Justification Studies of interior air exposures to various human and non-human components has lar... more Justification Studies of interior air exposures to various human and non-human components has largely been restricted to industrial exposures for the purpose of regulation. In contrast, little attention has been paid to exposure at the residential scale, where people spend much of their day and may be exposed to known toxins, such as lead, arsenic, and asbestos, to human-produced chemicals of yet unknown toxicity, such as flame retardants. To capitalize on experience with citizen science initiatives as they pertain to environmental health, researchers formed an international network called 360 Dust Analysis, which provides guidance on citizen science and interior dust collection, as well as research tools to examine dust through analysis in regional labs.
Newcastle-upon-Tyne is the regional capital of NE England with a rich industrial and mining histo... more Newcastle-upon-Tyne is the regional capital of NE England with a rich industrial and mining history. Urban Agriculture Sites (UAS), known in the UK as ‘allotments’, have developed as part of urban ...
The physiologically-based extraction test (PBET) is being applied to soil from contaminated land ... more The physiologically-based extraction test (PBET) is being applied to soil from contaminated land sites to assess the environmental risk to humans. Various procedures have evolved based on the use of simulated gastric and intestinal juices. This chapter evaluates one approach to assess the environmental risk to humans from soil contaminated with metals. Soil samples have been obtained from contaminated sites in N.E. England with a historic legacy of pollution from heavy metals. Initial work will assess the total metal content of soils using microwave acid digestion followed by inductively coupled plasma mass spectrometry. A PBET test is evaluated and undertaken on the soils. The results highlight the additional, or supplementary information, provided by PBET and the role bioaccessibility data might play in a site specific risk assessment.
Intellectual disability (ID) and cerebral palsy (CP) are serious neurodevelopment conditions and ... more Intellectual disability (ID) and cerebral palsy (CP) are serious neurodevelopment conditions and low birth weight (LBW) is correlated with both ID and CP. The actual causes and mechanisms for each of these child outcomes are not well understood. In this study, the relationship between bioaccessible metal concentrations in urban soil and these child conditions were investigated. A physiologically based extraction test (PBET) mimicking gastric and intestinal processes was applied to measure the bioaccessibility of four metals (cadmium (Cd), chromium (Cr), nickel (Ni), and lead (Pb)) in urban soil, and a Bayesian Kriging method was used to estimate metal concentrations in geocoded maternal residential sites. The results showed that bioaccessible metal concentrations of Cd, Ni, and Pb in the intestinal phase were statistically significantly associated with the child outcomes. Lead and nickel were associated with ID, lead and cadmium was associated with LBW, and cadmium was associated with CP. The total concentrations and stomach concentrations were not correlated to significant effects in any of the analyses. For lead, an estimated threshold value was found that was statistically significant in predicting low birth weight. The change point test was statistically significant (p value ¼ 0.045) at an intestine threshold level of 9.2 mg/kg (95% confidence interval 8.9e9.4, p value ¼ 0.0016), which corresponds to 130.6 mg/kg of total Pb concentration in the soil. This is a narrow confidence interval for an important relationship.
Ambient and indoor air pollution results in an estimated 7 million premature deaths globally each... more Ambient and indoor air pollution results in an estimated 7 million premature deaths globally each year, representing a major contemporary public health challenge, but one poorly quantified from a toxicological and source perspective. Indoor exposure represents possibly the greatest potential overall exposure, yet our indoor environments are still poorly understood, modelled and characterized. In rapidly growing cities, such as Lagos, Nigeria, environmental monitoring can play an important role in establishing baseline data, monitoring urban pollution trends and in environmental education. Classroom dust samples were collected from 40 locations from across the twenty local government areas (LGAs) of Lagos, in June 2019. The aim of the study was to assess the potential hazard posed by PTE in indoor dusts and to develop a suitable risk communication strategy to inform and educate the public, promoting environmental health literacy. Concentrations of total PTE in indoor dusts were assessed using Energy Dispersive X-Ray Fluorescence (ED-XRF) spectrometry. Oral bioaccessibility determinations using the unified BARGE method, and analysis by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) were also performed on the dust samples to determine the fraction available for absorption in the gastrointestinal tract. Results showed that the indoor dust samples were largely uncontaminated, with only few exceptions (2 samples). Enrichment factor pollution trend for the total PTE concentrations was in the order of Pb > Zn > U > Cr > Cu > Ba > Mn > V > As > Cd > Ni > Al. Source apportionment studies using factor analysis suggests concentrations of Al, As, Fe, Mn, Ni, and U may be influenced largely by lithogenic factors, while Cd, Cu and Pb originated principally from anthropogenic sources. Chromium, V and Zn appear to originate from mixed sources of both lithogenic and anthropogenic origin. Our oral bioaccessibility determinations indicate that the assumption of 100% bioavailability based on pseudototal or total concentrations would overestimate the hazard potential of PTE in these indoor dusts. Zinc was the most bioaccessible PTE (mean of 88%), with Mn (57%), Pb (48%), Ba (48%), Al (41%), As (37%), Cu (36%), Ni (28%), Cr (10%) and Fe (7%) the least bioaccessible. Human health risk assessment, for both children and adults using the bioaccessible fraction, showed values to be within acceptable risk levels. Environmental signicance Exposure to particulate matter can initiate or enhance disease in humans, yet the nature of the hazard that indoor dust presents remains poorly characterized from a toxicological and a source perspective. Our research provides key information about the spatial distributions and concentrations of contaminants in indoor dusts from school environments in Lagos, Nigeria, providing geochemical baseline information and source characterization of 12 Potentially Toxic Elements (PTE). A range of contamination assessment criteria were employed, as well as a modied approach incorporating oral bioaccessibility measurements into human exposure risk models. The online 'dust atlas' and ancillary supporting information enables participants to interactively view the levels of PTE in indoor dusts across all participating regions and the range of practical actions to improve indoor environmental quality.
We report on the concentration ranges and combustion source-related emission profiles of organic ... more We report on the concentration ranges and combustion source-related emission profiles of organic and inorganic species released during 34 major industrial fires in the UK. These episodic events tend to be acute in nature and demand a rapid public health risk assessment to indicate the likely impact on exposed populations. The objective of this paper is to improve our understanding of the nature, composition and potential health impacts of emissions from major incident fires and so support the risk assessment process. Real world monitoring data was obtained from portable Fourier Transform Infrared (FTIR) monitoring (Gasmet DX-4030/40) carried out as part of the UK's Air Quality in Major Incidents service. The measured substances include carbon monoxide, sulphur dioxide, nitrogen dioxide, ammonia, hydrogen chloride, hydrogen bromide, hydrogen fluoride, hydrogen cyanide, formaldehyde, 1,3-butadiene, benzene, toluene, xylenes, ethyl benzene, acrolein, phosgene, arsine, phosphine and methyl isocyanate. We evaluate the reported concentrations against Acute Exposure Guideline Values (AEGLs) and Emergency Response Planning Guidelines (ERPGs), as well as against UK, EU and WHO short-term ambient guideline values. Most exceedances of AEGL or ERPG guideline values were at levels likely only to cause discomfort to exposed populations (hydrogen cyanide, hydrogen chloride, hydrogen fluoride and formaldehyde), though for several substances the exceedances could have potentially given rise to more serious health effects (acrolein, phosphine, phosgene and methyl isocyanate). In the latter cases, the observed high concentrations are likely to be due to cross-interference from other substances that absorb in the mid-range of the infrared spectrum, particularly when the ground level plume is very concentrated.
In many urban contexts, non-dietary Pb exposure from street dusts may add to the overall exposure... more In many urban contexts, non-dietary Pb exposure from street dusts may add to the overall exposure burden, and the presence of high total Pb content is well documented in urban street dust from across the globe. Given the increasing recognition of the potential adverse health effects from both the quantity and the chemical and physical composition of the inhaled fraction, and the recognition that it is the soluble fraction rather than the total element content that has more direct links to health effects, attention has focused in this study on the human health risks via this exposure pathway. In order to investigate the environmental exposure to Pb from the inhalation of urban street dusts, a newly developed in vitro simulated epithelium lung fluid (SELF) has been applied to the b 10 μm fraction of urban street dusts. In this context, 21 urban street dust samples, across five UK cities, were selected based on their high pseudo-total Pb content. The work revealed that inhalation bioaccessibility, and hence inhalation dose, varied across the cities but was generally found to be low (b 10%). Indeed, the lung bioaccessibility was far lower (% lung bioaccessibility ranged from 1.2 to 8.8) than is currently applied in two of the most commonly employed risk assessment models i.e. the Integrated Exposure Uptake Biokinetic model (IEUBK, USA) and the Contaminated Land Exposure Assessment model (CLEA, UK). The estimated inhalation dose (for adults) calculated from the PM10 bioaccessibility ranged from 7 ng kg −1 BW day −1 (Edinburgh) to 1.3 ng kg −1 BW day −1 (Liverpool). The results indicate a low potential inhalation bioaccessibility for Pb in these urban street dust samples when modelled using the neutral pH conditions of the SELF.
The determination of sixteen polycyclic aromatic hydrocarbons in urban street dust has been done.... more The determination of sixteen polycyclic aromatic hydrocarbons in urban street dust has been done. Samples were collected from 12 sampling locations in a city centre location (Newcastle upon Tyne, north east England) and extracted using in situ pressurised fluid extraction followed by gas chromatography mass spectrometry. From the results it was possible to identify three groups, with respect to PAH concentration, with PAH contents ranging between 0.6-2.3 mg kg(-1), 15.6-22.5 mg kg(-1) and 36.1-46.0 mg kg(-1). The total PAH content of samples from these sampling sites has been compared to 22 urban locations around the world; comparable levels were found in these samples compared to the other cities around the world. The potential source of PAHs has been investigated by investigating the proportion of pyrogenic and petrogenic material in urban street dust using specific individual PAH ratios. The results indicate that the PAH content of urban street dust from the chosen sites are more likely to be due to pyrogenic sources i.e. vehicle exhaust emissions. The particle size fractions (<63 μm; 63-125 μm; 125-250 μm; 250-500 μm; 500-1,000 μm; and 1,000-2,000 μm) of individual PAHs in three selected sampling sites was investigated. In two of the selected sites the PAH content was independent of particle size whereas in sampling site 10 elevated PAH levels are noted in the <63 μm size fraction. Sampling site 10 is located at the junction of three road tributaries which are used as major access points to the east of the city centre. Finally, the potential health risk for unintentional consumption of PAHs was assessed in terms of a mean daily intake (based on an ingestion rate of 100 mg d(-1)). It was found that all 4-6 membered ring PAHs had concentrations in excess of the mean daily intake thereby reflecting a potential health risk, particularly in the smallest size particle fractions.
Justification Studies of interior air exposures to various human and non-human components has lar... more Justification Studies of interior air exposures to various human and non-human components has largely been restricted to industrial exposures for the purpose of regulation. In contrast, little attention has been paid to exposure at the residential scale, where people spend much of their day and may be exposed to known toxins, such as lead, arsenic, and asbestos, to human-produced chemicals of yet unknown toxicity, such as flame retardants. To capitalize on experience with citizen science initiatives as they pertain to environmental health, researchers formed an international network called 360 Dust Analysis, which provides guidance on citizen science and interior dust collection, as well as research tools to examine dust through analysis in regional labs.
Newcastle-upon-Tyne is the regional capital of NE England with a rich industrial and mining histo... more Newcastle-upon-Tyne is the regional capital of NE England with a rich industrial and mining history. Urban Agriculture Sites (UAS), known in the UK as ‘allotments’, have developed as part of urban ...
The physiologically-based extraction test (PBET) is being applied to soil from contaminated land ... more The physiologically-based extraction test (PBET) is being applied to soil from contaminated land sites to assess the environmental risk to humans. Various procedures have evolved based on the use of simulated gastric and intestinal juices. This chapter evaluates one approach to assess the environmental risk to humans from soil contaminated with metals. Soil samples have been obtained from contaminated sites in N.E. England with a historic legacy of pollution from heavy metals. Initial work will assess the total metal content of soils using microwave acid digestion followed by inductively coupled plasma mass spectrometry. A PBET test is evaluated and undertaken on the soils. The results highlight the additional, or supplementary information, provided by PBET and the role bioaccessibility data might play in a site specific risk assessment.
Intellectual disability (ID) and cerebral palsy (CP) are serious neurodevelopment conditions and ... more Intellectual disability (ID) and cerebral palsy (CP) are serious neurodevelopment conditions and low birth weight (LBW) is correlated with both ID and CP. The actual causes and mechanisms for each of these child outcomes are not well understood. In this study, the relationship between bioaccessible metal concentrations in urban soil and these child conditions were investigated. A physiologically based extraction test (PBET) mimicking gastric and intestinal processes was applied to measure the bioaccessibility of four metals (cadmium (Cd), chromium (Cr), nickel (Ni), and lead (Pb)) in urban soil, and a Bayesian Kriging method was used to estimate metal concentrations in geocoded maternal residential sites. The results showed that bioaccessible metal concentrations of Cd, Ni, and Pb in the intestinal phase were statistically significantly associated with the child outcomes. Lead and nickel were associated with ID, lead and cadmium was associated with LBW, and cadmium was associated with CP. The total concentrations and stomach concentrations were not correlated to significant effects in any of the analyses. For lead, an estimated threshold value was found that was statistically significant in predicting low birth weight. The change point test was statistically significant (p value ¼ 0.045) at an intestine threshold level of 9.2 mg/kg (95% confidence interval 8.9e9.4, p value ¼ 0.0016), which corresponds to 130.6 mg/kg of total Pb concentration in the soil. This is a narrow confidence interval for an important relationship.
Ambient and indoor air pollution results in an estimated 7 million premature deaths globally each... more Ambient and indoor air pollution results in an estimated 7 million premature deaths globally each year, representing a major contemporary public health challenge, but one poorly quantified from a toxicological and source perspective. Indoor exposure represents possibly the greatest potential overall exposure, yet our indoor environments are still poorly understood, modelled and characterized. In rapidly growing cities, such as Lagos, Nigeria, environmental monitoring can play an important role in establishing baseline data, monitoring urban pollution trends and in environmental education. Classroom dust samples were collected from 40 locations from across the twenty local government areas (LGAs) of Lagos, in June 2019. The aim of the study was to assess the potential hazard posed by PTE in indoor dusts and to develop a suitable risk communication strategy to inform and educate the public, promoting environmental health literacy. Concentrations of total PTE in indoor dusts were assessed using Energy Dispersive X-Ray Fluorescence (ED-XRF) spectrometry. Oral bioaccessibility determinations using the unified BARGE method, and analysis by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) were also performed on the dust samples to determine the fraction available for absorption in the gastrointestinal tract. Results showed that the indoor dust samples were largely uncontaminated, with only few exceptions (2 samples). Enrichment factor pollution trend for the total PTE concentrations was in the order of Pb > Zn > U > Cr > Cu > Ba > Mn > V > As > Cd > Ni > Al. Source apportionment studies using factor analysis suggests concentrations of Al, As, Fe, Mn, Ni, and U may be influenced largely by lithogenic factors, while Cd, Cu and Pb originated principally from anthropogenic sources. Chromium, V and Zn appear to originate from mixed sources of both lithogenic and anthropogenic origin. Our oral bioaccessibility determinations indicate that the assumption of 100% bioavailability based on pseudototal or total concentrations would overestimate the hazard potential of PTE in these indoor dusts. Zinc was the most bioaccessible PTE (mean of 88%), with Mn (57%), Pb (48%), Ba (48%), Al (41%), As (37%), Cu (36%), Ni (28%), Cr (10%) and Fe (7%) the least bioaccessible. Human health risk assessment, for both children and adults using the bioaccessible fraction, showed values to be within acceptable risk levels. Environmental signicance Exposure to particulate matter can initiate or enhance disease in humans, yet the nature of the hazard that indoor dust presents remains poorly characterized from a toxicological and a source perspective. Our research provides key information about the spatial distributions and concentrations of contaminants in indoor dusts from school environments in Lagos, Nigeria, providing geochemical baseline information and source characterization of 12 Potentially Toxic Elements (PTE). A range of contamination assessment criteria were employed, as well as a modied approach incorporating oral bioaccessibility measurements into human exposure risk models. The online 'dust atlas' and ancillary supporting information enables participants to interactively view the levels of PTE in indoor dusts across all participating regions and the range of practical actions to improve indoor environmental quality.
We report on the concentration ranges and combustion source-related emission profiles of organic ... more We report on the concentration ranges and combustion source-related emission profiles of organic and inorganic species released during 34 major industrial fires in the UK. These episodic events tend to be acute in nature and demand a rapid public health risk assessment to indicate the likely impact on exposed populations. The objective of this paper is to improve our understanding of the nature, composition and potential health impacts of emissions from major incident fires and so support the risk assessment process. Real world monitoring data was obtained from portable Fourier Transform Infrared (FTIR) monitoring (Gasmet DX-4030/40) carried out as part of the UK's Air Quality in Major Incidents service. The measured substances include carbon monoxide, sulphur dioxide, nitrogen dioxide, ammonia, hydrogen chloride, hydrogen bromide, hydrogen fluoride, hydrogen cyanide, formaldehyde, 1,3-butadiene, benzene, toluene, xylenes, ethyl benzene, acrolein, phosgene, arsine, phosphine and methyl isocyanate. We evaluate the reported concentrations against Acute Exposure Guideline Values (AEGLs) and Emergency Response Planning Guidelines (ERPGs), as well as against UK, EU and WHO short-term ambient guideline values. Most exceedances of AEGL or ERPG guideline values were at levels likely only to cause discomfort to exposed populations (hydrogen cyanide, hydrogen chloride, hydrogen fluoride and formaldehyde), though for several substances the exceedances could have potentially given rise to more serious health effects (acrolein, phosphine, phosgene and methyl isocyanate). In the latter cases, the observed high concentrations are likely to be due to cross-interference from other substances that absorb in the mid-range of the infrared spectrum, particularly when the ground level plume is very concentrated.
In many urban contexts, non-dietary Pb exposure from street dusts may add to the overall exposure... more In many urban contexts, non-dietary Pb exposure from street dusts may add to the overall exposure burden, and the presence of high total Pb content is well documented in urban street dust from across the globe. Given the increasing recognition of the potential adverse health effects from both the quantity and the chemical and physical composition of the inhaled fraction, and the recognition that it is the soluble fraction rather than the total element content that has more direct links to health effects, attention has focused in this study on the human health risks via this exposure pathway. In order to investigate the environmental exposure to Pb from the inhalation of urban street dusts, a newly developed in vitro simulated epithelium lung fluid (SELF) has been applied to the b 10 μm fraction of urban street dusts. In this context, 21 urban street dust samples, across five UK cities, were selected based on their high pseudo-total Pb content. The work revealed that inhalation bioaccessibility, and hence inhalation dose, varied across the cities but was generally found to be low (b 10%). Indeed, the lung bioaccessibility was far lower (% lung bioaccessibility ranged from 1.2 to 8.8) than is currently applied in two of the most commonly employed risk assessment models i.e. the Integrated Exposure Uptake Biokinetic model (IEUBK, USA) and the Contaminated Land Exposure Assessment model (CLEA, UK). The estimated inhalation dose (for adults) calculated from the PM10 bioaccessibility ranged from 7 ng kg −1 BW day −1 (Edinburgh) to 1.3 ng kg −1 BW day −1 (Liverpool). The results indicate a low potential inhalation bioaccessibility for Pb in these urban street dust samples when modelled using the neutral pH conditions of the SELF.
The determination of sixteen polycyclic aromatic hydrocarbons in urban street dust has been done.... more The determination of sixteen polycyclic aromatic hydrocarbons in urban street dust has been done. Samples were collected from 12 sampling locations in a city centre location (Newcastle upon Tyne, north east England) and extracted using in situ pressurised fluid extraction followed by gas chromatography mass spectrometry. From the results it was possible to identify three groups, with respect to PAH concentration, with PAH contents ranging between 0.6-2.3 mg kg(-1), 15.6-22.5 mg kg(-1) and 36.1-46.0 mg kg(-1). The total PAH content of samples from these sampling sites has been compared to 22 urban locations around the world; comparable levels were found in these samples compared to the other cities around the world. The potential source of PAHs has been investigated by investigating the proportion of pyrogenic and petrogenic material in urban street dust using specific individual PAH ratios. The results indicate that the PAH content of urban street dust from the chosen sites are more likely to be due to pyrogenic sources i.e. vehicle exhaust emissions. The particle size fractions (<63 μm; 63-125 μm; 125-250 μm; 250-500 μm; 500-1,000 μm; and 1,000-2,000 μm) of individual PAHs in three selected sampling sites was investigated. In two of the selected sites the PAH content was independent of particle size whereas in sampling site 10 elevated PAH levels are noted in the <63 μm size fraction. Sampling site 10 is located at the junction of three road tributaries which are used as major access points to the east of the city centre. Finally, the potential health risk for unintentional consumption of PAHs was assessed in terms of a mean daily intake (based on an ingestion rate of 100 mg d(-1)). It was found that all 4-6 membered ring PAHs had concentrations in excess of the mean daily intake thereby reflecting a potential health risk, particularly in the smallest size particle fractions.
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