Controls on coarse wood decay in temperate tree species: birth of the LOGLIFE experiment

Dead wood provides a huge terrestrial carbon stock and a habitat to wide-ranging organisms during its decay. Our brief review highlights that, in order to understand environmental change impacts on these functions, we need to quantify the contributions of different interacting biotic and abiotic drivers to wood decomposition. LOGLIFE is a new long-term 'common-garden' experiment to disentangle the effects of species' wood traits and site-related environmental drivers on wood decomposition dynamics and its associated diversity of microbial and invertebrate communities. This experiment is firmly rooted in pioneering experiments under the directorship of Terry Callaghan at Abisko Research Station, Sweden. LOGLIFE features two contrasting forest sites in the Netherlands, each hosting a similar set of coarse logs and branches of 10 tree species. LOGLIFE welcomes other researchers to test further questions concerning coarse wood decay that will also help to optimise forest management in view of carbon sequestration and biodiversity conservation.     

Adsorption of pharmaceutical compounds and an endocrine disruptor from aqueous solutions by carbon materials

Adsorption has been used to study the removal of atenolol, caffeine, diclofenac and isoproturon, pharmaceutical compounds as emerging contaminants and an endocrine disruptor from ultrapure water and a municipal wastewater treatment plant effluent with three carbonaceous materials: activated carbon, multiwalled carbon nanotubes and carbon nanofibers. The adsorption capacities were studied in the temperature range of 25-65°C and pH range from 3 to 9. Several model isotherms were used to model the adsorption equilibrium data. Also, the competitive adsorption was evaluated.     

pH对混合污泥水解酸化的影响

pH对剩余污泥和初沉污泥水解酸化的影响已有报道,但pH对混合污泥水解酸化的影响尚鲜见报道。为此对厌氧环境,(20±1)℃,pH=4～11以及不控制pH条件下混合污泥的水解酸化特征进行了研究。研究发现:对pH调控有利于污泥SCOD的溶出,在较强的碱性条件下污泥溶出的SCOD要大于其他条件下的,特别是pH=10和11条件下污泥溶出的SCOD要远高于其他条件下。碱性环境和酸性环境以及中性环境相比更有利于混合污泥产酸,最佳产酸pH条件为pH=10。在酸性和极端碱性条件下均有利于混合污泥中氨氮和磷的释放。碱性环境利于挥发性悬浮固体(VSS)的去除,但不利于总悬浮固体(TSS)的去除。在不同pH条件下将混合污泥的发酵特征和剩余污泥和初沉污泥发酵特征比较,发现3种污泥水解和产酸均在碱性条件下最好,且在20～22℃的条件下,产酸量均在pH=10的条件下达到最大。     

Ex situ bioremediation of a soil contaminated by mazut (heavy residual fuel oil)--a field experiment

Mazut (heavy residual fuel oil)-polluted soil was exposed to bioremediation in an ex situ field-scale (600 m(3)) study. Re-inoculation was performed periodically with biomasses of microbial consortia isolated from the mazut-contaminated soil. Biostimulation was conducted by adding nutritional elements (N, P and K). The biopile (depth 0.4m) was comprised of mechanically mixed polluted soil with softwood sawdust and crude river sand. Aeration was improved by systematic mixing. The biopile was protected from direct external influences by a polyethylene cover. Part (10 m(3)) of the material prepared for bioremediation was set aside uninoculated, and maintained as an untreated control pile (CP). Biostimulation and re-inoculation with zymogenous microorganisms increased the number of hydrocarbon degraders after 50 d by more than 20 times in the treated soil. During the 5 months, the total petroleum hydrocarbon (TPH) content of the contaminated soil was reduced to 6% of the initial value, from 5.2 to 0.3 g kg(-1) dry matter, while TPH reduced to only 90% of the initial value in the CP. After 150 d there were 96%, 97% and 83% reductions for the aliphatic, aromatic, and nitrogen-sulphur-oxygen and asphaltene fractions, respectively. The isoprenoids, pristane and phytane, were more than 55% biodegraded, which indicated that they are not suitable biomarkers for following bioremediation. According to the available data, this is the first field-scale study of the bioremediation of mazut and mazut sediment-polluted soil, and the efficiency achieved was far above that described in the literature to date for heavy fuel oil.     

Recycled crushed glass in road work applications

A comprehensive suite of geotechnical laboratory tests was undertaken on samples of recycled crushed glass produced in Victoria, Australia. Three types of recycled glass sources were tested being coarse, medium and fine sized glass. Laboratory testing results indicated that medium and fine sized recycled glass sources exhibit geotechnical behavior similar to natural aggregates. Coarse recycled glass was however found to be unsuitable for geotechnical engineering applications. Shear strength tests indicate that the fine and medium glass encompass shear strength parameters similar to that of natural sand and gravel mixtures comprising of angular particles. Environmental assessment tests indicated that the material meets the requirements of environmental protection authorities for fill material. The results were used to discuss potential usages of recycled glass as a construction material in geotechnical engineering applications particularly road works.     

Select chemical and engineering properties of wastewater biosolids

The select chemical and engineering characteristics of biosolids produced at a wastewater treatment plant in Eastern Australia were investigated to assess its suitability as structural fill material in road embankments. Results of comprehensive set of geotechnical experimentation including compaction, consolidation, creep, hydraulic conductivity and shear strength tests implied that biosolids demonstrate behavior similar to highly organic clays with a higher potential for consolidation and settlement. Results of chemical study including heavy metals, dichloro diphenyl trichloroethane (and derivatives) and organochlorine pesticides, indicate that biosolids samples are within the acceptable limits which allows their usage under certain guidelines. Results of tests on pathogens (bacteria, viruses or parasites) also indicated that biosolids were within the safe acceptable limits. Technical and management suggestions have been provided to minimize the possible environmental risks of using biosolids in road embankment fills.     

Using a contingent valuation approach for improved solid waste management facility: evidence from Kuala Lumpur, Malaysia

This study employed contingent valuation method to estimate the willingness to pay (WTP) of the households to improve the waste collection system in Kuala Lumpur, Malaysia. The objective of this study is to evaluate how household WTP changes when recycling and waste separation at source is made mandatory. The methodology consisted of asking people directly about their WTP for an additional waste collection service charge to cover the costs of a new waste management project. The new waste management project consisted of two versions: version A (recycling and waste separation is mandatory) and version B (recycling and waste separation is not mandatory). The households declined their WTP for version A when they were asked to separate the waste at source although all the facilities would be given to them for waste separation. The result of this study indicates that the households were not conscious about the benefits of recycling and waste separation. Concerted efforts should be taken to raise environmental consciousness of the households through education and more publicity regarding waste separation, reducing and recycling.     

Correlation between physicochemical and ecotoxicological approaches to estimate landfill leachates toxicity

Leachates from municipal solid waste (MSW) landfills may contain a huge diversity of contaminants; these wastewaters should be considered as potentially hazardous complex mixtures, representing a potential environmental risk for surface and groundwater. Current MSW landfill wastes regulatory approaches deem exclusively on the physicochemical characterization and does not contemplate the ecotoxicological assessment of landfill leachates. However, the presence of highly toxic substances in consumer products requires reconsideration on the need of more specific ecotoxicological assessments. The main aim of this study was to evaluate the toxicity of different MSW landfill leachates using a battery of toxicity tests including acute toxicity tests with Daphnia magna and the anuran Xenopus laevis and the in vitro toxicity test with the fish cell line RTG-2. The additional objective was to study the possible correlation between physicochemical properties and the toxicity results obtained for untreated landfill leachates. The results showed that the proposed test battery was effective for the ecotoxicological characterization of MSW landfill leachates. A moderate to strong correlation between the measured physicochemical parameters and the calculated toxicity units was detected for all toxicity assays. Correlation factors of 0.85, 0.86 and 0.55 for Daphnia, Xenopus and RTG-2 tests, respectively, were found. The discriminant analysis showed that certain physicochemical parameters could be used for an initial categorization of the potential aquatic acute toxicity of leachates; this finding may facilitate leachates management as the physicochemical characterization is currently the most common or even only monitoring method employed in a large majority of landfills. Ammonia, alkalinity and chemical oxygen demand (COD), together with chloride, allowed a proper categorization of leachates toxicity for up to 75% of tested samples, with a small percentage of false negatives.     

Historical trends in the mass and chemical species concentrations of coarse particulate matter in the Los Angeles Basin and relation to sources and air quality regulations

To assess the impact of past, current and proposed air quality regulations on coarse particulate matter (CPM), the concentrations of CPM mass and its chemical constituents were examined in the Los Angeles Basin from 1986 to 2009 using PM data acquired from peer-reviewed journals and regulatory agency database. PM10 mass levels decreased by approximately half from 1988 to 2009 at the three sampling sites examined- located in downtown Los Angeles, Long Beach and Riverside. Annual CPM mass concentrations were calculated from the difference between daily PM10 and PM2.5 from 1999 to 2009. High CPM episodes driven by high wind speed/stagnant condition caused year-to-year fluctuations in the 99th/98th percentile CPM levels. The reductions of average CPM levels were lower than those of PM10 in the same period, therefore the decrease of PM10 level was mainly driven by reductions in the emission levels of PM2.5 (or fine) particles, as demonstrated by the higher annual reduction of average PM2.5 (0.92 microg/m3) compared with CPM (0.39 microg/m3) from 1999 to 2009 in downtown Los Angeles despite their comparable concentrations. This is further confirmed by the significant decrease of Ni, Cr, V and EC in the coarse fraction after 1995. On the other hand, the levels of several inorganic ions (sulfate, chloride and to a lesser extent nitrate) remained comparable. From 1995 to 2008, levels of Cu, a tracer of brake wear, either remained similar or decreased at a smaller rate compared with elements of combustion origins. This differential reduction of CPM components suggests that past and current regulations may have been more effective in reducing fugitive dust (Al, Fe and Si) and combustion emissions (Ni, Cr, V, and EC) rather than CPM from vehicular abrasion (Cu) and inorganic ions (NO3(-), SO4(2-) and Cl(-)) in urban areas. Implications: Limited information is currently available to provide the scientific basis for understanding the sources and physical and chemical variations of CPM, and their relations to air quality regulations and adverse health effects. This study investigates the historical trends of CPM mass and its chemical components in the Los Angeles Basin to advance our understanding on the impact of past and current air quality regulations on the coarse fraction of PM. The results of this study will aid policy makers to design more targeted regulations to control CPM sources to ensure substantial protection of public health from CPM exposure. Supplemental Materials: Supplemental materials are available for this article. Go to the publisher's online edition of the Journal of the Air & Waste Management Association for (1) details of the sampling sites and (2) the daily concentrations of high CPM/PM10 episodes.