Combining Leaching and Passive Sampling to Measure the Mobility and Distribution between Porewater, DOC and Colloids of Native Oxy-PAHs, N-PACs and PAHs in Historically Contaminated Soil

Different methods to quantify soil porewater concentrations of contaminants will provide different types of information. Passive sampling measurements give freely dissolved porewater concentrations (Cpw,free), while leaching tests provide information on the mobile concentration (Cpw,leach), including contaminants associated with dissolved organic carbon (DOC) and particles/colloids in the porewater. This study presents a novel combination of these two measurements, to study the sorption and mobility of polycyclic aromatic compounds (PACs) to DOC and particulate organic carbon (POC) in 10 historically contaminated soils. The PACs investigated were polycyclic aromatic hydrocarbons (PAHs), oxygenated-PAHs, and nitrogen containing heterocyclic PACs. Observed Cpw,leach was up to 5 orders of magnitude higher than Cpw,free; implying large biases when Cpw,leach is used to assess bioavailability or soil partitioning. Sorption of PACs to DOC and POC was important for the mobility of compounds with log KOW > 4. Average DOC/water-partitioning coefficients (KDOC) correlated well with KOW (log KDOC = 0.89 × log KOW +1.03 (r2 = 0.89)). This relationship is likely more accurate for historically contaminated soils than previously published data, which suffer from artifacts caused by problems in measuring Cpw,free correctly or not using historically contaminated soils. POC/water-partitioning coefficients (KPOC) were orders of magnitude larger than corresponding KDOC, suggesting sorption to mobile particles/colloids is the dominant mechanism for PAC mobility

Ranking REACH registered neutral, ionizable and ionic organic chemicals based on their aquatic persistency and mobility

The contaminants that have the greatest chances of appearing in drinking water are those that are mobile enough in the aquatic environment to enter drinking water sources and persistent enough to survive treatment processes. Herein a screening procedure to rank neutral, ionizable and ionic organic compounds for being persistent and mobile organic compounds (PMOCs) is presented and applied to the list of industrial substances registered under the EU REACH legislation as of December 2014. This comprised 5155 identifiable, unique organic structures. The minimum cut-off criteria considered for PMOC classification herein are a freshwater half-life >40 days, which is consistent with the REACH definition of freshwater persistency, and a logDoc 40 days, logDoc < 1.0 between pH 4–10). Only 9% of neutral substances received the highest PMOC ranking, compared to 30% of ionizable compounds and 44% of ionic compounds. Predicted hydrolysis products for all REACH parents (contributing 5043 additional structures) were found to have higher PMOC rankings than their parents, due to increased mobility but not persistence. The fewest experimental data available were for ionic compounds; therefore, their ranking is more uncertain than neutral and ionizable compounds. The most sensitive parameter for the PMOC ranking was freshwater persistency, which was also the parameter that QSARs performed the most poorly at predicting. Several prioritized drinking water contaminants in the EU and USA, and other contaminants of concern, were identified as PMOCs. This identification and ranking procedure for PMOCs can be part of a strategy to better identify contaminants that pose a threat to drinking water sources.acceptedVersio

Towards threshold-based management of freshwater ecosystems in the context of climate change

Climate change is an increasing threat to freshwater ecosystem goods and services. We review recent research regarding the direct and indirect impacts of climate change on freshwater ecosystems and the severity of their undesirable effects on ecosystem processes and services. Appropriate management strategies are needed to mitigate the long-term or irreversible losses of ecosystem services caused by climate change. To address this, this review puts forward a threshold-based management framework as a potential platform for scientists, decision makers and stakeholders of freshwater ecosystems to work together in reducing risks from climate change. In this framework, the susceptibility of local freshwater ecosystems to change beyond thresholds is continuously investigated and updated by scientists, used to design policy targets by decision makers, and used to establish mitigation measures by local stakeholders

an Extended Matching Model

This paper develops a standard matching model to address the problem of the hidden sector (including non-registered firms but producing for legal markets), as it is characterised in Italy, i.e. framed in a rather advanced economic and institutional setting, but also linked to the socio-economic regional dualism. The main novel features of the model are that entrepreneurial ability is heterogeneous, and that regular firms receive negative externalities from the hidden sector, and positive externalities from the other regular firms. Not only does an interior equilibrium emerge, but two stable equilibria are possible, thus accounting for Italy’s dualism. The “bad ” equilibrium with respect to the “good ” one is in fact characterised by a larger hidden sector, lower levels of overall productivity, output, entrepreneurial ability used, extra-profits, skilled employment, wages, and investment in education, as well as positive externalities; while the negative externalities, which may capture th

Using REACH registration data to rank the environmental emission potential of persistent and mobile organic chemicals

Organic chemicals that are persistent and mobile in the aquatic environment exhibit a hazard to contaminate drinking water resources. In this study an emission score model was developed to rank the potential of substances registered under the REACH legislation to be emitted into the environment. It was applied to a list of 2167 REACH registered substances thatwere previously identified to be persistent andmobile organic chemicals (PMOCs) in groundwater or to be hydrolyzed to form transformation products fulfilling the PMOC criteria. The emission score model is based on the tonnage placed on the European market and on seven emission-related use characteristics (high release to environment, wide dispersive use, intermediate use, closed system use, professional use, consumer use, and substance in article), reported in the companies' registrations under REACH. Applying the model resulted in a list of 1110 substances (936 PMOCs and 174 precursors to PMOCs) that were estimated to be released into the environment,while 1054 substances had indicators of negligible environmental emissions and 3 substances could not be evaluated due to severe data gaps. The 936 PMOCs and the 174 precursors were ranked in two lists with regard to their emission potential. The model was shown to be fit for purpose in terms of suggesting and prioritizing substances for scientific investigations with a focus on environmental water quality. Though targeted for PMOCs, the presented scoring systemis illustrative of how REACH registration data can be used to assess the emission potential of various substances.acceptedVersio

Ranking REACH registered neutral, ionizable and ionic organic chemicals based on their aquatic persistency and mobility

The contaminants that have the greatest chances of appearing in drinking water are those that are mobile enough in the aquatic environment to enter drinking water sources and persistent enough to survive treatment processes. Herein a screening procedure to rank neutral, ionizable and ionic organic compounds for being persistent and mobile organic compounds (PMOCs) is presented and applied to the list of industrial substances registered under the EU REACH legislation as of December 2014. This comprised 5155 identifiable, unique organic structures. The minimum cut-off criteria considered for PMOC classification herein are a freshwater half-life >40 days, which is consistent with the REACH definition of freshwater persistency, and a logDoc 40 days, logDoc < 1.0 between pH 4–10). Only 9% of neutral substances received the highest PMOC ranking, compared to 30% of ionizable compounds and 44% of ionic compounds. Predicted hydrolysis products for all REACH parents (contributing 5043 additional structures) were found to have higher PMOC rankings than their parents, due to increased mobility but not persistence. The fewest experimental data available were for ionic compounds; therefore, their ranking is more uncertain than neutral and ionizable compounds. The most sensitive parameter for the PMOC ranking was freshwater persistency, which was also the parameter that QSARs performed the most poorly at predicting. Several prioritized drinking water contaminants in the EU and USA, and other contaminants of concern, were identified as PMOCs. This identification and ranking procedure for PMOCs can be part of a strategy to better identify contaminants that pose a threat to drinking water sources

The mass flow and proposed management of bisphenol A in selected Norwegian waste streams

Current initiatives for waste-handling in a circular economy favor prevention and recycling over incineration or landfilling. However, the impact of such a transition on environmental emissions of contaminants like bisphenol A (BPA) during waste-handling is not fully understood. To address this, a material flow analysis (MFA) was constructed for selected waste categories in Norway, for which the amount recycled is expected to increase in the future; glass, vehicle, electronic, plastic and combustible waste. Combined, 92 tons/y of BPA are disposed of via these waste categories in Norway, with 98.5% associated with plastic and electronic waste. During the model year 2011, the MFA showed that BPA in these waste categories was destroyed through incineration (60%), exported for recycling into new products (35%), stored in landfills (4%) or released into the environment (1%). Landfilling led to the greatest environmental emissions (up to 13% of landfilled BPA), and incinerating the smallest (0.001% of incinerated BPA). From modelling different waste management scenarios, the most effective way to reduce BPA emissions are to incinerate BPA-containing waste and avoid landfilling it. A comparison of environmental and human BPA concentrations with CoZMoMAN exposure model estimations suggested that waste emissions are an insignificant regional source. Nevertheless, from monitoring studies, landfill emissions can be a substantial local source of BPA. Regarding the transition to a circular economy, it is clear that disposing of less BPA-containing waste and less landfilling would lead to lower environmental emissions, but several uncertainties remain regarding emissions of BPA during recycling, particularly for paper and plastics. Future research should focus on the fate of BPA, as well as BPA alternatives, in emerging reuse and recycling processes, as part of the transition to a circular economy.acceptedVersio

Limited mobility of dioxins near San Jacinto super fund site (waste pit) in the Houston Ship Channel, Texas due to strong sediment sorption

Sediments from a waste pit in Houston Ship Channel (HSC) were characterized using a number of molecular markers of natural organic matter fractions (e.g., pyrogenic carbon residues, PAHs, lignins), in addition to dioxins, in order to test the hypothesis that the dispersal and mobility of dioxins from the waste pit in the San Jacinto River is minimal. Station SG-6, sampled at the site of the submerged waste pit, had the highest dioxin/furan concentrations reported for the Houston Ship Channel/Galveston Bay (HSC/GB) system (10,000e46,000 pg/g), which translated into some of the highest reported World Health Organization Toxic Equivalents (TEQs: 2000e11,000 pg/g) in HSC sediments. Using a multi-tracer approach, this study confirmed our hypothesis that sludges from chlorinated pulps are a very likely source of dioxins/furans to this pit. However, this material also contained large quantities of additional hydrophobic organic contaminants (PAHs) and pyrogenic markers (soot-BC, levoglucosan), pointing to the co-occurrence of petroleum hydrocarbons and combustion byproducts. Comparison of dioxin/furan signatures in the waste pit with those from sediments of the HSC and a control site suggests that the remobilization of contaminated particles did not occur beyond the close vicinity of the pit itself. The dioxins/furans in sediments outside the waste pit within the HSC are rather from other diffuse inputs, entering the sedimentary environment through the air and water, and which are comprised of a mixture of industrial and municipal sources. Fingerprinting of waste pit dioxins indicates that their composition is typical of pulp and paper sources. Measured pore water concentrations were 1 order of magnitude lower than estimated values, calculated from a multiphase sorption model, indicating low mobility of dioxins within the waste pit. This is likely accomplished by co-occurring and strong sorbing pyrogenic and petrogenic residues in the waste pit, which tend to keep dioxins strongly sorbed to particles.Limited mobility of dioxins near San Jacinto super fund site (waste pit) in the Houston Ship Channel, Texas due to strong sediment sorptionpublishedVersio

PAH in contaminated sediment: review of suitability of PAH- components/groups for assessment of remediation needs

-I Norge er det utarbeidet klassegrenser for til sammen 16 PAH-forbindelser i sediment og vann. Grenseverdiene baserer seg på kunnskap om toksisitet av de ulike stoffene og hva som er akseptabel eksponering for miljøet. I tillegg til grenseverdiene for enkeltkomponentene av PAH opererer norske miljømyndigheter med klassegrenser for PAH-grupperingen SUM PAH-16 i sediment. Disse klassegrensene bygger på overkonsentrasjoner i forhold til bakgrunnsnivå, og ikke økotoksikologiske data. Risikovurderinger av PAH-forurenset sediment gjøres for alle PAH-komponentene. SUM PAH-16 benyttes imidlertid til å vurdere behov for tiltak i PAH-forurenset sjøbunn. Det foreslås her en ny tilnærming som tillater bruk av de 16 PAH-forbindelsene. Dette er en gjennomsnittlig PAH-16 tilnærming, snarere enn en total PAH-16 tilnærming hvor konsentrasjonen av hver enkeltforbindelse ses relativt til sin respektive grenseverdi.The Norwegian Environment Agency has described the purpose of review/study follows: It should be investigated which PAH components or PAH groups in contaminated sediments that are best suited to assess the need for remedial measures. In Norway limit values (marginal values/quality standards) are developed for a total of 16 PAH compounds in sediment and water. The limit values are based on knowledge of the toxicity of individual compounds, and acceptable exposure in the environment. In addition to the limit values for individual compounds, Norwegian environmental authorities operate with limit values for SUM PAH-16 in sediment. These limit values are based on excess concentrations (relative to background) and not ecotoxicological data. Risk assessment of PAH-contaminated sediments is done using all individual PAH components. However, SUM PAH-16 is used to assess the need for remedial actions in PAH-contaminated sediments. The purpose of this review/study has been to provide alternatives to SUM PAH 16 in the assessment of need for remedial measures in PAH-contaminated sediments, either using individual PAH-components or appropriate groups of PAHs. To this end, important criteria have been the risk for human health, risk of ecological effects or practical considerations with regard to “Vannforskriften” (Norwegian law on water)

PAH in contaminated sediment: review of suitability of PAH- components/groups for assessment of remediation needs

I Norge er det utarbeidet klassegrenser for til sammen 16 PAH-forbindelser i sediment og vann. Grenseverdiene baserer seg på kunnskap om toksisitet av de ulike stoffene og hva som er akseptabel eksponering for miljøet. I tillegg til grenseverdiene for enkeltkomponentene av PAH opererer norske miljømyndigheter med klassegrenser for PAH-grupperingen SUM PAH-16 i sediment. Disse klassegrensene bygger på overkonsentrasjoner i forhold til bakgrunnsnivå, og ikke økotoksikologiske data. Risikovurderinger av PAH-forurenset sediment gjøres for alle PAH-komponentene. SUM PAH-16 benyttes imidlertid til å vurdere behov for tiltak i PAH-forurenset sjøbunn. Det foreslås her en ny tilnærming som tillater bruk av de 16 PAH-forbindelsene. Dette er en gjennomsnittlig PAH-16 tilnærming, snarere enn en total PAH-16 tilnærming hvor konsentrasjonen av hver enkeltforbindelse ses relativt til sin respektive grenseverdi.The Norwegian Environment Agency has described the purpose of review/study follows: It should be investigated which PAH components or PAH groups in contaminated sediments that are best suited to assess the need for remedial measures. In Norway limit values (marginal values/quality standards) are developed for a total of 16 PAH compounds in sediment and water. The limit values are based on knowledge of the toxicity of individual compounds, and acceptable exposure in the environment. In addition to the limit values for individual compounds, Norwegian environmental authorities operate with limit values for SUM PAH-16 in sediment. These limit values are based on excess concentrations (relative to background) and not ecotoxicological data. Risk assessment of PAH-contaminated sediments is done using all individual PAH components. However, SUM PAH-16 is used to assess the need for remedial actions in PAH-contaminated sediments. The purpose of this review/study has been to provide alternatives to SUM PAH 16 in the assessment of need for remedial measures in PAH-contaminated sediments, either using individual PAH-components or appropriate groups of PAHs. To this end, important criteria have been the risk for human health, risk of ecological effects or practical considerations with regard to “Vannforskriften” (Norwegian law on water).Miljødirektorate