Abdul Bari

Measurements of gaseous HONO, HNO3, SO2, HCl, NH3, particulate sulfate and PM2.5 in New York, NY

Simultaneous measurements of gaseous HONO, HNO3, HCl, SO2, and NH3 for a period of 1 year from July 1999 to June 2000 and fine-fraction particulate (<2.5 μm) sulfate (SO42−) from January 1999 to November 2000 were made at Bronx and Manhattan in New York City with an annular denuder system followed by ion chromatography. The hourly PM2.5 mass was measured with a Rupprecht and Patashnick TEOM Series 1400a real-time monitor for approximately 2 years (January 1999–November 2000) at the same sites. Concentrations at the two sites were highly correlated, with Manhattan being slightly higher than at the Bronx. The concentrations of HNO3, HCl, NH3 and SO42− were higher during summer than winter, the summer/winter ratios at Manhattan being 3.9, 3.1, 1.5, and 1.9, respectively. The concentrations of HONO and SO2 were lower during summer than winter, the summer/winter ratios at Manhattan being 0.48 and 0.44, respectively. Gaseous HONO concentrations were higher than that of HNO3 except in summer, when the HNO3 was higher. The annual mean concentration of PM2.5 was 15.2 μg/m3 at the Bronx, and 15.5 μg/m3 at Manhattan (based only on days when data were available from both sites). The monthly mean concentrations at Manhattan ranged from 13.2 to 21.7 μg/m3 and were highest in June and July 1999, and lowest in March and April. The monthly mean fraction of PM2.5 as SO42− ranged from 0.17 to 0.31, with the highest values observed during June–September. The hourly mean concentrations of PM2.5 showed a bimodal pattern, with peaks at around 7–8 AM and 8–9 PM. In general, the second maximum is lower than the morning one, but during summer this is reversed. The contributions from regional and local emissions and the influence of atmospheric transport and chemical reactions on the observed concentrations are discussed in a compendium paper.

Regional sources of particulate sulfate, SO2, PM2.5, HCl, and HNO3, in New York, NY

Abstract Simultaneous measurements of gaseous HONO, HNO3, HCl, SO2, and NH3 from July 1999 to June 2000 and fine-fraction particulate (

Trends in atmospheric elemental carbon concentrations from 1835 to 2005

225, and 62 ng m � 3 , respectively. We also collected � 55 cm long sediment cores from West Pine Pond near Whiteface Mountain. The cores were sliced and their 210 Pb ages determined. The first (top) five slices each represented sediment deposition over 7 years and the remaining 13 years each. EC was chemically separated from the sediment samples from four cores, and its concentration in each slice was determined using the thermal optical method. The [EC]sed followed closely that of [EC]atm from 1978 to 2005. Assuming wet and dry deposition as the only source, we can show that [EC]sed = K[EC]atm, where K (m 3 g � 1 ) is a constant for a given lake. From [EC]atm, and [EC]sed for the 1978–2005 period, K was determined to be 10,400 ± 4,400 m 3 g � 1 . With this value used for K and [EC]sed, the [EC]atm values were determined from 1835 to 1978. The [EC]atm from 1835–1862 was � 30 ng m � 3 , which may be close to the preindustrial background level. The [EC]atm was 65 ng m � 3 for the 1863–1875 period, then increased sharply, reaching a maximum value, 760 ng m � 3 , from 1917–1930. From 1931–1943 through 1978–1984, the concentration decreased gradually, from 680 to 560 ng m � 3 . The concentrations for 1985–1991, 1992–1998, and 1999–2005 were 295, 195, and 60 ng m � 3 , respectively. Model calculations for BC emissions from fossil fuel

Rapid alpha spectroscopy of evaporated liquid residues for emergency response.

A new method for &agr; spectroscopy of evaporated water residues was developed, consisting of evaporation of drinking water, flaming of the planchets, and &agr;-spectroscopic measurements using a grid ionization chamber. The method can identify and quantify radioactivity concentrations ≥3 mBq L−1 in a matter of several hours, whereas determination of sub-mBq L−1 levels is achievable in 1 day. Detailed investigations of flaming of the planchets, the humidity effect, and &agr; spectroscopy of thick sources are described. A three-dimensional calibration of the method was performed using standards containing 238U, 230Th, 239Pu, 241Am, and 244Cm radionuclides. In addition to its application to evaporated drinking water, this calibration is common for any environmental sample that can be prepared as a uniform layer, such as the residues from surface water, acidic washing or leaching from materials, as well as biological fluids such as urine. The developed method serves as a fast identifying or screening technique for emergency response involving &agr; radioactivity.

Non-destructive determination of 224Ra, 226Ra and 228Ra concentrations in drinking water by gamma spectroscopy.

Abstract— The U.S. Environmental Protection Agency mandates that drinking water showing gross alpha-activity greater than 0.19 Bq L−1 should be analyzed for radium, a known human carcinogen. The recommended testing methods are intricate and laborious. The method reported in this paper is a direct, non-destructive gamma-spectroscopic method for the determination of 224Ra, 226Ra, and 228Ra, the three radium isotopes of environmental concern in drinking water. Large-volume Marinelli beakers (4.1-L capacity), especially designed for measuring radioactive gases, in conjunction with a low-background, high-efficiency (131%) germanium detector were used in this work. It was first established that radon, the gaseous decay product of radium, and its progeny are quantitatively retained in this Marinelli beaker. The 224Ra, 226Ra, and 228Ra activity concentrations are determined from the equilibrium activities of their progeny: 212Pb, 214Pb (214Bi), and 228Ac; and the gamma-lines used in the analysis are 238.6, 351.9 (and 609.2), and 911.2 keV, respectively. The 224Ra activity is determined from the first 1,000-min measurement performed after expulsion of radon from the sample. The 226Ra activity is determined from the second, 2,400-min measurement, made 3 to 5 d later, and the 228Ra activity is determined from either the first or the second measurement, depending on its concentration level. The method’s minimum detectable activities are 0.017 Bq L−1, 0.020 Bq L−1, and 0.027 Bq L−1 for 224Ra, 226Ra, and 228Ra, respectively, when measured under radioactive equilibrium. These limits are well within the National Primary Drinking Water Regulations required limit of 0.037 Bq L−1 for 226Ra and for 228Ra. The precision and accuracy of the method, evaluated using the U.S. Environmental Protection Agency and the Environmental Resource Associates’ quality control samples, were found to be within acceptable limits.

History of atmospheric deposition of trace elements in lake sediments, ~1880 to 2007

We report measurements of 30 major and trace elements (TEs) in sediment cores from two high-altitude lakes, West Pine Pond (WPP), and Clear Pond (CP), in the Adirondack Mountains of New York State using inductively coupled plasma–mass spectrometry. The data are used to deduce atmospheric deposition histories of TEs over ~130 years. The cores were collected using a gravity corer, sliced, freeze dried, and ages determined using 210Pb and 137Cs techniques. TE data in WPP were supplemented with our earlier elemental carbon (EC) measurements. Lithophilic elements showed no systematic temporal pattern or any significant enrichment over their crustal abundances. Anthropogenic TEs exhibited distinct increases beginning ~1900, and peaked around 1920–1970, due apparently to energy-related emissions. Peak concentrations of most TEs, except Pb and Hg, were observed at ~1921 in WPP and ~1940s in CP. Concentration of Pb peaked in 1973 in both lakes and Hg only in CP at ~1965. Lead fluxes were reflective of historical smelter production and combustion of coal and leaded gasoline. Copper and zinc fluxes mimicked corresponding primary production, while EC fluxes followed the long-term trend for fossil and biofuel combustion. TE and EC flux trends were closely related to the growth of industrialization in the Central and Midwestern U.S. and changing fuel consumption patterns. Compared to peak values, the modern TE fluxes decreased by 25–85%, whereas EC decreased by 96%. Apparently, the regulations intended to control pollutant emissions have succeeded in reducing atmospheric concentrations of the species studied and have improved air quality.

Application of low-background gamma-ray spectrometry to monitor radioactivity in the environment and food

The results are described of an upgrade of the low-background gamma-ray spectrometry laboratory at New York State Department of Health by acquiring sensitivity to low-energy gamma rays. Tuning of the spectrometer and its low-energy response characteristics are described. The spectrometer has been applied to monitor the environment by measuring aerosols and water in New York State contaminated by the 2011 Fukushima accident plume. In addition, the spectrometer has been used to monitor radioactivity in food by performing a study of cesium in Florida milk.

Performance of a commercial radon-in-water measurement kit

Methods currently approved for the measurement of radon ((222)Rn) in water in New York State are liquid scintillation counting and emanation into alpha-scintillation cells. A passive system using an electret ion chamber (EIC) was evaluated as an alternative for the measurement of radon in water. Over 130 water samples from a community water supply containing 32BqL(-1) and 30 standards containing 686BqL(-1) were measured using the EIC method over 1- to 4-day exposure times. For comparison, identical samples were measured using liquid scintillation counting. Results of duplicate samples were typically within 5% for liquid scintillation counting and within 10% for the EIC. With respect to accuracy, the EIC produced results that were consistently low by 11-15%.

A new method for sealing containers with liquid samples for radioactivity measurements

It is imperative to use a leak-proof container for counting liquid sample to prevent contamination of costly gamma detectors. We report in this technical note a sealant that ensures no leak. It is a vinyl adhesive sealant used for household purposes, marketed by Gloucester Co., Inc, Franklin, MA under the trade name of Phenoseal (translucent variety). This sealant was superior to other sealants studied because it cures quickly, peels off easily after counting, and contains no detectable radioactivity. We have thoroughly tested this sealant in our laboratory and successfully employed it in the routine analysis of environmental liquid samples.

Rapid screening of radioactivity in food for emergency response

This paper describes the development of methods for the rapid screening of gross alpha (GA) and gross beta (GB) radioactivity in liquid foods, specifically, Tang drink mix, apple juice, and milk, as well as screening of GA, GB, and gamma radioactivity from surface deposition on apples. Detailed procedures were developed for spiking of matrices with (241)Am (alpha radioactivity), (90)Sr/(90)Y (beta radioactivity), and (60)Co, (137)Cs, and (241)Am (gamma radioactivity). Matrix stability studies were performed for 43 days after spiking. The method for liquid foods is based upon rapid digestion, evaporation, and flaming, followed by gas proportional (GP) counting. For the apple matrix, surface radioactivity was acid-leached, followed by GP counting and/or gamma spectrometry. The average leaching recoveries from four different apple brands were between 63% and 96%, and have been interpreted on the basis of ion transport through the apple cuticle. The minimum detectable concentrations (MDCs) were calculated from either the background or method-blank (MB) measurements. They were found to satisfy the required U.S. FDAs Derived Intervention Levels (DILs) in all but one case. The newly developed methods can perform radioactivity screening in foods within a few hours and have the potential to capacity with further automation. They are especially applicable to emergency response following accidental or intentional contamination of food with radioactivity.