Peppered with lead: An environmental forensics approach to identify the source of rising blood lead levels.

Despite the phase-out of lead-based products, lead contamination can still present a contemporary risk to public health. In situations where elevated blood lead cannot be attributed to common sources, detailed environmental investigation is needed to identify more elusive sources and manage harmful exposure pathways. We apply a forensics approach to assess common and elusive sources of lead in the home environment of two individuals with fluctuating blood lead levels in Sydney, Australia. Using multiple analytical lines of evidence (portable X-Ray Fluorescence spectrometry (pXRF), inductively coupled-plasma mass spectrometry (ICP-MS), lead isotopic compositional analysis (PbIC) and haematological assessment) a pewter pepper grinder containing lead (>6000 mg/kg; 70% bioavailable) was identified as a potential source. After removing the pepper grinder from the home, the couple's blood lead decreased to below the Australian intervention level of 5 µg/dL within a year (Person A: from 12.5 µg/dL in August 2020 to 4.4 µg/dL in March 2022; and Person B: 15.4 µg/dL in August 2020 to 2.1 µg/dL in July 2021). This case study demonstrates how environmental science investigations can play a crucial role in supporting people to take evidence-based action to improve their health.

Trace element contamination of soil and dust by a New Caledonian ferronickel smelter: Dispersal, enrichment, and human health risk.

Metallurgical industries remain a considerable source of trace element contamination and potential human health risk. Determination of sources is a key challenge. With respect to the South Pacific's largest and longest operating metallurgic smelter in Nouméa, New Caledonia, determining the environmental impact and subsequent human health risk associated with local ferronickel smelting is complicated by natural geological enrichment of Ni and Cr. This study applies a multi-method and multi-matrix approach to disentangle smelter emissions from geogenic sources and model the consequent health risk from industrial activity. Dust wipes (n = 108), roadside soil (n = 91), garden soil (n = 15) and household vacuum dust (n = 39) were assessed to explore geospatial trace element (As, Cr, Cu, Fe, Mn, Ni, Pb, S, V and Zn) variations across outdoor and indoor environments. Enrichment factors (EF) identified elevated levels of smelter-related trace elements: S (EF = 7), Ni (EF = 6) and Cr (EF = 4), as well as Zn (EF = 4). Smelter-related elements in soil and dust deposits were negatively correlated with distance from the facility. Similarity of Pb isotopic compositions between dust wipes, surface soil and vacuum dust indicated that potentially toxic trace elements are being tracked into homes. Non-carcinogenic health risk modelling (Hazard Index, HI) based on 15 spatial nodes across Nouméa revealed widespread exceedance of tolerable risk for children (0-2 years) for Ni (HI 1.3-15.8) and Mn (HI 0.6-1.8). Risk was greatest near the smelter and to the north-west, in the direction of prevailing wind. Given the elevated cancer risk documented in New Caledonia, disentanglement of environmental from industrial sources warrants further attention to ensure community health protection. Our analysis illustrates how the confounding effects from complex environmental factors can be distilled to improve the accuracy of point source apportionment to direct future mitigation strategies.

The production and characterisation of monoclonal antibodies to Lucilia cuprina larval antigens.

A panel of murine monoclonal antibodies was produced against three Lucilia cuprina larval preparations that are unlikely to be exposed to the sheep's immune system during a normal infection. Antibodies were successfully produced against a crude third instar midgut homogenate preparation (MG), and Sodium dodecyl sulphate (SDS) and Triton X-114 (TX) detergent extracts of first instar larvae. Characterisation of the relevant antigens was performed using 1- and 2D gel electrophoresis and immunoblotting, immunoperoxidase histological studies and in vitro larval growth cultures. All the mAbs were of the IgM isotype. Common recognition of bands at 40, 50 and 80 kDA was evident on 1D blots of larval organ preparations by most mAbs while recognition of antigens in the 2D blots appeared to be more specific. Immunohistological studies suggested that a number of the antibodies specifically bound to intracellular structures within the midgut epithelium. However, antibodies derived from one clone also recognised the epithelium of Malpighian tubules, oenocytes and muscle fibres. None of the antibodies raised against TX extracts were observed to bind to larval structures. Results of larval cultures suggested that certain antibodies could significantly inhibit larval survival and growth in vitro.

Epidemiology of infection by nontuberculous mycobacteria. VI. Identification and use of epidemiologic markers for studies of Mycobacterium avium, M. intracellulare, and M. scrofulaceum.

A comparison of clinical and environmental (e.g., soil, dust, water, and aerosol) isolates of the Mycobacterium avium-intracellulare and M. scrofulaceum (MAIS) group has been made. The frequency of M. avium-intracellulare clinical isolates able to grow without OADC enrichment, able to grow at 43 degrees C, or express resistance to streptomycin or cadmium was significantly higher than those among environmental isolates. Only the frequency of clinical M. scrofulaceum isolates able to grow at 43 degrees C and without OADC enrichment was significantly higher than that of environmental isolates. Because of the high frequency of clinical M. avium-intracellulare isolates able to grow without OADC, grow at 43 degrees C, and resistant to streptomycin, these 3 characteristics are suggested for use as epidemiologic markers for MAIS. There were no significant differences between clinical M. avium-intracellulare isolates from 3 widely separated geographic regions. Among M. avium-intracellulare environmental isolates, only those collected in droplets above bodies of water (i.e., aerosols) shared those characteristics unique to clinical MAIS. That observation suggests that these aerosols are a likely source of human MAIS infection. The ability of isolates to grow at 43 degrees C and without OADC enrichment was highly correlated. Gentamicin-, streptomycin-, and D-cycloserine-resistances were also frequently found together. Isolates carrying plasmids and either able to grow at 43 degrees C, without OADC enrichment, or mercury-resistant were found more frequently than expected as well. This suggests their genetic determinants are plasmid-encoded.

Comparison of selected measures of field dependence.

An examination was made to determine the extent to which the Flexibility of Closure subtest from Hakstian and Cattell's Comprehensive Ability Battery could be substituted for Witkin's Rod-and-frame Test of field dependency. Although the data for 48 subjects (aged 11 to 17 yr.) yielded a significant zero-order correlation between the two tests for females, it was judged insufficient to warrant substitution of the former for the latter test.