Blood arsenic exposure levels of preschool children and dietary factors analysis

Objective To explore the blood arsenic exposure levels of preschool children and analyze the factors of blood arsenic. Methods By the multi-stage cluster and simple randomized method, six districts of Shanghai City was chosen and the preschool children in the selected village were asked to fill in the questionnaire and have blood sampling. Inductively coupled plasma mass spectrometry (ICP-MS) was used to detect blood arsenic, of which the data was analyzed by multiple linear regression models. Marine fish, freshwater fish, freshwater shrimp and shellfish were grouped as follows: ≤3 times per month, 1-3 times per week, and 4-6 times per week. Rice, noodles and milk were grouped as <50, 50-100, and ≥100 g/d. Results 2 263 preschool children were recruited. The range of blood arsenic was 0.12-27.94 μg/L. The median (P25, P75) were 2.26 (1.63, 3.09) μg/L. Statistical analysis showed that the more intake of rice, wheaten food, and sea fish and shrimp, the more arsenic in children’s blood (P<0.05). Whereas highter intake of freshwater fish and shrimp group showed decreased blood arsenic (P<0.05). Conclusion Most preschool children’s blood arsenic levels (92.4%, 2 091/2 263) were at normal level (<5 μg/L). There was a positive correlation between blood arsenic concentration and the intake of rice, wheaten food, and sea fish and shrimp, while negative correlation with high freshwater fish and shrimp consumption

Predictive modeling of indoor dust lead concentrations: Sources, risks, and benefits of intervention

Lead (Pb) contamination continues to contribute to world-wide morbidity in all countries, particularly low- and middle-income countries. Despite its continued widespread adverse effects on global populations, particularly children, accurate prediction of elevated household dust Pb and the potential implications of simple, low-cost household interventions at national and global scales have been lacking. A global dataset (∼40 countries, n = 1951) of community sourced household dust samples were used to predict whether indoor dust was elevated in Pb, expanding on recent work in the United States (U.S.). Binned housing age category alone was a significant (p < 0.01) predictor of elevated dust Pb, but only generated effective predictive accuracy for England and Australia (sensitivity of ∼80%), similar to previous results in the U.S. This likely reflects comparable Pb pollution legacies between these three countries, particularly with residential Pb paint. The heterogeneity associated with Pb pollution at a global scale complicates the predictive accuracy of our model, which is lower for countries outside England, the U.S., and Australia. This is likely due to differing environmental Pb regulations, sources, and the paucity of dust samples available outside of these three countries. In England, the U.S., and Australia, simple, low-cost household intervention strategies such as vacuuming and wet mopping could conservatively save 70 billion USD within a four-year period based on our model. Globally, up to 1.68 trillion USD could be saved with improved predictive modeling and primary intervention to reduce harmful exposure to Pb dust sources

Environmental and geochemical analysis of lead contamination: its sources and pathways of exposure and impact on children

Thesis by publication.Bibliography: pages 323-346.Chapter 1. Introduction -- Chapter 2. Study area -- Chapter 3. Applying geochemical signatures and SEM methods to identify contamination sources of mining and smelting community -- Chapter 4. Blood Pb and its response to environmental Pb -- Chapter 5. Influences of contemporary mining activities on childhood blood Pb and dust Pb deposits in Broken Hill -- Chapter 6. Influences of environmental contamination on the children educational and behavioural performance -- Chapter 7. Discussion -- Chapter 8. Conclusion -- Appendices.Resolving the source of environmental contamination is a critical first step in planning remediation and intervention strategies to adduce exposure prevention. However, a major challenge in established mining and smelting communities is that the sources of contamination and related potential health risks are often minimised by polluters and government agencies, often using unsupported scientific claims. A significant and longstanding example of this vexed issue is the protracted dispute over contamination sources and causes of childhood blood Pb exposures in Broken Hill (New South Wales), Australia's longest-operating Pb-Ag-Zn mining city.In order to unravel the sources, causes and impacts of contemporary Pb contamination in Broken Hill, this study applied a multiple lines of evidence approach using a combination of geochemical analyses and human health data. The methods applied included analysis of trace element concentrations in soil, dust, tailing dumps and weathered ores, their Pb isotopic and chemical compositions and the morphological characteristics of individual Pb-rich particles. The results demonstrated that Broken Hill contemporary dust Pb deposits were primarily sourced from current mining emissions as opposed to naturally weathered or legacy source sheld in soil and dust around the city. Children living closest to the mining operations were found to be at an increased risk of Pb exposure due to higher dust Pb loading (mean 255μg/m2/day) and its high bioaccessibility (75% of total Pb). The effects of current mining emissions on the contemporary dust Pb loading were quantitatively estimated. The analysis showed that a 1% increase in distance away from the current mining operations was associated with -0.501% (95% CI: -0.728, -0.275) reduction in dust Pb loading, while a 1% increase in production intensity at the mine increased the expected amount of dust Pb loading by 1.487% (95% CI: 0.537, 2.437%).Consistent with the dust Pb decreasing with distance away from current active mining operations, contemporary blood Pb concentrations (2011-2015) also decreased with distance (i.e. 1% increase in distance was associated with a 0.173% reduction in blood Pb concentration). Soil Pb concentrations, which are a proxy for legacy contamination from atmospheric dust depositions across the city also showed a decreasing trend away from the mining operations. Consequently, analysis of the long-term relationship between environmental Pb and blood Pb (1991-2015) revealed that both soil and dust Pb were significantly correlated with blood Pb concentrations, complicating the specific attribution of these individual sources to blood Pb exposure. To quantify the relevant sources of Pb, two 'natural experiments' were examined to separate the specific role of dust and soil Pb on children's blood Pb exposures: (a) the city's northerly prevailing wind direction; (b) the 2009 dust storm that blanketed Broken Hill soil with desert borne sands, rich in crustal elements Al, Si and Fe. The analyses showed that children living within the prevailing wind direction were at the greatest risk of elevated blood Pb compared to those living in a non-prevailing wind direction, even after adjusting for effects of residential soil Pb contamination. The role of current emissions on driving exposures was further corroborated by the fact that children's blood Pb shifted systematically with mine Pb production volumes irrespective of remedial interventions. The second natural experiment, the 2009 dust storm, showed blood Pb concentrations still decreased with distance even though soil Pb-distance gradient was reduced after the dust storm. Generalised linear regression analysis of contemporary outdoor dust Pb deposits and blood Pb concentrations corroborated dust as being a significant driver of childhood Pb exposures.This thesis research confirms that soil Pb on its own cannot explain blood Pb distributions and that dust Pb depositions are a significant factor in driving contemporary exposures. This finding provides evidence-based support for the mitigation and remediation approaches that are likely to be the most effective in terms of reducing blood Pb exposures in children-these being a clear need to control current mining emissions in Broken Hill as has been identified in Australia's other mining and smelting communities of Mount Isa and Port Pirie. The adverse consequences of not implementing evidence-based and targeted mitigation and remediation strategies on childhood development outcomes were also evaluated in the thesis. Early childhood development indices (i.e. developmental vulnerabilities-Australian Early Development Census data; school test scores-National Assessment Program Literacy and Numeracy) showed that children from the most contaminated areas in Broken Hill had lower educational performance and higher developmental vulnerabilities, even when normalised for socio-economic status. Similarly, poor scores were identified for Australia's other Pb processing locations of Mount Isa (Queensland) and Port Pire (South Australia), indicating the urgent need to implement the highest standards to limit the impact of mining and smelting Pb emissions on adjoining communities. Finally, application of a multiple lines of evidence as used in this thesis research to establish more precisely the source(s) of exposure in mining and smelting communities could be applied to other locations. Such an approach would help to address unequivocally extant disputes over the sources, causes and impacts of environmental Pb contamination in order to better target remediation and prevention strategies.Mode of access: World wide web1 online resource (xii, 251 pages) illustrations (some colour), colour map

Magnetic fingerprinting of hydrodynamic variations and channel erosion across the turbidity maximum zone of the Yangtze Estuary, China

12 page(s

Environmental contamination in an Australian mining community and potential influences on early childhood health and behavioural outcomes

Arsenic, cadmium and lead in aerosols, dusts and surface soils from Australia's oldest continuous lead mining town of Broken Hill were compared to standardised national childhood developmental (year 1) and education performance measures (years 3,5,7,9). Contaminants close to mining operations were elevated with maximum lead levels in soil: 8900 mg/kg; dust wipe: 86,061 μg/m²; dust deposition: 2950 μg/m²/day; aerosols: 0.707 μg/m³. The proportion of children from Broken Hill central, the area with the highest environmental contamination, presented with vulnerabilities in two or more developmental areas at 2.6 times the national average. Compared with other school catchments of Broken Hill, children in years 3 and 5 from the most contaminated school catchment returned consistently the lowest educational scores. By contrast, children living and attending schools associated with lower environmental contamination levels recorded higher school scores and lower developmental vulnerabilities. Similar results were identified in Australia's two other major lead mining and smelting cities of Port Pirie and Mount Isa.12 page(s

A Magnetic Record of Heavy Metal Pollution in the Yangtze River Subaqueous Delta

The rapid industrial development in the Yangtze River watershed over the last several decades has drawn great attention with respect to heavy metal pollution to the Yangtze River estuary and nearby coastal areas. In this study, a 236cm long sediment core was retrieved from the Yangtze River subaqueous delta (122°36\u27 E, 31°00\u27 N) in 2008 and analyzed for magnetic properties and geochemical compositions to investigate heavy metal pollution history. The activity of 137Cs peaked at depth 140cm, with a broad plateau between 120cm and 140cm, suggesting an average sedimentation rate of 3.11cmyr-1 for the upper 140cm layer. Magnetic susceptibility (χ), saturation isothermal remanent magnetization (SIRM), anhysteretic remanent magnetization (χARM) and heavy metal enrichment factors (EF) all showed an upward increase trend above depth 140cm, suggesting that increased ferrimagnetic mineral concentration was accompanied by heavy metal enrichment in the sediment. Geochemical and granolumetric analyses showed that sediment sources and particle sizes played minor roles in the variations of magnetic properties. The effect of diagenesis, which can lead to the selective removal of magnetic minerals, was noticeable in the lower part of the core (140-236cm). Co-variation between magnetic properties (χ, SIRM and χARM) and EF of Cu and Pb suggests that the elevated ferrimagnetic mineral concentration can be used as an indicator of heavy metal pollution in the reconstruction of environmental changes in estuarine and coastal settings

Magnetic and Geochemical Evidence of Yellow and Yangtze River Influence on Tidal Flat Deposits in Northern Jiangsu Plain, China

The formation of a broad tidal flat along the coast of the northern Jiangsu Province of China depends largely on the sediment supply from the Yellow and Yangtze Rivers although the relative contributions from each of these two large rivers remain uncertain. Knowledge of sediment sources to the tidal flat is critical for understanding the evolution of this muddy coast impacted by the large rivers. The present study focuses on tracking the sediment source of the tidal flat deposits based on sediment magnetic properties and geochemical analyses as well as statistical analysis. The study shows that sediments to the north of Yangkougang (site 9) have lower values of saturation isothermal remanence magnetization (SIRM), magnetic susceptibility (χ), demagnetization parameter S -100 ratios, lower Fe/Al values and higher Ca concentrations, while the opposite is true for samples south to Haozhigang (site 18). In addition, SIRM values of the \u3c16μm and \u3e63μm fractions generally display increasing trend from north to south. These results suggest that sediment sources rather than particle size variation are the dominant factors influencing the bulk magnetic properties. In light of the sediment composition comparison between the Yellow River and Yangtze River, factor analysis is used to identify sediment source of the tidal flat sediments. It is indicated that the Yellow River in its former course is the dominant supplier for sites to the north of Yangkougang (site 9), while the Yangtze River is the dominant supplier for sites to the south of Haozhigang (site 18). The coast between Yangkougang (site 9) and Haozhigang (site 18) is a transition zone influenced by both rivers. The inferred provenance contrasts are consistent with the pattern of coastal geomorphological evolution. Our data also suggest that sediments eroded from the former Yellow River delta have contributed to the evolution of the Yangtze Estuary in historical time. This study demonstrates that a combined magnetic and geochemical fingerprinting techniques in couple with statistical analysis is valuable for identifying sediment sources of tidal flats and deltas influenced by large rivers in the world

Tracing Sediment Erosion in the Yangtze River Subaqueous Delta Using Magnetic Methods

We assessed the usefulness of magnetic properties for tracing sediment erosion in a deltaic environment. Surface and core sediments from the Yangtze River subaqueous delta were subjected to magnetic, granulometric, geochemical, and radionuclide analyses. Based on magnetic properties and particle size, the surface sediments can be divided into three groups. Groups I and II have a similar particle size distribution and geochemical composition, but the former has higher values of magnetic susceptibility (χ) and saturation isothermal remanent magnetization (SIRM). We interpret Group I as consisting of modern sediments, while Group II represents previously buried sediments that have undergone significant reductive diagenesis and that have been subsequently exposed by erosion. Group III has coarser particle size, which reflects the mixing of delta sediments with Pleistocene relict sands. Two cores from the areas occupied by Groups I and II have significantly different magnetic profiles. Core A3-4 (Group II) records a partial loss of magnetic mineral concentration due to diagenesis and has much lower χ, SIRM, and S −300 values than core A6-2 (Group I). Radionuclide dating reveals that core A3-4 sediments are older. We conclude that core A3-4 location has undergone erosion, which is consistent with recent bathymetric survey results. We propose that the ratio of SIRM/Fe can be potentially used to trace mobilized old sediment in this environment. Our study demonstrates that magnetic properties provide a robust approach for studying sediment dynamics in this type of environment. In addition, our findings provide insights into the nature of biogeochemical processes associated with deltaic erosion

Magnetic mineral diagenesis in the river-dominated inner shelf of the East China Sea, China

The inner shelf of the East China Sea is a river-dominated margin characterized by fine-grained mud deposits and a rapid sedimentation rate. Three short sediment cores (similar to 2.7m in length) were examined to characterize spatial variations in magnetic mineral diagenesis. The sediment cores were analyzed for sedimentation rates, magnetic properties, particle size distribution, organic carbon, and total sulfur content. The two more proximal cores with higher sedimentation rates (similar to 2.2cm/yr and similar to 0.96cm/yr) do not exhibit obvious effects of reductive dissolution of magnetite with increasing depth, which is consistent with their lower total sulfur content. The offshore core, A12-4, which has a lower sedimentation rate, contains clear evidence of magnetite dissolution and increasing total sulfur content with depth. The three cores have a similar sediment source and organic matter input; therefore, we suggest that a higher sedimentation rate will lead to less reductive diagenesis of magnetite, assuming that other factors are constant. The iron- to sulfate-reduction boundary, i.e., revealed by the onset of a rapid decline of magnetic susceptibility, is located 1.0m below seafloor in core A12-4. This is much deeper than is reported in many other coastal marine environments and can be explained by the higher sedimentation rate, the presence of refractory terrestrial organic matter, and an abundant input of detrital iron oxides. This study demonstrates that analyses of the magnetic mineral zonation provide a straightforward approach to assess diagenetic organic carbon decomposition pathways in marine environments