Christopher D. Palmer

The remediation of chromium-contaminated sites requires knowledge of the processes that control the migration and transformation of chromium. Advection, dispersion, and diffusion are physical processes affecting the rate at which contaminants can migrate in the subsurface. Heterogeneity is an important factor that affects the contribution of each of these mechanisms to the migration of chromium-laden waters. Redox reactions, chemical speciation, adsorption/desorption phenomena, and precipitation/dissolution reactions control the transformation and mobility of chromium. The reduction of CrVI to CrIII can occur in the presence of ferrous iron in solution or in mineral phases, reduced sulfur compounds, or soil organic matter. At neutral to alkaline pH, the CrIII precipitates as amorphous hydroxides or forms complexes with organic matter. CrIII is oxidized by manganese dioxide, a common mineral found in many soils. Solid-phase precipitates of hexavalent chromium such as barium chromate can serve either as sources or sinks for CrVI. Adsorption of CrVI in soils increases with decreasing chromium concentration, making it more difficult to remove the chromium as the concentration decreases during pump-and-treat remediation. Knowledge of these chemical and physical processes is important in developing and selecting effective, cost-efficient remediation designs for chromium-contaminated sites.

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 microg/L [95% confidence interval (CI), 2.58-2.89]; blood lead concentration was 1.79 microg/dL (95% CI, 1.73-1.86); and blood cadmium concentration was 0.77 microg/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 microg/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.

This review covers a relatively mature area of atomic spectrometry, hence, there are fewer new developments than in newer research fields. It should be read in conjunction with the previous year's review1 and with other related reviews in the series.2–6 A great deal of literature on sample introduction methods has been generated, mainly describing preconcentration or vapour generation, but with very little that is new. The main development in instrumentation is the advent of microplasmas for lab-on-a-chip applications. Laser based methods continue in popularity, as do coupled chromatography and atomic spectrometry techniques for speciation studies, though even here the bulk of papers describe applications, albeit novel and challenging ones.

BACKGROUND: and second hand smoke (SHS) exposures among non-smoking pregnant women in Ulaanbaatar, Mongolia. METHODS: data from centrally-located government monitors. We assessed blood cadmium in late pregnancy. Hair nicotine was quantified in a subset (n=125) to evaluate blood cadmium as a biomarker of SHS exposure. We evaluated air cleaner effectiveness using mixed effects and multiple linear regression models and used stratified models and interaction terms to evaluate potential modifiers of effectiveness. RESULTS: ), respectively. Air cleaner effectiveness was greater when air cleaners were first deployed (40%; 31, 48%) than after approximately five months of use (15%; 0, 27%). Blood cadmium concentrations were 14% (4, 23%) lower among intervention participants, likely due to reduced SHS exposure. CONCLUSIONS: concentrations and SHS exposures in highly polluted settings.