Journal of Environmental Analytical Chemistry

The analysis of carbon type distribution and chemical structure of natural organic matter (NOM) by 13C NMR spectroscopy is important for understanding its origins and reactivity. While prior work has used solution-state NMR, solid-state NMR has the potential to provide this information with less instrument time and sample processing, while providing an array of advanced filtering techniques. Quantitative and qualitative analyses with 13C solid-state magic angle spinning (MAS) NMR techniques are described for three commercially available samples and one fulvic acid sample isolated from the Rio Grande in New Mexico. This study demonstrates the utility of solid-state 13C NMR for aquatic NOM structural characterization by determining the % carbon type for three standard natural organic materials and comparing these results to the existing solution-state 13C NMR determinations. The solid-state 13C MAS NMR results are used to determine % carbon distribution, estimates of elemental composition (%C, %H, %(O+N)), aromatic fraction (fa), nonprotonated aromatic fraction (faN), an estimate of aromatic cluster size, and ratio of sp2 to sp3 carbons. Additionally, Gaussian deconvolution is used for a more detailed analysis of carbon type than frequency band integration techniques. The solid-state 13C NMR results of these analyses indicate the chemical composition of Rio Grande fulvic acid has higher aromatic fraction and nonprotonated aromatic fraction (fa =0.32, faN = 0.21) and a lower sp2/sp3 fraction and cluster size (sp2/sp3 = 0.66, C = 6) compared to Suwannee River fulvic acid (fa = 0.18, faN = 0.10, sp2/sp3 = 0.82, C = 8).

The dissipation of deltamethrin in silt clay under subtropical climate conditions was studied.14C- Deltamethrin labeled at gem–dimethyl groups of cyclopropane ring was used alone in one sets of columns and in presence of chloropyrifos in the other sets and kept under field conditions for eleven months. Radioactivity was concentrated in the upper zone of the columns 0-10 cm. The total dissipation of the insecticide amounted to 31%; 52% of the applied dose in silt clay soil in absence and presence of chlorpyrifos, respectively. The soil binding capacity increased with time whereby the extractable 14C-residues simultaneously decreased. The nature of methanolic extract of soils was determined by chromatographic analysis. Deltamethrin was the main degradation product of the extractable residues in addition to 3-phenoxybenzaldehyde, 3-phenoxybenzoic acid and 3-phenoxybenzyl alcohol.

Earlier this year the scientific world was shocked by the revelation that the famous Keeling Curve may come to an end due to lack of funding. The curve is the result of 56 years of continuous atmospheric monitoring of carbon dioxide, initially in Hawaii by Charles David Keeling and more recently by the Scripps Institute of Oceanography at the University of California San Diego. The data provided convincing evidence of carbon dioxide’s role in global warming and will be essential in assessing the success of mitigation strategies. After a heartfelt plea from Ralph Keeling, the project was saved, at least temporarily, thanks to a mixture of private and government funds and a successful crowd funding campaign. The plight of the project highlights the fragility and importance of long-term environmental monitoring. In a recent editorial, I lamented the lack of environment data for the New York City area which hampered our ability to draw concrete conclusions from data obtained following Hurricane Sandy. I contrasted this to the recent completion of a forty year project by the British Geological Survey which resulted in a comprehensive map of several elements in the United Kingdom. Why are similar initiatives not occurring in the United States? The difficulty appears to be in securing necessary funds for monitoring projects which do not appear to offer a useful product or exciting innovations.

This study assessed heavy metals and some physicochemical properties in rainwater harvested from Lagos, Nigeria. Rainwater was collected from three different locations using varying collectors from the months of April to July, 2013. Physicochemical parameters like pH, temperature, electrical conductivity (EC) and few heavy metals were assessed. Eight Heavy metals were determined by Flame Atomic Absorption Spectrophotometer (AAS). pH (5.1 to 7.6), Temperature (23.0 to 27.2Ë�C), EC (648 to 894 μS/cm ) is lower than the 1000 μS/cm limit by WHO. Mn and Cr were below the detection limits of the instrument. Ni, Pb and As were about 20 to 40 times higher in the rooftop samples and controls above the recommendation of standard organizations. Fe, Ca and Zn were detected but not believed to be of much environmental threats in all the study locations. The quadratic pattern was generated for the interaction between average monthly precipitation and heavy metal contents. Strong relationships were signaled by high R2 value from the best fitting lines. The study suggests that rainwater consumption in all the study locations irrespective of the collector type or method may result in severe health hazards associated with overexposure to the three notorious heavy metals. It is concluded therefore that metal concentrations particularly of Ni, Pb and Asis an important issue which must be addressed in the task of considering rainwater as reliable water complement drive.

A microbial depolymerization process of polyethylene glycol is studied with modeling and simulation based on experimental results. Weight distributions before and after cultivation of microbial consortium E1 for two, four, and seven days were introduced into analysis. Inverse problems for a molecular factor and a time factor of a degradation rate were formulated, and those problems were solved numerically. An initial value problem was solved numerically for simulation of an exogenous type depolymerization process. The role of microorganisms in the depolymerization process was interpreted.

The Adsorption isotherms and equilibrium of bentazon, carbofuran and 2,4-Dichlorophenoxyacetic acid (2,4-D) onto date seeds activated carbon (DSAC) were examined in batch process. Adsorption studies were conducted in the pesticides initial concentrations range of 25–250 mg/L and temperature of 30 oC. The experimental equilibrium data were analyzed by non-linear fitting using Langmuir, Freundlich and Temkin isotherm models. Equilibrium data fitted better with the Langmuir model showing maximum monolayer adsorption capacity of 78.13, 135.14 and 175.4 mg/g, for bentazon, carbofuran and 2,4-D respectively onto DSAC. A single stage batch absorber was designed for different operating line (V/M) ratios. Equilibrium data were obtained from the Langmuir isotherm at different V/M ratios using the mass balance equation for the batch absorber system. A simple linear expression relating the parameters involved in the  batchabsorber design was proposed for the studied system.

The cases of contact dermatitis due to using polyvinyl alcohol (PVA) towel containing isothiazolinone preservatives have been reported in Japan and we had investigated the concentrations of isothiazolinones and the removal of these preservatives from PVA towels by washing before initial use in the previous study conducted from 2011 to 2012. However, the clinical information regarding contact dermatitis due to using PVA cooling towels containing other preservatives was provided from the supplier of PVA towel in the summer of 2013. Thus, we analyzed 19 preservatives in 21 PVA towels by high performance liquid chromatography with photo diode array detector in this study. A good separation of these preservatives was observed using InertSustain® Phenyl column and 0.1 % formic acid solution as the mobile phase. 2-Methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4- isothiazolin-3-one were detected in 16 samples, including the sample which was sold in a dry condition; the concentrationsof these substances ranged from 7.9-84 μg/g-wet and 9.5-173 μg/g-wet, respectively (2.9 μg/g-dry and 9.3 μg/g-dry, respectively). 2-n-Octyl-4-isothiazolin-3-one was detected in one sample (484 μg/g-wet). 2- Bromo-2-nitropropane-1,3-diol (BP) was detected in 15 samples, including the sample which was sold in a dry condition; its concentration ranged from 68-2303 μg/g-wet (160 μg/g-dry). 2-Phenoxyethanol (PE) and benzoic acid (BA) were detected in 3 and 2 samples, and their concentrations ranged from 99-3171 μg/g-wet and 1896-23043 μg/g-wet. Other preservatives were not detected. Although isothiazolinone preservatives were detected in 17 samples, the product notes of 10 products, including the product with clinical information, did not describe about the use of isothiazolinone preservatives. Since PVA cooling towels in contact with human skin for a long time, the PVA cooling towels should be used with caution, especially on patients who are already sensitive to isothiazolinone preservatives. Furthermore, we evaluated the effectiveness of the washing process on the removal of BP, PE, and BA from the PVA towels before their initial use. The results of this laboratory-simulated washing procedure suggest that contact dermatitis is likely not related to the presence of BP, PE, and BA in washed PVA towels.

The detection and monitoring techniques for algal toxins and the causative harmful algal blooms (HABs) are essential for the protection of aquatic lives, shellfish safety, drinking water quality, and public health. Toward the development of fast, easy, and reliable techniques, much progress has been made during the last decade for the qualitative and quantitative analysis of algal toxins. This review highlights the recent progress and new trends of these analytical and monitoring tools, ranging from in-situ quick screening protocols for the monitoring of algal blooms to mass spectrometric analysis of trace levels of various algal toxins and structural elucidation. Solid-phase adsorption toxin tracking (SPATT) deployed in the field for the passive sampling of algal toxins has been recently validated, and improved ELISA-based methods with lower detection limits for more toxins have become commercially available for both screening and routine monitoring purposes. Liquid chromatography-mass spectrometry with several recent mass spectrometric innovations has expanded our understanding of traditional toxins, their metabolites along with newly discovered toxins of ecological importance. Several established in vivo and in vitro bioassays will continue to be used as benchmark toxicological testing of algal toxins; however, newly emerged molecular probing techniques such as real-time quantitative polymerase chain reaction (qPCR) have extended our ability to trace algal toxins from causative organisms at the molecular level. New chemical and biological sensors, lab-on-chip and remote sensing of blooms being developed will hold promise for early warning and routine monitoring to better manage and protect our freshwater, coastal and marine resources from adverse impact by harmful algal blooms.

In the past years biomedical research has recognized hydrogen sulfide (H2S) not only as an environmental pollutant but also, along with nitric oxide and carbon monoxide, as an important biological gasotransmiter with paramount roles in health and disease. Current research is focused on several aspects of H2S biology such as the biochemical pathways that generate the compound, functions in human pathology or drug synthesis that block or stimulate its biosynthesis. The present editorial addresses the knowledge we have to date on H2S production and its biological roles in the general human environment with a special focus on the oral cavity.

Recently, new pollution problems due to the presence of pharmaceuticals in the water environment have been reported, and research aimed at understanding the status of this pollution and assessing and dealing with the associated environmental risks is receiving worldwide attention. Because their concentrations in the water environment are quite low (roughly in the range from ng/L to μg/L), a method of highly sensitive and highly selective multicomponent simultaneous analysis is indispensable for detecting and quantifying these products. Here, I summarize the findings of previous research and case study analyses to date of an analytical method that combines solid phase extraction (SPE) and liquid chromatography – tandem mass spectrometry (LC-MS/MS); this is a versatile and reliable method of detecting and quantifying pharmaceutical pollutants in river water and wastewater samples. I also discuss the prospects for environmental analysis techniques.