Indoor Air 2015; 25: 547–556 wileyonlinelibrary.com/journal/ina Printed in Singapore. All rights reserved
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd INDOOR AIR doi:10.1111/ina.12168
Polybrominated diphenyl ethers and polychlorinated biphenyls in indoor dust in Durban, South Africa Abstract Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in indoor dust of three microenvironments in Durban, South Africa. The sum of eight PBDEs and three PCBs were quantified by gas chromatography with mass spectral detection. The mean concentrations of ∑n = 8 PBDEs and ∑n = 3 PCBs in 10 homes, 11 offices, and 13 university students’ computer laboratories were 1710, 1520, and 818 ng/g, and 891, 923, and 1880 ng/g for PBDEs and PCBs, respectively. The concentration of PCBs found in homes was independent (P = 0.0625) of building construction year. Similarly, no relationship was observed between PCB concentrations and floor type. The concentrations of PBDEs correlated (r = 0.60) with PCB concentrations in homes, thus assuming similar sources. The elevated concentrations of PBDEs and PCBs may have significant implications for human exposure.
O. A. Abafe, B. S. Martincigh School of Chemistry and Physics, University of KwaZuluNatal, Durban, South Africa Key words: PBDEs; PCBs; Indoor dust; Sources; Human exposure; Correlation.
Bice S. Martincigh School of Chemistry and Physics University of KwaZulu-Natal Westville Campus Private Bag X54001 Durban 4000, South Africa Tel.: +27 31 2601394 Fax: +27 31 2603091 e-mail: [email protected] Received for review 21 March 2014. Accepted for publication 13 October 2014.
Practical Implications
This study provides vital data on the concentrations of the environmentally most abundant PCBs and PBDEs in three indoor microenvironments, namely homes, offices, and university students’ computer laboratories, in Durban, South Africa. Potential sources of these contaminants were established in the various indoor environments. These data can be used to establish suitable legislation, and also for risk assessment and management of these ubiquitous persistent organic pollutants.
Introduction
The considerable length of time we spend indoors daily in homes, offices, schools, day care centers, and computer rooms, among other possible indoor locales, avails us ample opportunity for exposure to chemical contaminants such as polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). For instance, PBDE-treated products, and abrasion, alongside evaporation of PCBs in building materials in homes and public buildings constructed prior to 1977, are a reservoir of PBDEs and PCBs in the indoor environment (Takigami et al., 2009). Recent studies have reported elevated concentrations of PBDEs in indoor dust from several countries: Japan (Takigami et al., 2009), United Kingdom (Harrad et al., 2008a), China (Yu et al., 2012), Sweden (de Wit et al., 2012), Belgium (D’Hollander et al., 2010), Philippines (Fulong and
Espino, 2013), Germany (Fromme et al., 2014; Sj€ odin et al., 2008), and Pakistan and Kuwait (Ali et al., 2013). Although few reports are available on indoor exposure to PCBs, some authors have reported possible PCB contamination in the indoor environment in several locations, including Wisconsin, USA (Knobeloch et al., 2012), California, USA (Whitehead et al., 2012), Boston, USA (Herrick et al., 2004), Switzerland (Kohler et al., 2005), and China (Xing et al., 2011). Much attention has been focussed recently on the significance of indoor dust as a pathway of human exposure to PBDEs and other brominated flame retardants (BFRs) (Abdallah et al., 2009; Harrad and Abdallah, 2011; Harrad et al., 2008a). The relationship between dust and human body burdens is strongly implied by the correlation of PBDEs in household dusts and human milk (Harrad et al., 2008a), and dusts and human blood (Fischer et al., 2006). 547
Abafe & Martincigh Not much is known on the production, use, distribution, and fate of PBDEs and PCBs in South Africa. However, recent studies have reported PBDEs in sediments (La Guardia et al., 2013; Olukunle et al., 2012), indoor dust from Pretoria (Kefeni and Okonkwo, 2012, 2014; Kefeni et al., 2011, 2014), landfills (Odusanya et al., 2009), sewage sludge and wastewater effluent (Daso et al., 2012), bird eggs (Polder et al., 2008), and human breast milk (Darnerud et al., 2011). While PCBs were never produced in South Africa, PCB oils and equipment containing PCB oils were imported mainly for electricity generation (South Africa’s Plan for the Implementation of the Stockholm Convention on Persistent Organic Pollutants, 2011). PCBs have been reported in water and fish tissues from the Isipingo Estuary (Grobler et al., 1996), outdoor air, soil and milk in KwaZulu-Natal, South Africa (Batterman et al., 2009a), soil and sediment samples from the industrialized Vaal Triangle region (Quinn et al., 2009), and human breast milk from Limpopo Province, South Africa (Darnerud et al., 2011). No published work is available on indoor PCB contamination in South Africa, and indeed the African continent. Furthermore, despite the increasing proof of the significant implications of indoor dusts for human exposure to PBDEs and PCBs, attempts to link indoor contaminants with probable source items have had limited success. A dearth of information also exists for human exposure pathways to PBDEs and PCBs in Africa and other developing countries of the world. To breach these research gaps, we seek:
•
•
To provide a first report of PCB levels in indoor dust and to extend the range of microenvironments examined for PBDE contamination to include homes, offices, and university students’ computer laboratories in South Africa, and To study the relationship between PBDE and PCB levels and their probable sources in these indoor microenvironments.
Materials and methods Chemicals
Method 1614 Native PAR PBDE stock solution [(1 lg/ml 2,4,40 -tribromodiphenyl ether, BDE-28; 2,20 ,4,40 -tetrabromodiphenyl ether, BDE-47; 2,2,4,4, 50 -pentabromodiphenyl ether, BDE-99; 2,2,4,4,60 pentabromodiphenyl ether, BDE-100; 2,2,4,4,5,5-hexabromodiphenyl ether, BDE-153; 2,2,4,4,5,6-hexabromod iphenyl ether, BDE-154; 2,20 ,3,4,40 ,5,60 -heptabromodiphenyl ether, BDE-183) and (10 lg/ml 2,20 ,3,30 ,4, 40 ,5,50 ,6,60 -decabromodiphenyl ether, BDE-209)] was received as a kind donation from Cambridge Isotope Laboratories (Andover, MA, USA). 2,4,40 -Trichlorobiphenyl (PCB-28); 2,20 ,4,40 ,5,50 -hexachlorobiphenyl 548
(PCB-153); 2,20 ,3,4,40 ,5,50 -heptachlorobiphenyl (PCB180); and decachlorobiphenyl (PCB-209) were purchased from Sigma-Aldrich (Johannesburg, South Africa). 13C12-labeled decachlorobiphenyl (13C12 PCB209) was obtained from Wellington Laboratories (Guelph, ON, Canada). Silica gel 90 was from SigmaAldrich and Florisil PR 60-100 mesh was from Floridin Co. (Quincy, FL, USA). The standard reference material (SRM 2585: Organic contaminants in house dust) was purchased from the National Institute of Standards and Technology (NIST, Gaithersburg, MD, USA). Anhydrous sodium sulfate was from Associated Chemical Enterprises (ACE, Johannesburg, South Africa). A Rtxâ – 1614 fused silica (5% diphenyl, 95% dimethyl polysiloxane) capillary column was obtained as a generous gift from Restek Corporation (Bellefonte, PA, USA). All solvents were highperformance liquid chromatography or pesticide grade obtained from Sigma-Aldrich. Sampling
A total of 34 dust samples were collected from homes, n = 10; university students’ computer laboratories, n = 13; and university staff offices, n = 11, between August and October 2012 in Durban, South Africa. Computer laboratory and office samples were collected with a LG 1600 W vacuum cleaner following the description of Harrad et al. (2008a). The vacuum cleaner contained a dust unit which could easily be removed and emptied after each collection. Between each collection, it was cleaned with a disposable cloth wetted with iso-propanol. Samples from homes were obtained from the vacuum cleaner bags of each home collected under normal home use conditions as they reflect recently collected dusts and thereby provide an estimate of residential exposure to PBDE and PCB contamination. Samples were stored in amber glass bottles at 10°C until analysis. Detailed questionnaires were used to obtain pertinent information on homes, offices, and computer laboratories. This information included location, time since floor was last vacuumed, type of ventilation and flooring, and the number and types of electronic/electrical devices and furniture. Interviews were also conducted to obtain further information on building ages and to determine whether, and when, any renovations were carried out. These data were used to relate PBDE and PCB concentrations to potential sources. Extraction and clean-up
Non-dust particles, hair, and debris were hand-picked from all samples. Samples were homogenized by sieving through a 212-lm stainless steel sieve. Dusts were analyzed following the United States Environmental Protection Agency methods 3550c (USEPA, 2000b),
PBDEs and PCBs in Durban, South Africa 3620c (USEPA, 2000a), 1614 (USEPA, 2007), and 1668a (USEPA, 1999) with modifications. Briefly, approximately 0.8 g of sample was quantitatively weighed into a glass test tube and spiked with 50 ng PCB-209 as the internal standard. A volume of 10 ml n-hexane:methanol (1:3 v/v) was added. Samples were mixed in an orbital shaker for 10 min and then extracted in an ultrasonic water bath at 40°C for 30 min. The mixing and extraction was repeated for a second time without addition of fresh solvent. The samples were then centrifuged at 3500 rpm for 10 min, and the supernatants were stored at
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd INDOOR AIR doi:10.1111/ina.12168
Polybrominated diphenyl ethers and polychlorinated biphenyls in indoor dust in Durban, South Africa Abstract Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in indoor dust of three microenvironments in Durban, South Africa. The sum of eight PBDEs and three PCBs were quantified by gas chromatography with mass spectral detection. The mean concentrations of ∑n = 8 PBDEs and ∑n = 3 PCBs in 10 homes, 11 offices, and 13 university students’ computer laboratories were 1710, 1520, and 818 ng/g, and 891, 923, and 1880 ng/g for PBDEs and PCBs, respectively. The concentration of PCBs found in homes was independent (P = 0.0625) of building construction year. Similarly, no relationship was observed between PCB concentrations and floor type. The concentrations of PBDEs correlated (r = 0.60) with PCB concentrations in homes, thus assuming similar sources. The elevated concentrations of PBDEs and PCBs may have significant implications for human exposure.
O. A. Abafe, B. S. Martincigh School of Chemistry and Physics, University of KwaZuluNatal, Durban, South Africa Key words: PBDEs; PCBs; Indoor dust; Sources; Human exposure; Correlation.
Bice S. Martincigh School of Chemistry and Physics University of KwaZulu-Natal Westville Campus Private Bag X54001 Durban 4000, South Africa Tel.: +27 31 2601394 Fax: +27 31 2603091 e-mail: [email protected] Received for review 21 March 2014. Accepted for publication 13 October 2014.
Practical Implications
This study provides vital data on the concentrations of the environmentally most abundant PCBs and PBDEs in three indoor microenvironments, namely homes, offices, and university students’ computer laboratories, in Durban, South Africa. Potential sources of these contaminants were established in the various indoor environments. These data can be used to establish suitable legislation, and also for risk assessment and management of these ubiquitous persistent organic pollutants.
Introduction
The considerable length of time we spend indoors daily in homes, offices, schools, day care centers, and computer rooms, among other possible indoor locales, avails us ample opportunity for exposure to chemical contaminants such as polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). For instance, PBDE-treated products, and abrasion, alongside evaporation of PCBs in building materials in homes and public buildings constructed prior to 1977, are a reservoir of PBDEs and PCBs in the indoor environment (Takigami et al., 2009). Recent studies have reported elevated concentrations of PBDEs in indoor dust from several countries: Japan (Takigami et al., 2009), United Kingdom (Harrad et al., 2008a), China (Yu et al., 2012), Sweden (de Wit et al., 2012), Belgium (D’Hollander et al., 2010), Philippines (Fulong and
Espino, 2013), Germany (Fromme et al., 2014; Sj€ odin et al., 2008), and Pakistan and Kuwait (Ali et al., 2013). Although few reports are available on indoor exposure to PCBs, some authors have reported possible PCB contamination in the indoor environment in several locations, including Wisconsin, USA (Knobeloch et al., 2012), California, USA (Whitehead et al., 2012), Boston, USA (Herrick et al., 2004), Switzerland (Kohler et al., 2005), and China (Xing et al., 2011). Much attention has been focussed recently on the significance of indoor dust as a pathway of human exposure to PBDEs and other brominated flame retardants (BFRs) (Abdallah et al., 2009; Harrad and Abdallah, 2011; Harrad et al., 2008a). The relationship between dust and human body burdens is strongly implied by the correlation of PBDEs in household dusts and human milk (Harrad et al., 2008a), and dusts and human blood (Fischer et al., 2006). 547
Abafe & Martincigh Not much is known on the production, use, distribution, and fate of PBDEs and PCBs in South Africa. However, recent studies have reported PBDEs in sediments (La Guardia et al., 2013; Olukunle et al., 2012), indoor dust from Pretoria (Kefeni and Okonkwo, 2012, 2014; Kefeni et al., 2011, 2014), landfills (Odusanya et al., 2009), sewage sludge and wastewater effluent (Daso et al., 2012), bird eggs (Polder et al., 2008), and human breast milk (Darnerud et al., 2011). While PCBs were never produced in South Africa, PCB oils and equipment containing PCB oils were imported mainly for electricity generation (South Africa’s Plan for the Implementation of the Stockholm Convention on Persistent Organic Pollutants, 2011). PCBs have been reported in water and fish tissues from the Isipingo Estuary (Grobler et al., 1996), outdoor air, soil and milk in KwaZulu-Natal, South Africa (Batterman et al., 2009a), soil and sediment samples from the industrialized Vaal Triangle region (Quinn et al., 2009), and human breast milk from Limpopo Province, South Africa (Darnerud et al., 2011). No published work is available on indoor PCB contamination in South Africa, and indeed the African continent. Furthermore, despite the increasing proof of the significant implications of indoor dusts for human exposure to PBDEs and PCBs, attempts to link indoor contaminants with probable source items have had limited success. A dearth of information also exists for human exposure pathways to PBDEs and PCBs in Africa and other developing countries of the world. To breach these research gaps, we seek:
•
•
To provide a first report of PCB levels in indoor dust and to extend the range of microenvironments examined for PBDE contamination to include homes, offices, and university students’ computer laboratories in South Africa, and To study the relationship between PBDE and PCB levels and their probable sources in these indoor microenvironments.
Materials and methods Chemicals
Method 1614 Native PAR PBDE stock solution [(1 lg/ml 2,4,40 -tribromodiphenyl ether, BDE-28; 2,20 ,4,40 -tetrabromodiphenyl ether, BDE-47; 2,2,4,4, 50 -pentabromodiphenyl ether, BDE-99; 2,2,4,4,60 pentabromodiphenyl ether, BDE-100; 2,2,4,4,5,5-hexabromodiphenyl ether, BDE-153; 2,2,4,4,5,6-hexabromod iphenyl ether, BDE-154; 2,20 ,3,4,40 ,5,60 -heptabromodiphenyl ether, BDE-183) and (10 lg/ml 2,20 ,3,30 ,4, 40 ,5,50 ,6,60 -decabromodiphenyl ether, BDE-209)] was received as a kind donation from Cambridge Isotope Laboratories (Andover, MA, USA). 2,4,40 -Trichlorobiphenyl (PCB-28); 2,20 ,4,40 ,5,50 -hexachlorobiphenyl 548
(PCB-153); 2,20 ,3,4,40 ,5,50 -heptachlorobiphenyl (PCB180); and decachlorobiphenyl (PCB-209) were purchased from Sigma-Aldrich (Johannesburg, South Africa). 13C12-labeled decachlorobiphenyl (13C12 PCB209) was obtained from Wellington Laboratories (Guelph, ON, Canada). Silica gel 90 was from SigmaAldrich and Florisil PR 60-100 mesh was from Floridin Co. (Quincy, FL, USA). The standard reference material (SRM 2585: Organic contaminants in house dust) was purchased from the National Institute of Standards and Technology (NIST, Gaithersburg, MD, USA). Anhydrous sodium sulfate was from Associated Chemical Enterprises (ACE, Johannesburg, South Africa). A Rtxâ – 1614 fused silica (5% diphenyl, 95% dimethyl polysiloxane) capillary column was obtained as a generous gift from Restek Corporation (Bellefonte, PA, USA). All solvents were highperformance liquid chromatography or pesticide grade obtained from Sigma-Aldrich. Sampling
A total of 34 dust samples were collected from homes, n = 10; university students’ computer laboratories, n = 13; and university staff offices, n = 11, between August and October 2012 in Durban, South Africa. Computer laboratory and office samples were collected with a LG 1600 W vacuum cleaner following the description of Harrad et al. (2008a). The vacuum cleaner contained a dust unit which could easily be removed and emptied after each collection. Between each collection, it was cleaned with a disposable cloth wetted with iso-propanol. Samples from homes were obtained from the vacuum cleaner bags of each home collected under normal home use conditions as they reflect recently collected dusts and thereby provide an estimate of residential exposure to PBDE and PCB contamination. Samples were stored in amber glass bottles at 10°C until analysis. Detailed questionnaires were used to obtain pertinent information on homes, offices, and computer laboratories. This information included location, time since floor was last vacuumed, type of ventilation and flooring, and the number and types of electronic/electrical devices and furniture. Interviews were also conducted to obtain further information on building ages and to determine whether, and when, any renovations were carried out. These data were used to relate PBDE and PCB concentrations to potential sources. Extraction and clean-up
Non-dust particles, hair, and debris were hand-picked from all samples. Samples were homogenized by sieving through a 212-lm stainless steel sieve. Dusts were analyzed following the United States Environmental Protection Agency methods 3550c (USEPA, 2000b),
PBDEs and PCBs in Durban, South Africa 3620c (USEPA, 2000a), 1614 (USEPA, 2007), and 1668a (USEPA, 1999) with modifications. Briefly, approximately 0.8 g of sample was quantitatively weighed into a glass test tube and spiked with 50 ng PCB-209 as the internal standard. A volume of 10 ml n-hexane:methanol (1:3 v/v) was added. Samples were mixed in an orbital shaker for 10 min and then extracted in an ultrasonic water bath at 40°C for 30 min. The mixing and extraction was repeated for a second time without addition of fresh solvent. The samples were then centrifuged at 3500 rpm for 10 min, and the supernatants were stored at
