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]




















Follow this and additional works at: http://scholarworks.umass.edu/intljssw

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 07103-2714ABSTRAKKontaminasi tanah dengan bahan kimia berbahaya, racun tetap menjadi salah satu masalah yang paling sulit di era ini. Penilaian risiko kesehatan sering tidak mempertimbangkan jumlah bahan kimia dalam tanah yang diserap dan disposisi mereka (kinetika). Tujuan dari studi ini adalah untuk membandingkan tingkat ke mana adsorpsi pasir atau tanah liat konten tanah mempengaruhi kinetika dan cara benzena yang kemudian ditangani dengan secara lisan atau dermally terkena tikus. Paparan dermal meningkatkan penyerapan setengah-hidup (t1/2) oleh 25, 60 dan 44-fold dibandingkan dengan lisan paparan benzena sendiri, atau depan tanah berpasir atau tanah liat, masing-masing. Penghapusan t1/2 berikut dermal versus lisan paparan meningkat sekitar 2-lipatan dalam kelompok sendirian dan berpasir tanah benzena, sementara di kelompok tanah clay kenaikan 13-fold. Daerah di bawah konsentrasi darah versus waktu kurva (AUC) benzena depan tanah baik meningkat setelah lisan dan menurun setelah paparan dermal dibandingkan dengan paparan benzena sendirian. Pemulihan kemih, 48 jam setelah paparan dermal benzena sendirian, adalah 3-fold lebih besar daripada mengikuti pemaparan lisan. Jaringan distribusi setelah semua lisan eksposur mengakibatkan konsentrasi tertinggi radioaktivitas di lambung isi > perut > lemak > duodenum > adrenal. Konsentrasi tertinggi jaringan radioaktivitas setelah paparan dermal benzena saja yang ginjal > hati > diperlakukan kulit; Namun, setelah paparan hadapan tanah baik jaringan konsentrasi tertinggi diperlakukan kulit > ginjal > hati. Hasil penelitian ini mengungkapkan bahwa kehadiran pasir atau tanah liat Tanah konten dihasilkan perbedaan kualitatif dan kuantitatif§ Sesuai penulis: Mohamed S. Abdel Rahman, Ph.D., F.C.P., B.C.F.E., farmakologi dan sekolah kedokteran Departemen fisiologi, New Jersey, Universitas Kedokteran dan kedokteran gigi New Jersey, 185 South Orange Avenue, Newark, New Jersey, USA, 07103-2714; Telepon: 973-979-3146; Email: [e-mail]. Diproduksi oleh pers elektronik Berkeley, 2010 1 Jurnal internasional tanah, sedimen dan air, Vol. 3 [2010], Iss. 1, Art. 4 ISSN: 1940-3259disposisi benzena dalam tubuh mengikuti lisan atau dermal eksposur. Perbedaan-perbedaan ini akan mempengaruhi penilaian risiko benzena.Kata kunci: benzena, dermal atau lisan eksposur, tanah ketersediaanhayati efek1. PENDAHULUAN Kontaminasi tanah dengan bahan kimia beracun yang berbahaya tetap menjadi salah satu masalah yang paling sulit era ini. Kimia berbahaya dapat bertahan dalam lingkungan; oleh karena itu, ada potensi risiko kesehatan jangka panjang. Sumber-sumber limbah kimia berbahaya banyak. Industri, pertanian, dan lembaga-lembaga seperti rumah sakit dan Universitas adalah semua sumber bahan yang perlu dibuang. Orang-orang yang tinggal di dekat tempat pembuangan limbah berbahaya atau pekerja di situs ini adalah resiko kesehatan yang serius jika situs yang dikelola dengan buruk atau tidak semestinya dirancang. Kontaminasi tanah dan bocornya bahan kimia untuk permukaan dan air tanah dapat menyebabkan masalah Toksikologi tahan lama. Sebagai fasilitas industri ditutup, terlalu sering mereka meninggalkan di belakang tanah sangat tercemar. Selain itu, transportasi limbah berbahaya ke pembuangan situs juga menimbulkan bahaya karena kecelakaan yang selalu ada kemungkinan. Jika perumahan, sekolah, atau bangunan perkantoran dibangun di atas daerah-daerah tersebut, bahkan di masa depan yang jauh, eksposur mungkin terjadi. Anak-anak yang bermain di dan di sekitar tanah di daerah ini akan menerima paparan langsung. Anak-anak telah diperkirakan menelan 50-180 mg tanah setiap hari (Clausing et al., 1987; Map dan 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

Hasil (Bahasa Indonesia) 2:

International Journal of Tanah, Sedimen dan Air
Mendokumentasikan Cutting Edge of Environmental Stewardship Volume 3 | Edisi 1 Pasal 4 2010/02/06 Penentuan Oral atau Dermal Benzene Exposure dari Terkontaminasi Tanah Mohamed Abdel-Rahman S. Ph.D. Universitas Kedokteran dan Kedokteran Gigi New Jersey, [e-mail] Rita M. Turkall Ph.D. Universitas Kedokteran dan Kedokteran Gigi New Jersey, [e-mail] Ikuti ini dan karya tambahan di: http://scholarworks.umass.edu/ intljssw Direkomendasikan Citation Abdel-Rahman, Mohamed S. Ph.D. dan Turkall, Rita M. Ph.D. (2010) "Penentuan Oral atau Dermal Benzene Exposure dari Tanah Terkontaminasi," International Journal of Tanah, Sedimen dan Air: Vol. 3: Iss. 1, Pasal 4. Tersedia di: http://scholarworks.umass.edu/intljssw/vol3/iss1/4 Pasal ini dibawa ke Anda untuk akses gratis dan terbuka dengan ScholarWorks @ UMass Amherst. Telah diterima untuk dimasukkan ke dalam International Journal of Tanah, Sedimen dan Air oleh administrator resmi ScholarWorks @ UMass Amherst. Untuk informasi lebih lanjut, silahkan hubungi [e-mail]. Abdel-Rahman dan Turkall: Oral atau Dermal Benzene Bioavailabilitas dari Tanah PENENTUAN LISAN atau dermal BENZENE SAMBUNGAN DARI TANAH CONTAIMINATED Benzene Bioavailabilitas dari Tanah Mohamed Abdel-S. Rahman1, § dan rita M. Turkall1,2 1University Kedokteran dan Kedokteran Gigi New Jersey, Farmakologi dan Fisiologi Departemen, New Jersey Medical School dan 2Clinical Departemen Sciences Laboratory, Fakultas Kesehatan Terkait Profesi, Newark, NJ, USA 07103-2714 ABSTRAK kontaminasi tanah dengan berbahaya, bahan kimia beracun tetap menjadi salah satu masalah yang paling sulit di era ini. Penilaian risiko kesehatan sering tidak mempertimbangkan jumlah bahan kimia dalam tanah yang diserap dan disposisi mereka (kinetika). Tujuan dari penelitian ini adalah untuk membandingkan sejauh mana adsorpsi baik pasir atau tanah liat tanah konten mempengaruhi kinetika dan cara yang benzena selanjutnya ditangani pada tikus secara oral atau dermal terkena. Paparan Dermal peningkatan penyerapan paruh (t1 / 2) sebesar 25, 60 dan 44 kali lipat dibandingkan dengan paparan lisan untuk benzena sendiri, atau di hadapan tanah berpasir atau tanah liat, masing-masing. Penghapusan t1 / 2 dermal berikut dibandingkan paparan lisan meningkat sekitar 2 kali lipat dalam benzena sendiri dan kelompok tanah berpasir, sedangkan pada kelompok tanah liat kenaikan itu 13 kali lipat. Daerah di bawah kurva konsentrasi darah terhadap waktu (AUC) benzena di hadapan baik tanah meningkat setelah lisan dan menurun setelah terkena kulit dibandingkan dengan paparan benzena saja. Pemulihan kemih, 48 jam setelah paparan kulit untuk benzena saja, adalah 3 kali lipat lebih besar daripada mengikuti paparan lisan. Jaringan distribusi setelah semua eksposur lisan mengakibatkan konsentrasi tertinggi radioaktivitas dalam lambung isi> perut> lemak> duodenum> adrenal. Konsentrasi tertinggi jaringan radioaktivitas setelah terkena kulit untuk benzena sendiri adalah ginjal> hati> kulit dirawat; Namun, setelah paparan di hadapan baik tanah konsentrasi jaringan tertinggi diperlakukan skin> ginjal> hati. Hasil penelitian ini mengungkapkan bahwa kehadiran pasir atau konten liat tanah yang dihasilkan perbedaan kualitatif dan kuantitatif dalam § Sesuai Penulis: Mohamed Abdel-Rahman S., Ph.D., FCP, Bcfe, Farmakologi dan Fisiologi Departemen, New Jersey Medis Sekolah, Universitas Kedokteran dan Kedokteran Gigi New Jersey, 185 South Orange Avenue, Newark, New Jersey, Amerika Serikat, 07103-2714; Telepon: 973-979-3146; Email:. [e-mail] Diproduksi oleh The Electronic Berkeley Press, 2010 1 International Journal of Tanah, Sedimen dan Air, Vol. 3 [2010], Iss. 1, Art. 4 ISSN: 1940-3259 disposisi benzena dalam tubuh berikut eksposur lisan atau kulit. Perbedaan ini akan mempengaruhi penilaian risiko benzena. Kata kunci: benzena, kulit atau paparan lisan, efek bioavailabilitas tanah 1. PENDAHULUAN Kontaminasi tanah dengan bahan kimia beracun yang berbahaya tetap menjadi salah satu masalah yang paling sulit dari era ini. Bahan kimia berbahaya dapat bertahan dalam lingkungan; Oleh karena itu, potensi risiko kesehatan jangka panjang ada. Sumber limbah bahan kimia berbahaya banyak. Industri, pertanian, dan lembaga-lembaga seperti rumah sakit dan universitas adalah sumber bahan yang perlu dibuang. Masyarakat yang tinggal di dekat dengan tempat pembuangan limbah berbahaya atau pekerja di situs tersebut berada pada risiko kesehatan yang serius jika situs yang kurang berhasil atau dirancang tidak benar. Kontaminasi tanah dan bocornya bahan kimia ini untuk kedua permukaan dan air tanah dapat menyebabkan masalah toksikologi tahan lama. Sebagai fasilitas industri yang ditutup, terlalu sering mereka tinggalkan tanah yang terkontaminasi berat. Selain itu, transportasi limbah berbahaya ke tempat pembuangan juga menimbulkan bahaya karena kecelakaan adalah kemungkinan selalu hadir. Jika perumahan, sekolah, atau gedung perkantoran yang dibangun di daerah ini, bahkan di masa depan yang jauh, paparan mungkin terjadi. Anak-anak yang bermain di dalam dan sekitar tanah di daerah-daerah akan menerima paparan langsung. Anak-anak telah diperkirakan menelan 50-180 mg tanah per hari (Clausing et al, 1987;. Binder dan Sokal, 1986). Sejajar pertumbuhan limbah berbahaya, telah ada peningkatan minat dalam pengembangan prosedur untuk menilai publik risiko kesehatan yang berhubungan dengan paparan bahan berbahaya. Perkiraan risiko kesehatan berikut paparan tanah yang terkontaminasi sebagian besar telah didasarkan pada hasil penelitian yang dilakukan dengan bahan kimia murni. Namun, tanah liat, mineral, dan komponen organik kompleks bentuk tanah, permukaan heterogen yang mampu menyerap molekul organik (Hamaker dan Thompson, 1972). Kekuatan bahan kimia-tanah gaya tarik menarik sangat dapat mempengaruhi reversibilitas dari proses serap. Oleh karena itu, ketersediaan dan tingkat kimia memasuki tubuh, distribusinya ke jaringan, dan tingkat dan jumlah ekskresi mungkin sangat berbeda dari penyelidikan kimia murni. Lucier et al. (1986) dan McConnell et al. (1984) menunjukkan bahwa dioksin dalam tanah dari situs Pantai Times dan Minker Stout di Missouri adalah biologis tersedia, yang diukur dengan penelitian enzim mikrosomal pada marmut. Umbreit et al. (1986) melaporkan bahwa meskipun konsentrasi tinggi dioksin dari dua lokasi manufaktur di New Jersey, tanah ini tidak dapat menghasilkan efek toksik pada lisan terkena marmut http://scholarworks.umass.edu/intljssw/vol3/iss1/4 2 Abdel-Rahman dan Turkall: Oral atau Dermal Benzene Bioavailabilitas dari Tanah dibandingkan dengan jumlah yang sama dioksin murni. Ketat mengikat dioksin ke matriks tanah situs New Jersey berkorelasi langsung dengan bioavailabilitas yang berkurang. paparan luas untuk petrokimia di tempat pembuangan dan air tanah telah mendorong evaluasi kinetika benzena setelah pengobatan oral dan dermal. Benzene adalah industri kimia yang umum digunakan untuk sintesis komponen aromatik (Baselt, 1982; Sandmeyer, 1981). Telah diidentifikasi sebagai zat yang paling sering keempat tercatat dalam 818 TPS yang ditinggalkan di Daftar 1985 Prioritas Nasional AS Environmental Protection Agency untuk Cleanup. Frantz (1984) menyelidiki penyerapan perkutan benzena pada hewan dan manusia. Dia melaporkan bahwa kurang dari 0,2% dari dosis yang diterapkan diserap dalam semua spesies yang dipelajari. Peneliti lain (Susten et al., 1985) menunjukkan bahwa pekerja di pabrik ban dapat menyerap 4-8 mg benzena sehari-hari melalui kulit dari campuran pelarut karet yang mengandung 0,5% (v / v) benzena. Penelitian ini dilakukan untuk membandingkan sejauh mana adsorpsi ke salah satu dari dua tanah yang berbeda (berpasir dan tanah liat) mempengaruhi cara di mana benzena selanjutnya ditangani pada tikus jantan dewasa secara lisan dan dermal terkena. 2. BAHAN DAN METODE Bahan Kimia 2.1 Semua penelitian dilakukan dengan menggunakan seragam berlabel 14C-benzena 50 mCi / mmol (ICN Farmasi, Irvine, CA) dengan kemurnian radiokimia> 98%. Sebelum digunakan, pengenceran dengan HPLC-grade, benzena berlabel (Aldrich Chemical Co.) dilakukan untuk mengurangi aktivitas spesifik untuk berbagai diterapkan. 2.2 Tanah Studi dilakukan pada dua tanah yang berbeda yang mewakili jenis tanah luas di Amerika Negara (USDA, 1972, 1977). The Atsion tanah terdiri dari 90% pasir, 8% lumpur, 2% tanah liat, 4,4% bahan organik; memiliki pH 4,2; dan dikumpulkan dari formasi pasir Cohansey dekat Chatsworth di selatan pusat New Jersey. The Keyport tanah mengandung 50% pasir, 28% lumpur, 22% tanah liat, 1,6% bahan organik; memiliki pH 5; dan dikumpulkan dari formasi Woodbury dekat Moorestown di barat daya New Jersey. Partikel tanah distribusi ukuran adalah sebagai berikut: Atsion tanah = 50-100 m (22,2%), 100-250 m Diproduksi oleh The Electronic Berkeley Press, 2010 3 International Journal of Tanah, Sedimen dan Air, Vol. 3 [2010], Iss. 1, Art. 4 ISSN: 1940-3259 (76,3%),> 250 m (1,5%); Keyport tanah = 50-100 m (17%), 100-250 m (65,3%), 250-500 m (13,6%),> 500 m (4,1%). Analisis tanah dilakukan oleh Laboratorium Pengujian Tanah di Rutgers Koperasi Pusat Penyuluhan Sumber Daya, Rutgers University, New Brunswick, NJ. Kandungan bahan organik diukur dengan modifikasi Walkley dan Black (1934) metode oksidasi dikromat. Karena kandungan pasir tinggi Atsion tanah dan kandungan liat tinggi Keyport tanah itu, tanah ini akan disebut sebagai berpasir dan tanah liat, masing-masing. 2.3 Hewan Pria Sprague Dawley-tikus dengan berat 250-300 g yang dibeli dari Taconic Farms, Germantown, NY , dan segera dikarantina selama satu minggu. Hewan ditampung tiga per kandang pada suhu 25 oC dan kelembaban 50% dikontrol lingkungan dengan / siklus gelap 12 jam cahaya. Makanan dan air disediakan ad libitum. 2.4 Benzene Administrasi Pemerintahan oral benzena dilakukan sebagai berikut: 150 ml