|ognizant Communication Corporation|
A Journal of Science Serving Legislative, Regulatory, and Judicial Systems
Human Advancement · Environmental Protection · Industrial Development
Volume 9, Numbers 5-6
Technology, Vol. 9, pp. 225-231
1072-9240/05 $20.00 + 00.
Copyright © 2005 Cognizant Communication Corp.
Printed in the USA. All rights reserved.
Perfluorooctanoic Acid (PFOA) and Human Health: A Position Paper of the American Council on Science and Health
Concern has been raised about possible human health effects of perfluorooctanoic acid (PFOA) and related compounds, which have been detected in human blood in many locations. Evidence suggests that these compounds are persistent in the environment and human body. Studies of laboratory animals indicate that high doses can result in liver and kidney toxicity, and developmental and carcinogenic effects. However, the compounds do not appear to be mutagens. From mechanistic considerations, the relevance to humans of at least some effects seen in animals is questionable. Toxicities observed in animals have not been seen in worker populations. Comparisons of both blood levels and drinking water exposures of PFOA in the general population to levels associated with adverse effects in laboratory animals demonstrate that a margin of safety of hundreds to thousands exists. Thus, current data indicate that risk to the general population from PFOA and related compounds is quite low.
Key words: Perfluorooctanoic acid (PFOA); Perfluorooctanoate; Fluoropolymers; Teflon; Ammonium perfluorooctanoic acid (APFO)
Corresponding editor: Gilbert L. Ross, M.D., American Council on Science and Health, 1995 Broadway-2nd Floor, New York, NY 10023, USA. Tel: 212-362-7044, x242; Fax: 212-362-4919; E-mail: firstname.lastname@example.org
Life Cycle Methodology for Assessing Sustainable Growth of Energy Resources
Ryuji Matsuhashi,1 Eiki Ohashi,1 and Hisashi Ishitani2
1Institute of Environmental Studies, Graduate School of Frontier Sciences, and 2Department of Geosystem Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
Sequestration of CO2 is expected to be an effective option for mitigating climate change. This article aims at clarifying role of CO2 sequestration in global energy scenarios. For this purpose, the concept of "sustainable limits" on depletable resources and CO2 emissions is proposed. Based on this concept, energy resources and CO2 emissions require the introduction of measures such as CO2 sequestration or photovoltaic systems. Consequently, life cycle performances of CO2 sequestration and photovoltaic systems were evaluated. Input-output analysis was applied to develop life cycle inventories of the evaluated systems, and life cycle CO2 emissions and energy requirements of these technologies were quantitatively estimated. Based on the life cycle inventories, economic condition of each estimated technology with and without carbon tax was identified. The evaluated results showed the intrinsic difference between CO2 sequestration and renewable energy technologies. At the same time, they indicated how the economic incentives influence cost-effectiveness of the measures. Based on the results of this study it can be concluded that CO2 sequestration could play a transitional but significant role to realize sustainable energy systems.
Key words: Technology assessment; CO2 removal and disposal; Photovoltaic system; Cost-effectiveness; CO<->2 emissions; Life cycle assessment; Sustainable limit
Address correspondence to Ryuji Matsuhashi, Institute of Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Assessment of Temperature Changes in Various States of the United States
Sorin R. Straja
Institute for Regulatory Science, Columbia, MD 21045, USA
This article is the first of a larger study to evaluate regional temperature changes and attempt to draw conclusion on potential global temperature change. This aticle evaluates whether two states from the US have experienced a significant long-term temperature change. The two states chosen for this study are Alabama and North Dakota. Alabama was chosen because it is a southern state, while North Dakota was chosen as the state with the reputation to be the coldest state within the contiguous 48 states of the US. The data collected do not support the hypothesis of a significant temperature change. However, the sample size is relatively small with respect to the sampling frequency. For the North Dakota stations 322188 (Dickinson Experimental Station), 324178 (Hettinger) and 326315 (New England), although a significant temperature change was not detected, further analysis is necessary to understand the nature of the deterministic signals detected by the Lomb periodogram.
Key words: Temperature changes; United States; Global climate warming
Address correspondence to Sorin R. Straja, Institute for Regulatory Science, 9200 Rumsey Road, Suite 205, Columbia, MD 21045, USA.
Studies of Gap Space Effects on NO Removal in a Double Dielectric Barrier Discharge System
Yaw D. Yeboah,1 Zhicheng Wang,2 and Kofi B. Bota3
1Energy and Geo-Environmental Engineering Department, Penn
State University, University Park, PA 16802, USA
2Computer and Information Sciences Department and 3Chemistry Department, Clark Atlanta University, Atlanta, GA 30314, USA
Given the operational constraints of aerospace ground equipments (AGE), nonthermal plasma discharge (NTPD) has been identified as a promising technology for their NOx removal. As part of a program to optimize an NTPD system for this particular application, an investigation of the effect of discharge gap spacing and other factors on the electrical and chemical processes that occur in NTPDs was initiated. A number of experiments were performed to examine how the gap spacing affects the NO removal efficiency, discharge characteristics, and chemical reactions in a NTPD device. Optimum gap spacing and other conditions for NO removal were observed based on the experimental data and modeling. A physical explanation for the optimum was developed. The experiments, numerical approach, results, and conclusions are discussed in detail in this article.
Key words: Nonthermal plasma discharge (NTPD); Double dielectric barrier plasma discharge; NO removal; Modeling
Address correspondence to Yaw D. Yeboah, Energy and Geo-Environmental Engineering Department, Penn State University, University Park, PA 16802, USA. Tel: 814-865-0269; E-mail: email@example.com
NOx Removal From Continuous Gas Stream by a Silent Plasma Discharge
Yaw D. Yeboah,1 Zhicheng Wang,2 and Kofi B. Bota2
1Pennsylvania State University, University Park, PA 16802,
2Clark Atlanta University, Atlanta, GA 30314, USA
When released into the atmosphere, the group of compounds collectively known as nitrogen oxides (NOx) contributes to photochemical smog, acid rain, and ground-level ozone. Combustion processes are a primary source of NOxemissions and finding a cost-effective technology to remove NOx from combustion exhaust streams is essential. Given the operational constraints of aerospace ground equipment (AGE), nonthermal plasma discharge (NTPD) has been identified as a promising technology for NOx removal. As part of a program to optimize an NTPD system for this particular application, an investigation of the affect of discharge gap spacing on the electrical and chemical processes that occur in NTPDs was initiated. A number of experiments were performed to examine how the gap spacing affects the NOx removal efficiency, discharge characteristics, and chemical reactions in a NTPD device. Gap spacings ranging from 0.8 to 4.0 mm were considered in this study. An optimum gap spacing for NOx removal was observed at approximately 2 mm and, based on the experimental data, a physical explanation for the optimum was developed. The experiments, the results, and conclusions are discussed in detail in this article.
Key words: Nitrogen oxides; Nitrogen oxide removal; Gap spacing; Nonthermal plasma discharge (NTPD)
Address correspondence to Yaw D. Yeboah, Pennslyvania State University, 118 Hosler Building, University, PA 16802, USA. Tel: (814) 865-0269; E-mail: firstname.lastname@example.org
Mercury Content of Seawater Before Construction of Oil Sector Complex Ofshore of Al-Shuwaikh Coast, Kuwait
M. S. Massoud,1 M. A. Al-Sarawi,1 I. Diab,1 A. Shehab,1 and Kh. Al-Freij2
1Environment Public Authority, P.O. Box 24395, 13104 Safat,
2Water Resources Development Centre, Ministry of Water and Electricity, P.O. Box 12020, 71651, Shamia, Kuwait
Physical and chemical parameters were measured in the water body and in 442 seawater samples collected over a period of 6-11 months in 1998 from 13 nearshore stations along the coastline of Kuwait, including Al-Shuwaikh coast. Despite the marked regional and seasonal variations recorded in the properties of the seawater under study, all average values of the physical and chemical parameters, particularly nutrients, total petroleum hydrocarbons, and trace metals, are far below the concentration limit (CL) set for seawater and drinking water quality by local and international regulating bodies, emphasizing the good quality of the coastal waters in Kuwait at the present time. Values recorded for the physical and chemical properties of Al-Shuwaikh seawater are more or less similar to those recorded for Kuwaiti coastal waters and the northern Gulf waters and are all within the CLs set by local and international standards for the quality of seawater and/or drinking water, verifying the good quality of Al-Shuwaikh seawater during the whole period of 1998. Results obtained from the analysis of mercury in 102 water samples collected from 51 stations offshore Al-Shuwaikh coast emphasized that the mercury content of all samples is quite low and far below the CL of this pollutant, and hence the seawater in Al-Shuwaikh coastal area (including the area under study) can be regarded as currently unpolluted with mercury.
Key words: Mercury; Seawater; Al-Shuwaikh; Kuwait
Address correspondence to M. S. Massoud, Environment Public Authority, P.O. Box 24395, 13104 Safat, Kuwait.
Mercury Pollution in the Marine Silt Sediments of Al-Shuwaikh Coast, Kuwait
F. Bou-Rabee,1 M. A. Al-Sarawi,2 M. S. Massoud,2 Kh. Al-Ghareeb,2 W. Rajab,2 and Y. Marmoush3
1Department of Earth and Environmental Sciences, Kuwait University,
P.O. Box 5969, Safat 13060, Kuwait
2Environment Public Authority, P. O. Box 24395, 13104 Safat, Kuwait
3Kuwait Institute for Scientific Research, P. O. Box 24885 13104 Safat, Kuwait
Mercury analyses made on 249 surface and core sediment subsamples collected in 1998 have revealed that the silty bottom sediments in the southeastern nearshore area of the former Salt and Chlorine Plant (present Oil Sector Complex) along Al-Shuwaikh coast are currently contaminated with mercury, while the bottom sediments of the nearby Power and Desalination Plant nearshore area and the northern seaward area have low mercury content. The presence of high and intermediate concentrations of the element (from 2.7 to 17.5 mg/g), the weak nearshore current, and the low energy depositional regime in the southeastern nearshore area all suggest that the silt sediment column (~50 cm deep) beneath the sea floor in this limited marine area (20,000 m2) has acted as a sink for the mercury effluents dumped into Al-Shuwaikh coastal water via the outfalls of the chlorine plant during its production activity from 1964 to 1984. Any disturbance of the mercury-contaminated silt sediments (~10,000 m3) during offshore construction activity or due to accidental damage of the complex as a result of unforeseen military operations and/or seismic activities would lead to the upward migration of the mercury. Therefore, it appears prudent to remove completely the contaminated areas of marine silt and replace them with clean material before starting any construction activity in the study area.
Key words: Mercury; Silt sediments; Kuwait
Address correspondence to M. S. Massoud, Environment Public Authority, P. O. Box 24395, 13104 Safat, Kuwait.
Distribution of Trace Metals in Intertidal Flat Sediments of the Upper New Calabar River, Port Harcourt, Nigeria
Michael Horsfall, Jr.,1 Ayebaemi I. Spiff,1 and Fred E. Ogban2
1Department of Pure & Industrial Chemistry, University
of Port Harcourt, Uniport P.O. Box 402, Choba, Port Harcourt, Nigeria
2Department of Chemistry, Delta State University, P. M. B. 1, Abraka, Delta State, Nigeria
New data on the spatial distribution of trace metals in inter-tidal flat sediments in 10 sampling stations, which were clustered into four variable zones of the upper New Calabar River in Port Harcourt, Nigeria, are presented. The flame atomic absorption spectrophotometric technique was used for all metal determination. Much higher concentrations were detected near most likely anthropogenic sources of trace metals inputs, which may be ascribed to petroleum refinery, industrial, and domestic effluents discharged into the river from a number of outfalls within the zones. Trace metals in these contaminated intertidal sediment cluster zones were up to 0.95 mg g-1 for Hg, 38.30 mg g-1 for Ni, 17.75 mg g-1 for Co, 27.35 mg g-1 for Cu, 201.30 mg g-1 for Cr, 3.60 mg g-1 for Cd, 265.65 mg g-1 for Mn, 131.15 mg g-1 for Pb, and 136.25 mg g-1 for Zn. Cluster analysis of distribution pattern and of available tidal hydraulic data indicates that the metal concentrations are due to a combination of sources and tidal hydraulics. All metals except Hg form strong correlation (p < 0.05) with the sediment organic carbon, indicative of sediment as an adsorptive sink. Comparison of trace metal levels in intertidal flat sediments of the upper New Calabar River and sediments of rivers from other geographical regions indicates that the upper segments of the New Calabar River intertidal flat sediments have elevated levels of trace metals, but have not been grossly contaminated.
Key words: Trace metals; Intertidal sediments; Nigeria; New Calabar River
Address correspondence to Dr. Michael Horsfall, Jr., Department of Pure & Industrial Chemistry, University of Port Harcourt, Uniport P.O. Box 402, Choba, Port Harcourt, Nigeria. E-mail: email@example.com
Assessment of Lead in Roadside Vegetation in the Lower Niger Delta, Nigeria
Tubonimi J. K. Ideriah and Solomon A. Braide
Institute of Pollution Studies, University of Science and Technology, P.M.B. 5080, Port Harcourt, Nigeria
Leaf samples from 16 plants were collected from selected roads in parts of the Niger Delta region of Nigeria and analyzed for lead using the dithizone colorimetric method. The results show that lead concentrations in samples from the high traffic density areas were significantly (p < 0.05) higher than lead concentrations in samples from low traffic density areas and a positive correlation (r = 0.9162) exists between them. Lead concentrations in the leaves decreased with increasing distance from the road (r = -0.8579). Lead levels in the dry season samples were higher than the wet season samples but the difference between them was not statistically significant (p > 0.05). The lead levels found in the high traffic density areas exceeded threshold limits. Farming activities along major traffic roads are discouraged because the concentration of lead in the environment is increasing.
Key words: Lead; Roadside vegetation; Niger Delta; Nigeria
Address correspondence to Tubonimi J. K. Ideriah, Institute of Pollution
Stidues, University of Science and Technology, P.M.B. 5080, Port Harcourt,