Breast-feeding exposure of infants to cadmium, lead, and mercury: a public health viewpoint

Evaluation of cadmium and mercury on cardiovascular and neurological systems: Effects on humans and fish

Chemicals are at the top of public health concerns and metals have received much attention in terms of toxicological studies. Cadmium (Cd) and mercury (Hg) are among the most toxic heavy metals and are widely distributed in the environment. They are considered important factors involved in several organ disturbances. Heart and brain tissues are not among the first exposure sites to Cd and Hg but they are directly affected and may manifest intoxication reactions leading to death. Many cases of human intoxication with Cd and Hg showed that these metals have potential cardiotoxic and neurotoxic effects. Human exposure to heavy metals is through fish consumption which is considered as an excellent source of human nutrients. In the current review, we will summarize the most known cases of human intoxication with Cd and Hg, highlight their toxic effects on fish, and investigate the common signal pathways of both Cd and Hg to affect heart and brain tissues. Also, we will present the most common biomarkers used in the assessment of cardiotoxicity and neurotoxicity using Zebrafish model.

Detection of Cadmium and Lead in Kidney Stones. Associations with Patient Demographics, Stone Composition, and Smoking

BACKGROUND

Kidney stones are a highly prevalent disease worldwide. Additionally, both environmental and occupational exposure to Pb and Cd continue to be prevalent globally and can result in renal toxicity. The objective of this study was to examine the potential presence of Pb and Cd in kidney stones, and to assess for correlation with demographic factors including smoking, gender, age, and kidney stone matrix composition.

METHODS

Patient kidney stones (n = 96) were analyzed using Fourier transform infrared spectroscopy to identify the stone constituents. Cd and Pb concentrations (µg/g) were determined by inductively coupled plasma mass spectrometry. Cd and Pb concentrations were correlated using bivariable and multivariable statistical analysis with demographic factors (age, gender, smoking status), and kidney stone composition.

RESULTS

Kidney stone Cd (median 0.092 µg/g, range 0.014 to 2.46) and Pb concentrations (median 0.95 µg/g, range 0.060 to 15.4) were moderately correlated (r = 0.56, P < 0.0001). Cd concentrations were positively associated with patient history of smoking, patient age, and calcium oxalate monohydrate levels while negatively associated with struvite and uric acid/uric acid dihydrate. Pb concentrations were positively associated with females and apatite levels while negatively associated with uric acid/uric acid dihydrate. After holding constant other stone type composition levels, smoking status, and age, both Pb and Cd were positively associated with apatite and negatively associated with uric acid/uric acid dihydrate, struvite, and calcium carbonate.

CONCLUSIONS

Cd and Pb kidney stone concentrations are associated with specific kidney stone types. Cd and Pb kidney stone concentrations are both associated with smoking.

Contamination of breast milk with lead, mercury, arsenic, and cadmium in Iran: a systematic review and meta-analysis

Breast milk is a complete food for the development of the newborn, but it can also be an important route for environmental pollutants transmission to the infants. This study was aimed to evaluate the status of heavy metals including lead (Pb), mercury (Hg), cadmium (Cd) and arsenic (As) in the breast milk of Iranian mothers. The international databases including Scopus, PubMed, Web of Science and the Persian electronic databases including Scientific Information Database, IranMedex and Magiran were examined to find relevant articles published until July 2021. A total of 23 studies examined the levels of toxic metals in Iranian breast milk samples. According to the findings, the pooled average concentrations (µg/L) of Pb, Cd, Hg and As were 25.61, 2.40, 1.29 and 1.16, respectively. The concentration of Hg and Pb in colostrum milk was more than twice of mature milk. The Hg mean concentration in the breast milk of mothers with at least one amalgam-filled tooth was approximately three times that of mothers without amalgam-filled teeth. Risk assessment analysis indicated that the intake of Pb and Hg by infants through breastfeeding can be considered a health concern in Iran. It seems necessary to reduce the Pb exposure of pregnant and lactating women in Iran. However, more extensive studies are needed to clarify the toxic metals' exposure status of infants through breast milk in other parts of the country.

Breast milk contribution to tissue mercury levels in rat pups examined by cross-fostering at birth

The developing perinatal brain is vulnerable to methylmercury (MeHg) exposure. The contribution of breast milk to tissue MeHg levels in offspring is a significant public health concern because breast milk contains a certain amount of MeHg. Here, the contribution of MeHg transferred via breast milk to the Hg levels in the tissues of pups (Wistar rats) was investigated. Mated maternal rats were fed a MeHg (2 ppm)-supplemented or a control diet during pregnancy. Following parturition, male neonates from each group were cross-fostered between exposed or control dams, and they were further raised by dams fed a MeHg-supplemented diet or a control diet during lactation. Consequently, we evaluated three pup groups, which were raised by dams exposed to MeHg during pregnancy (P pups), lactation (L pups), or pregnancy and lactation (PL pups). Total mercury (THg) concentrations in the tissues of the offspring were measured at birth (postnatal day 0 [PD0]), during lactation (PD6, PD12, and PD19), and after weaning (PD29 and PD36). Blood and brain THg levels in the P and PL pups declined dramatically during lactation, however, there were no considerable differences between the two groups at PD6 and PD12. In contrast, blood and brain THg levels in the L pups increased slightly during lactation. The increase in the THg levels in the blood and brain of L pups at PD12 were approximately 3.3% and 1.5%, respectively, compared to the corresponding THg levels in the neonates in the P and PL groups. Our results suggest that if the MeHg exposure level during pregnancy is not high enough to cause neuronal development defects in the fetus, the exposure via breast milk is not a significant concern.

Water Security and Nutrition: Current Knowledge and Research Opportunities

Water is an essential nutrient that has primarily been considered in terms of its physiological necessity. But reliable access to water in sufficient quantities and quality is also critical for many nutrition-related behaviors and activities, including growing and cooking diverse foods. Given growing challenges to water availability and safety, including climate change, pollution, and infrastructure degradation, a broader conceptualization of water and its diverse uses is needed to sustainably achieve global nutrition targets. Therefore, we review empirical and qualitative evidence describing the linkages between water security (the reliable availability, accessibility, and quality of water for all household uses) and nutrition. Primary linkages include water security for drinking, food production and preparation, infant and young child feeding, and limiting exposure to pathogens and environmental toxins. We then identify knowledge gaps within each linkage and propose a research agenda for studying water security and nutrition going forward, including the concurrent quantification of both food and water availability, accessibility, use, and stability. By making explicit the connections between water security and nutritional well-being, we aim to promote greater collaboration between the nutrition and water, sanitation, and hygiene sectors. Interdisciplinary policies and programs that holistically address the water-nutrition nexus, versus those that focus on water and nutrition independently, are likely to significantly advance our ability to ensure equitable access to healthy foods and safe water for all.

Cadmium exposure activates NADPH oxidase, renin-angiotensin system and cyclooxygenase 2 pathways in arteries, inducing hypertension and vascular damage

Exposure to high concentrations of cadmium (Cd), widely used in many industries and found in air, food and contaminated water, is not uncommon. Cd damages the cardiovascular system, but the vascular mechanisms involved are not fully understood. This study investigated the mechanisms involved in cardiovascular damage after exposure to high Cd concentrations. Three-month-old male Wistar rats were treated intraperitoneally for 14 days with distilled water (Untreated group) or 1 mg/kg cadmium chloride (Cd group). We investigated the systolic blood pressure (SBP) and vascular reactivity of mesenteric resistance arteries (MRA) and the aorta by analysing contractile and relaxation responses in the absence and presence of the endothelium; we also evaluated pathways involved in vascular tone regulation. Superoxide anion production, COX-2 protein expression and in situ detection of COX-2, AT-1, and NOX-1 were evaluated. Oxidative status, creatinine level and angiotensin-converting enzyme (ACE) activity in plasma were also evaluated. Fourteen-day exposure to a high Cd concentration induced hypertension associated with vascular dysfunction in MRA and the aorta. In both vessels, there was increased participation of cyclooxygenase 2 (COX2), angiotensin II type 1 (AT1) receptor and NOX1. MRA also presented endothelial dysfunction, denoted by impaired acetylcholine-mediated relaxation. All vascular changes were accompanied by increased reactive oxygen species production and COX2, NOX1 and AT1 receptor expression in vascular tissue. Overall, high Cd concentrations induced cardiovascular damage: hypertension, endothelial dysfunction and vascular damage in conductance and resistance arteries, NADPH oxidase, renin-angiotensin system and COX2 pathway activation.

Mercury exposure and its effects on fertility and pregnancy outcome

Mercury (Hg), a highly toxic environmental pollutant, shows harmfulness which still represents a big concern for human health, including hazards to fertility and pregnancy outcome. Research has shown that Hg could induce impairments in the reproductive function, cellular deformation of the Leydig cells and the seminiferous tubules, and testicular degeneration as well as abnormal menstrual cycles. Some studies investigated spontaneous abortion and complicated fertility outcome due to occupational Hg exposure. Moreover, there is a relation between inhaled Hg vapour and reproductive outcome. This MiniReview evaluates the hypothesis that exposure to Hg may increase the risk of reduced fertility, spontaneous abortion and congenital deficits or abnormalities.

Total, organic, and inorganic mercury in human breast milk: levels and maternal factors of exposure, systematic literature review, 1976-2017

This systematic review summarizes the finding of 58 studies from 33 countries, which assessed mercury concentrations in breast milk and the factors related to the level of contamination. We performed a literature search in Pubmed, Science Direct, and Google Scholar databases for studies published between 1976 and 2017 that are monitoring and measuring mercury in human breast milk and investigating the associated factors. Then, we extracted more information about the aim of the study, the country, samples size, time of lactation, mercury concentration, and other data. Most of the studies used mature milk or colostrum for analysis and in about 60% of them, the concentrations exceed significantly the limit set by the World Health Organization (WHO) of 1.7 µg/l; In addition, many factors and parameters were related to the level of mercury contamination in breast milk. Periodic monitoring surveys are recommended in each country to evaluate the level of mercury in milk of lactating women and to estimate the level of exposure of newborns.

Optimization and validation of a fast digestion method for the determination of major and trace elements in breast milk by ICP-MS

Breast milk guarantees all the nutrients required by infants during their first few months of life and remains the most important food source for their health and growth. However, the mother may transfer potentially toxic chemicals to the suckling infant through breastfeeding. The aim of this study was to optimize and validate a fast method for the determination of a total content of 34 elements (Al, As, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cs, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, Sb, Se, Si, Sn, Sr, Te, Ti, Tl, U, V, and Zn) in liquid and lyophilized breast milk. The samples were subjected to HNO₃:H₂O₂ (2:1) digestion in an open vessel heated in a water bath (WBD; 80 °C) and subsequently analysed by quadrupole inductively coupled plasma mass spectrometry equipped with a collision-reaction interface. The performance of the proposed method was evaluated in terms of selectivity, detection and quantification limits, linearity, accuracy, and robustness by using standard reference materials and filed samples of breast milk. Compared to microwave-assisted acid digestion, the proposed open vessel digestion allows a significant reduction in treatment time and sample manipulation, while maintaining a similar analytical performance. Masses of 0.5 g of breast milk were efficiently digested with the WBD treatment allowing a residual carbon content lower than 60 mg L^-1 and a residual acidity lower than 0.87 mol L^-1 in final digested samples. Thus, it shows great potential for application to routine analysis. The method provides satisfactory detection limits and good performance (trueness and recovery percentages 80-111%; coefficient of variation <10%; and relative repeatability <15%) and allows a high sample throughput for multi-elemental determination in human biomonitoring studies.

Use of human milk in the assessment of toxic metal exposure and essential element status in breastfeeding women and their infants in coastal Croatia

Pregnant and lactating women and infants are vulnerable population groups for adverse effects of toxic metals due to their high nutritional needs and the resultant increased gastrointestinal absorption of both, essential and toxic elements. Although breastfeeding is recommended for infants worldwide, as human milk is the best source of nutrients and other required bioactive factors, it is also a pathway of maternal excretion of toxic substances including toxic metals and thus a source of infant exposure. The aim of this research was to assess health risks in breastfeeding women in the coastal area of the Republic of Croatia and their infants (N=107) due to maternal exposure to Cd and Pb via cigarette smoking, and Hg via seafood and dental amalgam fillings, and their interaction with essential elements. Biological markers of exposure were the concentrations of main toxic metals Pb, Cd and Hg in maternal blood and three types of breast milk throughout lactation stages. Biological markers of effects were the levels of essential elements Ca, Fe, Cu, Zn and Se in maternal serum and breast milk. With regard to cigarette smoking as a source of exposure to Cd and Pb, there were effects of smoking on Cd concentration in blood and correlations between the smoking index and Cd concentrations in maternal blood (ρ=0.593; P<0.001) and mature milk (ρ=0.271; P=0.011) and Pb concentration in transitional milk (ρ=0.280; P=0.042). Regarding fish, we found correlations between weekly consumption frequency and total Hg concentrations in maternal blood (ρ=0.292; P=0.003) and mature milk (ρ=0.303; P=0.003). The number of dental amalgam fillings correlated with total Hg concentrations in colostrum (ρ=0.489; P=0.005) and transitional milk (ρ=0.309; P=0.018). As for the essential element status, only Se levels in maternal serum decreased by 10% in persons who continued smoking during pregnancy compared to non-smokers. In conclusion, the levels of main toxic metals Cd, Pb and Hg and essential elements Ca, Fe, Cu, Zn and Se in maternal blood and three types of breast milk samples in the studied area of coastal Croatia showed no risk of disrupted essential element levels with regard of toxic metal exposure in both breastfeeding women and their infants.

Breast Milk Lead Levels in 3 Major Regions of the West Bank of Palestine

BACKGROUND

Lead is a neurotoxic pollutant that is ubiquitously spread in our environment. Breast milk contaminated with lead poses a potential risk of exposing a recipient infant to lead.

OBJECTIVES

The primary aims of this study were to evaluate the breast milk lead levels (BMLLs) in breastfeeding mothers in 3 major regions of the West Bank of Palestine and to investigate the effects of some sociodemographic variables on the BMLLs.

METHODS

Breast milk samples were collected from 89 breastfeeding mothers from the Nablus, Ramallah, and Jerusalem regions and analyzed for their BMLLs using graphite furnace atomic absorption spectrophotometry. Breastfeeding mothers were interviewed and responded to a sociodemographic questionnaire.

RESULTS

The median BMLL was 4.0 µg/L, ranging from 2.0 to 12.0 µg/L. Breast milk lead levels in 19.1% of the samples analyzed were higher than the World Health Organization's safety limits of 2.0 to 5.0 µg/L for an occupationally unexposed population. Breast milk lead levels were significantly higher in breast milk of mothers who lived in cities and refugee camps (P < .01), had lower monthly household income levels (P < .05), lived close to paint shops (P < .05), lived in houses with peeling or chipping paint (P < .05), used eye kohl (P < .01), and worked in agriculture for a duration longer than 3 years (P < .01).

CONCLUSION

Breast milk lead levels were higher than the safety limits for occupationally unexposed populations. Authorities need to implement measures to eliminate or reduce lead exposure, especially in refugee camps and cities. Marketed eye kohl preparations should be tested for their lead contents.

Arsenic, cadmium, lead, and aluminium concentrations in human milk at early stages of lactation

BACKGROUND

Human milk is considered to be the best nutrition for all infants because it provides the optimal source of nutritional, immunological, developmental, psychological, economic, practical, and environmental benefits in both the short and long terms. To the best of our knowledge, few studies in Taiwan have examined the toxicant levels in breast milk and associated factors.

METHODS

The research was carried out over a 6-month period. Forty-five healthy lactating women, who delivered full-term newborns at our maternity ward, were recruited, and all participants had been living in coastal urban areas of mid-Taiwan for at least 3 years. One hundred and eighty human milk samples were collected on four occasions, which were classified into four lactation stages as follows: colostrums, transitional milk, early mature milk, and mature milk.

RESULTS

We found that lead, cadmium, aluminium, and arsenic concentrations were the highest in colostrums: 13.22 ± 3.58 ng/mL, 1.37 ± 0.94 ng/mL, 56.45 ± 22.77 ng/mL, and 1.50 ± 1.50 ng/mL, respectively. The results of lead, cadmium, aluminium, and arsenic determination in human milk samples demonstrated a trend of decline of microelement concentrations with advancing stages of lactation. We found that the infants of smoking mothers were exposed to more cadmium than infants of nonsmoking mothers (p < 0.05).

CONCLUSION

According to our findings, frequent routine sampling of breast milk is worthwhile. Prevention strategies including behavior modification and education on proper nutrition should be provided to women who are at high risk of toxicant exposure. In summary, breastfeeding is still generally encouraged and recommended.

Maternal blood, plasma, and breast milk lead: lactational transfer and contribution to infant exposure

BACKGROUND

Human milk is a potential source of lead exposure. Yet lactational transfer of lead from maternal blood into breast milk and its contribution to infant lead burden remains poorly understood.

OBJECTIVES

We explored the dose-response relationships between maternal blood, plasma, and breast milk to better understand lactational transfer of lead from blood and plasma into milk and, ultimately, to the breastfeeding infant.

METHODS

We measured lead in 81 maternal blood, plasma, and breast milk samples at 1 month postpartum and in 60 infant blood samples at 3 months of age. Milk-to-plasma (M/P) lead ratios were calculated. Multivariate linear, piecewise, and generalized additive models were used to examine dose-response relationships between blood, plasma, and milk lead levels.

RESULTS

Maternal lead levels (mean±SD) were as follows: blood: 7.7±4.0 μg/dL; plasma: 0.1±0.1 μg/L; milk: 0.8±0.7 μg/L. The average M/P lead ratio was 7.7 (range, 0.6-39.8) with 97% of the ratios being >1. The dose-response relationship between plasma lead and M/P ratio was nonlinear (empirical distribution function=6.5, p=0.0006) with the M/P ratio decreasing by 16.6 and 0.6 per 0.1 μg/L of plasma lead, respectively, below and above 0.1 μg/L plasma lead. Infant blood lead level (3.4±2.2 μg/dL) increased by 1.8 μg/dL per 1 μg/L milk lead (p<0.0001, R2=0.3).

CONCLUSIONS

The M/P ratio for lead in humans is substantially higher than previously reported, and transfer of lead from plasma to milk may be higher at lower levels of plasma lead. Breast milk is an important determinant of lead burden among breastfeeding infants.

Heavy metals in raw cow and ewe milk from north-east Iran

The presence of toxic metals in milk may create significant health problems for the population. In this study, 1440 raw cow and ewe milk samples from 18 townships in north-east Iran were analysed in four different seasons. Lead, cadmium and mercury levels were determined using atomic absorption spectrophotometry. Mean concentration of lead, cadmium and mercury in cow milk samples was 12.9 ± 6.0, 0.3 ± 0.3 and 3.1 ± 0.3 ng g⁻¹, respectively, and in ewe milk samples, these mean values were 14.9 ± 7.8, 1.6 ± 1.2 and 3.1 ± 0.3 ng g⁻¹, respectively. Statistical analyses showed that lead and cadmium concentrations in ewe milk were significantly higher than in cow milk. Concentrations of these metals in ewe milk varied significantly with different seasons. As the concentrations did not exceed the safety limits, they could not pose a serious danger to public health.

Breast milk lead and cadmium levels in suburban areas of Nanjing, China

OBJECTIVE

To evaluate levels of lead (Pb) and cadmium (Cd) in the breast milk in the second postpartum month, to investigate the relationship between Pb/Cd levels in breast milk and some sociodemographic parameters, and to explore whether these levels affect the infants' physical status or the mothers' psychological status (postpartum depression).

METHODS

A cross-sectional study was conducted between November 2009 and December 2010. Altogether 170 healthy mothers were enrolled from Nanjing Maternity and Child Health Care Hospital. The inclusion criteria were: voluntary to participate in this study, healthy, with no chronic disease, breastfeeding in the second postpartum month, living in a suburban but not non-industrial area of Nanjing, and not occupationally exposed to toxic metals. All the mothers completed a questionnaire and were evaluated based on the Edinburgh Postpartum Depression Scale (EPDS) to identify the risk of postpartum depression. Pb and Cd levels in breast milk were determined by inductively coupled plasma mass spectroscopy. The infants of these mothers were examined for their z scores of weight for age, length for age, head circumference for age, and body mass index for age.

RESULTS

The median breast milk levels of Pb and Cd were 40.6 μg/L and 0.67 μg/L, respectively. In 164 (96.5%) of the 170 samples, Pb levels were higher than the limit reported by the World Health Organization (> 5 μg/L). Breast milk Cd level was > 1 μg/L in 54 (31.8%) mothers. The mothers with a history of anemia had a higher breast milk Pb level than those without a history of anemia (41.1 μg/L vs. 37.9 μg/L, P = 0.050). The median breast milk Cd level in those who were active and passive smokers during pregnancy was significantly higher than that in non-smokers (0.88 μg/L vs. 0.00 μg/L, P = 0.025). The breast milk Cd level in the mothers not taking iron and vitamin supplements for 2 months postpartum was higher than in those taking the supplements (iron supplement: 0.74 μg/L vs. 0.00 μg/L, P = 0.025; vitamin supplement: 0.78 μg/L vs. 0.00 μg/L, P = 0.005). Breast milk Cd level at the second postpartum month was negatively correlated with the z scores of head circumference (r = - 0.248, P = 0.042) and weight for age at birth (r =- 0.241, P = 0.024) in girls. No correlation was found between the breast milk Pb/Cd levels and the EPDS scores.

CONCLUSION

Considering the high levels of Pb and Cd in breast milk in this study, breast milk monitoring programs are necessary.

Hair analysis in health assessment

BACKGROUND

Hair analysis is used for estimation of the nutritional status of individuals. In the present work, a systematic review on the relation between the mineral composition of hair and the physical or mental disorders is discussed. Detailed information of examined populations, methods of sample preparations and analytical techniques are presented.

METHODS

A systematic literature search in four electronic databases Scopus, PubMed, Web of Science and Medline (from 1997 to 2012/01/31) for English language articles was performed. In addition, a reference list and manual search was undertaken.

RESULTS

The following number of studies was included: 66. Most of the authors reported that there exists a correlation between deficiency or excess of some elements in hair and occurrence of some diseases, such as: autism, cancer, hypertension, myocardial infarction, kidney disease and diabetes mellitus. However, not all results were consistent.

CONCLUSIONS

Most of the authors concluded that the profile of hair mineral imbalance might be useful as a diagnostic tool for the early diagnosis of many diseases. However, it seems that there is a need to standardize sample preparation procedures, in particular washing and mineralization methods.

Comparison of digestion procedures and methods for quantification of trace lead in breast milk by isotope dilution inductively coupled plasma mass spectrometry

Measurement of lead in breast milk is an important public health consideration and can be technically quite challenging. The reliable and accurate determination of trace lead in human breast milk is difficult for several reasons including: potential for contamination during sample collection, storage, and analysis; complexities related to the high fat content of human milk; and poor analytic sensitivity at low concentrations. Breast milk lead levels from previous published studies should therefore be reviewed with caution. Due to the difficulty in identifying a method that would successfully digest samples with 100% efficiency, we evaluated three different digestion procedures including: (1) dry ashing in a muffle furnace, (2) microwave oven digestion, and (3) digestion in high pressure asher. High temperature, high pressure asher digestion was selected as the procedure of choice for the breast milk samples. Trace lead analysis was performed using isotope dilution (ID) inductively coupled plasma mass spectrometry (ICP-MS). Measured lead concentrations in breast milk samples (n = 200) from Mexico ranged from 0.2 to 6.7 ng ml^-1. The precision for these measurements ranged from 0.27-7.8% RSD. Use of strict contamination control techniques and of a very powerful digestion procedure, along with an ID-ICP-MS method for lead determination, enables us to measure trace lead levels as low as 0.2 ng ml^-1 in milk (instrument detection limit = 0.01 ng ml^-1).

Role of essential trace minerals on the absorption of heavy metals with special reference to lead

Heavy metals are important toxicants known to exert adverse effects in humans and animals, given sufficient exposure and accumulation in the body. This has a great concern both at personal and public health risk. Heavy metals are also known to interact with the essential trace minerals at the level of absorption and also during the metabolism. The adverse effects of the absorbed and accumulated heavy metals include neurological, reproductive, renal and hematological systems. Children are more sensitive than adults to the effects of lead. Efforts are made to understand the mechanism of the interactions of heavy metals with essential trace minerals at the level of absorption. With available sensitive and specific methodologies like Anodic Stripping Voltammetry for the evaluation of the levels of toxic heavy metals such as lead, cadmium, mercury etc., better understanding of heavy metal absorption is made possible.Due to the poor nutritional standards, risk of heavy metal exposure is still a major concern in developing countries. Studies carried out by the author have provided evidence towards the understanding of the prevailing mechanisms of metal-metal interaction at the intestinal level. During growth and development the demand for the essential minerals being at higher level, differentiation of various essential metals and heavy metals pose an inherent problem due to certain common properties shared by them. With this approach to the problem of heavy metal toxicity, it is preventable not only with environmental intervention but also by the nutritional management.

Mercury, lead and cadmium in human milk in relation to diet, lifestyle habits and sociodemographic variables in Madrid (Spain)

BACKGROUND

Although breastfeeding is the ideal way of nurturing infants, it can be a source of exposure to toxicants. This study reports the concentration of Hg, Pb and Cd in breast milk from a sample of women drawn from the general population of the Madrid Region, and explores the association between metal levels and socio-demographic factors, lifestyle habits, diet and environmental exposures, including tobacco smoke, exposure at home and occupational exposures.

METHODS

Breast milk was obtained from 100 women (20 mL) at around the third week postpartum. Pb, Cd and Hg levels were determined using Atomic Absorption Spectrometry. Metal levels were log-transformed due to non-normal distribution. Their association with the variables collected by questionnaire was assessed using linear regression models. Separate models were fitted for Hg, Pb and Cd, using univariate linear regression in a first step. Secondly, multivariate linear regression models were adjusted introducing potential confounders specific for each metal. Finally, a test for trend was performed in order to evaluate possible dose-response relationships between metal levels and changes in variables categories.

RESULTS

Geometric mean Hg, Pb and Cd content in milk were 0.53 μg L(-1), 15.56 μg L(-1), and 1.31 μg L(-1), respectively. Decreases in Hg levels in older women and in those with a previous history of pregnancies and lactations suggested clearance of this metal over lifetime, though differences were not statistically significant, probably due to limited sample size. Lead concentrations increased with greater exposure to motor vehicle traffic and higher potato consumption. Increased Cd levels were associated with type of lactation and tended to increase with tobacco smoking.

CONCLUSIONS

Surveillance for the presence of heavy metals in human milk is needed. Smoking and dietary habits are the main factors linked to heavy metal levels in breast milk. Our results reinforce the need to strengthen national food safety programs and to further promote avoidance of unhealthy behaviors such as smoking during pregnancy.

Mercury content of blood transfusions for infants with extremely low birth weight

OBJECTIVES

To assess whether blood transfusions for infants with birth weights of 1000 g or less are a source of mercury and whether any mercury delivered through the transfusion is above the currently set oral reference dose.

PATIENTS AND METHODS

We studied an observational cohort. Inclusion criteria included birth weight 1000 g or less and receipt of 1 or more packed red blood cell transfusions. Packed red blood cell units were tested prospectively for mercury levels. The quantity of transfused mercury was calculated on the basis of transfused volume and packed red blood cell mercury level. The resulting mercury level was compared with the reference dose as set by the Agency for Toxic Substances and Disease Registry, the World Health Organization, and the US Environmental Protection Agency.

RESULTS

Thirty-seven infants (birth weight: 736 ± 157 g; gestational age: 25.5 ± 1.5 weeks) met the inclusion criteria. A total of 325 transfusions from 49 packed red blood cell units were administered. Mercury was detected in 40 units. The average mercury level in a packed red blood cell unit was 1.9 ± 2.6 μg/L (median: 0.9 μg/L [interquartile range: 0.3-2.5]). None of the infants received any mercury above the reference dose set by the Agency for Toxic Substances and Disease Registry and the World Health Organization. Twelve infants received 1 transfusion, and 5 infants received 2 transfusions above the Environmental Protection Agency reference dose during their entire hospitalization.

CONCLUSIONS

Packed red blood cells are a source of mercury for infants. However, the amount delivered is low compared with currently set safety levels. The episodes in which mercury intake exceeded the reference dose were rare. However, without long-term follow-up, no conclusions can be made about the cognitive implications of these episodes.

Breast milk lead and cadmium levels from suburban areas of Ankara

The objectives of this study were (1) to evaluate levels of lead (Pb) and cadmium (Cd) in the breast milk at 2 months postpartum, (2) to investigate the relationship between Pb and Cd levels in breast milk and some sociodemographic parameters and (3) to detect whether these levels have any influence on the infant's physical status or on postpartum depression in the mothers. Pb and Cd levels in breast milk were determined by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The median breast milk concentrations of Pb and Cd were 20.59 and 0.67 μg/l, respectively. In 125 (87%) of 144 samples, Pb levels were higher than the limit in breast milk reported by the World Health Organization (WHO) (> 5 μg/l). Breast milk Cd levels were > 1 μg/l in 52 (36%) mothers. The mothers with a history of anemia at any time had higher breast milk Pb levels than those without a history of anemia (21.1 versus 17.9 μg/l; p=0.0052). The median breast milk Cd levels in active and passive smokers during pregnancy were significantly higher than in non-smokers (0.89, 0.00 μg/l, respectively; p=0.023). The breast milk Cd levels of the mothers who did not use iron and vitamin supplements for 2 months postpartum were found to be higher than in those who did use the supplements (iron: 0.73, 0.00 μg/l, p=0.023; vitamin: 0.78, 0.00 μg/l, p=0.004, respectively). Breast milk Cd levels at the 2nd month were correlated negatively with the z scores of head circumference and the weight for age at birth (r=-0.257, p=0.041 and r=-0.251, p=0.026, respectively) in girls. We found no correlation between the breast milk Pb and Cd levels and the Edinburgh Postpartum Depression Scale scores. Breast milk monitoring programs should be conducted that have tested considerable numbers of women over time in view of the high levels of Pb in breast milk in this study.

Lead levels in human milk and children's health risk: a systematic review

Lead (Pb), a naturally-occurring element and industrially-produced metal, is highly toxic to children, causing intellectual and behavioral deficits, hyperactivity, fine motor function deficits, decreased intelligence quotient, alteration of hand-eye coordination, and problems in reaction time. Children's exposure to Pb occurs mainly through ingestion of contaminated food, water and soil. Few discussions have been held on the magnitude and potential risk associated with exposure from the consumption of breast milk. Hence, this research was designed to systematically review the scientific literature on published epidemiologic studies, with an emphasis on the study designs and analytical procedures used for Pb assessment in breast milk. From a total of 112 selected articles published since the 1980s, 11 met the inclusion criteria. A review of the data indicated that Pb levels varied from 0.15 to 6.1 microg L(-1) in mature milk samples, from 0.48 to 14.6 microg L(-1) in colostrum samples, and were non-detectable in some samples. The milk/blood ratio, which estimates the mean efficiency transfer of lead from blood to milk, varied between 0.01 and 0.48. The heterogeneity of methods revealed by our assessment of published studies underscores the need for harmonization of study designs and sample collection and analysis protocols to reflect specific exposure scenarios. Human milk seems to be one of the relevant biological matrices for use as a biomarker for assessing children's health risk to Pb poisoning.

Lead levels in milk and blood from donors to the Breast Milk Bank in Southern Brazil

Brazilian scientific literature on the adverse effects of lead on the general population is still very limited. Lead, a potentially toxic substance, has become a public health problem due to its effects, mainly those affecting the central nervous system and on the synthesis of heme. The aim of this study is to evaluate the level of lead exposure of donors to the Breast Milk Bank in the city of Londrina, Parana, by estimating the levels of that metal in milk and blood samples. This is a cross-sectional study conducted during the period between January and July 2007. All mothers enrolled as donors in the Breast Milk Bank were included in this study. A total of 92 volunteers presenting the following inclusion criteria were evaluated in the project: volunteers who were healthy, without any chronic disease, full-term pregnancy, breastfeeding between the 15th and 210 th day after giving birth, and living in the city of the study. Lead in milk and blood was quantified using the inductive coupled plasma mass spectroscopy (ICP-MS) technique. All mothers signed a consent form approved by the Research Ethics Committee from Londrina State University. The median lead concentration in milk samples was 3.0 microg/L, varying from 1.0 to 8.0 microg/L. The median of lead in blood was of 2.7 microg/dl, varying from 1.0 to 5.5 microg/dl. In Spearman correlation analysis, significant but modest correlations could be observed between the concentration of lead in blood and in milk (r(s)=0.207, p=0.048), hemoglobin and ALAD activity (r(s)=-0.264, p=0.011), level of lead in blood and mother's age (r(s)=0.227, p=0.029). However, for hematocrit and hemoglobin, the correlation was higher (r(s)=0.837, p<0.001). No statistically significant associations were found between concentrations of lead in milk and blood and demographic variables studied, obtained through interviews and validated questionnaire. The mean of milk/blood lead ratio was equal to 0.11. In general, the values found in the present study are similar to those obtained in populations in other countries, and are within background levels.

Applicability of non-invasively collected matrices for human biomonitoring

With its inclusion under Action 3 in the Environment and Health Action Plan 2004-2010 of the European Commission, human biomonitoring is currently receiving an increasing amount of attention from the scientific community as a tool to better quantify human exposure to, and health effects of, environmental stressors. Despite the policy support, however, there are still several issues that restrict the routine application of human biomonitoring data in environmental health impact assessment. One of the main issues is the obvious need to routinely collect human samples for large-scale surveys. Particularly the collection of invasive samples from susceptible populations may suffer from ethical and practical limitations. Children, pregnant women, elderly, or chronically-ill people are among those that would benefit the most from non-invasive, repeated or routine sampling. Therefore, the use of non-invasively collected matrices for human biomonitoring should be promoted as an ethically appropriate, cost-efficient and toxicologically relevant alternative for many biomarkers that are currently determined in invasively collected matrices. This review illustrates that several non-invasively collected matrices are widely used that can be an valuable addition to, or alternative for, invasively collected matrices such as peripheral blood sampling. Moreover, a well-informed choice of matrix can provide an added value for human biomonitoring, as different non-invasively collected matrices can offer opportunities to study additional aspects of exposure to and effects from environmental contaminants, such as repeated sampling, historical overview of exposure, mother-child transfer of substances, or monitoring of substances with short biological half-lives.

Persistent environmental contaminants in human milk: concentrations and time trends in Italy

Breast milk monitoring studies of persistent and toxic environmental contaminants are of primary importance for carrying out an adequate risk assessment at the actual levels of human exposure and represent a major source of information on infant perinatal exposure. Milk specimens from mothers of the general population of the Venice and Rome areas were collected over the 1998-2001 period, pooled, and analyzed for selected persistent organic pollutants such as polychlorodibenzodioxins (PCDDs), polychlorodibenzofurans (PCDFs), polychlorobiphenyls (PCBs), organochlorinated pesticides (p,p'-DDE, p,p'-DDT, hexachlorobenzene), and polybromodiphenyl ethers (PBDEs), and the heavy metals Cd, Co, Cu, Hg, Mn, Pb, Sn, and Zn. The goal was to verify whether mother milk from the Venice area, whose lagoon is partly under direct industrial impact, had a contaminant load greater than that from the Rome area, primarily urban. For mothers from the Venice area, the correlation between fish and fishery product consumption and contaminant concentrations in milk was also explored, with however inconclusive results. The concentrations of PCDDs, PCDFs, dioxin-like PCBs, and organochlorinated pesticides determined in this study were compared with those available from a previous analytical work carried out on 1987 human milk pools of domestic origin: the declining trend of the aforesaid contaminants in milk is confirmed to be in agreement with what was observed in other European countries. The breast milk content of (137)Cs and (40)K radionuclides was also determined and compared with data obtained in other research programmes carried out in Italy: the health risk for breastfed infants was deemed to be not significant.

Testicular dysgenesis syndrome and Leydig cell function

Fertility among human beings appear to be on the decline in many Western countries, and part of the explanation may be decreasing male fecundity. A hypothesis has been put forward that decreasing semen quality may be associated with a testicular dysgenesis syndrome (TDS), a spectrum of disorders originating in early foetal life. TDS comprises various aspects of impaired gonadal development and function, including testicular cancer. A growing body of evidence, including animal models and research in human beings, points to lifestyle factors and endocrine disrupters as risk factors for TDS. We present our view of the emerging role of Leydig cell dysfunction with subsequent decreased testosterone levels in the pathogenesis of TDS.

Regulatory and nonregulatory strategies for improving children's environmental health in Canada

Epidemiological and toxicological studies established positive associations between environmental hazards and adverse child health outcomes, including cancer, learning disabilities, behavioral problems, developmental effects, low birth weight, and birth defects. The economic and societal costs associated with children's environmental health disorders were estimated to be substantial. The existence of knowledge gaps, lack of capacity, and the jurisdictional overlap of children's environmental health issues are some of the barriers that impede effective policy decision making. To improve children's environmental health and reduce economic and societal costs, current legislative frameworks could implement a series of amendments. The main federal, provincial, and municipal legislation used to protect children in Canada, either explicitly or implicitly, is reviewed. Recommendations for improving the existing framework for protecting and strengthening children's environmental health are proposed.

Smoking, cereal consumption, and supplementation affect cadmium content in breast milk

Breast milk might be a source of potentially toxic metals such as cadmium (Cd). The purpose of the present study is to provide data pertaining to the influence of maternal lifestyles on Cd concentrations in breast milk in the Austrian setting. Breast milk was obtained from 124 Austrian women. Each participant provided 10 ml of milk. A second group of eight mothers were recruited to investigate changes in their milk cadmium levels at 1, 3, 5, 7 and 9 weeks post partum. The study participants filled a questionnaire concerning nutrition, supplementation, and smoking habits. The samples were analyzed using GF-Atomic Absorption Spectrophotometer (AAS). The mean Cd content in breast milk was among the lowest in Europe (0.086 +/- 0.085 microg/l, 95% CI: 0.07-0.10; n = 124). Increased Cd levels in breast milk were found to be significantly associated with frequent cereal consumption and smoking. Smokers had a two-fold higher concentration than did non-smokers (0.15 versus 0.07 microg/l; P = 0.000). In contrast, low Cd levels in breast milk were associated with the intake of supplements containing trace elements or vitamins and trace elements (P < 0.05). This protective effect of supplements on Cd levels was only observed in non-smokers. The Cd levels registered in the present investigation were far below critical levels. We conclude that the current maternal Cd levels in Austria signify no risk for the breastfed infant of a healthy mother. Further research will have to focus on the specific effects of supplementation and smoking on Cd concentrations.

Analysis of the health risk of exposure to breast milk mercury in infants in Taiwan

The aim of this study was to assess the total concentration and health risk to infants of breast milk mercury in urban mothers and mothers married to fishermen in relation to fish intake in Taiwan. A total of sixty-eight healthy mothers were recruited for the study. The breast milk mercury geometric mean concentration was 2.02 microgl(-1) (n=56, range: 0.24-9.45 microgl(-1)) for the city group and 2.04 microgl(-1) (n=12, range: 0.26-8.62 microgl(-1)) for the fishermen's group. Of the three sources of mercury exposure (i.e., ingestion (breast milk), inhalation (ambient air), and dermal exposure (shower)), breast-feeding was found to be the largest (96.3-99.6% of the total). From a Monte Carlo simulation, in which methyl mercury accounted for about 50% of total mercury, the hazard quotient (exposure estimate/oral minimal risk level or target organ toxicity dose) exceeded 1.0 for 12.9% of urban babies and 18.8% of fishermen's babies (chronic oral minimal risk level and target organ toxicity dose: 3 x 10(-4)mgkg(-1)d(-1)). The calculated mercury exposure was 3.02 x 10(-1) microgkg(-1)d(-1) for a 3.49 kg urban baby boy and 3.06 x 10(-1) microgkg(-1)d(-1) for a 3.44 kg urban baby girl. These results suggest the life style of mothers (eating raw fish and shellfish such as used in "Sashimi" and "Sushi," and vitamin supplementation) may influence the mercury concentration in breast milk.

Níveis de chumbo em colostro humano: um estudo no Vale do Paraíba

OBJETIVOS: estimar os valores de chumbo em colostro humano, no Vale do Paraíba. MÉTODOS: trata-se de um estudo transversal, realizado em Taubaté, São Paulo, nos meses de outubro e novembro de 2003, com mães que deram à luz no Hospital Universitário de Taubaté. O colostro foi coletado em tubo apropriado e resfriado a -20º C. As variáveis independentes foram idade materna, paridade e peso do recém-nascido e idade gestacional. O chumbo foi quantificado utilizando-se a técnica de espectrometria de absorção atômica, por forno de grafite. Para análise estatística utilizou-se o teste "t" de Student e quando os dados não tinham distribuição normal, o teste U de Mann-Whitney; para as variáveis contínuas foi utilizada a correlação de Pearson. O nível de significância adotado foi alfa=5%. RESULTADOS: o chumbo foi detectado em 72 amostras das 76 estudadas (94,7% das amostras com IC95%: 88,2%-98,4%); o valor médio encontrado foi 154,4µg/L (dp=173,7µg/L). Não houve correlação nem diferenças entre os valores de chumbo e as variáveis estudadas. CONCLUSÕES: os valores encontrados estão acima dos descritos na literatura e torna-se necessária a identificação de possíveis fontes desse metal pesado no meio ambiente.

Human milk biomonitoring data: interpretation and risk assessment issues

Biomonitoring data can, under certain conditions, be used to describe potential risks to human health (for example, blood lead levels used to determine children's neurodevelopmental risk). At present, there are very few chemical exposures at low levels for which sufficient data exist to state with confidence the link between levels of environmental chemicals in a person's body and his or her risk of adverse health effects. Human milk biomonitoring presents additional complications. Human milk can be used to obtain information on both the levels of environmental chemicals in the mother and her infant's exposure to an environmental chemical. However, in terms of the health of the mother, there are little to no extant data that can be used to link levels of most environmental chemicals in human milk to a particular health outcome in the mother. This is because, traditionally, risks are estimated based on dose, rather than on levels of environmental chemicals in the body, and the relationship between dose and human tissue levels is complex. On the other hand, for the infant, some information on dose is available because the infant is exposed to environmental chemicals in milk as a "dose" from which risk estimates can be derived. However, the traditional risk assessment approach is not designed to consider the benefits to the infant associated with breastfeeding and is complicated by the relatively short-term exposures to the infant from breastfeeding. A further complexity derives from the addition of in utero exposures, which complicates interpretation of epidemiological research on health outcomes of breastfeeding infants. Thus, the concept of "risk assessment" as it applies to human milk biomonitoring is not straightforward, and methodologies for undertaking this type of assessment have not yet been fully developed. This article describes the deliberations of the panel convened for the Technical Workshop on Human Milk Surveillance and Biomonitoring for Environmental Chemicals in the United States, held at the Hershey Medical Center, Pennsylvania State College of Medicine, on several issues related to risk assessment and human milk biomonitoring. Discussion of these topics and the thoughts and conclusions of the panel are described in this article.

Risk assessment of chemicals and pharmaceuticals in the pediatric population: a workshop report

ATSDR and RIVM organized an Expert Panel Workshop on the Differences Between Children and Adults and Their Relevance to Risk Assessment. The workshop was held in June 2003, in Brussels, Belgium. The purpose of the workshop was to identify data gaps in current scientific knowledge related to children's health and to recognize areas of mutual interest that would serve as the basis for upcoming ATSDR/RIVM cooperative projects. The aim for both agencies is a better understanding of the issues related to children's health, and the improvement of scientifically based (chemical) risk assessment in children. Topics discussed included clinical trials/toxicity studies, testing in juvenile animals, PBPK modeling in children, and children's risk assessment.

Thiomersal in Vaccines

A number of affluent countries are moving to eliminate thiomersal (thimerosal), an ethylmercury preservative, from vaccines as a precautionary measure because of concerns about the potential adverse effects of mercury in infants. The WHO advocates continued use of thiomersal-containing vaccines in developing countries because of their effectiveness, safety, low cost, wide availability and logistical suitability in this setting. The guidelines for long-term mercury exposure should not be used for evaluating risk from intermittent single day exposures, such as immunisation using thiomersal-containing vaccines. Similar or higher mercury exposures likely occur from breast feeding and the health benefit of eliminating thiomersal from a vaccine, if any, is likely to be very small. On the other hand, the benefits accrued from the use of thiomersal-containing vaccines are considerably greater but vary substantially between affluent and developing regions of the world. Because of the contribution to overall mercury exposure from breast milk and diet in later life, the removal of thiomersal from vaccines would produce no more than a 50% reduction of mercury exposure in infancy and <1% reduction over a lifetime. Different public policy decisions are appropriate in different settings to achieve the lowest net risk, viewed from the perspectives of the individual vaccinee or on a population basis. In developing regions of the world, at least over the next decade, far more benefit will accrue from protecting children against widely prevalent vaccine-preventable diseases by focusing efforts aimed at improving infant immunisation uptake by using current, inexpensive, domestically-manufactured, thiomersal-containing vaccines, than by investing in thiomersal-free alternatives.

Persistent chemicals found in breast milk and their possible interactions

Chlorinated dibenzo-p-dioxins (CDDs), hexachlorobenzene, dichlorodiphenyl dichloroethane (p,p'-DDE), methylmercury, and polychlorinated biphenyls (PCBs) were selected as an important subset of persistent chemicals detected in breast milk for the purpose of reviewing data on their joint toxic actions following oral exposure. Epidemiological studies of possible health hazards associated with exposure to biopersistent chemicals in breast milk identify mild neurodevelopmental deficits as a possible health hazard. However, the studies did not analyze all the components of the above defined mixture, and, therefore, they are not directly useful for the purposes of conducting exposure-based assessments of hazards associated with this mixture. For this purpose, component-based methodology such as binary weight-of-evidence, the hazard index (HI) and the target-organ toxicity dose (TTD) approaches are recommended. Weight-of-evidence evaluation of the limited animal studies' data on interactions among CDDs, hexachlorobenzene, p,p-DDE, methylmercury, and PCBs indicates that the data are inadequate to warrant a concern for deviations from the additivity assumption. Further, exposure-based health assessments are used, in conjunction with evaluation of community-specific health outcome data, consideration of community health concerns, and biomedical judgement, to assess the degree of public health hazard presented by mixtures of substances released into the environment.

Effect of breast milk lead on infant blood lead levels at 1 month of age

Nursing infants may be exposed to lead from breast milk, but relatively few data exist with which to evaluate and quantify this relationship. This route of exposure constitutes a potential infant hazard from mothers with current ongoing exposure to lead as well as from mothers who have been exposed previously due to the redistribution of cumulative maternal bone lead stores. We studied the relationship between maternal breast milk lead and infant blood lead levels among 255 mother-infant pairs exclusively or partially breast-feeding through 1 month of age in Mexico City. A rigorous, well-validated technique was used to collect, prepare, and analyze the samples of breast milk to minimize the potential for environmental contamination and maximize the percent recovery of lead. Umbilical cord and maternal blood lead were measured at delivery; 1 month after delivery (+/- 5 days) maternal blood, bone, and breast milk and infant blood lead levels were obtained. Levels of lead at 1 month postpartum were, for breast milk, 0.3-8.0 microg/L (mean +/- SD, 1.5 +/- 1.2); maternal blood lead, 2.9-29.9 microg/dL (mean +/- SD, 9.4 +/- 4.5); and infant blood lead, 1.0-23.1 microg/dL (mean +/- SD, 5.5 +/- 3.0). Infant blood lead at 1 month postpartum was significantly correlated with umbilical cord (Spearman correlation coefficient rS = 0.40, p < 0.0001) and maternal (rS= 0.42, p < 0.0001) blood lead at delivery and with maternal blood (rS= 0.67, p < 0.0001), patella rS = 0.19, p = 0.004), and breast milk (rS = 0.32, p < 0.0001) lead at 1 month postpartum. Adjusting for cord blood lead, infant weight change, and reported breast-feeding status, a difference of approximately 2 microg/L (ppb; from the midpoint of the lowest quartile to the midpoint of the highest quartile) breast milk lead was associated with a 0.82 microg/dL increase in blood lead for breast-feeding infants at 1 month of age. Breast milk lead accounted for 12% of the variance of infant blood lead levels, whereas maternal blood lead accounted for 30%. Although these levels of lead in breast milk were low, they clearly have a strong influence on infant blood lead levels over and above the influence of maternal blood lead. Additional information on the lead content of dietary alternatives and interactions with other nutritional factors should be considered. However, because human milk is the best and most complete nutritional source for young infants, breast-feeding should be encouraged because the absolute values of the effects are small within this range of lead concentrations.

Six interaction profiles for simple mixtures

The Agency for Toxic Substances and Disease Registry (ATSDR) has a program for chemical mixtures that encompasses research on chemical mixtures toxicity, health risk assessment, and development of innovative computational methods. ATSDR prepared a guidance document that instructs users on how to conduct health risk assessment on chemical mixtures (Guidance Manual for the Assessment of Joint Toxic Action of Chemical Mixtures). ATSDR also developed six interaction profiles for chemical mixtures. Two profiles were developed for persistent environmental chemicals that are often found in contaminated fish and also can be detected in human breast milk. The mixture included chlorinated dibenzo-p-dioxins, hexachlorobenzene, dichlorodiphenyl dichloroethane, methyl mercury, and polychlorinated biphenyls. Two profiles each were developed for mixtures of metals and mixtures of volatile organic chemicals (VOCs) that are frequently found at hazardous waste sites. The two metal profiles dealt with (a) lead, manganese, zinc, and copper; and (b) arsenic, cadmium, chromium, and lead; the two VOCs mixtures dealt with (a) 1,1,1-trichloroethane, 1,1-dichloroethane, trichloroethylene, and tetrachloroethylene; and (b) benzene, ethylbenzene, toluene, and xylenes (BTEX). Weight-of-evidence methodology was used to assess the joint toxic action for most of the mixtures. Physiologically based pharmacokinetic modeling was used for BTEX. In most cases, a target-organ toxicity dose modification of the hazard index approach is recommended for conducting exposure-based assessments of noncancer health hazards.

Lead and mercury in breast milk

OBJECTIVE

Heavy metals are potentially toxic substances, especially for the susceptible infant. Exposure to mercury (Hg) and lead (Pb) may result in neurotoxic and nephrotoxic impairment and in anemia. Previous data on breast milk Pb and Hg contents are sparse or missing for the Austrian population. No evaluations of the influence of mothers' lifestyles on Pb and Hg levels in breast milk are available.

METHODS

Five- to 10-mL individual samples of breast milk were provided from healthy mothers in Vienna (urban; n = 59), Linz (industrial; n = 47), and Tulln (rural; n = 59). A questionnaire about area of residence, maternal nutrition, smoking habits, and dental fillings was filled out by the lactating mothers. Milk samples and infant formulas were lyophilized, wet-ashed with nitric acid (65%), and analyzed with atomic absorption spectrophotometry. Spiked skim milk powder was used as reference material. Statistical analysis included the Kruskal-Wallis test and multiple robust regression analysis.

RESULTS

Breast milk showed low Hg and Pb concentrations (Hg: 1.59 +/- 1.21 1g/l, n = 116; Pb: 1.63 +/- 1.66 6g/l, n = 138). Eight percent of the breast milk samples marginally exceeded the screening level of 3.5 micro g/L for Hg. Austrian Pb values declined strongly during the last 20 years. Bivariate comparison revealed that the factors significantly related to metal levels in breast milk were area of residence (Hg, Pb), prematurity (Hg), consumption of fish (Pb) and cereals (Hg), vitamin supplementation (Hg), and smoking (Pb). The Hg and Pb contents of cow milk and infant formulas were far below respective guideline values.

CONCLUSIONS

Neither Hg nor Pb concentrations exceeded critical levels. There are no reports on infants harmed by the intake of milk from unexposed mothers. We conclude that even theoretical risks from current Hg or Pb levels for the breastfed infant of a healthy mother can be ruled out.

Environmental exposure of the pediatric age groups in Cairo City and its suburbs to cadmium pollution

In a trial to assess the exposure of subjects in the pediatric age group to cadmium (Cd) pollution, serum Cd was estimated by atomic absorption spectrometry in 405 subjects, birth-18 years old, from Cairo City and its suburbs. Serum Cd mean concentrations were: 0.92 microg/l in 32 neonates (birth-4 weeks); 1.33 microg/l in 70 infants (4 weeks-2 years); 1.11 microg/l in 100 children in the preschool period (2-6 years); 1.34 microg/l in 103 primary school children (6-12 years); and 1.24 microg/l in 100 adolescents (12-18 years). In neonates, serum Cd was higher in babies with weights and heights that remained below the 5th percentile for age. Breast-fed infants had a serum Cd geometric mean level (1.25 microg/l) that was not in accordance to that of their mothers' milk (0.52 microg/l, P < 0.001), suggesting alternative routes of exposure. Environmental tobacco-smoke exposure was the most important determinant of Cd status in the school-aged children, the geometric mean being 1.42 microg/l in passive smokers vs. 1.2 microg/l in non-exposed children (P < 0.05). Moreover, adolescents who were active smokers had a significantly higher serum Cd level (1.7 microg/l) as compared to non-smokers (1.2 microg/l). Gender did influence the Cd status in adolescents, being higher among males, probably related to smoking, or to the difference in lifestyle of adolescents according to gender in the community. Alpha-1-microglobulinuria was accompanied by a higher serum Cd concentration in the group of adolescents only, suggesting a subclinical renal effect after several years of cumulative exposure. The residential classification, whether urban or suburban, did not influence the serum Cd status; neither did the present or past history of bronchial asthma. These findings certainly justify further evaluation of the problem of Cd pollution among Cairene individuals, knowing the long-term consequences of exposure to it. Systematic efforts for the proper disposal of Cd wastes and prevention of smoking in public places are recommended.

Breastfeeding in countries of the European Union and EFTA: current and proposed recommendations, rationale, prevalence, duration and trends

Recommendations suggest exclusive breast feeding for at least the first 4 to 6 months after birth. Paradoxically, an overwhelming proportion of breast feeding (BF) data in Europe refers to all BF, i.e. not only exclusive but also partial BF (including formula, juices, water, sweetened water etc). This makes it difficult to estimate to what extent the recommendations are met. There is currently strong evidence for recommending exclusive breast feeding for at least 6 months. Exclusive BF has progressively gained scientific support. Prevention of infections, allergies and chronic diseases and a favourable cognitive development are highlighted in the recent scientific literature. Further long-term studies on the effects of BF on prevention of chronic disease in the adult are needed. Great differences exist in BF prevalence and duration both within and between European countries. Trends point towards higher prevalence and duration, with some exceptions. Young mothers breast feed less than older mothers; single and/or less educated mothers breast feed less than married mothers with more education. However, inefficient and unreliable monitoring systems prevail, and the data are scarce, not only on exclusive BF but also on demographic, socio-economic, psychosocial and medical determinants of BF patterns. National BF coordinators have not been appointed in many countries, and only every second country has promotion of BF incorporated into their national plan of action for nutrition.

CONCLUSIONS

Efficient surveillance systems, comparable across Europe and using common definitions and methodology, need to be developed. These should include determinants of breast feeding. A European consensus conference should urgently be organised, in which strategies for successful promotion of exclusive BF should be particularly considered. There is now strong evidence for a recommendation to breast feed exclusively for about 6 months, which is more than the duration recommended previously.

Characterization of the New Jersey lead hazard control workforce

Individuals performing lead evaluation and abatement activities in New Jersey must complete certified training, an examination, and have a state permit card. Key demographic information was collected and summarized to describe this newly emerging lead workforce, to enhance lead training, to identify education and outreach needs, and to promote environmental justice. Summarizing these data also will assist other states implementing similar lead training and certification programs. As of June 30, 1998, the New Jersey Department of Health and Senior Services (NJDHSS) issued 2,370 permits to individuals in six disciplines. The lead workforce s average age was 38 years and 88 percent male. Most females were in the Inspector/Risk Assessor and Worker-Housing and Public Buildings (HPB) disciplines. Eighty percent of the workforce resided in New Jersey. Whites and Asians/Pacific Islanders were more educated than Hispanics or Blacks and a greater proportion of them were employed in the more skilled disciplines. Inadequate work experience may have prevented Blacks from qualifying for the more skilled disciplines; for Hispanics, there was also a language barrier. Twenty-nine percent of Workers and Supervisors had children less than six years of age residing in their household, which was higher than comparable state rates. The proportion of households with children under six years of age were similar for Black (32 percent), Hispanic (30 percent), and White (27 percent) households. The number of children less than six years of age per Black and Hispanic permittee was significantly higher than for Whites. Take-home lead issues and possible initiatives to promote minorities in the more skilled disciplines are discussed.

Breast-feeding exposure of infants to selected pesticides: a public health viewpoint

In this paper, we provide an overview of the public health implications of exposure to some pesticides via breast milk and provide health-based guidance. The presence of organochlorine pesticides in breast milk has been documented in many studies around the world. Included in our review are aldrin/dieldrin, chlordane, 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT)/1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), endrin, hexachlorobenzene (HCB), and hexachlorocyclohexane (HCH). Toxicological and environmental data on these chemicals are compiled in toxicological profiles published by the Agency for Toxic Substances and Disease Registry (ATSDR). Based on the data, ATSDR derives chemical-specific minimal risk levels (MRLs) that assist in evaluating public health risks associated with exposure. MRLs are health-based guidance values designed to protect the most sensitive populations, including breast-fed infants. We compare MRLs and projected intakes from the breast milk for the listed pesticides, explore the possibilities of toxicological interactions, and provide health-based recommendations.

Agency for Toxic Substances and Disease Registry's 1997 priority list of hazardous substances. Latent effects--carcinogenesis, neurotoxicology, and developmental deficits in humans and animals

In support of Superfund re-authorization legislation, the Division of Toxicology of the Agency for Toxic Substances and Disease Registry (ATSDR) prepared a chemical-specific consultation document for Congress that identified those chemicals with carcinogenic, neurological, or developmental adverse effects having a latency period longer than 6 years. The review was limited to the top 50 substances listed on ATSDR's 1997 Priority List of Hazardous Substances (Priority List). Among the top 50 chemicals, a review of the technical literature indicated that 38 (76%) were classified as "reasonably anticipated," "possibly," or "probably" capable of causing cancer in humans, based either on human and animal data. Eight chemicals (16%) had well-established cancer latency periods in humans of 6 years or more following exposure. Three substances (6%)--arsenic, creosote, and benzidine--had data indicating latency periods longer than 6 years. The technical literature review likewise confirmed the potential for neurological and developmental effects with a latency of 6 years. Twenty-seven (54%) of the top 50 substances caused acute and/or chronic neurotoxic effects; a number of these also caused neurological effects that persisted beyond 6 years (or the equivalent in animal studies) such as: behavioral problems, neurological deficiencies, reduced psychomotor development, cognitive deficiencies, and reduced IQ. Twenty-eight substances (56%) caused adverse developmental effects in offspring of exposed individuals or animals including increased fetal and infant mortality, decreased birth weights and litter sizes, and growth delays. Latency periods for related chemicals are expected to be similar due to structural and toxicological similarities.