Recent studies have shown that engineered nanoparticles (ENPs) are incorporated into toner powder used in printing equipment and released during their use. Thus, understanding the functional and structural composition and the potential synergistic effects of this complex aerosol and released gaseous co-pollutants is critical in assessing their potential toxicological implications and risks. In this study, toner powder and PEPs were thoroughly examined for the functional and molecular composition of the organic fraction and the concentration profile of 16 Environmental Protection Agency (EPA)-priority polycyclic aromatic hydrocarbons (PAH) using state-of-the-art analytical methods. Results show significant differences in abundance of the non-exchangeable organic hydrogen of toner powder and PEPs, with a stronger aromatic spectral signature in PEPs. Changes in the structural composition of PEPs are indicative of radical additions and free-radical polymerization favored by catalytic reactions, resulting in formation of functionalized organic species. Particularly, accumulation of aromatic carbons with strong styrene-like molecular signatures on PEPs is associated with formation of semi-volatile heavier aromatic species (i.e., PAHs). Further, the transformation of low molecular weight PAHs in the toner powder to high molecular weight PAHs in PEPs was documented and quantified. This may be a result of synergistic effects from catalytic metal/metal oxide ENPs incorporated into the toner and the presence/release of semi-volatile organic species (SVOCs). The presence of known carcinogenic PAHs on PEPs raises public health concerns and warrants further toxicological assessment.
This review evaluates Minoan and Indus Valley hydro-technologies in southeastern Greece and Indus Valley Pakistan, respectively. The Minoan civilization first inhabited Crete and several Aegean islands shortly after the Late Neolithic times and flourished during the Bronze Age (ca 3200–1100 BC). At that time, the Minoan civilization developed fundamental technologies and reached its pinnacle as the first and most important European culture. Concurrently, the Indus Valley civilization populated the eastern bank of the Indus River, its tributaries in Pakistan, and the Ganges plains in India and Nadia (Bangladesh), spreading over an area of about one million km2. Its total population was unknown; however, an estimated 43,000 people resided at Harappa. The urban hydro-technologies, characteristics of a civilization can be determined by two specific aspects, the natural and the social environment. These two aspects cover a variety of factors, such as climate and social conditions, type of terrain, water supply, agriculture, water logging, sanitation and sewerage, hygienic conditions of communities, and racial features of the population. Therefore, these factors were used to understand the water resources management practices in early civilizations (e.g., Minoan and Indus Valley) and similarities, despite the large geographic distance between places of origin. Also discussed are the basic principles and characteristics of water management sustainability in both civilizations and a comparison of basic water supply and sanitation practices through the long history of the two civilizations. Finally, sustainability issues and lessons learned are considered.
Non-point source pollution of stormwater contributes high contaminant loads into surface water bodies and poses a threat to the ecosystem, public health and economy. Although (pre)treatment standards have not been introduced at the federal level, Rhode Island (RI) has set minimal contaminant reduction standards for stormwater using structural best management practices (BMP). As BMP performance depends highly on geographical location and climate, and the Northeastern United States experiences broad ranges of temperatures throughout the year along with long intermittent periods between precipitation events, stormwater treatment can be challenging. In this field study, two tree filters were evaluated: a conventional unit (CTF) with sand/shale mix as filter media, and a modified tree filter (ITF) with an added layer of red cedar wood chips amended with 3-(trihydroxysilyl)propyldimethyloctadecyl ammonium chloride. Both BMPs were monitored for 346 days primarily for Escherichia coli and polycyclic aromatic hydrocarbons (PAH). Both tree filters met or outperformed RI’s standards for bacteria removal (60%) and TSS (85%), making them a good choice for BMP use in this climate. Total suspended solids, E. coli, PAHs, nitrate, and phosphate removal is higher in ITF. A controlled field scale tracer test using E. coli confirmed these results.
17 June 2014 in ACS Sustainable Chemistry & Engineering