International Journal of Soil, Sedi

International Journal of Soil, Sediment and Water
Documenting the Cutting Edge of Environmental Stewardship

Volume 3 | Issue 1 Article 4



2-6-2010

Determination of Oral or Dermal Benzene Exposure from Contaminated Soils

Mohamed S. Abdel-Rahman Ph.D.

University of Medicine and Dentistry of New Jersey, [e-mail]

Rita M. Turkall Ph.D.

University of Medicine and Dentistry of New Jersey, [e-mail]




















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Recommended Citation

Abdel-Rahman, Mohamed S. Ph.D. and Turkall, Rita M. Ph.D. (2010) "Determination of Oral or Dermal Benzene Exposure from Contaminated Soils," International Journal of Soil, Sediment and Water: Vol. 3: Iss. 1, Article 4.
Available at: http://scholarworks.umass.edu/intljssw/vol3/iss1/4



This Article is brought to you for free and open access by ScholarWorks@UMass Amherst. It has been accepted for inclusion in International Journal of Soil, Sediment and Water by an authorized administrator of ScholarWorks@UMass Amherst. For more information, please contact [e-mail].

Abdel-Rahman and Turkall: Oral or Dermal Benzene Bioavailability from Soil








DETERMINATION OF ORAL OR DERMAL BENZENE EXPOSURE FROM CONTAIMINATED SOILS

Benzene Bioavailability from Soil


Mohamed S. Abdel-Rahman1,§ and Rita M. Turkall1,2

1University of Medicine and Dentistry of New Jersey, Pharmacology and Physiology Department, New Jersey Medical School and 2Clinical Laboratory Sciences Department, School of Health Related Professions, Newark, NJ, USA 07103-2714



ABSTRACT


Soil contamination with dangerous, toxic chemicals remains one of the most difficult problems in this era. Health risk assessments often do not consider the amount of chemicals in soil that are absorbed and their disposition (kinetics). The aim of these studies was to compare the extent to which adsorption to either a sand or clay content soil affects the kinetics and manner which benzene is subsequently handled in orally or dermally exposed rats. Dermal exposure increased absorption half-lives (t1/2) by 25, 60 and 44-fold compared with oral exposure to benzene alone, or in the presence of sandy or clay soil, respectively. The elimination t1/2 following dermal versus oral exposure were increased about 2-fold in benzene alone and sandy soil groups, while in the clay soil group the increase was 13-fold. The area under the blood concentration versus time curve (AUC) of benzene in the presence of either soil was increased after oral and decreased after dermal exposure compared with exposure to benzene alone. The urinary recovery, 48 hours following dermal exposure to benzene alone, was 3-fold greater than following oral exposure. Tissue distribution after all oral exposures resulted in the highest concentrations of radioactivity in gastric contents > stomach > fat > duodenum > adrenal. The highest tissue concentrations of radioactivity after dermal exposure to benzene alone were kidney > liver > treated skin; however, after exposure in the presence of either soil the highest tissue concentrations were treated skin > kidney > liver. The results of these studies reveal that the presence of sand or clay content soil produced qualitative and quantitative differences in the


§ Corresponding Author: Mohamed S. Abdel-Rahman, Ph.D., F.C.P., B.C.F.E., Pharmacology and Physiology Department, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, 185 South Orange Avenue, Newark, New Jersey, USA, 07103-2714; Telephone: [phone]; Email: [e-mail].









Produced by The Berkeley Electronic Press, 2010 1

International Journal of Soil, Sediment and Water, Vol. 3 [2010], Iss. 1, Art. 4 ISSN: 1940-3259







disposition of benzene in the body following oral or dermal exposures. These differences will impact the risk assessment of benzene.

Keywords: benzene, dermal or oral exposures, soil bioavailability effects


1. INTRODUCTION


Soil contamination with dangerous toxic chemicals remains one of the most difficult problems of this era. The hazardous chemical may persist in the environment; therefore, the potential for long-term health risk exists. The sources of hazardous chemical wastes are numerous. Industry, agriculture, and institutions such as hospitals and universities are all sources of materials that need to be discarded. People living in proximity to hazardous waste disposal sites or workers at these sites are at serious health risk if the sites are poorly managed or improperly designed. Contamination of soil and the leaking of these chemicals to both surface and ground water may lead to long-lasting toxicological problems. As industrial facilities are shut down, all too often they leave behind heavily contaminated soil. Furthermore, transportation of hazardous wastes to disposal sites also poses hazards since accidents are an ever-present possibility. If housing, schools, or office buildings are built over these areas, even in the distant future, exposure is likely to occur. Children who play in and around the soil in these areas will receive direct exposure. Children have been estimated to ingest 50-180 mg of soil per day (Clausing et al., 1987; Binder and Sokal, 1986).

Paralleling the growth of hazardous wastes, there has been an increasing interest in the development of procedures for assessing public health risks associated with exposures to hazardous materials. Estimates of health risk following exposure to contaminated soils have largely been based on results of studies performed with pure chemicals. However, the clay, mineral, and organic components of soil form complex, heterogeneous surfaces which are capable of adsorbing organic molecules (Hamaker and Thompson, 1972). The strength of the chemical-soil attractive forces can profoundly affect the reversibility of the adsorptive process. Therefore, the availability and the rate of chemical entering the body, its distribution to tissues, and the rate and amount of excretion may greatly differ from pure chemical investigation. Lucier et al. (1986) and McConnell et al. (1984) suggest that dioxin in soil from Times Beach and Minker Stout sites in Missouri was biologically available, as measured by microsomal enzyme studies in guinea pigs. Umbreit et al. (1986) reported that despite the high concentration of dioxin from two manufacturing sites in New Jersey, this soil was unable to produce toxic effects in orally exposed guinea pigs









http://scholarworks.umass.edu/intljssw/vol3/iss1/4 2

Abdel-Rahman and Turkall: Oral or Dermal Benzene Bioavailability from Soil







compared with similar amounts of pure dioxin. Tight binding of dioxin to the soil matrix of the New Jersey sites correlated directly with its reduced bioavailability.

Widespread exposure to petrochemicals in dumping sites and groundwater has prompted an evaluation of the kinetics of benzene after oral and dermal treatment. Benzene is a common industrial chemical used for the synthesis of aromatic components (Baselt, 1982; Sandmeyer, 1981). It has been identified as the fourth most frequent substance recorded in 818 abandoned dump sites on the U.S. Environmental Protection Agency’s 1985 National Priority List for Cleanup.

Frantz (1984) investigated the percutaneous absorption of benzene in animals and men. He reported that less than 0.2% of the applied doses were absorbed in all species studied. Other investigators (Susten et al., 1985) suggest that workers in tire plants may absorb 4-8 mg of benzene daily through the skin from a rubber solvent mixture containing 0.5% (v/v) benzene.

This study was conducted to compare the extent to which adsorption to either of two different soils (sandy and clay) affects the manner in which benzene is subsequently handled in orally and dermally exposed adult male rats.


2. MATERIALS AND METHODS


2.1 Chemicals

All studies were conducted using uniformly labeled 14C–benzene 50 mCi/mmole (ICN Pharmaceuticals, Irvine, CA) with radiochemical purity >98%. Prior to use, dilution with HPLC-grade, unlabeled benzene (Aldrich Chemical Co.) was carried out to reduce specific activity to a workable range.

2.2 Soils


Studies were conducted on two different soils that are representative of soil types widely distributed in the United States (USDA, 1972, 1977). The Atsion soil consists of 90% sand, 8% silt, 2% clay, 4.4% organic matter; has a pH of 4.2; and was collected from the Cohansey sand formation near Chatsworth in south central New Jersey. The Keyport soil contains 50% sand, 28% silt, 22% clay, 1.6% organic matter; has a pH of 5; and was collected from the Woodbury formation near Moorestown in southwestern New Jersey. Soil particle size distribution was as follows: Atsion soil = 50-100 µm (22.2%), 100-250 µm









Produced by The Berkeley Electronic Press, 2010 3

International Journal of Soil, Sediment and Water, Vol. 3 [2010], Iss. 1, Art. 4 ISSN: 1940-3259







(76.3%), > 250 µm (1.5%); Keyport soil = 50-100 µm (17%), 100-250 µm (65.3%), 250-500 µm (13.6%), > 500 µm (4.1%). Soil analyses were performed by the Soil Testing Laboratory at Rutgers Cooperative Extension Resource Center, Rutgers University, New Brunswick, NJ. Organic matter content was measured by a modified Walkley and Black (1934) dichromate oxidation method. Because of the Atsion soil’s higher sand content and the Keyport soil’s higher clay content, these soils will be referred to as sandy and clay, respectively.

2.3 Animals


Male Sprague-Dawley rats weighing 250-300 g were purchased from Taconic Farms, Germantown, NY, and were immediately quarantined for one week. Animals were housed three per cage at a temperature of 25 oC and humidity 50% controlled environment with a 12 hour light/dark cycle. Food and water were provided ad libitum.

2.4 Benzene Administration

The oral administration of benzene was performed as follows: 150 µl

Hasil (Bahasa Indonesia) 1:

Jurnal internasional tanah, sedimen dan airMendokumentasikan tepi pemotongan lingkungan StewardshipVolume 3 | Edisi 1 pasal 42-6-2010Penentuan benzena lisan atau Dermal paparan dari tanah yang terkontaminasiMohamed S. Abdel Rahman Ph.D.Universitas Kedokteran dan kedokteran gigi New Jersey, [e-mail] M. Turkall Ph.D.Universitas Kedokteran dan kedokteran gigi New Jersey, [e-mail] ini dan karya-karya tambahan di: http://scholarworks.umass.edu/intljsswKutipan yang direkomendasikanAbdel Rahman, Mohamed S. Ph.D. dan Turkall, Rita M. Ph.D. (2010) "Tekad benzena lisan atau Dermal eksposur dari tanah yang terkontaminasi," jurnal internasional tanah, sedimen dan air: Vol. 3: Iss. 1, Pasal 4.Tersedia di: http://scholarworks.umass.edu/intljssw/vol3/iss1/4 Artikel ini dibawa ke Anda secara gratis dan terbuka akses oleh ScholarWorks@UMass Amherst. Telah diterima untuk dimasukkan dalam jurnal internasional tanah, sedimen dan air oleh administrator resmi ScholarWorks@UMass Amherst. Untuk informasi lebih lanjut, silahkan hubungi [e-mail]. Abdel Rahman dan Turkall: benzena lisan atau Dermal ketersediaanhayati dari tanahPENENTUAN BENZENA LISAN ATAU DERMAL PAPARAN DARI TANAH CONTAIMINATEDBenzena ketersediaanhayati dari tanahMohamed S. Abdel-Rahman1, § dan Rita M. Turkall1, 21University Kedokteran dan kedokteran gigi New Jersey, farmakologi dan Departemen fisiologi, New Jersey sekolah kedokteran dan sekolah kesehatan 2Clinical laboratorium ilmu departemen terkait profesi, Newark, NJ, Amerika Serikat 07103-2714ABSTRAKSoil contamination with dangerous, toxic chemicals remains one of the most difficult problems in this era. Health risk assessments often do not consider the amount of chemicals in soil that are absorbed and their disposition (kinetics). The aim of these studies was to compare the extent to which adsorption to either a sand or clay content soil affects the kinetics and manner which benzene is subsequently handled in orally or dermally exposed rats. Dermal exposure increased absorption half-lives (t1/2) by 25, 60 and 44-fold compared with oral exposure to benzene alone, or in the presence of sandy or clay soil, respectively. The elimination t1/2 following dermal versus oral exposure were increased about 2-fold in benzene alone and sandy soil groups, while in the clay soil group the increase was 13-fold. The area under the blood concentration versus time curve (AUC) of benzene in the presence of either soil was increased after oral and decreased after dermal exposure compared with exposure to benzene alone. The urinary recovery, 48 hours following dermal exposure to benzene alone, was 3-fold greater than following oral exposure. Tissue distribution after all oral exposures resulted in the highest concentrations of radioactivity in gastric contents > stomach > fat > duodenum > adrenal. The highest tissue concentrations of radioactivity after dermal exposure to benzene alone were kidney > liver > treated skin; however, after exposure in the presence of either soil the highest tissue concentrations were treated skin > kidney > liver. The results of these studies reveal that the presence of sand or clay content soil produced qualitative and quantitative differences in the§ Corresponding Author: Mohamed S. Abdel-Rahman, Ph.D., F.C.P., B.C.F.E., Pharmacology and Physiology Department, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, 185 South Orange Avenue, Newark, New Jersey, USA, 07103-2714; Telephone: [phone]; Email: [e-mail]. Produced by The Berkeley Electronic Press, 2010 1 International Journal of Soil, Sediment and Water, Vol. 3 [2010], Iss. 1, Art. 4 ISSN: 1940-3259disposition of benzene in the body following oral or dermal exposures. These differences will impact the risk assessment of benzene.Keywords: benzene, dermal or oral exposures, soil bioavailability effects1. INTRODUCTION Soil contamination with dangerous toxic chemicals remains one of the most difficult problems of this era. The hazardous chemical may persist in the environment; therefore, the potential for long-term health risk exists. The sources of hazardous chemical wastes are numerous. Industry, agriculture, and institutions such as hospitals and universities are all sources of materials that need to be discarded. People living in proximity to hazardous waste disposal sites or workers at these sites are at serious health risk if the sites are poorly managed or improperly designed. Contamination of soil and the leaking of these chemicals to both surface and ground water may lead to long-lasting toxicological problems. As industrial facilities are shut down, all too often they leave behind heavily contaminated soil. Furthermore, transportation of hazardous wastes to disposal sites also poses hazards since accidents are an ever-present possibility. If housing, schools, or office buildings are built over these areas, even in the distant future, exposure is likely to occur. Children who play in and around the soil in these areas will receive direct exposure. Children have been estimated to ingest 50-180 mg of soil per day (Clausing et al., 1987; Binder and Sokal, 1986).Paralleling the growth of hazardous wastes, there has been an increasing interest in the development of procedures for assessing public health risks associated with exposures to hazardous materials. Estimates of health risk following exposure to contaminated soils have largely been based on results of studies performed with pure chemicals. However, the clay, mineral, and organic components of soil form complex, heterogeneous surfaces which are capable of adsorbing organic molecules (Hamaker and Thompson, 1972). The strength of the chemical-soil attractive forces can profoundly affect the reversibility of the adsorptive process. Therefore, the availability and the rate of chemical entering the body, its distribution to tissues, and the rate and amount of excretion may greatly differ from pure chemical investigation. Lucier et al. (1986) and McConnell et al. (1984) suggest that dioxin in soil from Times Beach and Minker Stout sites in Missouri was biologically available, as measured by microsomal enzyme studies in guinea pigs. Umbreit et al. (1986) reported that despite the high concentration of dioxin from two manufacturing sites in New Jersey, this soil was unable to produce toxic effects in orally exposed guinea pigs http://scholarworks.umass.edu/intljssw/vol3/iss1/4 2 Abdel-Rahman and Turkall: Oral or Dermal Benzene Bioavailability from Soilcompared with similar amounts of pure dioxin. Tight binding of dioxin to the soil matrix of the New Jersey sites correlated directly with its reduced bioavailability.Widespread exposure to petrochemicals in dumping sites and groundwater has prompted an evaluation of the kinetics of benzene after oral and dermal treatment. Benzene is a common industrial chemical used for the synthesis of aromatic components (Baselt, 1982; Sandmeyer, 1981). It has been identified as the fourth most frequent substance recorded in 818 abandoned dump sites on the U.S. Environmental Protection Agency’s 1985 National Priority List for Cleanup.Frantz (1984) investigated the percutaneous absorption of benzene in animals and men. He reported that less than 0.2% of the applied doses were absorbed in all species studied. Other investigators (Susten et al., 1985) suggest that workers in tire plants may absorb 4-8 mg of benzene daily through the skin from a rubber solvent mixture containing 0.5% (v/v) benzene.This study was conducted to compare the extent to which adsorption to either of two different soils (sandy and clay) affects the manner in which benzene is subsequently handled in orally and dermally exposed adult male rats.2. MATERIALS AND METHODS 2.1 Chemicals All studies were conducted using uniformly labeled 14C–benzene 50 mCi/mmole (ICN Pharmaceuticals, Irvine, CA) with radiochemical purity >98%. Prior to use, dilution with HPLC-grade, unlabeled benzene (Aldrich Chemical Co.) was carried out to reduce specific activity to a workable range.2.2 Soils Studies were conducted on two different soils that are representative of soil types widely distributed in the United States (USDA, 1972, 1977). The Atsion soil consists of 90% sand, 8% silt, 2% clay, 4.4% organic matter; has a pH of 4.2; and was collected from the Cohansey sand formation near Chatsworth in south central New Jersey. The Keyport soil contains 50% sand, 28% silt, 22% clay, 1.6% organic matter; has a pH of 5; and was collected from the Woodbury formation near Moorestown in southwestern New Jersey. Soil particle size distribution was as follows: Atsion soil = 50-100 µm (22.2%), 100-250 µm Produced by The Berkeley Electronic Press, 2010 3 International Journal of Soil, Sediment and Water, Vol. 3 [2010], Iss. 1, Art. 4 ISSN: 1940-3259(76.3%), > 250 µm (1.5%); Keyport soil = 50-100 µm (17%), 100-250 µm (65.3%), 250-500 µm (13.6%), > 500 µm (4.1%). Soil analyses were performed by the Soil Testing Laboratory at Rutgers Cooperative Extension Resource Center, Rutgers University, New Brunswick, NJ. Organic matter content was measured by a modified Walkley and Black (1934) dichromate oxidation method. Because of the Atsion soil’s higher sand content and the Keyport soil’s higher clay content, these soils will be referred to as sandy and clay, respectively.2.3 Animals Male Sprague-Dawley rats weighing 250-300 g were purchased from Taconic Farms, Germantown, NY, and were immediately quarantined for one week. Animals were housed three per cage at a temperature of 25 oC and humidity 50% controlled environment with a 12 hour light/dark cycle. Food and water were provided ad libitum.2.4 Benzene Administration The oral administration of benzene was performed as follows: 150 µl