Influence of suspended particles on the emission of organophosphate flame retardant from insulation boards

The influence of the presence of the so-called seed particles on the emission rate of Tris (1-chloroisopropyl) phosphate (TCIPP) from polyisocyanurate (PIR) insulation boards was investigated in this study. Two Field and Laboratory Emission Test cells (FLEC) were placed on the surface of the same PIR board and respectively supplied with clean air (reference FLEC) and air containing laboratory-generated soot particles (test FLEC). The behavior of the area-specific emission rates (SER _A ) over a time period of 10 days was studied by measuring the total (gas?+?particles) concentrations of TCIPP at the exhaust of each FLEC. The estimated SER _A of TCIPP from the PIR board at the quasi-static equilibrium were found to be 0.82 μg m^?2 h^?1 in the absence of seed particles, while the addition of soot particles led to SER _A of 2.16 μg m^?2 h^?1. This indicates an increase of the SER _A of TCIPP from the PIR board with a factor of 3 in the presence of soot particles. The TCIPP partition coefficient to soot particles at the quasi-static equilibrium was 0.022?±?0.012 m³ μg^?1. In the next step, the influence of real-life particles on TCIPP emission rates was investigated by supplying the test FLEC with air from a professional kitchen where mainly frying and baking activities took place. Similar to the reference FLEC outcomes, SER _A was also found to increase in this real-life experiment over a time period of 20 days by a factor 3 in the presence of particles generated during cooking activities. The median value of estimated particle–gas coefficient for this test was 0.062?±?0.037 m³ μg^?1.

     

Occurrence, source diagnosis, and biological effect assessment of DDT and its metabolites in various environmental compartments of the Pearl River Delta, South China: A review

This review summarizes and analyzes available data in the literature (mostly after 2000) on the occurrence of dichlorodiphenyltrichloroethane (DDT) and its main metabolites, dichlorodiphenyldichloroethane (DDD) and chlorodiphenyldichloroethylene (DDE), in the environment of the Pearl River Delta (PRD), South China. Generally, the concentration levels of the sum of DDT, DDD, and DDE, designated as DDTs thereafter, have not significantly declined since 1983. However, the composition of DDTs residues has changed with time. DDTs in soil, freshwater sediment and freshwater fish species were mainly residues from chronological use. There is evidence that new point sources, such as dicofol and anti-fouling paint, may have contributed DDTs to various environmental compartments. Risk assessment against existing criteria indicated that the levels of DDTs in water and some fish species may pose adverse effects to humans or wildlife, and those in sediment/soil may also cause negative impacts to the eco-environment of the PRD.     

Polychlorinated biphenyls and organochlorine pesticides in various bird species from northern China

Little data are available on organochlorine contamination in Chinese terrestrial birds of prey. This study examined the presence of PCBs, DDTs and other organochlorine pesticides in various raptors from northern China. DDE exhibited the highest concentrations among targeted compounds. Greatest levels (23.5-1020 mg/kg lipid weight) were observed in Eurasian sparrowhawks. This may be due to their stopover in southeastern China, where high DDT and dicofol applications have been documented. Residential kestrels exhibited much lower DDE, but similar PCB and HCH concentrations. ΣTEQs and PCB-126/-77 concentration ratios exhibited significant positive correlations with ΣPCB concentrations, respectively. Similar results were also demonstrated by a meta-analysis of previously published data across avian species. Possible hepatic sequestration of coplanar PCB-77, -126, -169 and -118 was observed as liver TEQs increased in Eurasian sparrowhawks. These observations may indicate an induction of CYP1A enzymes, as a result of elevated contamination in some species.     

Modeling Inorganic Aerosols and Their Response to Changes in Precursor Concentration in Mexico City

Abstract

Based on data from the 1997 Investigación sobre Materia Particulada y Deterioro Atmosférico-Aerosol and Visibility Evaluation Research (IMADA-EVER) campaign and the inorganic aerosol model ISORROPIA, the response of inorganic aerosols to changes in precursor concentrations was calculated. The aerosol behavior is dominated by the abundance of ammonia and thus, changes in ammonia concentration are expected to have a small effect on particle concentrations. Changes in sulfate and nitrate are expected to lead to proportional reductions in inorganic fine particulate matter (PM_2.5). Comparing the predictions of ISORROPIA with the observations, the lowest bias and error are achieved when the aerosols are assumed to be in the efflorescence branch. Including crustal species reduces the bias and error for nitrate but does not improve overall model performance. The estimated response of inorganic PM_2.5 to changes in precursor concentrations is affected by the inclusion of crustal species in some cases, although average responses are comparable with and without crustal species. Observed concentrations of particle chloride suggest that gas phase concentrations of hydrogen chloride may not be negligible, and future measurement campaigns should include observations to test this hypothesis. Our ability to model aerosol behavior in Mexico City and, thus, design control strategies, is constrained primarily by a lack of observations of gas phase precursors. Future campaigns should focus in particular on better understanding the temporal and spatial distribution of ammonia concentrations. In addition, gas phase observations of nitric acid are needed, and a measure of particle water content will allow stable versus metastable aerosol behavior to be distinguished.     

Approaches to the implementation of the Water Framework Directive: targeting mitigation measures at critical source areas of diffuse phosphorus in Irish catchments

The Water Framework Directive (WFD) has initiated a shift towards a targeted approach to implementation through its focus on river basin districts as management units and the natural ecological characteristics of waterbodies. Due to its role in eutrophication, phosphorus (P) has received considerable attention, resulting in a significant body of research, which now forms the evidence base for the programme of measures (POMs) adopted in WFD River Basin Management Plans (RBMP). Targeting POMs at critical sources areas (CSAs) of P could significantly improve environmental efficiency and cost effectiveness of proposed mitigation strategies. This paper summarises the progress made towards targeting mitigation measures at CSAs in Irish catchments. A review of current research highlights that knowledge related to P export at field scale is relatively comprehensive however; the availability of site-specific data and tools limits widespread identification of CSA at this scale. Increasing complexity of hydrological processes at larger scales limits accurate identification of CSA at catchment scale. Implementation of a tiered approach, using catchment scale tools in conjunction with field-by-field surveys could decrease uncertainty and provide a more practical and cost effective method of delineating CSA in a range of catchments. Despite scientific and practical uncertainties, development of a tiered CSA-based approach to assist in the development of supplementary measures would provide a means of developing catchment-specific and cost-effective programmes of measures for diffuse P. The paper presents a conceptual framework for such an approach, which would have particular relevance for the development of supplementary measures in High Status Waterbodies (HSW). The cost and resources necessary for implementation are justified based on HSWs' value as undisturbed reference condition ecosystems.     

Assessing heavy metal pollution in the surface soils of a region that had undergone three decades of intense industrialization and urbanization

Heavy metals in the surface soils from lands of six different use types in one of the world’s most densely populated regions, which is also a major global manufacturing base, were analyzed to assess the impact of urbanization and industrialization on soil pollution. A total of 227 surface soil samples were collected and analyzed for major heavy metals (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn) by using microwave-assisted acid digestion and inductively coupled plasma–mass spectrometry (ICP-MS). Multivariate analysis combined with enrichment factors showed that surface soils from the region (>7.2?×?10⁴ km²) had mean Cd, Cu, Zn, and As concentrations that were over two times higher than the background values, with Cd, Cu, and Zn clearly contributed by anthropogenic sources. Soil pollution by Pb was more widespread than the other heavy metals, which was contributed mostly by anthropogenic sources. The results also indicate that Mn, Co, Fe, Cr, and Ni in the surface soils were primarily derived from lithogenic sources, while Hg and As contents in the surface soils were controlled by both natural and anthropogenic sources. The pollution level and potential ecological risk of the surface soils both decreased in the order of: urban areas?>?waste disposal/treatment sites?～?industrial areas?>?agricultural lands?～?forest lands?>?water source protection areas. These results indicate the significant need for the development of pollution prevention and reduction strategies to reduce heavy metal pollution for regions undergoing fast industrialization and urbanization.     

Economic sustainability and the preservation of environmental assets

The core requirement of sustainability is that current economic activities should not result in an excessive burden on future generations. This criterion is general enough to imply different decision rules for the preservation of environmental assets. Neoclassical economics does not have a sustainability criterion for environmental assets independent of the intertemporal efficiency criterion, which allocates environmental and man-made capital based on projected monetary benefits and costs. This criterion is examined in terms of the feasibility of valuing the benefits of environmental assets, the substitution possibilities between natural and man-made capital, and the ethical grounds for using efficiency as the sole determinant of the allocation of environmental assets. An alternative ecological sustainability criterion is the preservation of safe minimum levels of environmental assets in physical terms rather than the dollar value of a composite of natural and man-made capital. Safe minimum standards for environmental assets constrain the efficiency criterion in order to ensure the sustainability of economic systems. It is argued that the ecological approach to sustainability should limit the economic approach for decisions involving the allocation of environmental assets.     

Modeling Pre‐ and Post‐Dam Removal Sediment Dynamics: The Kalamazoo River,Michigan1

Abstract:  The state of Michigan is interested in removing two low‐head dams in an 8.8 km reach of the Kalamazoo River between Plainwell and Otsego, Michigan, while minimizing impacts locally and to downstream reaches. The study was designed to evaluate the erosion, transport, and deposition of sediments over a 37.3‐year period using the channel evolution model CONCEPTS for three simulation scenarios: Dams In (DI), Dams Out (DO), and Design (D). The total mass of sediment emanating from the channel boundary, for the DI case, shows net deposition of 4,100 T/y for the study reach, with net transport (suspended and bed load) of 10,500 T/y passing the downstream boundary. For the DO case, net erosion is 19,200 T/y with net transport of 30,100 T/y (187% increase) passing the downstream boundary. For the D case, net deposition is 2,570 T/y (37% decrease) with transport of 14,200 T/y (35% increase) passing the downstream boundary. The most significant findings were: (1) removal of the low‐head dams will cause significant erosion of sediments stored behind the dams and increased sediment loads passing the downstream boundary and (2) sediment loads for the proposed channel design are similar to existing conditions and offer reduced fine‐sediment loadings.