Organic aerosol source apportionment from highly time-resolved molecular composition measurements

Organic molecular composition measurements with 3.5 min time resolution were performed with the photoionization aerosol mass spectrometer (PIAMS) over an 18-day period in October–November 2007 in Wilmington, Delaware, USA. Mass spectra were obtained for a total of 6244 time periods, and the signal intensities of 60 specific m/z ratios corresponding to key organic molecular species were modeled by positive matrix factorization (PMF). Six factors were identified that could be tentatively linked to specific sources (diesel exhaust, car emissions/road dust, meat cooking) or types of compounds (alkanes/alkanoic acids, phthalates, PAHs). Owing to the inherent high time resolution of PIAMS, the temporal (diurnal) and wind direction dependencies of these factors could be examined in detail to assess the impacts of point sources and atmospheric processes. Time-resolved EC/OC and gas-phase data (O₃, NO_x, CO) were also obtained during the measurement period to help distinguish primary (POC) and secondary (SOC) organic carbon. The total organic carbon (TOC) concentration averaged 2.6 μg m^?3 during the measurement period and most (>90%) was classified as primary. Of this, approximately one-third could be assigned as combustion POC and the other two-thirds as non-combustion POC. The PMF results were combined with EC/OC data for source apportionment. The diesel and car/road dust factors together represented about two-thirds of TOC, while the alkane/alkanoic acid and meat cooking factors contributed most of the remaining one-third. The phthalate and PAH factors contributed very little, only a few percent of the total. The diesel factor correlated most strongly to combustion POC, while the sum of the remaining factors correlated well with non-combustion POC.     

Benefit‐Cost Analysis of Integrated Water Resource Management: Accounting for Interdependence in the Yakima Basin Integrated Plan

Integrated water resource management (IWRM) requires accounting for many interrelated facets of water systems, water uses and stakeholders, and water management activities. The consequence is that project analysis must account for the nonseparability among the component parts of IWRM plans. This article presents a benefit‐cost (B‐C) analysis of a set of projects included in the Yakima Basin Integrated Plan proposed for the Yakima Basin in south‐central Washington State. The analysis accounts for interdependence among proposed water storage projects and between water storage and water market development in the context of historical and more adverse projected future climate scenarios. Focusing on irrigation benefits from storage, we show that the value of a given proposed storage project is lower when other proposed storage projects in the basin are implemented, and when water markets are functioning effectively. We find that none of the water storage projects satisfy a B‐C criterion, and that assuring proposed instream flow augmentation is less expensive by purchasing senior diversion rights than relying on new storage to provide it.     

Multimedia Integrated Modeling for Environmental Protection: Introduction to a Collaborative Framework

The EPA's Office of Research and Development is embarking on a long term project to develop a Multimedia Integrated Modeling System (MIMS). The system will have capabilities to represent the transport and fate of nutrients and chemical stressors over multiple spatial and temporal scales. MIMS will be designed to improve the environmental management community's ability to evaluate the impact of air and water quality and watershed management practices on stream and estuarine conditions. The system will provide a computer-based problem-solving environment for testing understanding of multimedia (atmosphere, land, water) environmental problems, such as the movement of chemicals through the hydrologic cycle, and the response of aquatic ecological systems to land-use change, with initial emphasis on the fish health endpoint. The design will attempt to combine the state-of-the-art in computer science, system design, and numerical analysis (i.e., object-oriented design, parallel processing, advanced numerical libraries including analytic elements) with the latest advancements in process level science (hydrology, atmospheric sciences, chemistry, ecology). The purpose of this paper is to introduce a vision for a MIMS and anticipate the challenges to its development.     

Protected area characteristics that help waterbirds respond to climate warming

Protected area networks help species respond to climate warming. However, the contribution of a site's environmental and conservation-relevant characteristics to these responses is not well understood. We investigated how composition of nonbreeding waterbird communities (97 species) in the European Union Natura 2000 (N2K) network (3018 sites) changed in response to increases in temperature over 25 years in 26 European countries. We measured community reshuffling based on abundance time series collected under the International Waterbird Census relative to N2K sites’ conservation targets, funding, designation period, and management plan status. Waterbird community composition in sites explicitly designated to protect them and with management plans changed more quickly in response to climate warming than in other N2K sites. Temporal community changes were not affected by the designation period despite greater exposure to temperature increase inside late-designated N2K sites. Sites funded under the LIFE program had lower climate-driven community changes than sites that did not received LIFE funding. Our findings imply that efficient conservation policy that helps waterbird communities respond to climate warming is associated with sites specifically managed for waterbirds.     

Driving total process efficiency

Reductions in pollution and improvements in profitability are not mutually exclusive. In the first 18 months of a project established to demonstrate the benefits of waste minimization and cleaner technology, the 11 participating companies have made savings of over £2 million a year. Further savings of a similar magnitude are possible in subsequent years. Reductions in the use of inputs such as water, energy and raw materials exceeded savings in effluent production by a significant margin, thereby confirming the profitability of programmes which drive Total Process Efficiency     

Influence of temperature on muscle-fibre development in larvae of the herringClupea harengus

The development of swimming (myotomal) muscles was studied in herring larvae (Clupea harengus L.) caught in the Firth of Clyde, Scotland, in spring 1990 and reared at either 5, 10 or 15°C. Two muscle-fibre types can be distinguished in the myotomes of herring larvae using ultrastructural criteria. A single layer of small-diameter muscle fibres, packed with mitochondria, is present beneath the entire surface of the skin (superficial muscle fibres). The remaining bulk of the muscle is composed of larger diameter fibres (inner muscle fibres) containing significantly more myofibrils than the superficial fibres. In 1 d-old larvae, the number of inner muscle fibres in myotomes immediately posterior to the yolk-sac was 311±41 at 15°C, 257±22 at 10°C and 187±22 at 5°C (mean±SD,n=6). The average diameter of inner muscle fibres increased with decreasing temperature, so that the total cross-sectional area of muscle was similar at each temperature. After 6 to 7 d, the number of muscle fibres had significantly increased at 15°C (383±25), but not at 10°C (281±32) or 5°C (192±17). In contrast, the average cross-sectional area of inner muscle fibres had increased by 19% at 15°C, 34% at 10°C, and 26% at 5°C. Temperature also influenced the relative proportions and spatial distributions of muscle-fibre organelles. For example, in 1 d-old larvae, the fraction of muscle-fibre volume (volume density) occupied by mitochondria in the superficial fibres was significantly higher at 15°C (46.0%) than at either 5°C (37.6%) or 10°C (38.8%). In the inner muscle fibres, the volume density of mitochondria was 26.1% at 15°C, 20.5% at 10°C and 15.9% at 5°C, whereas the volume density of myofibrils was similar at the three temperatures (33 to 38%). Typically, inner muscle fibres from 10°C larvae, but not from 5 or 15°C larvae contained a large central mitochondrion.     

Estuarine dredge and fill activities: A review of impacts

Dredge and fill activities in estuaries have many environmental effects, most, although not all, of them deleterious. These effects include reduced light penetration by increased turbidity; altered tidal exchange, mixing, and circulation; reduced nutrient outflow from marshes and swamps; increased saltwater intrusion; and creation of an environment highly susceptible to recurrent low dissolved oxygen levels. Coral, oysters, and barnacles are particularly vulnerable to the effects of siltation. Both estuarine flora and fauna may be harmed by contaminants released into the water column by dredging operations. Ways to mitigate the effects of dredge and fill operations include careful pre- and post-construction environmental studies; use of bridging to create roadbeds where coastal wetlands cannot be avoided; use of a turbidity diaper and other means to control turbidity; dredging during periods of low benthic populations or during tides that would carry coarser sediments away from productive areas such as oyster reefs; and thoughtful disposal of spoil, such as locating spoil sites on the uplands with proper diking.     

Effect thresholds and ‘Adequate Control’ of risks

BACKGROUND: Preparation of the new European REACH (Registration, Evaluation and Authorisation of CHemicals) regulation on chemicals has reached a critical stage. Depending on how key elements of the legislative proposal are finalised, especially that on authorisation of uses of 'substances of very high concern', REACH could either provide an effective measure to drive innovation towards cleaner and safer alternatives, or instead lead to further avoidable chemical exposures on the basis of demonstrated 'adequate control' of risks. Given that some key indicators of human and wildlife reproductive health continue to decline in parts of Europe, while evidence for chemical exposure as a contributory factor grows, it will clearly be vital to get the legislation right. GOAL AND SCOPE: Whereas there is now a consensus between the European Parliament and Council of the European Union that uses of persistent, bioaccumulative and toxic (PBT) and very persistent and very bioaccumulative (vPvB) substances should only be permitted when no safer alternatives are available, major differences remain regarding the manner in which other 'substances of very high concern' (including substances which are carcinogenic, mutagenic or toxic to reproduction (CMRs) and endocrine disruptors) are addressed. This paper examines those differences in more detail and proposes some ways forward. METHODS: Using case studies of specific chemicals as examples, the paper critically evaluates the concepts of 'effect thresholds' and 'adequate control' of risks, which underpin the Council's proposal for many CMRs and endocrine disruptors. RESULTS: The subjectivity and uncertainties inherent in the threshold approach proposed by the Council, as illustrated by these case examples, bring its ability to ensure a high level of protection for the environment and human health into question: i. the nature and extent of toxic effects recorded depend on many different factors, including the type of test and conditions selected, the organisms exposed, the timing of exposure and precisely which effects are measured and over what timeframe. ii. doses considerably below 'no effect levels' for survival could nevertheless be causing significant impairment to health and/or reproductive success. iii. chemicals present in mixtures at levels below established thresholds for effects may, in combination, induce significant toxicological responses. DISCUSSION: Under the Council's current proposal, companies will be granted authorisations for some uses of CMRs and endocrine disruptors, even if safer alternatives without these properties are already on the market. The high level of evidence required for identification of substances as being of equivalent concern represents an additional weakness in the Council approach. CONCLUSIONS: Instead, a requirement (along the lines of the Parliament's proposals) to address the availability of alternatives in all cases, to use them when available and to initiate their development when not, represents a more robust, defensible and protective approach to the management of 'substances of very high concern'. The possibility for authorisation of essential uses would remain, while all avoidable uses and exposures would progressively be prevented and sustainable innovation supported. PERSPECTIVES: In the long run, this can only lead to a more sustainable future for the chemical industry in Europe, as well as delivering benefits of increased protection for our environment and health for generations to come.