Louise Jane Kristensen

Environmental arsenic, cadmium and lead dust emissions from metal mine operations: Implications for environmental management, monitoring and human health

Although blood lead values in children are predominantly falling globally, there are locations where lead exposure remains a persistent problem. One such location is Broken Hill, Australia, where the percentage of blood lead values >10 μg/dL in children aged 1-4 years has risen from 12.6% (2010), to 13% (2011) to 21% (2012). The purpose of this study was to determine the extent of metal contamination in places accessible to children. This study examines contemporary exposure risks from arsenic, cadmium, lead, silver and zinc in surface soil and dust, and in pre- and post-play hand wipes at six playgrounds across Broken Hill over a 5-day period in September 2013. Soil lead (mean 2,450 mg/kg) and zinc (mean 3,710 mg/kg) were the most elevated metals in playgrounds. Surface dust lead concentrations were consistently elevated (mean 27,500 μg/m(2)) with the highest lead in surface dust (59,900 μg/m(2)) and post-play hand wipes (60,900 μg/m(2)) recorded close to existing mining operations. Surface and post-play hand wipe dust values exceeded national guidelines for lead and international benchmarks for arsenic, cadmium and lead. Lead isotopic compositions ((206)Pb/(207)Pb, (208)Pb/(207)Pb) of surface dust wipes from the playgrounds revealed the source of lead contamination to be indistinct from the local Broken Hill ore body. The data suggest frequent, cumulative and ongoing mine-derived dust metal contamination poses a serious risk of harm to children.

Estimates of potential childhood lead exposure from contaminated soil using the US EPA IEUBK Model in Sydney, Australia

ABSTRACT Surface soils in portions of the Sydney (New South Wales, Australia) urban area are contaminated with lead (Pb) primarily from past use of Pb in gasoline, the deterioration of exterior lead‐based paints, and industrial activities. Surface soil samples (n=341) were collected from a depth of 0–2.5 cm at a density of approximately one sample per square kilometre within the Sydney estuary catchment and analysed for lead. The bioaccessibility of soil Pb was analysed in 18 samples. The blood lead level (BLL) of a hypothetical 24 month old child was predicted at soil sampling sites in residential and open land use using the United States Environmental Protection Agency (US EPA) Integrated Exposure Uptake and Biokinetic (IEUBK) model. Other environmental exposures used the Australian National Environmental Protection Measure (NEPM) default values. The IEUBK model predicted a geometric mean BLL of 2.0±2.1 &mgr;g/dL using measured soil lead bioavailability measurements (bioavailability =34%) and 2.4±2.8 &mgr;g/dL using the Australian NEPM default assumption (bioavailability =50%). Assuming children were present and residing at the sampling locations, the IEUBK model incorporating soil Pb bioavailability predicted that 5.6% of the children at the sampling locations could potentially have BLLs exceeding 5 &mgr;g/dL and 2.1% potentially could have BLLs exceeding 10 &mgr;g/dL. These estimations are consistent with BLLs previously measured in children in Sydney. Highlights341 surface soil samples from Sydney were analysed for lead concentrations.Soil absolute bioavailability calculated at 34±5%.IEUBK model predicted a geometric mean BLL of 2.0±2.1 &mgr;g/dL.Modelling predicts 5.6% of the BLLs exceed 5 &mgr;g/dL and 2.1% exceed 10 &mgr;g/dL.Predicted IEUBK BLLs mirror childhood BLL from between 2002 and 2006.

Handheld X-ray Fluorescence Spectrometers: Radiation Exposure Risks of Matrix-Specific Measurement Scenarios:

This study investigates X-ray intensity and dispersion around handheld X-ray fluorescence (XRF) instruments during the measurement of a range of sample matrices to establish radiation exposure risk during operation. Four handheld XRF instruments representing three manufacturers were used on four smooth, flat-lying materials of contrasting matrix composition. Dose rates were measured at 10, 20, 30, and 40 cm intervals every 30° around the instrument at 0 and 45° from the horizontal, as well as vertically from the instrument screen. The analysis of polyethylene recorded dose rates 156 times higher (on average) than steel measurements and 34 times higher than both quartz sand and quartz sandstone. A worst-case exposure scenario was assumed where a user analyses a polyethylene material at arms reach for 1 h each working day for one year. This scenario resulted in an effective body dose of 73.5 μSv, equivalent to three to four chest X-rays (20 μSv) a year, 20 times lower than the average annual background radiation exposure in Australia and well below the annual exposure limit of 1 mSv for non-radiation workers. This study finds the advantages of using handheld XRF spectrometers far outweighs the risk of low radiation exposure linked to X-ray scattering from samples.

Reply to Gulson's comments on 'Tracing changes in atmospheric sources of lead contamination using lead isotopic compositions in Australian red wine'.

a Department of Environmental Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, North Ryde, NSW 2109, Australia b Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA c Macquarie University Energy and Environmental Contaminants Research Centre, Sydney, North Ryde, NSW 2109, Australia d National Measurement Institute, Department of Industry, Innovation and Science, 105 Delhi Road, North Ryde, NSW 2113, Australia

Fields and forests in flames: lead and mercury emissions from wildfire pyrogenic activity.

In the article “Fields and Forests in Flames,” Weinhold (2011) addressed the toxic health effects associated with fire smoke. Although he acknowledged the limited data on the toxicity of wildfires, several important studies on environmental emissions from fire events and their consequences were omitted. Weinhold (2011) listed multiple compounds from wildfires, back burning, and incinerated buildings, but listed only four elements: potassium, chlorine, sulfur, and silicon. Significant omissions were the toxic elements lead and mercury. Lead has been identified as one of the most environmentally pervasive and damaging metals to human health (Patterson 1965). Several studies have detailed the remobilization of metals from fire events (e.g., Finley et al. 2009; Nriagu 1989; Odigie and Flegal 2011; Young and Jan 1977). These studies showed that significant levels of toxic and nontoxic metals are emitted into the environment during fires. Young and Jan (1977) found that smoke from a 1975 Californian wildfire emitted various metals, including cadmium, chromium, copper, iron, lead, manganese, nickel, silver, and zinc, up to 100 km from the fire. Contamination of local marine waters with lead, iron, and manganese from the wildfire exceeded the polluting effects of the local municipal wastewater, the main source of metals. Nriagu (1989) and Finley et al. (2009) estimated that the amount of lead (plus other trace metals) and mercury, respectively, from fires were comparable to emissions from anthropogenic sources such as industrial processes and city pollution. Nriagu (1989) estimated that global emissions of lead from wildfires ranged from 60,000 to 3,800,000 kg/year, with an average of 1,900,000 kg/year. Global mercury emissions from wildfires are also significant, estimated at 890,000 ± 490 kg/year for gaseous elemental mercury and 170 ± 100 kg/year for particulate-bound mercury (Finley et al. 2009). Until recently it was not known whether lead released by wildfires is from natural and or industrial sources. Odigie and Flegal (2011) measured the isotopic lead composition of ash from the 2009 Jesusita Fire in Southern California. Their work showed clearly that the ash from the wildfire contained industrial lead primarily from leaded gasoline used in Southern California during the 1960s through the 1980s. Environmental media, such as air, dust, sediment, soil, and water, have well-defined and strict environmental and human health guidelines because of their damaging effect on natural and anthropogenic systems. Even low levels of atmospheric lead emissions are known to cause adverse human health effects, including irreversible neurological damage. For example, the U.S. Environmental Protection Agency (EPA) recently reduced the lead-in-air guideline by an order magnitude—from 1.5 µg/m3 to 0.15 µg/m3—after reviewing > 6.000 human health–lead-related studies (U.S. EPA 2008). Although pyrogenic activity affects environmental quality, its effects remain ill-defined, despite evidence of harmful human health effects from exposure to toxicants, even at very low levels (Lanphear et al. 2005). The risk from fires is likely to increase as the frequency of climatically driven fire events rises in response to predicted global warming (Intergovernmental Panel on Climate Change 2007). The predicted environmental changes present a significant research opportunity for those interested in monitoring the biogeochemical cycling of metals and their potential risk of harm to human and environmental health systems.