Biological contaminants in the built environment and their health implications

The building environment provides ecological niches for the development of biological agents. Dr Singh describes how investigations can provide a better understanding of building-related sickness and comments on how non-destructive environmental control strategies can be effective.     

Soil metal concentrations and toxicity: Associations with distances to industrial facilities and implications for human health

Urban and rural areas may have different levels of environmental contamination and different potential sources of exposure. Many metals, i.e., arsenic (As), lead (Pb), and mercury (Hg), have well-documented negative neurological effects, and the developing fetus and young children are particularly at risk. Using a database of mother and child pairs, three areas were identified: a rural area with no increased prevalence of mental retardation and developmental delay (MR/DD) (Area A), and a rural area (Area B) and an urban area (Area C) with significantly higher prevalence of MR/DD in children as compared to the state-wide average. Areas were mapped and surface soil samples were collected from nodes of a uniform grid. Samples were analyzed for As, barium (Ba), beryllium (Be), chromium (Cr), copper (Cu), Pb, manganese (Mn), nickel (Ni), and Hg concentrations and for soil toxicity, and correlated to identify potential common sources. ArcGIS^® was used to determine distances between sample locations and industrial facilities, which were correlated with both metal concentrations and soil toxicity. Results indicated that all metal concentrations (except Be and Hg) in Area C were significantly greater than those in Areas A and B (p ≤ 0.0001) and that Area C had fewer correlations between metals suggesting more varied sources of metals than in rural areas. Area C also had a large number of facilities whose distances were significantly correlated with metals, particularly Cr (maximum r = 0.33; p = 0.0002), and with soil toxicity (maximum r = 0.25; p = 0.007) over a large spatial scale. Arsenic was not associated with distance to any facility and may have a different anthropogenic, or natural source. In contrast to Area C, both rural areas had lower concentrations of metals, lower soil toxicity, and a small number of facilities with significant associations between distance and soil metals.     

Environmental stressors,urban design and planning: implications for human behaviour and health

Urban and neighbourhood design can moderate the effects of building design on human behaviour and well-being, and vice versa. The interdependence between built environments across scales is critical yet is often poorly understood. This paper overviews several psychological processes linking human behaviour to environmental design, both inside and out. In particular, the paper focuses on two environmental stressors ? crowding and noise ? in four daily indoor environments: residential, school, work and commuting. These two stressors are often linked and can adversely impact people if improperly designed. Moreover, urban and neighbourhood design can mitigate such negative effects. Key suggestions for practitioners and policy makers include proper acoustic design, easily accessible semi-public or outdoor places and walkable streets. Some illustrations of the nexus between neighbourhood and building design show that the tendency of research traditions in environment and behaviour to focus on one scale of environmental design probably misses important human-environment transactions.     

Total and inorganic arsenic in the fauna of the Guadalquivir estuary: environmental and human health implications

To evaluate the impact on fauna of the release of toxic waste from the tailings dam operated by the Boliden Apirsa S.L company at Aznalcóllar, Seville (Spain) a study was carried out of total and inorganic arsenic contents in 164 samples from six different estuary species, including molluscs, crustaceans and fish, collected at six sampling stations distributed along the estuary and mouth of the River Guadalquivir. The contents found, expressed in micrograms per gram wet weight, were as follows. Total arsenic: Crassostrea angulata--giant cupped oyster (2.44 +/- 0.45); Scrobicularia plana--peppery furrow (2.50 +/- 0.73); Palaemon longirostris--delta prawn (1.33 +/- 0.54); Uca tangeri--AfroEuropean fiddler crab (1.76 +/- 0.08); Melicertus kerathurus--shrimp (3.60 +/- 1.92); and Liza ramada--mullet (0.65 +/- 0.38). Inorganic arsenic: C. angulata (0.09 +/- 0.02); S. plana (0.38 +/- 0.23); P. longirostris (0.04 +/- 0.01); U. tangeri (0.22 +/- 0.03); M. kerathurus (0.03 +/- 0.01); and L. ramada (0.03 +/- 0.03). The levels of total As are comparable to those obtained by other authors. With respect to inorganic arsenic, only S. plana and U. tangeri present high levels of inorganic arsenic. This may be due to the fact that these organisms live in estuary sediments, reservoirs of inorganic arsenic, and ingest particles of sediments during feeding. Because of the lack of information for this area concerning previous levels of total and inorganic arsenic in the species analysed, it was not possible to establish the impact on the fauna of the River Guadalquivir estuary of the toxic spill resulting from the failure of the mine tailings dam at Aznalcóllar. With respect to the implications to human health as a result of consumption of species from the Guadalquivir estuary, only with the species Scrobicularia plana, as a high consumption of this mollusc might, in some cases, exceed the maximum tolerable intake for inorganic arsenic indicated by the FAO/WHO. Consumption of the liver of L. ramada does not appear to present problems to human health.     

Depleted uranium contamination by inhalation exposure and its detection after approximately 20 years: implications for human health assessment

Inhaled depleted uranium (DU) aerosols are recognised as a distinct human health hazard and DU has been suggested to be responsible in part for illness in both military and civilian populations that may have been exposed. This study aimed to develop and use a testing procedure capable of detecting an individual's historic milligram-quantity aerosol exposure to DU up to 20 years after the event. This method was applied to individuals associated with or living proximal to a DU munitions plant in Colonie New York that were likely to have had a significant DU aerosol inhalation exposure, in order to improve DU-exposure screening reliability and gain insight into the residence time of DU in humans. We show using sensitive mass spectrometric techniques that when exposure to aerosol has been unambiguous and in sufficient quantity, urinary excretion of DU can be detected more than 20 years after primary DU inhalation contamination ceased, even when DU constitutes only approximately 1% of the total excreted uranium. It seems reasonable to conclude that a chronically DU-exposed population exists within the contamination 'footprint' of the munitions plant in Colonie, New York. The method allows even a modest DU exposure to be identified where other less sensitive methods would have failed entirely. This should allow better assessment of historical exposure incidence than currently exists.     

Spatially-resolved spray measurements and their implications

Fire sprinkler manufacturers have developed a great variety of application specific sprinkler designs. Advances in product development practices, performance based design, risk analysis, and fire suppression research have increased stakeholder interest in quantifying the spray produced by these devices. These sprinkler spray patterns consist of complex spatio-stochastic features originating near the sprinkler head. A Spatially-resolved Spray Scanning System (4S) has been developed to capture the complete spatio-stochastic nature of the spray at its point of origin for documentation and analysis. The 4S synthesizes spray measurements, transport analysis, and statistical representation frameworks providing high-fidelity spray characteristics suitable for evaluation of component-level performance (e.g. sprinkler spray pattern uniformity) or system-level performance (e.g. fire suppression system simulations). Each sprinkler's unique spray pattern is captured through optical and mechanical probing of the spray over a measurement (or initialization) surface close to the sprinkler head (0.4−0.8 m) and analyzing local drop characteristics (e.g. drop size, velocity, and volume flux). These high-fidelity 4S spray measurements consisting of terabyte scale data densities present remarkable challenges with regard to data management, test repeatability, and test timing. These challenges are addressed through integration of automation, flow control, data acquisition, and data analysis systems. Spatially-resolved sprinkler spray measurements are presented providing insight into the sprinkler spray patterns and their connection with deflector geometry. Comparisons between far-field spray dispersion measurements and simulations initialized with 4S measurements demonstrate unprecedented agreement further highlighting the value of spatially-resolved sprinkler measurements for modern suppression analysis.     

Adelaide's aged population: Changing spatial patterns and their policy implications

Abstract

The number of older persons living in Adelaide's middle and inner suburbs increased significantly between 1971 and 1981. Siumultaneously, many inner suburbs experienced a decline in the number of older residents, though old people continued to make up a large proportion of their total populations and the inner areas commanded a disproportionate share of resources for the aged. This paper examines, with the aid of two local case studies, the nature and causes of these changes, and analyses their policy implications.     

Microbiology of pond ecosystems in rural Bangladesh: its public health implications

In rural Bangladesh various components of four ponds, including aquatic plants, snails, water, oysters, and sediment were studied for faecal contamination for three years, from July 1994, to June 1997. Faecal coliform counts ranged from 2.80–5.45, 2.95–5.64, 1.49–2.05, 2.51–4.60 and 1.30–3.15 log₁₀cfu/gm or ml in plant, snail, water, oyster and sediment samples respectively during the study period. Snail and sediment samples showed highest and lowest counts, respectively. All components of the studied ponds included in this study yielded coliform counts higher than the accepted limit for potability and domestic use, as recommended by the WHO. Therefore these ponds have a high potential for transmission of diarrhoeal and other water‐borne diseases.     

Contributions to “Soils and Foundations”: Ground Improvement

To date, numerous ground improvement techniques have been developed and applied to various types of ground for various improvement purposes. However, they were not developed at the same time, but were developed and applied one by one according to social demands and the development of society. As the development ground improvement techniques improved and such techniques came to used more widely, a great deal of research effort was devoted to their design, execution, quality control and quality assurance, with the results published in many journals and conference proceedings. Soils and Foundations has published a large number of papers related to ground improvement. This article introduces a brief historical review of the development of ground improvement techniques, and then highlights the major papers published in Soils and Foundations over the last 50 years.     

Determination of the bioaccessibility of chromium in Glasgow soil and the implications for human health risk assessment

The Unified Bioaccessibility Method (UBM), which simulates the fluids of the human gastrointestinal tract, was used to assess the oral bioaccessibility of Cr in 27 Glasgow soils. These included several contaminated with Cr(VI), the most toxic form of Cr, from the past disposal of chromite ore processing residue (COPR). The extraction was employed in conjunction with the subsequent determination of the bioaccessible Cr by ICP-OES and Cr(VI) by the diphenylcarbazide complexation colorimetric procedure. In addition, Cr(III)-containing species were determined by (i) HPLC-ICP-MS and (ii) ICP-OES analysis of gel electrophoretically separated components of colloidal and dissolved fractions from centrifugal ultrafiltration of extracts. Similar analytical procedures were applied to the determination of Cr and its species in extracts of the < 10 μm fraction of soils subjected to a simulated lung fluid test to assess the inhalation bioaccessibility of Cr.The oral bioaccessibility of Cr was typically greater by a factor of 1.5 in the ‘stomach’ (pH ~ 1.2) compared with the ‘stomach + intestine’ (pH ~ 6.3) simulation. On average, excluding two COPR-contaminated soil samples, the oral bioaccessibility (‘stomach’) was 5% of total soil Cr and, overall, similar to the soil Cr(VI) concentration. Chromium(VI) was not detected in the extracts, a consequence of pH- and soil organic matter-mediated reduction in the ‘stomach’ to Cr(III)-containing species, identified as predominantly Cr(III)-humic complexes. Insertion of oral bioaccessible fraction data into the SNIFFER human health risk assessment model identified site-specific assessment criteria (for residential land without plant uptake) that were exceeded by the soil total Cr (3680 mg kg^-1) and Cr(VI) (1485 mg kg^-1) concentration at only the most COPR-Cr(VI)-contaminated location. However, the presence of measurable Cr(VI) in the < 10 μm fraction of the two most highly Cr(VI)-contaminated soils demonstrated that inhalation of Cr(VI)-containing dust remains the most potentially harmful exposure route.     

Polychlorinated biphenyls in indoor dust from urban dwellings of Lahore,Pakistan: Congener profile,toxicity equivalency,and human health implications

This study is the pioneer assessment of the PCBs in indoor dust particles (from air conditioners) of an urbanized megacity from South Asian. The ∑₃₅ PCB concentration ranged from 0.27 to 152.9 ng/g (mean: 24.84 ± 22.10 ng/g). The tri- and tetra-PCBs were dominant homologues, contributing 57.36% of the total PCB concentrations. The mean levels of Σ₈-dioxin-like (DL), Σ₆-indicator PCBs and WHO₂₀₀₅-TEQ for DL-PCBs were 2.22 ± 2.55 ng/g, 9.49 ± 8.04 ng/g and 4.77 ± 4.89 pg/g, respectively. The multiple linear regression indicated a significant correlation of dusting frequency (p = 1.06 × 10–04) and age of the house (p = 1.02 × 10–06) with PCB concentrations in indoor environment. The spatial variation of PCB profile revealed relatively higher concentrations from sites near to illegal waste burning spots, electrical locomotive workshops, and grid stations. Human health risk assessment of PCBs for adults and toddlers through all three exposure routes (ie, inhalation, ingestion, and dermal contact) demonstrated that toddlers were vulnerable to high cancer risk (4.32 × 10⁻⁰⁴), while adults were susceptible from low to moderate levels of risk (3.16 × 10⁻⁰⁵). Therefore, comprehensive investigations for PCBs in the indoor settings, focusing particularly on the sensitive populations with relationship to the electronic devices, transformers, and illegal waste burning sites, are recommended.     

DDT and human health

1,1,1-Trichloro-2,2'bis(p-chlorophenyl) ethane (DDT) was the first widely used synthetic pesticide and is extremely persistent in both the environment and the human body. The introduction of DDT revolutionised agricultural production and has been credited with the elimination of malaria from the United States and Europe. However, DDT is also known to have had major environmental consequences and has been associated with dramatic declines in many animal populations. Although DDT use has generally been restricted since the early 1970s, exposure to the pesticide remains widespread. In developed countries, slow elimination from the body means a large proportion of the population still have detectable levels of DDT, or its metabolite DDE, in their serum or adipose tissue. In developing countries, the pesticide continues to be used for vector control and a significant proportion of breast-fed babies has daily intakes above recommended levels. This review considers the epidemiological evidence for possible adverse effects of human exposure to DDT. Much of this research is weakened by methodological flaws. However, recent methods in breast cancer research using nested studies in cohorts with stored biological samples have allowed a more rigorous assessment of a putative role for DDT in disease aetiology. While DDT does not appear to play a causative role in breast cancer development, there is suggestive evidence for a role in the aetiology of other conditions such as pancreatic cancer, neuropsychological dysfunction, and reproductive outcomes. Research into these and other conditions would benefit from the same rigorous approaches used in breast cancer research. Until further high quality evidence is available, it is still too early, even 60 years after the introduction of this once ubiquitous chemical, to pass judgement on the role of DDT in a number of common diseases.     

不同质地土对氟在土中运移规律的影响研究

采用垂直土柱易混置换法,就不同质地及不同的加溶质方式对氟在土中运移规律的影响进行了研究,结果表明:氟在黏粒含量高的土中的水动力弥散系数和阻滞因子均大于黏粒含量低的土,在溶质注入方式上,同时加NaF和NaCl混合液比单独加NaF溶液在浓度峰值到达时间上要来得慢些,浓度峰值也小,但在解吸过程中合加NaF溶液时淋出氟的浓度比单加溶液时要大。