Telemetry-Determined Habitat Use Informs Multi-Species Habitat Management in an Urban Harbour

Environmental Management - Widespread human development has led to impairment of freshwater coastal wetlands and embayments, which provide critical and unique habitat for many freshwater fish...     

Pre-Colombian Mercury Pollution Associated with the Smelting of Argentiferous Ores in the Bolivian Andes

The development of the mercury (Hg) amalgamation process in the mid-sixteenth century triggered the onset of large-scale Hg mining in both the Old and New Worlds. However, ancient Hg emissions associated with amalgamation and earlier mining efforts remain poorly constrained. Using a geochemical time-series generated from lake sediments near Cerro Rico de Potosí, once the world’s largest silver deposit, we demonstrate that pre-Colonial smelting of Andean silver ores generated substantial Hg emissions as early as the twelfth century. Peak sediment Hg concentrations and fluxes are associated with smelting and exceed background values by approximately 20-fold and 22-fold, respectively. The sediment inventory of this early Hg pollution more than doubles that associated with extensive amalgamation following Spanish control of the mine (1574–1900 AD). Global measurements of [Hg] from economic ores sampled world-wide indicate that the phenomenon of Hg enrichment in non-ferrous ores is widespread. The results presented here imply that indigenous smelting constitutes a previously unrecognized source of early Hg pollution, given naturally elevated [Hg] in economic silver deposits.     

Use of Standardized Visual Assessments of Riparian and Stream Condition to Manage Riparian Bird Habitat in Eastern Oregon

The importance of riparian vegetation to support stream function and provide riparian bird habitat in semiarid landscapes suggests that standardized assessment tools that include vegetation criteria to evaluate stream health could also be used to assess habitat conditions for riparian-dependent birds. We first evaluated the ability of two visual assessments of woody vegetation in the riparian zone (corridor width and height) to describe variation in the obligate riparian bird ensemble along 19 streams in eastern Oregon. Overall species richness and the abundances of three species all correlated significantly with both, but width was more important than height. We then examined the utility of the riparian zone criteria in three standardized and commonly used rapid visual riparian assessment protocols—the USDI BLM Proper Functioning Condition (PFC) assessment, the USDA NRCS Stream Visual Assessment Protocol (SVAP), and the U.S. EPA Habitat Assessment Field Data Sheet (HAFDS)—to assess potential riparian bird habitat. Based on the degree of correlation of bird species richness with assessment ratings, we found that PFC does not assess obligate riparian bird habitat condition, SVAP provides a coarse estimate, and HAFDS provides the best assessment. We recommend quantitative measures of woody vegetation for all assessments and that all protocols incorporate woody vegetation height. Given that rapid assessments may be the only source of information for thousands of kilometers of streams in the western United States, incorporating simple vegetation measurements is a critical step in evaluating the status of riparian bird habitat and provides a tool for tracking changes in vegetation condition resulting from management decisions.     

Trace contamination with dioxin-like chemicals: evaluation of bioassay-based TEQ determination for hazard assessment and regulatory responses

Many recent dioxin contamination events have been traced back to poisoned animal feed or feed ingredients. Therefore, enforcement authorities placed limits on the levels of dioxins in food and feed or implemented strict monitoring and control programs. The levels in force are generally expressed as TEQ values, which inherently accepts the underlying hypothesis that the effects of dioxin-like chemicals are additive. TEQ determination involves either chemo-analysis, with high-resolution gas chromatography in combination with high-resolution mass spectroscopy, or bio-analysis. Bio-analytical methods, more particularly the reporter gene expression method CALUX, are advantageous due to their high throughput rate and low cost. Moreover, the CALUX methodology detects the overall dioxin-like toxicity, rather than the limited number of compounds investigated by chemo-analysis. Bioanalytical methods such as CALUX also differ from chemo-analysis in that the contribution of antagonistic as well as synergistic effects, which violate the additivity principle, can be detected. The application of bio-analytical methods can facilitate a broader assessment of public health risks by intensifying the current monitoring programs in terms of both sample numbers and types. Bio-analysis provides information on the total dioxin-like activity of the samples under study (hazard assessment); however, chemo-analysis is still needed to identify the predominant contaminants (congener identification) for risk management.     

Uniparental isodisomy for chromosome 16 in a growth-retarded infant with congenital heart disease

We report a growth-retarded infant with congenital heart disease and maternal isodisomy for chromosome 16. Non-mosaic trisomy 16 was detected at mid-trimester chorionic villus sampling, performed because biochemical screening indicated an increased Down's syndrome risk. Further karyotyping analysis of the placenta, after delivery, showed a 50 per cent mosaic trisomy 16. The infant had an atrioventricular (A-V) canal defect, scoliosis, and several minor dysmorphic features. Although uniparental disomy for chromosome 16 has been reported previously, to our knowledge this is the first case of uniparental isodisomy for chromosome 16 which has been investigated with multiple DNA probes.     

Effect of drying and composting biosolids on the movement of nitrate and phosphate through repacked soil columns under steady-state hydrological conditions

Effects of two "enhanced" treatments (drying and composting mesophilic anaerobically digested (MAD) biosolid) on nutrient leaching were investigated. Repacked sandy or sandy loam textured soil cores amended with fresh, dried and composted MAD biosolid (250 kg N ha(-1)), were investigated under steady-state hydrological conditions. Two 24 h, 4.5 mm h(-1) rainfall events, with a 14-day interval, were simulated using water-tracers. Losses of nitrate from the sandy loam soil during rainfall event 1 (43.9-68.0 mg kg(-1)) were significantly greater (P < or = 0.05) than during event 2 (6.4-11.9 mg kg(-1)). Phosphate losses were significantly greater (P < or = 0.05) during event 2 (up to 0.30 mg kg(-1)) compared to the first (< 0.05 mg kg(-1)). The sand soil showed similar effects. Losses of nitrate-N (percentage of total N applied) from the sand soil were small (around 0.06% for fresh/dried and 0.63% for composted MAD biosolids). Losses of nitrate-N from the sandy loam soil were greater; 4% for fresh and dried and 3% for composted MAD biosolids. This research showed that drying MAD biosolid had little impact on nitrate and phosphate losses from soil compared to fresh MAD biosolid. The effect of composting MAD biosolid on nutrient losses was more variable.     

Fluoride accumulation and toxicity in wild small mammals

Populations of two species of small mammal, the field vole (Microtus agrestis L.) and the bank vole (Clethrionomys glareolus L.), inhabiting grasslands contaminated by industrial sources of fluoride were examined for fluoride concentrations in skeletal tissue and for morphological changes in the teeth. Concentrations of fluoride in teeth and bones were higher for C. glareolus than for M. agrestis at the chemical works and smelter sites. Severe dental lesions were recorded on the incisor and molar teeth of both species at the chemical works and smelter sites, with less marked damage at the mine tailings dam. This is attributed to inter-site differences in fluoride speciation and the consequent effects on the availability of fluoride in the diet for bioassimilation.     

Estimating the aqueous solubility of aromatic hydrocarbons by high performance liquid chromatography

Empirical equations which correlate high performance liquid chromatography capacity factor (k′) to aromatic hydrocarbon aqueous solubility are developed. The correlations of k′ to octanol-water partition coefficients, and k′ to hydrocarbon surface area are also shown.     

Comparison of vesicular-arbuscular mycorrhizae in plants from disturbed and adjacent undisturbed regions of a coastal salt marsh in Clinton,Connecticut, USA

Roots of salt marsh plant speciesSpartina alterniflora, S. patens, Distichlis spicata, and others were examined for the presence of vesicular-arbuscular mycorrhizal (VAM) fungi. Samples were taken from introduced planted material in a salt marsh restoration project and from native material in adjacent marsh areas along the Indian River, Clinton, Connecticut, USA. After ten years the replanted area still has sites devoid of vegetation. The salt marsh plants introduced there were devoid of VAM fungi, while high marsh species from the adjacent undisturbed region showed consistent infection, leading the authors to suggest that VAM fungal infection of planting stocks may be a factor in the success of marsh restoration.