Nadeem Ali

Occurrence of alternative flame retardants in indoor dust from New Zealand: Indoor sources and human exposure assessment

Due to worldwide restrictions on polybrominated diphenyl ethers (PBDEs), the demand for alternative flame retardants (AFRs), such as organophosphate flame retardants (OPFRs), novel brominated FRs (NBFRs) and hexabromocyclododecanes (HBCDs), has recently increased. Little is known about human exposure to NBFRs and OPFRs and that their levels in dust have been scarcely evaluated worldwide. To increase the knowledge regarding these chemicals, we measured concentrations of five major NBFRs, ten OPFRs and three HBCD isomers in indoor dust from New Zealand homes. Dust samples were taken from living room floors (n=34) and from mattresses of the same houses (n=16). Concentrations (ngg(-1)) of NBFRs were: 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) (<2-175), decabromodiphenyl ethane (DBDPE) (<5-1430), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB) (<2-2285) and bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBPH) (<2-640). For OPFRs, concentrations (ngg(-1)) ranged between: tri-ethyl-phosphate (TEP) (<10-235), tri-n-butyl-phosphate (TnBP) (<20-7545), tris-(2-chloroethyl)-phosphate (TCEP) (<20-7605), tris-(1-chloro-2-propyl) phosphate (TCPP) (20-7615), tri-(2-butoxyethyl)-phosphate (TBEP) (50-27325), tris-(2,3-dichloropropyl)-phosphate (TDCPP) (20-16560), tri-phenyl-phosphate (TPhP) (20-35190), and tri-cresyl-phosphate (TCP) (<50-3760). HBCD concentrations fell in the range <2-4100ngg(-1). BTBPE, DBDPE, TBPH, TBEP, and TnBP showed significant positive correlation (p<0.05) between their concentrations in mattresses and the corresponding floor dust (n=16). These data were used to derive a range of plausible exposure scenarios. Although the estimated exposure is well below the corresponding reference doses (RfDs), caution is needed given the likely future increase in use of these FRs and the currently unknown contribution to human exposure by other pathways such as inhalation and diet.

Multi-residue method for the determination of brominated and organophosphate flame retardants in indoor dust

A new method was optimized for the simultaneous determination of several flame retardants (FRs) in indoor dust, namely polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), novel brominated flame retardants (NBFRs) and organophosphate ester flame retardants (OPFRs). The method was based on two previously validated analytical methods for NBFRs and OPFRs, which were combined in order to include even a large number of FRs. An ultrasonic extraction method and two-stage clean-up by adsorption chromatography was optimized using an indoor dust standard reference material (SRM 2584). The 1st cleanup step was essential for fractionation of analytes in the dust extracts, while the 2nd step was important for the further removal of interferences. Analysis of cleaned dust extracts was performed with gas chromatography electron impact ionization mass spectrometry for OPFRs, gas chromatography electron capture negative ionization mass spectrometry for PBDEs and NBFRs and liquid chromatography electrospray ionization tandem mass spectrometry for HBCDs. Method validation by matrix spiking demonstrated good accuracy ranging from 81 to 130%. Matrix effects were investigated by spiking sodium sulfate and dust with analyte standards. Typical recoveries ranged between 80 and 110% at both spiking levels, though occasional deviations were observed at low spiking concentrations. Precision between different days was generally below 24% relative standard deviation (RSD) at low concentrations and below 11% RSD at high concentrations. Method limits of quantification for BFRs ranged between 0.04 (BDE 28) and 17 ng/g (BDE 209), 6 ng/g for sum HBCDs, and for OPFRs between 10 (triphenyl phosphate) and 370 ng/g (tri-isobutyl phosphate). The method was applied to SRM 2585 and to a set of indoor dust samples from various countries. The newly developed method will be employed for the monitoring of human exposure via dust ingestion to phased-out and alternate FRs.

Levels and profiles of organochlorines and flame retardants in car and house dust from Kuwait and Pakistan: implication for human exposure via dust ingestion.

There are only few studies documenting indoor pollution in the Middle East and the Indian subcontinent. In present study, we have evaluated the occurrence of various organochlorines (OCs) and flame retardants (FRs) in dust from cars and houses of Pakistan and Kuwait. Polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), organophosphate FRs (PFRs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) were investigated in indoor dust from urban houses (N=15 per country) and cars (N=15 per country). PFRs were the major analytes in all four microenvironments, followed by PBDEs>NBFRs>OCPs>PCBs. For all classes of analytes, relatively lower levels were observed in car and house dust from Pakistan than Kuwait. Levels of ∑PBDEs, ∑NBFRs and ∑PFRs were higher in car dust, while ∑OCPs and ∑PCBs were higher in house dust from both countries. ∑PFRs occurred at average concentrations of 16,900, 87,900, 475, and 2500ng/g in Kuwaiti house and car, and Pakistani house and car dust, respectively. For both countries, the profiles of analytes in car dust were different from those in the house dust. Different exposure scenarios using 5th percentile, median, mean, and 95th percentile levels were estimated for adult, taxi drivers and toddlers. For Kuwaiti toddlers, assuming high dust intake and mean and 95th percentile concentrations, the values computed for ∑OCPs (1500ng/kg bw/day) were higher than RfD values, while for ∑PCBs (14.5ng/kg bw/day) it was only two-fold lower than the corresponding RfDs.

Brominated flame retardants (BFRs) in air and dust from electronic waste storage facilities in Thailand

This study reports concentrations of brominated flame retardants in dust samples (n=25) and in indoor (n=5) and outdoor air (n=10) (using PUF disk passive air samplers) from 5 electronic and electrical waste (e-waste) storage facilities in Thailand. Concentrations of Sigma(10)PBDEs (BDEs 17, 28, 47, 49, 66, 85, 99, 100, 153 and 154) in outdoor air in the vicinity of e-waste storage facilities ranged from 8 to 150 pg m(-3). Indoor air concentrations ranged from 46 to 350 pg m(-3), with highest concentrations found in a personal computer and printer waste storage room at an e-waste storage facility. These are lower than reported previously for electronic waste treatment facilities in China, Sweden, and the US. Concentrations of Sigma(21)PBDEs (Sigma(10)PBDEs+BDEs 181, 183, 184, 191, 196, 197, 203, 206, 207, 208 and 209), decabromodiphenylethane (DBDPE), decabromobiphenyl (BB-209) in dust were 320-290,000, 43-8700 and <20-2300 ng g(-1) respectively, with the highest concentrations of Sigma(21)PBDEs, BDE-209 and DBDPE in a room used to house discarded TVs, stereos and radios. PBDE concentrations in dust were slightly higher but within the range of those detected in workshop floor dust from an e-waste recycling centre in China. The highest concentration of BB-209 was detected in a room storing discarded personal computers and printers. Consistent with recent reports of elevated ratios of BDE-208:BDE-209 and BDE-183:BDE-209 in household electronics from South China, percentage ratios of BDE-208:BDE-209 (0.64-2.9%) and of BDE-208:BDE-183 (2.8-933%) in dust samples exceeded substantially those present in commercial deca-BDE and octa-BDE formulations. This suggests direct migration of BDE-208 and other nonabrominated BDEs from e-waste to the environment. Under realistic high-end scenarios of occupational exposure to BDE-99, workers in the facilities were exposed above a recently-published Health Based Limit Value for this congener. Reassuringly, estimated exposures to BDE-209 were below the USEPAs reference dose for this congener.

Country specific comparison for profile of chlorinated, brominated and phosphate organic contaminants in indoor dust. Case study for Eastern Romania, 2010

We have evaluated the levels and specific profiles of several organohalogenated contaminants, including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and flame retardants (FRs), such as polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), novel brominated FRs (NBFRs), and organophosphate FRs (OPFRs), in 47 indoor dust samples collected in 2010 from urban locations from Iasi, Eastern Romania. The dominant contaminants found in the samples were OPFRs (median sum OPFRs 7890 ng/g). Surprisingly, OCPs were also measured at high levels (median 1300 ng/g). Except for BDE 209 (median 275 ng/g), PBDEs were present in dust samples at relatively low levels (median sum PBDEs 8 ng/g). PCBs were also measured at low levels (median sum PCBs 35 ng/g), while NBFRs were only occasionally detected, showing a low usage in goods present on the Romanian market. The results of the present study evidence the existence of a multitude of chemical formulations in indoor dust. FRs are usually associated to human exposure via ingestion of dust, but other chemicals, such as OCPs, are not commonly reported in such matrix. Although OCPs were found at comparable levels with OPFRs in Romanian dust, OCPs possess a higher risk to human health due to their considerably lower reference dose (RfD) values. Indeed, the OCP exposure calculated for various intake scenarios was only 2-fold lower than the corresponding RfD. Therefore, the inclusion of OCPs as target chemicals in the indoor environment becomes important for countries where elevated levels in other environmental compartments have been previously shown.

Human exposure to toxic metals via contaminated dust: Bio-accumulation trends and their potential risk estimation.

We assessed the levels of potentially toxic trace metals, Zinc (Zn), Lead (Pb), Manganese (Mn), Copper (Cu), Nickel (Ni), Chromium (Cr), Cobalt (Co), and Cadmium (Cd), in dust, hair, nail and serum, sampled in rural, urban and industrial areas of Punjab, Pakistan. Trace metals occurrence in all samples, in descending order, was: Zn, Pb, Mn, Cu, Cr, Ni, Co, Cd. The samples from the urban areas showed significantly higher concentration of toxic trace metals (Zn, Ni, Cr, Co, Mn, and Cd) than those from industrial (which conversely had higher levels of Pb and Cu), and than samples from rural areas. Bioaccumulation patterns showed that dust exposure is one of the major routes into human body for Cd, Pb, Co, Mn and Cr, while the burden of Zn, Cu, and Ni can be more linked to dietary sources. The concentrations of trace metals in the samples from Punjab were comparable and/or higher than those reported worldwide. In many cases, the levels of Zn, Cr, Pb, Ni and Cd in hair and nail were beyond the ATSDR threshold guideline values that may cause some serious health effects. Hazard Index (HI) calculated for trace metal concentrations in the human population of Punjab points particularly to health risks from Cd (for children in urban and industrial areas) and from Pb (for all sub-groups).

Avian feathers as a non-destructive bio-monitoring tool of trace metals signatures: A case study from severely contaminated areas

The concentrations of trace metals were assessed using feathers of cattle egrets (Bubulcus ibis), collected within two industrial areas of Pakistan, Lahore and Sialkot. We found, in order of descending concentration: Zinc (Zn), Iron (Fe), Nickel (Ni), Copper (Cu), Cadmium (Cd), and Manganese (Mn), Chromium (Cr), Arsenic (As), and Lithium (Li), without any significant difference (except Fe, Zn, and Ni) between the two areas. The concentrations of trace metals, we recorded were among the highest ever reported in the feathers of avian species worldwide. The concentrations of Cr, Pb, Cd were above the threshold that affects bird reproductive success. The high contamination by heavy metals in the two areas is due to anthropogenic activities as well to natural ones (for As and Fe). The bioaccumulation ratios in eggs and feathers of the cattle egret, their prey, and the sediments from their foraging habitats, confirmed that avian feathers are a convenient and non-destructive sampling tool for the metal contamination. The results of this study will contribute to the environmental management of the Lahore and Sialkot industrial areas.

Concentrations of polybrominated diphenyl ethers in matched samples of indoor dust and breast milk in New Zealand

Polybrominated diphenyl ethers (PBDEs) are present in many consumer goods. There is evidence that PBDEs are toxic to humans, particular young children. The purpose of this study was to assess indoor dust as an exposure source for PBDEs. Concentrations of 16 PBDEs were determined in dust samples from 33 households in New Zealand, and in breast milk samples from 33 mothers living in these households. Associations between dust and breast milk PBDE concentrations were assessed, and childrens PBDE intake from breast milk and dust estimated. Influences of household and demographic factors on PBDE concentrations in dust were investigated. Indoor dust concentrations ranged from 0.1ng/g for BDE17 to 2500ng/g for BDE209. Breast milk concentrations were positively correlated (p<0.05) with mattress dust concentrations for BDE47, BDE153, BDE154, and BDE209 and with floor dust for BDE47, BDE183, BDE206, and BDE209. The correlation for BDE209 between dust and breast milk is a novel finding. PBDE concentrations in floor dust were lower from households with new carpets. The estimated childrens daily intake of PBDEs from dust and breast milk was below U.S. EPA Reference Dose values. The study shows that dust is an important human exposure source for common PBDE formulations in New Zealand.

Brominated and organophosphate flame retardants in indoor dust of Jeddah, Kingdom of Saudi Arabia: Implications for human exposure.

Different flame retardants (FRs) namely polybrominated diphenyl ethers (PBDEs), emerging brominated/chlorinated flame retardants (Br/Cl FRs), and organophosphate FRs (OPFRs) were analyzed in cars, air conditioner (AC) filters and floor dust of different households from Jeddah, Kingdom of Saudi Arabia (KSA). To the best of our knowledge, this is first study in literature reporting emerging Br/Cl FRs and OPFRs in AC filter dust and also first to report on their occurrence in dust from KSA. Chlorinated alkyl phosphate, penta-BDEs, BDE-209, and decabromodiphenylethane (DBDPE) were the major chemicals in dust samples from all microenvironments. ΣOPFRs occurred at median concentrations (ng/g dust) of 15,400, 10,500, and 3750 in AC filter, car and house floor dust, respectively. For all analyzed chemicals, relatively lower levels were observed in floor dust than car and AC filter dust. The profiles of FRs in car dust were different from AC filter and floor dust, which reflected their wider application as FR and plasticizer in variety of household and commercial products. For toddlers, assuming high dust intake and 95th percentile concentrations, the computed exposure estimation for BDE-99 was higher than RfD values.

Analysis of Physiochemical Parameters to Evaluate the Drinking Water Quality in the State of Perak, Malaysia

The drinking water quality was investigated in suspected parts of Perak state, Malaysia, to ensure the continuous supply of clean and safe drinking water for the public health protection. In this regard, a detailed physical and chemical analysis of drinking water samples was carried out in different residential and commercial areas of the state. A number of parameters such as pH, turbidity, conductivity, total suspended solids (TSS), total dissolved solids (TDS), and heavy metals such as Cu, Zn, Mg, Fe, Cd, Pb, Cr, As, Hg, and Sn were analysed for each water sample collected during winter and summer periods. The obtained values of each parameter were compared with the standard values set by the World Health Organization (WHO) and local standards such as National Drinking Water Quality Standard (NDWQS). The values of each parameter were found to be within the safe limits set by the WHO and NDWQS. Overall, the water from all the locations was found to be safe as drinking water. However, it is also important to investigate other potential water contaminations such as chemicals and microbial and radiological materials for a longer period of time, including human body fluids, in order to assess the overall water quality of Perak state.