Evaluation of gas well setback policy in the Marcellus Shale region of Pennsylvania in relation to emissions of fine particulate matter

Shale gas has become an important strategic energy source with considerable potential economic benefits and the potential to reduce greenhouse gas emissions in so far as it displaces coal use. However, there still exist environmental health risks caused by emissions from exploration and production activities. In the United States, states and localities have set different minimum setback policies to reduce the health risks corresponding to the emissions from these locations, but it is unclear whether these policies are sufficient. This study uses a Gaussian plume model to evaluate the probability of exposure exceedance from EPA concentration limits for PM2.5 at various locations around a generic wellsite in the Marcellus shale region. A set of meteorological data monitored at ten different stations across Marcellus shale gas region in Pennsylvania during 2015 serves as an input to this model. Results indicate that even though the current setback distance policy in Pennsylvania (500 ft. or 152.4 m) might be effective in some cases, exposure limit exceedance occurs frequently at this distance with higher than average emission rates and/or greater number of wells per wellpad. Setback distances should be 736 m to ensure compliance with the daily average concentration of PM2.5, and a function of the number of wells to comply with the annual average PM2.5 exposure standard.

Implications: The Marcellus Shale gas is known as a significant source of criteria pollutants and studies show that the current setback distance in Pennsylvania is not adequate to protect the residents from exceeding the established limits. Even an effective setback distance to meet the annual exposure limit may not be adequate to meet the daily limit. The probability of exceeding the annual limit increases with number of wells per site. We use a probabilistic dispersion model to introduce a technical basis to select appropriate setback distances.     

Salinity modulates biochemical and histopathological changes caused by silver nanoparticles in juvenile Persian sturgeon (Acipenser persicus)

Environmental Science and Pollution Research - The objective of this study was to evaluate the effect of salinity on the acute and sub-chronic toxicity of silver nanoparticles (AgNPs) in Persian...     

Multi-elements atmospheric deposition study in Albania

For the first time, the moss biomonitoring technique and inductively coupled plasma–atomic emission spectrometric (ICP-AES) analytical technique were applied to study multi-element atmospheric deposition in Albania. Moss samples (Hypnum cupressiforme) were collected during the summer of 2011 and September–October 2010 from 62 sites, evenly distributed over the country. Sampling was performed in accordance with the LRTAP Convention–ICP Vegetation protocol and sampling strategy of the European Programme on Biomonitoring of Heavy Metal Atmospheric Deposition. ICP-AES analysis made it possible to determine concentrations of 19 elements including key toxic metals such as Pb, Cd, As, and Cu. Cluster and factor analysis with varimax rotation was applied to distinguish elements mainly of anthropogenic origin from those predominantly originating from natural sources. Geographical distribution maps of the elements over the sampled territory were constructed using GIS technology. The median values of the elements in moss samples of Albania were high for Al, Cr, Ni, Fe, and V and low for Cd, Cu, and Zn compared to other European countries, but generally were of a similar level as some of the neighboring countries such as Bulgaria, Croatia, Kosovo, Macedonia, and Romania. This study was conducted in the framework of ICP Vegetation in order to provide a reliable assessment of air quality throughout Albania and to produce information needed for better identification of contamination sources and improving the potential for assessing environmental and health risks in Albania, associated with toxic metals.     

Active moss biomonitoring of small-scale spatial distribution of airborne major and trace elements in the Belgrade urban area

In urban environments, human exposure to air pollutants is expected to be significantly increased, especially near busy traffic streets, street canyons, tunnels, etc. where urban topography and microclimate may additionally cause poor air conditions giving rise to pollution hotspots. As a practical and cost-effective approach, active moss biomonitoring survey of some major and trace element air pollution was performed in the Belgrade street canyons and city tunnel in 2011 with the aim to evaluate possibility of using Sphagnum girgensohnii moss bags for investigation of the small-scale vertical and horizontal distribution patterns of the elements. In five street canyons, the moss bags were hung at heights of about 4, 8 and 16 m, during 10 weeks, and also, for the same time, the moss bags were exposed in the tunnel, in front of and out of it. After the exposure period, the concentrations of Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, V and Zn in the moss were determined by inductively coupled plasma optical emission spectrometry. According to the results, in all street canyons, the vertical distribution patterns of the moss elements concentration (Al, Ba, Co, Cr, Cu, Ni, Pb, Sr, V and Zn) showed statistically significant decrease from the first to the third heights of bags exposure. In the tunnel experiment, from inner to out of the tunnel, for Al, Ba, Cd, Co, Cr, Cu, Fe, K and Zn, decreasing trend of concentrations was obtained. Significantly higher concentration of the elements was pronounced for the tunnel in comparison with the street canyons. The results indicate that the use of S. girgensohnii moss bags is a simple, sensitive and inexpensive way to monitor the small-scale inner city spatial distribution of airborne major and trace element content.     

A microcosm approach for evaluating the microbial nonylphenol and butyltin biodegradation and bacterial community shifts in co-contaminated bottom sediments from the Gulf of Finland,the Baltic Sea

Environmental Science and Pollution Research - Pollution of aquatic ecosystems with nonylphenol (NP) and butyltins (BuTs) is of great concern due to their effects on endocrine activity, toxicity to...