Heavy metal exposure from man-made pollution of the environment is potentially a major public health risk. Dusts and particles from land contamination, air pollution and smoking, can result human exposure to metals through the skin or lungs. Higher exposures to metals such as arsenic (As), and cadmium (Cd) are associated with various health outcomes but the impact of heavy metal exposure on human health is not fully understood. The contribution of the physical environment to exposure and risks from metals is also unclear. This PhD studentship combines exposure assessment of metals in the indoor environment and laboratory microbiological analyses to determine public health risks. It is based at Public Health England (PHE)/National Institute of Health Protection (NIHP) and University of Leicester.
PHE has previously measured metals in household dust arising from contaminated soils and found correlations between local soil contaminants, indoor dust and biomonitoring samples. Environmental public health surveillance in England has found high exposures to heavy metals through outdoor air, soil and dust. We spend up to 90% of our time indoors but the full extent of how the indoor environment is affected by the outdoor environment is not known.
There is evidence that cadmium impacts nasopharyngeal colonisation by Methicillin Resistant Staphylococcus Aureus (MRSA) and is linked with the development of chronic respiratory diseases. Additionally, cadmium can affect epithelial integrity and induce an immune response but the impact of this on respiratory health is not fully understood. Additionally, our recent data show that cadmium and arsenic at biological concentrations alter the interaction of key respiratory bacteria with human epithelial cells. Further understanding of these novel findings is an aim of this project.
Worryingly, environmental exposure to metals can select for antibiotic resistance in human pathogens. Heavy metal pollution leads to the selection of bacteria with metal resistance genes and these genes are encoded on the same mobile genetic elements as antibiotic resistance genes and can be co-acquired through horizontal gene transfer from environmental bacteria to human pathogens. Our data show that acquisition of genes conferring copper hyper-resistance increases the resistance of MRSA to the innate immune system (Purves, 2018). Thus metal contamination has the potential to increase antimicrobial resistance (AMR), disrupt host-microbial interactions and exacerbate conditions such as asthma and COPD.
The aim of this interdisciplinary project is to test our hypothesis that metal pollution from the outdoor environment affects the indoor environment and increases the risk to human health by altering host-pathogen interaction and AMR.
1. Investigate the risk of metal pollution on the immune response and host-pathogen interactions.
2. Determine the risk of environmental metal contamination on antimicrobial resistance.
3. Establish the relationship between metal contamination of indoor dust, outdoor soil and air quality to support epidemiological risk assessments through fieldwork and analysis of existing datasets.
This is a unique interdisciplinary project based on microbiological, environmental and public health research that will establish how the indoor dust metal content is affected by outdoor concentrations, and the subsequent risk on AMR and respiratory health.
The student will be supervised by a multi-disciplinary team in molecular microbiology and environmental science (Morrissey/Whelan) and public health (Fletcher/Crabbe) and be well-provided with access to training and research facilities. The student will be registered with the University of Leicester for the PhD but have the benefit of having an honorary contract and spending part of the project in PHE/UK Health Security Agency (UKHSA) in Oxfordshire, becoming familiar with environmental public health, and work of the Health Protection Research Unit (HPRU).
Expected outcomes and training:
Training will include molecular microbiology, tissue culture infection models, advanced imaging, bioinformatics, environmental sampling and laboratory analysis, and public health research. There will also be an opportunity for fieldwork in England.
The student will also benefit from being part of a large inter-disciplinary HPRU collaborative project between the University of Leicester, PHE and other collaborators, which has several funded projects to quantify the risks to health from environmental exposures