Phenanthrene adsorption by soils treated with humic substances under different pH and temperature conditions

The mobility of phenanthrene (PHE) in soils depends on its sorption and is influenced by either the existing soil humus or exogenous humic substances. Exogenous humic acids (HAs) were added to soil to enhance the amount of soil organic carbon (SOC) by 2.5, 5.0, and 10.0 g kg⁻¹. PHE desorption of the treated soils was determined at two pH levels (3.0 and 6.0) and temperatures (15 and 25 °C). Soil PHE adsorption was related to pH and the type and quantity of added HAs. Humic acid (HA) and fulvic acid (FA) derived from peat had different effects on adsorption of PHE. Adsorption increased at first and then decreased with increasing quantity of exogenous FA. When the soil solution pH (in 0.005 M CaCl₂) was 4.5 or 3.0, the turning points were 2.5 g FA kg⁻¹ at pH 3.0 and 5 g FA kg⁻¹ at pH 4.5. When soil solution pH was 6, the amount of adsorbed PHE was enhanced with increasing exogenous HAs (HA or FA) and amount of adsorption by soil treated with FA was higher than with HA. Adsorption of PHE in the FA treatment at 10.0 g kg⁻¹ was lower than the controls (untreated soil or treatment with HAs at 0 g kg⁻¹) when the soil solution pH was 3.0. This suggests that FA adsorbed by soil was desorbed at low pH and would then increase PHE solubility, and PHE then combined with FA. PHE adsorption was usually higher under lower pH and/or lower temperature conditions. PHE sorption fitted the Freundlich isotherm, indicating that exogenous humic substances influenced adsorption of phenanthrene, which in turn was affected by environmental conditions such as pH and temperature. Thus, exogenous humic substances can be used to control the mobility of soil PAHs under appropriate conditions to decrease PAH contamination.     

An Assessment of the Economic Effectiveness of Recreation Policy Using Contingent Valuation

Arrangements within the UK to enhance recreation opportunities in the countryside are currently implemented in a somewhat ad hoc manner. This paper analyses the economic effectiveness of such provision in Grampian Region, Scotland. This is achieved by quantifying, using the contingent valuation method, the economic benefits accruing from recreation enhancements and comparing these benefits with the level of expenditure currently being undertaken on these improvements. The subsequent analysis provides a strategic framework for the assessment of recreation needs in the region, thus enabling future priorities for provision to be identified. It is argued that the quantification of public preferences for recreation enhancements provides a powerful tool to aid strategic planning of recreation provision. The issue of using public funds to finance recreation facilities in the countryside is also discussed.     

Long-term demographic and genetic effects of releasing captive-born individuals into the wild

Because of continued habitat destruction and species extirpations, the need to use captive breeding for conservation purposes has been increasing steadily. However, the long-term demographic and genetic effects associated with releasing captive-born individuals with varied life histories into the wild remain largely unknown. To address this question, we developed forward-time, agent-based models for 4 species with long-running captive-breeding and release programs: coho salmon (Oncorhynchus kisutch), golden lion tamarin (Leontopithecus rosalia), western toad (Anaxyrus boreas), and Whooping Crane (Grus americana). We measured the effects of supplementation by comparing population size and neutral genetic diversity in supplemented populations to the same characteristics in unaltered populations 100 years after supplementation ended. Releasing even slightly less fit captive-born individuals to supplement wild populations typically resulted in reductions in population sizes and genetic diversity over the long term when the fitness reductions were heritable (i.e., due to genetic adaptation to captivity) and populations continued to be regulated by density-dependent mechanisms over time. Negative effects for species with longer life spans and lower rates of population replacement were smaller than for species with shorter life spans and higher rates of population replacement. Programs that released captive-born individuals over fewer years or that avoided breeding individuals with captive ancestry had smaller reductions in population size and genetic diversity over the long term. Relying on selection in the wild to remove individuals with reduced fitness mitigated some negative demographic effects, but at a substantial cost to neutral genetic diversity. Our results suggest that conservation-focused captive-breeding programs should take measures to prevent even small amounts of genetic adaptation to captivity, quantitatively determine the minimum number of captive-born individuals to release each year, and fully account for the interactions among genetic adaptation to captivity, population regulation, and life-history variation.     

A new procedure combining GC-MS with accelerated solvent extraction for the analysis of phthalic acid esters in contaminated soils

An optimized procedure based on gas chromatography-mass spectrometry (GC-MS) combined with accelerated solvent extraction (ASE) is developed for the analysis of six phthalic acid esters (PAEs), which are priority soil pollutants nominated by United States Environmental Protection Agency (USEPA). Quantification of PAEs in soil employs ultrasonic extraction (UE) (USEPA 3550) and ASE (USEPA 3545), followed by clean up procedures involving three different chromatography columns and two combined elution methods. GC-MS conditions under selected ion monitoring (SIM) mode are described and quality assurance and quality control (QA/QC) criteria with high accuracy and sensitivity for target analytes were achieved. Method reliability is assured with the use of an isotopically labeled PAE, di-n-butyl phthalate-d4 (DnBP-D4), as a surrogate, and benzyl benzoate (BB) as an internal standard, and with the analysis of certified reference materials (CRM). QA/QC for the developed procedure was tested in four PAE-spiked soils and one PAE-contaminated soil. The four spiked soils were originated from typical Chinese agricultural fields and the contaminated soil was obtained from an electronic waste dismantling area. Instrument detection limits (IDLs) for the six PAEs ranged 0.10–0.31 μg·L^-1 and method detection limits (MDLs) of the four spiked soils varied from a range of 20–70 μg·kg^-1 to a range of 90– 290 μg·kg^-1. Linearity of response between 20 μg·L^-1 and 2 mg·L^-1 was also established and the correlation coefficients (R) were all>0.998. Spiked soil matrix showed relative recovery rates between 75 and 120% for the six target compounds and about 93% for the surrogate substance. The developed procedure is anticipated to be highly applicable for field surveys of soil PAE pollution in China.     

The challenge of biased evidence in conservation

Efforts to tackle the current biodiversity crisis need to be as efficient and effective as possible given chronic underfunding. To inform decision-makers of the most effective conservation actions, it is important to identify biases and gaps in the conservation literature to prioritize future evidence generation. We used the Conservation Evidence database to assess the state of the global literature that tests conservation actions for amphibians and birds. For the studies in the database, we investigated their spatial and taxonomic extent and distribution across biomes, effectiveness metrics, and study designs. Studies were heavily concentrated in Western Europe and North America for birds and particularly for amphibians, and temperate forest and grassland biomes were highly represented relative to their percentage of land coverage. Studies that used the most reliable study designs—before-after control-impact and randomized controlled trials—were the most geographically restricted and scarce in the evidence base. There were negative spatial relationships between the numbers of studies and the numbers of threatened and data-deficient species worldwide. Taxonomic biases and gaps were apparent for amphibians and birds—some entire orders were absent from the evidence base—whereas others were poorly represented relative to the proportion of threatened species they contained. Metrics used to evaluate effectiveness of conservation actions were often inconsistent between studies, potentially making them less directly comparable and evidence synthesis more difficult. Testing conservation actions on threatened species outside Western Europe, North America, and Australasia should be prioritized. Standardizing metrics and improving the rigor of study designs used to test conservation actions would also improve the quality of the evidence base for synthesis and decision-making.     

Foreword

Preface

Foreword     

The role of arbuscular mycorrhizal fungi in the transfer of nutrients between white clover and perennial ryegrass

A glasshouse experiment was conducted in which 15N was used as a tracer applied as (15NH4)2SO4 to donor plants of white clover and perennial ryegrass. Nitrogen transfer via hyphae of arbuscular mycorrhizal fungi (AMF) or by other routes was studied by separating the root systems of the two plant species, as donors and receivers, when growing in the same pot, with selective mesh barriers of varying pore sizes in the presence and absence of AMF. Inoculation with AMF increased DM production and nitrogen (N) yield of clover plants. Transfer of 15N occurred between white clover and grass plants but was independent of AMF. Pore size of the mesh barriers controlled the degree of 15N enrichment in the grass, suggesting that transfer was mediated by mass flow and/or diffusion. Additional experiments showed that grass roots could pass through pores of 60-microm diameter, and hyphal links could not be detected by autoradiography, thus supporting the conclusions of the tracer experiment.     

Starting point or solution? Community-based marine protected areas in the Philippines

In 1985, in response to declining coral reef conditions, local residents and officials established small, no-take marine sanctuaries on Balicasag and Pamilacan Islands through a community-based process. The implementation of marine protected areas (MPAs) on Balicasag and Pamilacan Islands has been a partial success. As a direct result of protection, living hard coral cover has increased by 119% in Balicasag's sanctuary and by 67% in the non-sanctuary during the period 1984 to 1999, but Balicasag's reef is increasingly affected by breakage from anchors from dive boats and Crown-of-thorns starfish infestations. During the same period, living hard coral cover decreased by 20% in Pamilacan's sanctuary and by 45% in the non-sanctuary from 1984 to 1999. The decrease in living hard coral cover in Pamilacan's sanctuary is most likely a result of the 1998 bleaching event, Crown-of-thorn starfish and possible storm damage. Although there was an initial increase in the economically important target fish abundance in the Balicasag sanctuary and non-sanctuary and in the Pamilacan sanctuary during the first two years of implementation in the mid-1980s, there has since been a significant decline. Mean target fish abundance for the Balicasag non-sanctuary at 230 (+/- 65) individuals per 500 m2 is not significantly different from control sites without MPAs on nearby Panglao and Cabilao Islands at 164 (+/- 67) individuals per 500 m2. In general, fish abundance and diversity inside and outside the sanctuaries peaked in 1986, a year after the establishment of the sanctuaries when enforcement was strictest. Therefore, despite considerable success in enforcing regulations associated with these small MPAs at Balicasag and Pamilacan Islands, a trend of declining fish abundance and species richness among economically valuable species immediately outside the no-take areas highlights the limitations of small and isolated MPAs. This study contributes to the growing sentiment that it is not realistic for scattered, small no-take areas to maintain fish abundance and diversity on surrounding reefs when intensive fishing effort immediately adjacent to no-take areas removes most fish that exit these areas. This finding emphasizes the importance of nesting individual MPAs within broader management regimes that lead to overall fishing effort reduction and networking of MPAs. Among other recommendations, the authors advocate for continued support for community-based MPAs, a network of MPAs, reduced fishing effort in areas surrounding the MPAs and other management measures to improve the quality of the coral reef habitats.     

Biodegradation by Composting of Surface Modified Starch and PVA Blended Films

Several starch/PVA/glycerol polymer blends were prepared by a solution casting technique and examined for biodegradation by composting over 45 days. Within this time frame, the starch and glycerol components were fully degraded, leaving the PVA component essentially intact. The lowest PVA content film (20%) was selected as a polymer with enough PVA to impart important physical characteristics, but also enough starch to be considered biodegradable. The film characteristics were further improved by surface modification with chitosan. This modification did not interfere with the biodegradation of the starch component. Furthermore, there was slight evidence that PVA biodegradation had been initiated in composted, surface modified starch/PVA blends.