Christopher D. Palmer

A biomonitoring study of lead, cadmium, and mercury in the blood of New York city adults.

Objectives We assessed the extent of exposure to lead, cadmium, and mercury in the New York City (NYC) adult population. Methods We measured blood metal concentrations in a representative sample of 1,811 NYC residents as part of the NYC Health and Nutrition Examination Survey, 2004. Results The geometric mean blood mercury concentration was 2.73 μg/L [95% confidence interval (CI), 2.58–2.89]; blood lead concentration was 1.79 μg/dL (95% CI, 1.73–1.86); and blood cadmium concentration was 0.77 μg/L (95% CI, 0.75–0.80). Mercury levels were more than three times that of national levels. An estimated 24.8% (95% CI, 22.2–27.7%) of the NYC adult population had blood mercury concentration at or above the 5 μg/L New York State reportable level. Across racial/ethnic groups, the NYC Asian population, and the foreign-born Chinese in particular, had the highest concentrations of all three metals. Mercury levels were elevated 39% in the highest relative to the lowest income group (95% CI, 21–58%). Blood mercury concentrations in adults who reported consuming fish or shellfish 20 times or more in the last 30 days were 3.7 times the levels in those who reported no consumption (95% CI, 3.0–4.6); frequency of consumption explained some of the elevation in Asians and other subgroups. Conclusions Higher than national blood mercury exposure in NYC adults indicates a need to educate New Yorkers about how to choose fish and seafood to maximize health benefits while minimizing potential risks from exposure to mercury. Local biomonitoring can provide valuable information about environmental exposures.

Determination of total mercury in whole blood by flow injection cold vapor atomic absorption spectrometry with room temperature digestion using tetramethylammonium hydroxide

An improved method is described for the determination of total Hg in whole blood based on flow injection cold vapor atomic absorption spectrometry (FI-CVAAS). Aliquots of whole blood (300 µl) are diluted 1 + 1 v/v with 10% v/v tetramethylammonium hydroxide (TMAH) solution, incubated for 1 h at room temperature and then further diluted 1 + 4 v/v with 2% v/v HCl. The TMAH approach is directly compared to a previously published method that utilizes an on-line microwave-assisted heating step as part of the FI arrangement. Thus, the key issue addressed here is the elimination of the on-line microwave digestion step from the FI manifold, because of problems observed with precipitation in the reaction coil and high back pressure in FI manifold. Matrix-matched calibration standards are used and the method detection limit (3σ) is 0.2 µg l−1. Method accuracy is traceable to Standard Reference Material (SRM) 966 Toxic Metals in Bovine Blood from the National Institute of Standards and Technology (NIST). Additional validation data are provided based on the analysis of whole blood materials from the New York State Department of Healths Proficiency Testing Program for Trace Elements and from the trace elements intercomparison program operated by the Institut National de Sante Publique du Quebec, Canada. Accuracy (−2.5%) and precision (<6.0% repeatability and <10% intermediate precision) of the TMAH method compare favorably with values obtained for the on-line microwave method (<10.0% repeatability and <15% reproducibility), and the TMAH method is essentially free of the disadvantages associated with the latter method.

Fish consumption, low-level mercury, lipids, and inflammatory markers in children

There is considerable evidence that consuming fish has numerous health benefits, including a reduced risk of cardiovascular disease. However, fish is also the primary source of human exposure to mercury (Hg). In a cross-sectional study of 9-11 year old children (N=100), we measured fish consumption, blood lipids, total blood Hg, diurnal salivary cortisol (4 samples collected throughout the day), and performed a proteomic analysis of serum proteins using spectral count shotgun proteomics. Children who consumed fish had a significantly more atheroprotective lipid profile but higher levels of blood Hg relative to children that did not consume fish. Although the levels of blood Hg were very low in these children (M=0.77 μg/L; all but 1 participant had levels below 3.27 μg/L), increasing blood Hg was significantly associated with blunted diurnal cortisol levels. Blood Hg was also significantly associated with acute-phase proteins suggesting systemic inflammation, and several of these proteins were found to significantly reduce the association between Hg and diminished cortisol when included in the model. This study of a pediatric population is the first to document an association between blood Hg, systemic inflammation, and endocrine disruption in humans. Without a better understanding of the long-term consequences of an atheroprotective lipid profile relative to blunted diurnal cortisol and systemic inflammation, a determination of the risk-benefit ratio for fish consumption by children is not possible.

Atomic Spectrometry Update. Advances in atomic spectrometry and related techniques

This is the second iteration of this review covering developments in ‘Atomic Spectrometry’. It covers atomic emission, absorption, fluorescence and mass spectrometry, but excludes material on speciation and coupled techniques which is included in a separate review. It should be read in conjunction with the other related reviews in the series.1-5 A critical approach to the selection of material has been adopted, with only novel developments in instrumentation, techniques and methodology being included. The major growth areas in evidence were the use of MC-ICP-MS as the method of choice for isotope ratio analyses, and new applications of AMS. The decline in the number of fundamental studies and developments in chemometrics continued. Some novel instrumental methods, such as the portable liquid electrode plasma, were reported and there were many new applications of solid phase extractants for on-line sample pretreatment, particularly using carbon nanotubes.

Advances in atomic spectrometry and related techniques

This is the second iteration of this review covering developments in ‘Atomic Spectrometry’. It covers atomic emission, absorption, fluorescence and mass spectrometry, but excludes material on speciation and coupled techniques which is included in a separate review.1 It should be read in conjunction with the other related reviews in the series.2–5 A critical approach to the selection of material has been adopted, with only novel developments in instrumentation, techniques and methodology being included. Most techniques have reached a level of maturity which precludes the emergence of ‘stand-out’ new developments. It is noteworthy that there are very few novel publications in sections on chemometrics, fundamental studies, or direct solids analysis. Sample introduction continues to generate a steady stream of research outputs, but these are mainly derivative and focused on applications. The advent of SF-ICP-MS is becoming widely adopted as a reliable technique for IR measurements, so this had been the main growth area. Likewise, the use of femtosecond UV lasers has now entered the mainstream for geological applications.

Low-level Pb and cardiovascular responses to acute stress in children: The role of cardiac autonomic regulation

OBJECTIVE A number of studies suggest that Pb exposure increases cardiovascular disease risk in humans. As a potential mechanism for this effect, we recently reported a significant association between early childhood Pb levels and cardiovascular response to acute stress. The current study considers the association between current Pb levels and the autonomic nervous system activation pattern underlying the cardiovascular response to stress in a new cohort of children. METHODS We assessed blood Pb levels as well as cardiovascular responses to acute stress in 9-11 year old children (N=140). Sympathetic activation (measured with pre-ejection period) and parasympathetic activation (measured with high frequency heart rate variability) were also assessed. RESULTS In a sample with very low levels of blood Pb (M=1.0 μg/dL), we found that increasing blood Pb was associated with coinhibition of sympathetic and parasympathetic activation in response to acute stress. In addition, increasing Pb levels were associated with the hemodynamic stress response pattern typical of coinhibition--significantly greater vascular resistance and reduced stroke volume and cardiac output. CONCLUSIONS Blood Pb levels were associated with significant autonomic and cardiovascular dysregulation in response to acute psychological stress in children. Moreover, these effects were significant at Pb levels considered to be very low and notably well below the 10 μg/dL, the Centers for Disease Control and Prevention definition of an elevated blood Pb level. The potential for autonomic dysregulation at levels of Pb typical for many US children would suggest potentially broad public health ramifications.

Childhood exposure to manganese and postural instability in children living near a ferromanganese refinery in southeastern Ohio

Airborne manganese (Mn) exposure can result in neurotoxicity and postural instability in occupationally exposed workers, yet few studies have explored the association ambient exposure to Mn in children and postural stability. The goal of this study was to determine the association between Mn and lead (Pb) exposure, as measured by blood Pb, blood and hair Mn and time weighted distance (TWD) from a ferromanganese refinery, and postural stability in children. A subset of children ages 7-9 years enrolled in the Marietta Community Actively Researching Exposure Study (CARES) were invited to participate. Postural balance was conducted on 55 children residing in Marietta, Ohio and the surrounding area. Samples of blood were collected and analyzed for Mn and Pb, and samples of hair were analyzed for Mn. Neuromotor performance was assessed using postural balance testing with a computer force platform system. Pearson correlations were calculated to identify key covariates. Associations between postural balance testing conditions and Mn and Pb exposure were estimated with linear regression analyses adjusting for gender, age, parent IQ, and parent age. Mean blood Mn was 10 μg/L (SEM=0.36), mean blood Pb was 0.85 μg/dL (SEM=0.05), and mean hair Mn was 0.76 μg/g (SEM=0.16). Mean residential distance from the refinery was 11.5 km (SEM=0.46). All three measures of Mn exposure were significantly associated with poor postural balance. In addition, low-level blood Pb was also negatively associated with balance outcomes. We conclude that Mn exposure and low-level blood Pb are significantly associated with poor postural balance.

Trace elements and endometriosis: The ENDO Study

There has been limited study of trace elements and endometriosis. Using a matched cohort design, 473 women aged 18-44 years were recruited into an operative cohort, along with 131 similarly aged women recruited into a population cohort. Endometriosis was defined as surgically visualized disease in the operative cohort, and magnetic resonance imaging diagnosed disease in the population cohort. Twenty trace elements in urine and three in blood were quantified using inductively coupled plasma mass spectrometry. Logistic regression estimated the adjusted odds (aOR) of endometriosis diagnosis for each element by cohort. No association was observed between any element and endometriosis in the population cohort. In the operative cohort, blood cadmium was associated with a reduced odds of diagnosis (aOR=0.55; 95% CI: 0.31, 0.98), while urinary chromium and copper reflected an increased odds (aOR=1.97; 95% CI: 1.21, 3.19; aOR=2.66; 95% CI: 1.26, 5.64, respectively). The varied associations underscore the need for continued research.

Effects of Lead and Mercury on the Blood Proteome of Children

Heavy metal exposure in children has been associated with a variety of physiological and neurological problems. The goal of this study was to utilize proteomics to enhance the understanding of biochemical interactions responsible for the health problems related to lead and mercury exposure at concentrations well below CDC guidelines. Blood plasma and serum samples from 34 children were depleted of their most abundant proteins using antibody-based affinity columns and analyzed using two different methods, LC-MS/MS and 2-D electrophoresis coupled with MALDI-TOF/MS and tandem mass spectrometry. Apolipoprotein E demonstrated an inverse significant association with lead concentrations (average being one microgram/deciliter) as deduced from LC-MS/MS and 2-D electrophoresis and confirmed by Western blot analysis. This coincides with prior findings that Apolipoprotein E genotype moderates neurobehavioral effects in individuals exposed to lead. Fifteen other proteins were identified by LC-MS/MS as proteins of interest exhibiting expressional differences in the presence of environmental lead and mercury.

Simultaneous detection of selenium by atomic fluorescence and sulfur by molecular emission by flow-injection hydride generation with on-line reduction for the determination of selenate, sulfate and sulfite

An inductively coupled plasma atomic fluorescence spectrometry (ICP-AFS) instrument, was modified so that it was capable of monitoring transient chromatographic or flow-injection profiles and that sulfur molecular emission and selenium atomic fluorescence could be monitored simultaneously in an argon-hydrogen diffusion flame on a glass burner. The analytes were introduced as hydrogen selenide and hydrogen sulfide, generated on a flow-injection manifold. Selenate was reduced to hydride-forming selenite by microwave-assisted on-line reaction with hydrochloric acid, and sulfate, or sulfite, was reduced to hydride-forming sulfide by a mixture of hydriodic acid, acetic acid and sodium hypophosphite. The effects of the nature of reducing agent, flow rate, microwave power and coil length were studied. The limit of detection (3s) for selenium was 10microgL(-1), and for sulfide was 70microgL(-1) (200-microL injection volume). The calibration was linear for selenium up to 2mgL(-1) and to 10mgL(-1) for sulfide. The throughput was 180h(-1). The three sulfur species could be differentiated on the basis of reactivity at various microwave powers.