Variability of Lotic Macroinvertebrate Assemblages and Stream Habitat Characteristics Across Hierarchical Landscape Classifications

Streams are naturally hierarchical systems, and their biota are affected by factors effective at regional to local scales. However, there have been only a few attempts to quantify variation in ecological attributes across multiple spatial scales. We examined the variation in several macroinvertebrate metrics and environmental variables at three hierarchical scales (ecoregions, drainage systems, streams) in boreal headwater streams. In nested analyses of variance, significant spatial variability was observed for most of the macroinvertebrate metrics and environmental variables examined. For most metrics, ecoregions explained more variation than did drainage systems. There was, however, much variation attributable to residuals, suggesting high among-stream variation in macroinvertebrate assemblage characteristics. Nonmetric multidimensional scaling (NMDS) and multiresponse permutation procedure (MRPP) showed that assemblage composition differed significantly among both drainage systems and ecoregions. The associated R-statistics were, however, very low, indicating wide variation among sites within the defined landscape classifications. Regional delineations explained most of the variation in stream water chemistry, ecoregions being clearly more influential than drainage systems. For physical habitat characteristics, by contrast, the among-stream component was the major source of variation. Distinct differences attributable to stream size were observed for several metrics, especially total number of taxa and abundance of algae-scraping invertebrates. Although ecoregions clearly account for a considerable amount of variation in macroinvertebrate assemblage characteristics, we suggest that a three-tiered classification system (stratification through ecoregion and habitat type, followed by assemblage prediction within these ecologically meaningful units) will be needed for effective bioassessment of boreal running waters.     

Mineral wool waste in Europe: a review of mineral wool waste quantity,quality, and current recycling methods

The construction and demolition (C&D) industry has been identified as a major source of waste. European Union legislation states that, by 2020, 70 % of C&D waste must be prepared for reuse, recycled or recovered. European Union member states must increase their C&D waste recycling percentages in order to meet this binding target. Utilization of mineral wool waste, often considered unrecyclable, could improve the recycling percentage of C&D waste. In this article, mineral wool production and waste volumes are estimated based on information from the Eurostat database. A literature survey is conducted to collect information about mineral wool material properties, current recycling methods, and barriers to recycling of mineral wool, and suitable methods for separating mineral wool from C&D waste streams and the economic viability of mineral wool recycling are discussed. It is noted that accurate estimation of mineral wool waste volumes is problematic due to the fragmented nature of available data. Based on the literature review, current methods for recycling mineral wool waste include utilization of mineral wool waste as a raw material in various products. Barriers to recycling include economic questions and issues related to the purity and health effects of mineral wool waste. Material properties of mineral wool waste, such as fire resistance, could provide improved properties in products utilizing mineral wool waste as a raw material.     

Assessing temporal representativeness of water quality monitoring data

The effectiveness of different monitoring methods in detecting temporal changes in water quality depends on the achievable sampling intervals, and how these relate to the extent of temporal variation. However, water quality sampling frequencies are rarely adjusted to the actual variation of the monitoring area. Manual sampling, for example, is often limited by the level of funding and not by the optimal timing to take samples. Restrictions in monitoring methods therefore often determine their ability to estimate the true mean and variance values for a certain time period or season. Consequently, we estimated how different sampling intervals determine the mean and standard deviation in a specific monitoring area by using high frequency data from in situ automated monitoring stations. Raw fluorescence measurements of chlorophyll a for three automated monitoring stations were calibrated by using phycocyanin fluorescence measurements and chlorophyll a analyzed from manual water samples in a laboratory. A moving block bootstrap simulation was then used to estimate the standard errors of the mean and standard deviations for different sample sizes. Our results showed that in a temperate, meso-eutrophic lake, relatively high errors in seasonal statistics can be expected from monthly sampling. Moreover, weekly sampling yielded relatively small accuracy benefits compared to a fortnightly sampling. The presented method for temporal representation analysis can be used as a tool in sampling design by adjusting the sampling interval to suit the actual temporal variation in the monitoring area, in addition to being used for estimating the usefulness of previously collected data.     

Personal Exposure to Fine Particulate Matter in Elderly Subjects: Relation between Personal,Indoor, and Outdoor Concentrations

ABSTRACT

The time-series correlation between ambient levels, indoor levels, and personal exposure to PM_2.5 was assessed in panels of elderly subjects with cardiovascular disease in Amsterdam, the Netherlands, and Helsinki, Finland. Subjects were followed for 6 months with biweekly clinical visits. Each subject's indoor and personal exposure to PM_2.5 was measured biweekly, during the 24-hr period preceding the clinical visits. Outdoor PM_2.5 concentrations were measured at fixed sites. The absorption coefficients of all PM_2.5 filters were measured as a marker for elemental carbon (EC). Regression analyses were conducted for each subject separately, and the distribution of the individual regression and correlation coefficients was investigated. Personal, indoor, and ambient concentrations were highly correlated within subjects over time. Median Pearson's R between personal and outdoor PM_2.5 was 0.79 in Amsterdam and 0.76 in Helsinki. For absorption, these values were 0.93 and 0.81 for Amsterdam and Helsinki, respectively. The findings of this study provide further support for using fixed-site measurements as a measure of exposure to PM_2.5 in epidemiological time-series studies.     

Study of Miller timing on exhaust emissions of a hydrotreated vegetable oil (HVO)-fueled diesel engine

The effect of intake valve closure (IVC) timing by utilizing Miller cycle and start of injection (SOI) on particulate matter (PM), particle number, and nitrogen oxide (NO_x) emissions was studied with a hydrotreated vegetable oil (HVO)-fueled nonroad diesel engine. HVO-fueled engine emissions, including aldehyde and polyaromatic hydrocarbon (PAH) emissions, were also compared with those emitted with fossil EN590 diesel fuel. At the engine standard settings, particle number and NO_x emissions decreased at all the studied load points (50%, 75%, and 100%) when the fuel was changed from EN590 to HVO. Adjusting IVC timing enabled a substantial decrease in NO_x emission and combined with SOI timing adjustment somewhat smaller decrease in both NO_x and particle emissions at IVC??50 and??70 °CA points. The HVO fuel decreased PAH emissions mainly due to the absence of aromatics. Aldehyde emissions were lower with the HVO fuel with medium (50%) load. At higher loads (75% and 100%), aldehyde emissions were slightly higher with the HVO fuel. However, the aldehyde emission levels were quite low, so no clear conclusions on the effect of fuel can be made. Overall, the study indicates that paraffinic HVO fuels are suitable for emission reduction with valve and injection timing adjustment and thus provide possibilities for engine manufacturers to meet the strictening emission limits.

Implications: NO_x and particle emissions are dominant emissions of diesel engines and vehicles. New, biobased paraffinic fuels and modern engine technologies have been reported to lower both of these emissions. In this study, even further reductions were achieved with engine valve adjustment combined with novel hydrotreated vegetable oil (HVO) diesel fuel. This study shows that new paraffinic fuels offer further possibilities to reduce engine exhaust emissions to meet the future emission limits.

Supplementary Materials: Supplementary materials are available for this paper. Go to the publisher's online edition of the Journal of the Air & Waste Management Association for a complete list of analysed PAH compounds.     

BOD biosensors for pulp and paper industry wastewater analysis

Introduction

Two semi-specific microbial biosensors were constructed for the analysis of biochemical oxygen demand (BOD) in high-cellulose-content pulp and paper industry wastewaters. The biosensors were based on living cells of Bacillus subtilis and Paenibacillus sp. immobilized in an agarose gel matrix. Semi-specific microorganisms were isolated from various samples (decaying sawdust and rabbit manure) and were chosen based on their ability to assimilate cellulose.

Materials &; methods

The biosensors were calibrated with the Organization for Economic Cooperation and Development synthetic wastewater, and measurements with different wastewaters were conducted.

Results

The response time of biosensors using the steady-state method was 20?C25 min, and the service life of immobilized microorganisms was 96 days. Detection limit was 5 mg/l of BOD₇ while linear ranges extended up to 55 and 50 mg/l of the BOD₇ for B. subtilis- and Paenibacillus sp.-based biosensors, respectively. Repeatability and reproducibility of both biosensors were within the limits set by APHA??less than 15.4%. In comparison, both biosensors overestimated the BOD₇ values in paper mill wastewaters and underestimated the BOD₇ in aspen pulp mill wastewater.

Conclusions

The semi-specific biosensors are suitable for the estimation of organic pollution derived from cellulose, while the detection of pollution derived from tannins and lignins was minor. Better results in terms of accuracy and repeatability were gained with Paenibacillus sp. biosensor.     

The dependence of the beta coefficient of REA system with dynamic deadband on atmospheric conditions

We simulated the REA system with dynamic deadband to study numerical value and the effect of atmospheric conditions on the empirical constant beta which relates vertical flux to concentration difference between updrafts and downdrafts. We found that the value of beta depends only weakly on the friction velocity and atmospheric stability. In agreement with previous studies, the median value obtained for a system with dynamic deadband proportional to 0.5 times the running mean of the standard deviation of vertical wind speed was beta=0.42+/-0.03. For a single half-hour measurement one has to consider the large uncertainty of +/-0.2. According to our study, the dynamic deadband enables the use of a constant value of beta in flux calculation.     

Landsat ETM+ Images in the Estimation of Seasonal Lake Water Quality in Boreal River Basins

We investigated the use of Landsat ETM+ images in the monitoring of turbidity, colored dissolved organic matter (CDOM), and Secchi disk transparency (Z(SD)) in lakes of two river basins located in southern Finland. The ETM+ images were acquired in May, June, and September 2002 and were corrected for atmospheric disturbance using the simplified method of atmospheric correction (SMAC) model. The in situ measurements consisted of water sampling in the largest lake of the region, routine monitoring results for the whole study area, and Z(SD) observations made by volunteers. The ranges of the water quality variables in the dataset were as follows: turbidity, 0.6-25 FNU; absorption coefficient of CDOM at 400 nm, 1.0-12.2 m(-1); Z(SD), 0.5-5.5 m; and chlorophyll a concentration, 2.4-80 mug L(-1). The estimation accuracies of the image-specific empirical algorithms expressed as relative errors were 23.0% for turbidity, 17.4% for CDOM, and 21.1% for Z(SD). If concurrent in situ measurements had not been used for algorithm training, the average error would have been about 37%. The atmospheric correction improved the estimation accuracy only slightly compared with the use of top-of-atmospheric reflectances. The accuracy of the water quality estimates without concurrent in situ measurements could have been improved if in-image atmospheric parameters had been available. The underwater reflectance simulations of the ETM+ channel wavelengths using water quality typical for Finnish lakes (data from 1113 lakes) indicated that region-specific algorithms may be needed in other parts of the country, particularly in the case of Z(SD). Despite the limitations in the spectral and radiometric resolutions, ETM+ imagery can be an effective aid, particularly in the monitoring and management of small lakes (<1 km(2)), which are often not included in routine monitoring programs.