Intertidal invertebrates locally enhance primary production

The contribution of autochthonous vs. allochthonous inputs to productivity is an important determinant of ecosystem function across multiple habitats. In coastal marine systems, nutrients are thought to come primarily from the upwelling of deep, nutrient-rich water. Using experimental manipulations of a dominant tide pool animal, the mussel Mytilus californianus, I show that the presence of mussels greatly increases the supply of inorganic nitrogen and phosphorus. Mussels further had a direct effect on productivity: benthic microalgal abundance increased by a factor of 4-8, while the growth of a red alga was four times greater in the presence of mussels. The increase in nitrite and nitrate associated with mussels further suggests nitrifying activity by microbes. These findings have broad implications for coastal marine systems, including that regenerated nutrients may contribute more to productivity than previously recognized and that the presence of animal-generated nutrients sets the stage for numerous positive interactions.     

The impact of domestic wood burning on personal, indoor and outdoor levels of 1,3-butadiene, benzene, formaldehyde and acetaldehyde

The aim of this study was to quantify personal exposure and indoor levels of the suspected or known carcinogenic compounds 1,3-butadiene, benzene, formaldehyde and acetaldehyde in a small Swedish town where wood burning for space heating is common. Subjects (wood burners, n = 14), living in homes with daily use of wood-burning appliances were compared with referents (n = 10) living in the same residential area. Personal exposure and stationary measurements indoors and at an ambient site were performed with diffusive samplers for 24 h. In addition, 7 day measurements of 1,3-butadiene and benzene were performed inside and outside the homes. Wood burners had significantly higher median personal exposure to 1,3-butadiene (0.18 microg m(-3)) compared with referents (0.12 microg m(-3)), which was also reflected in the indoor levels. Significantly higher indoor levels of benzene were found in the wood-burning homes (3.0 microg m(-3)) compared with the reference homes (1.5 microg m(-3)). With regard to aldehydes, median levels obtained from personal and indoor measurements were similar although the four most extreme acetaldehyde levels were all found in wood burners. High correlations were found between personal and indoor levels for all substances (r(s) > 0.8). In a linear regression model, type of wood-burning appliance, burning time and number of wood replenishments were significant factors for indoor levels of 1,3-butadiene. Domestic wood burning seems to increase personal exposure to 1,3-butadiene as well as indoor levels of 1,3-butadiene and benzene and possibly also acetaldehyde. The cancer risk from these compounds at exposure to wood smoke is, however, estimated to be low in developed countries.     

Characterisation of polymer fractions from waste electrical and electronic equipment (WEEE) and implications for waste management

There is an increasing interest in the end-of-life management of polymers present in waste electrical and electronic equipment (WEEE). This is mainly due to high recycling and recovery quotas set by the European WEEE directive, which can only be fulfilled by including the plastic fraction in recycling and recovery approaches. Previous studies identified a high material diversity and various contaminants in WEEE plastics, including heavy metals, polybrominated biphenyls (PBB), diphenyl ethers (PBDE), as well as polybrominated dibenzodioxins and dibenzofurans (PBDD/F). These substances are regulated by European directives that limit their levels in marketable products. Consequently, both material diversity and contaminants are strong arguments against material recycling and point to hazardous waste treatment. However, recent developments in the production of flame retardants and electrical and electronic goods aimed to reduce contaminants and material diversity. Thus, the present study summarises updated contaminant levels of plastic fractions of European WEEE, as well as data on materials in waste housing polymers. Material characterisation revealed housing fractions to be interesting sources for polymer recycling, which however has to implement potent material separation and/or bromine elimination techniques. With respect to contaminants, our data indicate an effective phase-out of PBB, but still high levels of PBDE and PBDD/F are found. Sources and implications for the material recycling and thermal recovery approaches are discussed in detail.     

工业粉体下落过程粉尘排放特性的实验研究

根据与维也纳工业大学化学工程研究所共同确定的实验方案,在实验室开发并设计了一套自由下落装置,研究粉体下落过程中粉尘的排放特性。通过实验主要测定下落高度、空气湿度和质量流量对粉尘排放的影响。实验结果表明,下落高度和空气湿度对粉尘排放均有影响,且空气湿度对粗粒子的排放影响较大,对细粒子影响较小;随着质量流量的增加,粉尘产生率逐渐减小,但质量流量的增加也会增加粉尘浓度,加重了对工人的危害。建立了影响因素与粉尘产生率之间的数学模型,经检验,二者之间存在显著相关,实测值与理论计算值基本一致,可以应用已建立的数学模型定量评价粉尘产生量。     

Imaging Chemical Patches on Near-surface Atmospheric Dust Particles with NanoSIMS 50 to Identify Material Sources

The increase of traffic and the rising energy consumption mean a challenge to the air pollution control and to environmental protection. Measures of air pollution control concentrated primarily on the reduction of gaseous pollutants. However, in the field of air hygiene in Central Europe, especially the load of near-surface atmospheric dust becomes threatening to human health. A SIMS microprobe for ultra fine feature analysis is used to image the elemental composition at the surface of submicrometer urban dust particles collected at two measurement stations in the Grand Duchy of Luxembourg. The NanoSIMS 50 has been chosen because it creates one intensity image for each selected element in a high spatial resolution down to 50 nm. The atmospheric fine dust consists of a mixture of organic and inorganic compounds. The elemental composition at the surface of particles was studied using a global image segmentation technique to separate the signal from the background of the particles. The analysis of the binary intensity images was carried out using several shape and proximity measures. The patch shape complexity and distribution for industrial/urban particles were found to differ significantly from the solids collected from a forest site. We conclude that the methodology developed in the study is a reliable tool to differentiate between potential sources of airborne particulate matter.     

Role of waste management with regard to climate protection: a case study.

According to the Kyoto Protocol and the burden-sharing agreement of the European Union, Austria is required to cut greenhouse gas (GHG) emissions during the years 2008 to 2012 in order to achieve an average reduction of 13%, based on the level of emissions for the year 1990. The present contribution gives an overview of the history of GHG emission regulation in Austria and identifies the progress made towards the realization of the national climate strategy to attain the GHG emission targets. The contribution uses Austria as an example of the way in which proper waste management can help to reduce GHG emissions. The GHG inventories show that everything must be done to minimize the carbon input due to waste deposition at landfill sites. The incineration of waste is particularly helpful in reducing GHG emissions. The waste-to-energy by incineration plants and recovery of energy yield an ecologically proper treatment of waste using state-of-the-art techniques of a very high standard. The potential for GHG reduction of conventional waste treatment technologies has been estimated by the authors. A growing number of waste incinerators and intensified co-incineration of waste in Austrian industry will both help to reduce national GHG emissions substantially. By increasing the number and capacity of plants for thermal treatment of waste the contribution of proper waste management to the national target for reduction of GHG emissions will be in the range of 8 to 14%. The GHG inventories also indicate that a potential CO2 reduction of about 500 000 t year(-1) is achievable by co-incineration of waste in Austrian industry.     

Simultaneous monitoring of profiles of polycyclic aromatic hydrocarbons in contaminated air with semipermeable membrane devices and spruce needles

Gaseous emissions of combusted electronic scrap, PVC, carpet and wood were monitored for polycyclic aromatic hydrocarbons (PAHs) by simultaneous use of semipermeable membrane devices (SPMDs) and shoots of spruce needles (Picea abies). It was found that phenanthrene, acenaphthylene and fluorene were the dominating PAHs in all samples. SPMDs and needles mainly sequestered PAH associated with the vapor phase. Particle-bound PAHs were only detected in small amounts, at which the needles tended to uptake more of these compounds in comparison to the SPMDs. Nevertheless, the logarithm of the concentrations of PAHs analyzed in both passive samplers after the same sampling period exhibited a significant linear correlation with correlation coefficients larger than 0.8073. SPMDs and spruce needles can complement each other in passive air sampling for compounds with a preference to the gas phase rather than aerosols.     

A seventeen-year study of the rose star Crossaster papposus population in a coastal bay in southeast Alaska

A 17 yr study of a population of the rose star Crossaster papposus (Linnaeus, 1767) in Auke Bay, near Juneau, Alaska, used SCUBA to follow a total of 956 individually marked stars. Population density was relatively constant over the 17 yr of study, although the influx of smaller individuals varied by an order of magnitude. Growth in diameter of individual stars was inversely related to size, with the largest individuals showing negligible growth for periods of months or years. Annual survivorship was relatively high (from 76.3 to 90.4%), and some individuals persisted throughout the study, indicating longevities of at least 20 yr in this species. Observations of food habits indicated that the principal prey item is the reddish scallop Chlamys rubida. In summary, this rose star population was characterized by a relatively stable number of long-lived, slow-growing individuals. Received: 7 April 1998 / Accepted: 5 October 1998     

Re-evaluation of the conformational structure of sulfadiazine species using NMR and ab initio DFT studies and its implication on sorption and degradation

In the environment, the sorption and the degradation of organic pollutants are of increasing interest. The investigation of the chemical structures provides a basis for the development of a suitable binding model approach and for the mechanistic understanding of the chemical fate processes. The aim of this study was the identification of different species of the antibiotic compound sulfadiazine (SDZ) using (1)H and (13)C NMR experiments and ab initio density functional theory (DFT) calculations. In the neutral, aprotic solvent dimethylsulfoxide-d(6) (DMSO-d(6)), a new sulfadiazine structure containing an O-H-N hydrogen bond was identified. In the protic solvent water-d(2) and in dependence on pH and the position of the amidogen hydrogen atom nine possible SDZ conformations were analyzed and five structures were identified. Good conformity between theory and calculation of (1)H NMR was observed. Unfortunately, (13)C NMR is not sensitive enough for comparison and differentiation. In order to verify the identified structures, additional NBO/NLMO (natural localized molecular orbital) analyses were conducted (calculation of net atomic charges, bond polarity, atomic valence, and electron delocalization). Finally, conformation optimizations were performed in order to investigate the stability of the SDZ species. We showed that SDZ contains no S=O double bond, but that it has two S-O single bonds. Surprisingly, negative charges were observed at the pyrimidine nitrogen atom. With these results, the known structure of SDZ was revised. Studies of the geometrical structure and the torsion angles showed that SDZ is very flexible and can be easily fitted to the sorbent. These observations would explain the strong sorbance and hence the rapid formation of non-extractable residues in the environment because SDZ acts as a strong ligand. These results show that that the sulfonamide hydrogen is important for the biological activity but the pyrimidine nitrogen and the sulfonamide oxygen is responsible for the sorbance in environment.