Repeatability of Phase 1 habitat survey

As the major part of a Habitat Survey of Wales, over 80% of the land surface was surveyed in the field between 1987 and 1997 using the Phase 1 method. A resurvey of 294 randomly selected points was carried out during the early stages to audit the quality of the data being collected, leading to the development of a set of recommendations for the surveyors to improve the consistency and accuracy of habitat mapping. Recent studies have indicated a high level of discrepancy between organisations in field habitat mapping using the Phase 1 method. The findings of the Phase 1 audit in Wales are presented here to show the level of repeatability that was achieved within an organisation. There was 76% correspondence in habitat mapping between 'surveyor' and 'assessor' at the level of individual Phase 1 habitat classes. The degree of repeatability varied according to habitat strata: it was highest for modified land cover types (88%), lowest for semi-improved types (56%) and intermediate for semi-natural types (75%). An overall estimate of the repeatability of Phase 1 survey in the study area of 83% was obtained by weighting the figures for the three strata by the proportion of land area occupied by each stratum. This figure increased to 85% when habitats were amalgamated into Broad Habitat groups. These results are considerably better than those reported by studies of consistency between organisations. Most of the discrepancies between surveyor and assessor were caused by differences in habitat identification. However, at almost two thirds of the points where such a difference occurred, the assessor noted that the vegetation was transitional or borderline with that mapped by the surveyor.     

The GANE Roof Project: The impact of reduced N & S deposition and experimental warming in an acid grassland

A field-based system used to quantify the response of acid grassland to reduced atmospheric nitrogen and sulphur deposition, and to investigate the effects of elevated soil temperature on acid grassland development is described. The system is based on 12 retractable roofs, covering undisturbed experimental plots of acid grassland and three controls. Nine roofs are used to exclude natural precipitation and three roofs used to retain emitted IR radiation at night. An irrigation system has been developed to simulate natural precipitation, allowing for the application of specific treatment regimes of ambient, reduced nitrogen and reduced nitrogen/sulphur deposition beneath the nine rain exclusion plots. Plant, soil parameters, leachate chemistry and gaseous fluxes are being monitored and initial results on soil water chemistry are described. Warming appeared to enhance nitrate concentrations in soil water but this was not sustained beyond the first year of treatment. In contrast, the deposition reduction treatments decreased soil water nitrate concentrations within a few weeks of reducing deposition. This was not observed for other solutes such as sulphate or ammonium suggesting a more direct link between deposition of nitrate and leaching losses.     

EFFECT OF PRICE STRUCTURE ON RESIDENTIAL WATER DEMAND1

ABSTRACT: Little is known about how different types of municipal water rate structures influence residential water use. Conventional wisdom suggests that increasing block rate structures promote conservation, but analysis of data from 85 Massachusetts communities does not support this view.     

CHANGES IN PHYSICAL AND CHEMICAL VARIABLES IN A NEW RESERVOIR DUE TO PUMPED STORAGE OPERATIONS1

ABSTRACT: Information on biologically important physical and chemical variables is presented for Lake Oconee, a newly impounded pumped storage reservoir in Georgia. During its first summer, when no pumping occurred, temperature, oxygen, pH, inorganic nitrogen, and phosphorus were vertically stratified with severe hypolimnetic oxygen depletion. During the second summer, when pumped storage was in operation, more homogenous vertical profiles, generally higher oxygen, and lower dissolved nutrient concentrations were observed. These pumped storage effects were observed at all stations, rather than being confined to the immediate vicinity of the dam.     

Satisfaction with environmental change: An empirical analysis of attitudes toward air quality by recent interstate migrants

How (and whether) people perceive environmental change is a question which economists have generally chosen to finesse rather than explore. The three components of attitudes (cognitive, affective, behavioral) are identified and a “satisfaction” metric is used to evaluate the nonbehavioral components for recent in-migrants to Oregon. An interaction model is used to relate changes in satisfaction to changes in air quality and to personal characteristics of the migrants. In general, a valid cognitive dimension exists; changes in satisfaction are in fact consistent with changes in air quality data.     

Comparing spatial and temporal changes in metal trends (Cr,Ni, Pb and Zn) on the Portuguese shelf since the 1970s

Comparison between an archive dataset, collected during the 1970s (1974–1977), and samples taken during the PALEO1 cruise (2002) enabled evaluation of large-scale and long-term spatiotemporal changes in Al, Cr, Ni, Pb and Zn contents in bulk surface sediments in four areas of the Portuguese shelf. The so-called gradient method (GM) with normalisation to Al, a proxy for terrigenous clay content, was applied. The studied areas are distributed from north to south along the western margin, with the northernmost located off shore the Ave and Douro rivers, a central one located off shore the Lis River and a southern one located off shore the Mira River. One-way ANOVA and Kruskal-Wallis tests were used to identify differences among study areas and periods of sample collection. A comparison of metal contents in 2002 samples with the Portuguese classification scheme regulation for deposition of dredged materials in coastal areas indicates good environmental quality in terms of Cr, Ni, Pb and Zn levels. Nevertheless, the GM results suggest an increase in metal loadings relative to Al from the 1970s to the 2002 samples (except for Pb). The Algarve area on the southern shelf is characterised by having high number of sites with metal level on class 2. These high values have traditionally been explained by a substantial supply of natural metals from the Guadiana, Tinto and Odiel rivers that drain areas Iberian Pyrite Belt formations. This supply has probably been magnified by present and past mining activities. For quality evaluation of marine sediments, especially when using total metal contents, this study shows the importance of considering all possible sources of metal loading. The natural grain size and composition variability have also a crucial influence on the metal content, and the combined evaluation allows a more holistic perspective.     

Cadmium- and calcium-mediated toxicity in rainbow trout (Oncorhynchus mykiss) in vivo: interactions on fitness and mitochondrial endpoints

Rainbow trout were exposed to sublethal waterborne Cd (5 and 10 μg L⁻¹) and dietary Ca (60 mg g⁻¹), individually and in combination, for 30 d to elucidate the interactive effects and evaluate the toxicological significance of mitochondrial responses to these cations in vivo. Indices of fish condition and mortality were measured and livers, centers of metabolic homeostasis, were harvested to assess mitochondrial function and cation accumulation. All indices of condition assessed (body weight, hepatosomatic index and condition factor) were reduced in all the treatment groups. Mortality occurred in the Cd-exposed groups with dietary Ca partly protecting against and enhancing it in the lower and higher Cd exposure, respectively. State 3 mitochondrial respiration was inhibited by 30%, 35% and 40% in livers of fish exposed to Ca, Cd and Cd + Ca, respectively, suggesting reduced ATP turnover and/or impaired substrate oxidation. While the phosphorylation efficiency was unaffected, state 4 and state 4+ (+ oligomycin) respirations were inhibited by all the exposures. Mitochondrial coupling was reduced and transiently restored denoting partially effective compensatory mechanisms to counteract Cd/Ca toxicity. The respiratory dysfunction was associated with accumulation of both Cd and Ca in the mitochondria. Although fish that survived acute effects of Cd and Ca exposure apparently made adjustments to energy generation such that liver mitochondria functioned more efficiently albeit at reduced capacity, reduced fitness was persistent possibly due to increased demands for maintenance and defense against toxicity. Overall, interactions between Cd and Ca on condition indices and mitochondrial responses were competitive or cooperative depending on exposure concentrations and duration.     

Bioconcentration of triclosan, methyl-triclosan, and triclocarban in the plants and sediments of a constructed wetland

Constructed wetlands are a potential method for the removal of two pharmaceutical and personal care products from wastewater effluent. Triclosan (TCS; 5-chloro-2-[2,4-dichlorophenoxy]phenol) and triclocarban (TCC; 3,4,4′-trichlorocarbanillide) are antimicrobial agents added to a variety of consumer products whose accumulation patterns in constructed wetlands are poorly understood. Here, we report the accumulation of TCS, its metabolite methyl-triclosan (MTCS; 5-chloro-2-[2,4-dichlorophenoxy]), and TCC in wetland plant tissues and sediments. Three wetland macrophytes: Typha latifolia, Pontederia cordata, and Sagittaria graminea were sampled from a constructed wetland in Denton, Texas, USA. MTCS concentrations were below the method detection limit (MDL) for all species. TCS root tissue concentrations in T. latifolia were significantly greater than root concentrations in P. cordata (mean ± SE in ng g⁻¹: 40.3 ± 11.3 vs. 15.0 ± 1.9, respectively), while for TCC, shoot tissue concentrations in S. graminea were significantly greater than in T. latifolia (22.8 ± 9.3 vs. 9.0 (MDL), respectively). For both TCS and TCC, T. latifolia root tissue concentrations were significantly greater than shoot concentrations (TCS: 40.3 ± 11.3 vs. 17.2 ± 0.2, TCC: 26.0 ± 3.6 vs. 9.0, (MDL)). TCC concentrations in P. cordata roots were significantly greater than in shoots (34.4 ± 5.3 vs. 15.4 ± 2.8, respectively). TCS concentrations in T. latifolia roots and sediments and TCC concentrations in sediments generally decreased from wetland inflow to outflow. To our knowledge, this is the first study documenting species and tissue specific differences in the accumulation of TCS and TCC in plants from an operational constructed wetland. The species specific differences in bioaccumulation suggest TCS and TCC removal from constructed wetlands could be enhanced through targeted plantings.     

Revaluation of the “Chattanooga School Children Study” in the Light of Other Contemporary Governmental Studies: The Possible Impact of These Findings On the Present NO2 Air Quality Standard

Data have been collected to indicate the presence of a number of biologically antagonistic air contaminants in ambient air in the immediate vicinity of Chattanooga, Tenn., as a result of the operation of the Volunteer Army Ammunition Plant, Tyner, Tenn. It follows, therefore, from these data that adverse health effects observed in the course of the Chattanooga School Children Study may be accounted for either totally or in part by the presence of epidemiologically interfering compounds such as sulfuric and nitric acid vapors which were not measured in air at the time of the health effects study. It is suggested that the presence of these interferences be considered detrimental to the formulation of a valid air quality standard for nitrogen dioxide.