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Concentrations of mercury (Hg) were determined in surface waters and associated river bank sediment samples in a river—reservoir system contaminated by mine wastes. The distribution of total and methyl Hg in surface waters along the Carson River was similar to that measured in river bank sediments and influenced by flow regimes. High levels of Hg (up to 7,585 and 7.2 ng Hg/L for total and methyl Hg, respectively) determined on surface water samples were in large part discharged from Hg‐contaminated tailings, distributed in the river bank sediments. Once introduced into the river during the spring snowmelt runoff, Hg was transported downstream and accumulated in the lacustrine part of the system. Elemental Hg (Hg0) increased from 0.02 ng/L in the noncontaminated region to about 2 ng/L in the reservoir. The vertical distribution of total methylmercury (MeHgT) in water of the reservoir differs from that observed elsewhere, in both Hg‐contaminated and noncontaminated lakes. The highest levels of MeHgT (<1 ng/L as Hg) and acid‐reactive Hg (4 ng/L) were observed in the alkaline and oxic surface waters. The decrease of pH with depth and the absence of oxygen in depth >10 m did not enhance MeHg production. In the anoxic hypolimnion of the reservoir, the recycling of MeHgT was more influenced by the redox cycling of Mn. The addition of group VI anions (SeO2−4, MoO2−4, and WO2−4) in the range of concentrations of oxyanion‐forming elements found in the Carson River system to anoxic sediment slurry spiked with SO2−4 resulted in the reduction of rates of MeHg production. Their negative effect on MeHg production was enhanced by increasing pH. Group VI anions, analogous to SO2−4 are inhibitory to sulfate‐reducing bacteria, which are known to play a key role in MeHg production in anoxic sediments. Accordingly, the particular water geochemistry of the Carson River system could partly explain the observed low levels of MeHg where one would expect higher concentrations.

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Objectives A fundamental assumption in biological anthropology is that living individuals will present with different growth than non‐survivors of the same population. The aim is to address the question of whether growth and development data of non‐survivors are reflective of the biological consequences of selective mortality and/or stress. Materials and Methods The study compares dental development and skeletal growth collected from radiographic images of contemporary samples of living and deceased individuals from the United States (birth to 20 years) and South Africa (birth to 12 years). Further evaluation of deceased individuals is used to explore differential patterns among manners of death (MOD). Results Results do not show any significant differences in skeletal growth or dental development between living and deceased individuals. However, in the South African deceased sample the youngest individuals exhibited substantially smaller diaphyseal lengths than the living sample, but by 2 years of age the differences were negligible. In the US sample, neither significant nor substantial differences were found in dental development or diaphyseal length according to MOD and age (>2 years of age), though some long bones in individuals <2 years of age did show significant differences. No significant differences were noted in diaphyseal length according to MOD and age in the SA sample. Discussion The current findings refute the idea that contemporary deceased and living individuals would present with differential growth and development patterns through all of ontogeny as well as the assumptions linking short stature, poor environments, and MOD.

Abstract-Concentrations of mercury (Hg) were determined in surface waters and associated river bank sediment samples in a riverreservoir system contaminated by mine wastes. The distribution of total and methyl Hg in surface waters along the Carson River was similar to that measured in river bank sediments and influenced by flow regimes. High levels of Hg (up to 7,585 and 7.2 ng Hg/L for total and methyl Hg, respectively) determined on surface water samples were in large part discharged from Hg-contaminated tailings, distributed in the river bank sediments. Once introduced into the river during the spring snowmelt runoff, Hg was transported downstream and accumulated in the lacustrine part of the system. Elemental Hg (Hg 0 ) increased from 0.02 ng/L in the noncontaminated region to about 2 ng/L in the reservoir. The vertical distribution of total methylmercury (MeHg T ) in water of the reservoir differs from that observed elsewhere, in both Hg-contaminated and noncontaminated lakes. The highest levels of MeHg T (Ͻ1 ng/L as Hg) and acidreactive Hg (4 ng/L) were observed in the alkaline and oxic surface waters. The decrease of pH with depth and the absence of oxygen in depth Ͼ10 m did not enhance MeHg production. In the anoxic hypolimnion of the reservoir, the recycling of MeHg T was more influenced by the redox cycling of Mn. of oxyanion-forming elements found in the Carson River system to anoxic sediment slurry spiked with S resulted in the reduction 2Ϫ

ObjectivesThe steady development and subsequent eruption of the dentition is particularly useful for the estimation of age in juveniles. There are few studies that examine and test methods on a population‐diverse sample. Our goal is to test the Ubelaker () and London Atlas (2010) dental charts on a sample representing several different population backgrounds to infer if refinement for population‐specific standards should be developed.Materials and methodsThe first and second authors examined panoramic radiographs of 335 individuals from the James K. Economides Orthodontic Collection blind to chronological age, sex, and ancestry and scored using both dental atlases.ResultsThe age of Native Americans and African Americans was generally overestimated, suggesting faster rates of development. European Americans and New Mexico Hispanics, while not always showing the highest success rates, generally were closer to the correct age than other ancestry groups. The overall success rate for Ubelaker () was 80.00% for both observers, while the London Atlas was significantly lower at approximately 21.79–23.28%. Accuracy rates did not differ significantly between ancestry groups, though patterns were evident regarding under‐ or over‐estimation of age.DiscussionThe present study demonstrates that incorrect age estimations were typically still within 1.5 years of the actual age. Ubelaker () had higher rates of success due to broader age ranges. The results suggest that though accuracy rates did not significantly differ, different developmental rates may affect age estimates and population‐specific standards should be considered for known‐ancestry individuals, while aging standards constructed from a diverse sample should be utilized for unknown‐ancestry cases.