Unregulated greenhouse gas and ammonia emissions from current technology heavy-duty vehicles

The study presents the measurement of carbonyl, BTEX (benzene, toluene, ethyl benzene, and xylene), ammonia, elemental/organic carbon (EC/OC), and greenhouse gas emissions from modern heavy-duty diesel and natural gas vehicles. Vehicles from different vocations that included goods movement, refuse trucks, and transit buses were tested on driving cycles representative of their duty cycle. The natural gas vehicle technologies included the stoichiometric engine platform equipped with a three-way catalyst and a diesel-like dual-fuel high-pressure direct-injection technology equipped with a diesel particulate filter (DPF) and a selective catalytic reduction (SCR). The diesel vehicles were equipped with a DPF and SCR. Results of the study show that the BTEX emissions were below detection limits for both diesel and natural gas vehicles, while carbonyl emissions were observed during cold start and low-temperature operations of the natural gas vehicles. Ammonia emissions of about 1 g/mile were observed from the stoichiometric natural gas vehicles equipped with TWC over all the driving cycles. The tailpipe GWP of the stoichiometric natural gas goods movement application was 7% lower than DPF and SCR equipped diesel. In the case of a refuse truck application the stoichiometric natural gas engine exhibited 22% lower GWP than a diesel vehicle. Tailpipe methane emissions contribute to less than 6% of the total GHG emissions.

Implications: Modern heavy-duty diesel and natural gas engines are equipped with multiple after-treatment systems and complex control strategies aimed at meeting both the performance standards for the end user and meeting stringent U.S. Environmental Protection Agency (EPA) emissions regulation. Compared to older technology diesel and natural gas engines, modern engines and after-treatment technology have reduced unregulated emissions to levels close to detection limits. However, brief periods of inefficiencies related to low exhaust thermal energy have been shown to increase both carbonyl and nitrous oxide emissions.     

Sorption of selected pesticides on soils,sediment and straw from a constructed agricultural drainage ditch or pond

Buffer zones such as ponds and ditches are used to reduce field-scale losses of pesticides from subsurface drainage waters to surface waters. The objective of this study was to assess the efficiency of these buffer zones, in particular constructed wetlands, focusing specifically on sorption processes. We modelled the sorption processes of three herbicides [2-methyl-4-chlorophenoxyacetic acid (2,4-MCPA), isoproturon and napropamide] and three fungicides (boscalid, prochloraz and tebuconazole) on four substrates (two soils, sediment and straw) commonly found in a pond and ditch in Lorraine (France). A wide range of Freundlich coefficient (K _fads) values was obtained, from 0.74 to 442.63 mg^1???n ?L ⁿ ?kg^?1, and the corresponding K _foc values ranged from 56 to 3,725 mg^1???n ?L ⁿ ?kg^?1. Based on potential retention, the substrates may be classified as straw >> sediments > soils. These results show the importance of organic carbon content and nature in the process of sorption. Similarly, the studied pesticides could be classified according to their adsorption capacity as follows: prochloraz >> tebuconazole–boscalid > napropamide >> MCPA–isoproturon. This classification is strongly influenced by the physico-chemical properties of pesticides, especially solubility and K _oc. Straw exhibited the largest quantity of non-desorbable pesticide residues, from 12.1 to 224.2 mg/L for all pesticides. The presence of plants could increase soil–sediment sorption capacity. Thus, establishment and maintenance of plants and straw filters should be promoted to optimise sorption processes and the efficiency of ponds and ditches in reducing surface water pollution.     

Fish and seafood availability in markets in the Baie des Chaleurs region, New Brunswick, Canada: a heavy metal contamination baseline study

The consumption of halieutic products has many health benefits. However, their contaminants loads need to be addressed to better understand the risk from consuming these products. The aquatic biota from the Baie des Chaleurs in New Brunswick is contaminated by cadmium, zinc and lead. In spite of this, no study has examined the heavy metal concentrations in commercial halieutic products sold in this Canadian region. The objective of this pilot study was to characterize the species and origin of fish and seafood sold in the Baie des Chaleurs region by using an ecosystemic approach. Additionally, a baseline picture of the heavy metal levels found in these products has been determined. In 2008, interviews were carried out in markets located in the Baie des Chaleurs area. Species that were identified as the most purchased were then bought for analysis. Samples were freeze-dried and homogenized before nitric acid digestions. Aluminum, copper, cadmium, iron, manganese, and zinc concentrations were determined by inductively coupled plasma optical emission spectrometry. Results show that 36 % of seafood species sold in markets were caught in the Baie des Chaleurs. Lobsters, shrimps, scallops and oysters are the most purchased species regardless of the season. High amounts of cadmium exceeding tolerable daily intake are found in lobster hepatopancreas and can cause deleterious effects on health, in particular in vulnerable populations such as children and heavy consumers. The ecosystemic approach to health used in this pilot study shows the feasibility of an exhaustive study on the exposure of coastal population to heavy metal from fish and seafood consumption and the source of halieutic products sold in markets.     

A survey of valleys and basins of the western United States for the capacity to produce winter ozone

High winter ozone in the Uintah Basin, Utah, and the Upper Green River Basin, Wyoming, occurs because of the confluence of three separate factors: (1) extensive oil or natural gas production, (2) topography conducive to strong multiple-day thermal inversions, and (3) snow cover. We surveyed 13 basins and valleys in the western United States for the existence and magnitude of these factors. Seven of the basins, because winter ozone measurements were available, were assigned to four different behavioral classes. Based on similarities among the basins, the remaining six were also given a tentative assignment. Two classes (1 and 2) correspond to basins with high ozone because all three factors just listed are present at sufficient magnitude. Class 3 corresponds to rural basins with ozone at background levels, and occurs because at least one of the three factors is weak or absent. Class 4 corresponds to ozone below background levels, and occurs, for example, in urban basins where emissions scavenge ozone. All three factors are present in the Wind River Basin, Wyoming, but compared to the Uintah or the Upper Green Basins, it has only moderate oil and gas production and is assigned to class 3. We predict that the Wind River Basin, as well as other class 3 basins that have inversions and snow cover, would transition from background (class 3) to high ozone behavior (class 1 or 2) if oil or gas production were to intensify, or to class 4 (low winter ozone) if they were to become urban.

Implications: High ozone concentrations in winter only occur in basins or valleys that have an active oil and natural gas production industry, multiple-day thermal inversions, and snow cover, and have only been documented in two basins worldwide. We have examined a number of other candidate basins in the western United States and conclude that these factors are either absent or too weak to produce high winter ozone. This study illustrates how strong each factor needs to be before winter ozone can be expected, and can be used by planners and regulators to foresee the development of winter ozone problems.     

Meta-Modeling to Assess the Possible Future of Paris Agreement

In the meta-modeling approach, one builds a numerically tractable dynamic optimization or game model in which the parameters are identified through statistical emulation of a detailed large scale numerical simulation model. In this paper, we show how this approach can be used to assess the economic impacts of possible climate policies compatible with the Paris Agreement. One indicates why it is appropriate to assume that an international carbon market, with emission rights given to different groups of countries will exist. One discusses the approach to evaluate correctly abatement costs and welfare losses incurred by different groups of countries when implementing climate policies. Finally, using a recently proposed meta-model of game with a coupled constraint on a cumulative CO₂ emissions budget, we assess several new scenarios for possible fair burden sharing in climate policies compatible with the Paris Agreement.     

Mercury speciation in the Persian Gulf sediments

The concentrations of total mercury (Hg) and methyl mercury (MMHg) were determined in 78 marine sediments in the Iranian coastal waters of the Persian Gulf along nine transects perpendicular to the coastline. Total Hg ranged from 10 to 56 ng g( - 1)d.w. and MMHg from 0.1 to 0.4 ng g( - 1) d.w. The fraction of methyl mercury accounted from 0.3% to 1.1% of the total mercury amount. The organic carbon (OC) content ranged from 0.4% to 1.8%. The present study indicates that the levels of Hg in the sediments of the Iranian coast of the Persian Gulf were all in the concentration range of unpolluted areas regarding Hg (<100 ng g( - 1)). The concentrations of total Hg, methyl mercury and organic carbon were generally higher in the deeper stations. Total Hg and MMHg were significantly correlated, but no significant correlations could be found between the Hg and OC levels.     

On how environmental stringency influences adoption of best management practices in agriculture

There are relatively few Federal environmental regulations that influence agricultural production in the US. However, many local and state environmental rules may influence the management practices on US farms as might interactions between urban population centers and agricultural producers. Detailed analysis of corn farms gives insight into these relationships and suggests that stringent environmental regulations could increase the likelihood of adoption of certain conservation practices, all else being constant, but that the interaction between urban populations has less of an effect on the adoption decisions.     

Propanil in a Manitoba soil: an interactive spreadsheet model based on conventional chemical kinetics

An interactive spreadsheet model has been created for quantitative predictions of propanil sorption and reaction in a slurried Manitoba clay soil. Based on experimental values for the numbers of empty and filled sorption sites as reactants and products, the reaction mechanism has been described with conventional chemical kinetics. The on line HPLC μ extraction method revealed labile sorption, intraparticle diffusion, and a chemical reaction. Laidler's integral rate law for second order kinetics describes the labile sorption. Desorption, intraparticle diffusion, and the chemical reaction are all described by first order kinetics. The time dependent effects of initial concentration and amount of slurried soil can be predicted for sorption, intraparticle diffusion, and the amount of reaction product. Suggested applications include storm runoff and inputs for fate and transport hydrology models.     

Different collector types for sampling deposition of polycyclic aromatic hydrocarbons--comparison of measurement results and their uncertainty

Different collector types, sample workup procedures and analysis methods to measure the deposition of polycyclic aromatic hydrocarbons (PAH) were tested and compared. Whilst sample workup and analysis methods did not influence the results of PAH deposition measurements, using different collector types changed the measured deposition rates of PAH significantly. The results obtained with a funnel-bottle collector showed the highest deposition rates and a low measurement uncertainty. The deposition rates obtained with the wet-only collectors were the lowest at industrial sites and under dry weather conditions. For the open-jar collectors the measurement uncertainty was high. Only at an industrial site with extremely high PAH deposition rates the results of open-jar collectors were comparable to those obtained with funnel-bottle collectors. Thus, if bulk deposition of PAH has to be measured, funnel-bottle combinations are proved to be the collectors of choice. These collectors were the only ones always fulfilling the requirements of European legislation.     

Characterization of ²⁴¹ Am and ¹³⁴Cs bioaccumulation in the king scallop Pecten maximus: investigation via three exposure pathways

In order to understand the bioaccumulation of ²⁴¹Am and ¹³⁴Cs in scallops living in sediments, the uptake and depuration kinetics of these two elements were investigated in the king scallop Pecten maximus exposed via seawater, food, or sediment under laboratory conditions. Generally, ²⁴¹Am accumulation was higher and its retention was stronger than ¹³⁴Cs. This was especially obvious when considering whole animals exposed through seawater with whole-body concentration factors (CF_7d) of 62 vs. 1, absorption efficiencies (A_0l) of 78 vs. 45 for seawater and biological half-lives (T_b½l) of 892 d vs. 22 d for ²⁴¹Am and ¹³⁴Cs, respectively. In contrast, following a single feeding with radiolabelled phytoplankton, the assimilation efficiency (AE) and T_b½l of ¹³⁴Cs were higher than those of ²⁴¹Am (AE: 28% vs. 20%; T_b½l: 14 d vs. 9 d). Among scallop tissues, the shells always contained the higher proportion of the total body burden of ²⁴¹Am whatever the exposure pathway. In contrast, the whole soft parts presented the major fraction of whole-body burden of ¹³⁴Cs, which was generally associated with muscular tissues. Our results showed that the two radionuclides have contrasting behaviors in scallops, in relation to their physico-chemical properties.