Heavy metal ecotoxicology of vervet monkeys (Chlorocebus pygerythrus) across field sites in South Africa.

Primatologists use ecological models for understanding nonhuman primate (NHP) behavior and biology. Yet few studies have focused on the impacts of naturally occurring and anthropogenically derived toxicants in NHP habitats. For humans and NHPs, toxic levels of heavy metals frequently result in poor health outcomes including improper neurological development, immune system depression, and endocrine disruption. We analyzed the concentrations of lead (Pb), arsenic (As), and cadmium (Cd) in 48 vervet monkey (Chlorocebus pygerythrus) hair samples collected from eight South African groups living in environments with varying degrees of anthropogenic disturbance. We used two systems to categorize anthropogenic disturbance. The first was based on behavioral observations, home range overlap with human modified environments, and interviews with local people. The second system used stable isotope analysis (mean δ13C and δ15N hair values) from each group to estimate the consumption of C4 resources and the utilization of anthropogenically disturbed habitats. Preliminary analyses revealed differences in the Pb and As hair concentrations across the field sites (p < 0.05). Comparisons between anthropogenic disturbance using observations and interviews revealed differences in As (p < 0.01). In contrast, comparisons between categories using δ13C hair values revealed differences in Pb (p < 0.05). The results from this study suggest that multiple approaches using both qualitative and quantitative data should be employed to estimate the relationship between anthropogenic disturbance and environmental toxicants. Since many NHP populations share their habitats with humans, efforts to improve these landscapes would likely be beneficial for NHP and human health.

Speciation of chromium via laser-induced breakdown spectroscopy of ion exchange polymer membranes.

A new method for the speciation of ng/mL concentrations of Cr(III) and Cr(VI) solutions with analysis by laser-induced breakdown spectroscopy (LIBS) is reported. Speciation is achieved by pre-concentration of the chromium onto commercially available cation exchange polymer membranes. Chromium(III) is removed directly by cation exchange; chromium(VI) in the filtrate is reduced to Cr(III) and concentrated onto a second cation exchange membrane, affording independent measurement of both species. Large volumes of waters containing Cr(III) and Cr(VI) can be concentrated onto the membranes and directly analyzed by laser-induced breakdown spectroscopy. The estimated limit of detection corresponds to 500 ng of Cr on the membrane: if a solution volume of 1 L is used, then the detection limit corresponds to a solution concentration of 0.5 ng/mL. Excellent separation of the chromium species is attained. Results show that overall method efficiencies range from 94-116% and are independent of the matrix. The influence of pH has been measured, and although Cr(VI) converts to Cr(III) in acidic solutions, the total Cr recoveries are not appreciably influenced by pH over the range of natural waters (4 to 9). In addition, speciation was performed in the presence of a number of different cations and showed that the method is robust in many different and complex matrices.

Resonance-enhanced multiphoton ionization for real-time monitoring of trichloroethylene formed by degradation of tetrachloroethylene using zero-valent zinc.

Resonance-enhanced multiphoton ionization (REMPI) is investigated as a potential technique for real-time monitoring of selected volatile organochloride compounds (VOCs). In a proof-of-concept experiment, the progress of the reductive-degradation of tetrachloroethylene (PCE) to trichloroethylene (TCE) by zero-valent zinc was monitored by REMPI measurements performed in the headspace above the PCE solution. Two-photon resonant REMPI spectra of TCE and PCE were recorded over the wavelength range 305-320 nm. The concentrations of PCE and TCE in the headspace were monitored by measurement of the ionization signal with 315.64- and 310.48-nm excitation for PCE and TCE, respectively. Calibration curves yielded a linear range of more than 2 orders of magnitude for both compounds. The REMPI headspace results agreed well with the solution-phase results from gas chromatography analysis, which was used for independent verification of the progress of the reaction.