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161.
A cod liver oil reference material, Standard Reference Material (SRM) 1588, which was issued by the National Institute of Standards and Technology (NIST) in 1989, has certified concentrations for five polychlorinated biphenyl (PCB) congeners and ten chlorinated pesticides. Recently, this SRM has been extensively characterized by additional analyses at NIST and by analyses at the Canadian Wildlife Service (CWS) where the SRM was used as a control sample during routine analyses of wildlife tissue specimens. In this paper the results from NIST and CWS are compared and the concentrations for over 40 PCB congeners and 20 chlorinated hydrocarbons are reported.  相似文献   
162.
163.
We have investigated the dependence of the rate of the production of biogas upon the concentration of nickel, cobalt and iron at sub-toxic concentration and monitored its composition as amount of hydrogen, methane and carbon dioxide. The distribution of the added metals between the liquid and solid phase has also been monitored.

The results of our investigations show that the addition of any of the listed metals to the sludge may cause the production of a higher amount of biogas and influence the methane or carbon dioxide percentage. Conversely, the effect on the hydrogen production depends upon the metal added, the age of the active sludge used, and its adaptation to the susbtrate. As a general feature, during the acidogenesis phase, nickel reduces, while iron increases, the percentage of dihydrogen in the biogas, while cobalt has no influence.  相似文献   
164.
Water quality monitoring data typically consist of \(J\) parameters and constituents measured at \(I\) number of static locations at \(K\) sets of seasonal occurrences. The resulting \(I \times J \times K\) three-way array can be difficult to interpret. Additionally, the constituent portion of the dataset (e.g., major ion and trace element concentration, pH, etc.) is compositional in that it sums to a constant (e.g., 1 kg/L) and is mathematically confined to the simplex, the sample space for compositional data. Here we apply a Tucker3 model on centered log-ratio data to find low dimensional representation of latent variables as a means to simplify data processing and interpretation of three years of seasonal compositional groundwater chemistry data for 14 wells at a study site in Wyoming, USA. The study site has been amended with treated coalbed methane produced water, using a subsurface drip irrigation system, to allow for irrigation of forage crops. Results from three-way compositional data analysis indicate that primary controls on water quality at the study site include: solutes concentration by evapotranspiration, cation exchange, and dissolution of native salts. These findings agree well with results from more detailed investigations of the site. In addition, the model identified Ba uptake during gypsum precipitation in some portions of the site during the final 6–9 months of investigation, a process for which the timing and extent had not previously been identified. These results suggest that multi-way compositional analyses hold promise as a means to more easily interpret water quality monitoring data.  相似文献   
165.

Background

Immigrant Latino day laborers working in residential construction are at particularly high risk of fatal and non-fatal traumatic injury and benefit from targeted training.

Objective

To understand the impact of a participatory, peer-facilitated health and safety awareness training customized to the needs of Latino day laborers.

Methods

Baseline surveys exploring exposures, PPE use, attitudes, work practices and work-related injuries were collected from more than 300 New Jersey Latino day laborers in construction prior to their participation in a one day (minimum of six hour) Spanish language health and safety training class. The classes, led by trained worker trainers, engaged participants in a series of tasks requiring teamwork and active problem solving focused on applying safe practices to situations they encounter at their worksites. Follow-up surveys were difficult to obtain among mobile day laborers, and were collected from 70 men (22% response rate) 2-6 months following training. Chi-square analysis was used to compare pre- and post-intervention PPE use, self protective actions, and self-reported injury rates. Focus groups and in-depth interviews addressing similar issues provided a context for discussing the survey findings.

Results

At baseline, the majority of day laborers who participated in this study reported great concern about the hazards of their work and were receptive to learning about health and safety despite limited influence over employers. Changes from baseline to follow-up revealed statistically significant differences in the use of certain types of PPE (hard hats, work boots with steel toes, safety harnesses, and visible safety vests), and in the frequency of self-protective work practices (e.g., trying to find out more about job hazards on your own). There was also a suggestive decrease in self-reported injuries (receiving an injury at work serious enough that you had to stop working for the rest of the day) post-training based on small numbers. Sixty-six percent of workers surveyed post-training reported sharing information from their safety workbook with friends and co-workers. Focus groups and interview results generally confirmed the quantitative findings.

Conclusions

Participatory, peer led training tailored to the needs of construction day laborers may have a positive effect on Latino immigrant workers’ attitudes, work practices, and self reported injury rates, but major changes would require employer engagement.

Impact on Industry

Health and safety researchers have identified reducing the number of traumatic injuries among the immigrant construction workforce as an increasingly important priority. This project provides one model for collaboration between university-based researchers, a union, and a community-based organization. The specific elements of this project—participatory curriculum customized to the needs of day laborers in residential construction, training day laborers to facilitate training classes, and involving peer leaders in outreach and research—could be adapted by other organizations. The findings of this study suggest that the Latino day laborers have a strong interest in and some ability to act on health and safety information. Widespread implementation of this type of training, especially if supported with cooperation from residential contractors, could lead to reduced rates of traumatic injury in the residential construction industry.  相似文献   
166.
<正>President Donald Trump's 1 June 2017 decision to withdraw the United States from the Paris Climate Accord understandably generated significant concern about the future of the planet.To be sure,the US withdrawal is an unfortunate setback in the global effort to address climate change;it is a missed opportunity to exercise leadership and advance the interna-  相似文献   
167.
Regional Environmental Change - The reality of global climate change demands novel approaches to science that are reflective of the scales at which changes are likely to occur, and of the new forms...  相似文献   
168.
Stomatal ozone uptake, determined with the Jarvis' approach, was related to photosynthetic efficiency assessed by chlorophyll fluorescence and reflectance measurements in open-top chamber experiments on Phaseolus vulgaris. The effects of O3 exposure were also evaluated in terms of visible and microscopical leaf injury and plant productivity. Results showed that microscopical leaf symptoms, assessed as cell death and H2O2 accumulation, preceded by 3-4 days the appearance of visible symptoms. An effective dose of ozone stomatal flux for visible leaf damages was found around 1.33 mmol O3 m−2. Significant linear dose-response relationships were obtained between accumulated fluxes and optical indices (PRI, NDI, ΔF/Fm). The negative effects on photosynthesis reduced plant productivity, affecting the number of pods and seeds, but not seed weight. These results, besides contributing to the development of a flux-based ozone risk assessment for crops in Europe, highlight the potentiality of reflectance measurements for the early detection of ozone stress.  相似文献   
169.
The paper reports on global release and mass partitioning in the flux of residues of PCDD/Fs, evaluated with dedicated field campaigns at a municipal solid waste incineration plant during normal and transient operation. Results are compared with those obtained in other installations equipped with furnaces, energy recovery options and flue gas treatment technologies representative of most of the European incineration plants currently in operation. Levels of the pollutants of interest were determined in all the solid, liquid and gaseous residues produced by every single facility, and the results analysed in terms of the effects arising from the fed waste and the configuration of the plant. PCDD/Fs total release between 1.5 and 45 microg I-TEQ per ton of burned waste was evaluated, with lower values resulting from the adoption of catalytic conversion process for flue gas treatment. Most of the mass flux emitted is associated with solid residues deriving from activated carbon PCCD/F dry removal options, with significant contributions also from fly ash produced by particulate removal devices located immediately downstream the boiler and from scrubber blowdowns treatment sludge. During transient operating conditions the dioxin total release may increase by 50% with comparison to steady-state functioning.  相似文献   
170.
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