessary to examine children prospectively over many years in longitudinal epidemiologic studies that use standardized examination protocols that specifically assess breast milk exposures. Finally, current risk assessment methods need to be expanded to include consideration of the potential risks posed to infants and children by exposures to chemical residues in breast milk.

Congener-distribution patterns and risk assessment of polychlorinated biphenyls, dibenzo- p-dioxins and dibenzofurans in Korean human milk

Polychlorinated dibenzo- p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) were analyzed by high-resolution gas chromatography/high-resolution mass spectrometry in human milk samples from an urban and an industrial area in Korea. All PCB congeners were analyzed to characterize the congener distribution as well as to evaluate the toxic equivalent quotient (TEQ) values and the total concentration. In homologue distributions of PCBs, two distinct patterns were found. The mean concentrations of PCDD/Fs and PCBs were 15.13 and 5.64 TEQ pg/g fat (based on WHO TEF, 1997), respectively. The contamination in Korean human milk is comparable to that found in other countries. From these results a daily intake of 60 TEQ pg/kg/day for an infant was estimated. The assumptions were that the infant breast feeds for 1 year, has an average body weight of 10 kg during this period, and ingests 800 g/day of human milk containing a mean concentration of 20.84 TEQ (PCDD/Fs) pg/g fat (based on primipara mothers).

Association of maternal blood pressure and hemoglobin level with organochlorines in human milk.

Milk samples of women from the general population in Lucknow were analysed by gas-liquid chromatography to determine the concentration of organochlorine pesticides and their possible association with maternal characteristics. p,p'-DDT (dichloro diphenyltrichloroethane), p,p-DDE (dichloro diphenyltrichloroethylene), p,p'-DDD (dichloro diphenyl dichloroethane), alpha, beta gamma and delta isomers of hexachlorocyclohexane (HCH) and aldrin were detected. The calculated daily intake of DDT and HCH by the neonates exceeded their acceptable daily intake (ADI) set by the WHO. A statistically significant association was noted between alpha-HCH residues in milk and hemoglobin (Hb) level in maternal blood (P < 0.001). Also, there was a significant association between gamma-HCH and p,p'-DDT levels in milk and diastolic blood pressure of mother (P < 0.05). An apparent negative relationship between p,p'-DDE level in mother's milk and birthweight of the baby was also noticed (P < 0.05). These results highlight the need for periodic monitoring to determine organochlorine contamination in human milk and assess their impact on mother and on neonatal health.

Development of dioxin toxicity evaluation method in human milk by enzyme-linked immunosorbent assay––assay validation for human milk

In this study, the development of a toxicity evaluation method for dioxins in human milk by enzyme-linked immunosorbent assay (ELISA) was reported. A total of 17 human milk samples were tested by ELISA and by gas chromatography/mass spectrometry (GC/MS) to assess whether the ELISA performed on samples obtained from primiparas could be considered as reliable enough for identifying a dioxins contamination in human milk. The concept of toxicity equivalent quantity (TEQ) screening was validated by comparing TEQ values for a set of human milk samples to the ELISA responses predicted for those samples. A fairly good correlation ( r=0.920) between immunoassay and GC/MS was achieved for human milk. This ELISA should be useful for biological samples monitoring.

Analysis of organochlorine pesticides in human milk: preliminary results.

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, Almería. 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.

Method for evaluation of immunotoxicity of dioxin compounds using human T-lymphoblastic cell line, L-MAT

Caspase-3 was activated in apoptotic L-MAT cells by treatment with 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD). Treatment with tributyltin, which has been reported to induce apoptosis in rat thymocytes, also activated caspase-3 and led to cell death in L-MAT cells. Blocking caspase-3 activity with the peptide inhibitor, DEVE-CHO, prevented TCDD from inducing subsequent apoptotic changes. The potent Ah receptor ligand, 2,3,7,8-tetrachlorodibenzofuran (TCDF), the low acute toxicity compound, 1,2,3,4,6,7,9-heptachlorodibenzo- p-dioxin (HCDD), and one of the major contaminants in human milk, 3,3 ′,4,4 ′,5-pentachlorobiphenyl (PCBP), increased the activation level of caspase-3, each in a dose-dependent manner. Thus, we propose that measuring caspase-3 activation in the human T-lymphoblastic cell line, L-MAT, is a useful evaluation method for the immunotoxicity of dioxin compounds.

Presence of ochratoxin A in human milk in relation to dietary intake

Individual and geographical variations in ochratoxin A (OA) levels in human blood and milk samples may be due to differences in dietary habits. The purpose of this study was to examine the relationship between OA contamination of human milk and dietary intake. Human milk samples were collected from 80 Norwegian women. The usual food intake during the last year was recorded using a quantitative food frequency questionnaire. The concentration of OA in the human milk was determined by HPLC (detection limit 10 ng/l). Seventeen (21%) out of 80 human milk samples contained OA in the range 10–182 ng/l. The women with a high dietary intake of liver paste (liverwurst, liver pâté) and cakes (cookies, fruitcakes, chocolate cakes, etc.) were more likely to have OA-contaminated milk. The risk of OA contamination was also increased by the intake of juice (all kinds). In addition, the results indicate that breakfast cereals, processed meat products, and cheese could be important contributors to dietary OA intake. OA contamination of the milk was unrelated to smoking, age, parity, and anthropometric data other than body weight.

Presence of ochratoxin A in human milk in relation to dietary intake

Individual and geographical variations in ochratoxin A (OA) levels in human blood and milk samples may be due to differences in dietary habits. The purpose of this study was to examine the relationship between OA contamination of human milk and dietary intake. Human milk samples were collected from 80 Norwegian women. The usual food intake during the last year was recorded using a quantitative food frequency questionnaire. The concentration of OA in the human milk was determined by HPLC (detection limit 10 ng/l). Seventeen (21%) out of 80 human milk samples contained OA in the range 10–182 ng/l. The women with a high dietary intake of liver paste (liverwurst, liver pâté) and cakes (cookies, fruitcakes, chocolate cakes, etc.) were more likely to have OA-contaminated milk. The risk of OA contamination was also increased by the intake of juice (all kinds). In addition, the results indicate that breakfast cereals, processed meat products, and cheese could be important contributors to dietary OA intake. OA contamination of the milk was unrelated to smoking, age, parity, and anthropometric data other than body weight.

Consumption of lipophilic contaminants in human milk by infants: quantities are usually incorrect.

We evaluated several reports on the detection of nitromusks (artificial perfumes) in human milk. The nitromusks found were separated by gas-liquid chromatography and identified by mass spectrometry. However, the quantities reported as being consumed by infants were often questionable (Jensen, 1995). The investigators did not always a) obtain a representative samples of milk, b) extract and quantify the fat by a recognized, accurate method, or c) determine the amount of milk, hence fat, consumed by the infant. Some investigators gave almost no data on the milk, except to say that a sample was obtained. Reports on some other contaminants in human milk were similarly deficient. We have published a description of recommended extraction procedures in a paper presenting a detailed protocol for the processing of milk so as to determine the actual amounts of lipophilic contaminants ingested by the nursing infant (Jensen et al. 1997).

Environmental contaminants in human milk.

Environmental contaminants can be stored in the mother's body or can be transiently present from current diet, occupational exposures or personal habits. These chemicals can be transferred prenatally to the developing fetus or postnatally from breast milk to the nursing infant. Exposures through breast milk can be substantial, especially when the mother has significant ongoing exposures or has accumulated an unusually high body burden of persistent chemicals. Several studies demonstrate that organochlorines (OCs) acquired from breast milk elevate a child's body burden for several years. The decline of persistent OC residues in Western countries suggests that these exposures through breast milk will also diminish. Heavy metals such as lead and mercury are also present in milk, but the pharmacokinetics are quite different from OCs. Less persistent environmental agents, including solvents, polycyclic aromatic hydrocarbons, certain pesticides, and nicotine, can also be detected in milk. There is little information on currently used pesticides and other more recently identified environmental agents for which exposures are common today. Epidemiologic research has established that pre- and postnatal exposures to environmental contaminants including lead and OCs are associated with developmental deficits in early childhood. Therefore, characterization of these contaminants in breast milk can add to our knowledge of potential environmental exposures among children.

Certain organochlorine and organobromine contaminants in Swedish human milk in perspective of past 20–30 years

The investigations of organochlorine compounds in breast milk from women living in the Stockholm region started in 1967. The present study summarises the investigations of polychlorinated biphenyls (PCBs), naphthalenes (PCNs), dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), polybrominated diphenyl ethers (PBDEs) and pesticides (DDT, DDE, hexachlorobenzene, dieldrin) as well as methylsulfonyl metabolites of PCBs and DDE in human milk sampled during different periods up to 1997. During the course of 20–30 yr the levels of organochlorine compounds in human milk have decreased to various extent. A decrease to the half of the original concentration was attained in the range of 4–17 yr periods. On the contrary to the organochlorine compounds, the concentrations of PBDEs have increased during the period 1972–1997, indicating a doubling of the levels by 5 yr. The levels reflect the environmental contamination and background levels in the population. The accumulation and ongoing increase in the levels of PBDEs calls for immediate measures to stop the environmental pollution and human exposure to PBDEs.