Can the legacy of industrial pollution influence antimicrobial resistance in estuarine sediments?

Antimicrobial resistance (AMR) represents a major global health threat, as well as a major hazard to sustainable economic development and national security. It remains, therefore, vital that current research aligns to policy development and implementation to alleviate a potential crisis. One must consider, for example, whether drivers of antibiotic resistance can be controlled in the future, or have they already accumulated in the past? Whether from antibiotics and/or other pollutants. Unfortunately, industrial heritage and its pollution impact on the prevalence of environmental AMR have largely been ignored. Focussing on industrialised estuaries we demonstrate that anthropogenic pollution inputs in addition to the natural diurnal environmental conditions can sufficiently create stressful conditions to the microbiome, and thus promote selective pressures to shift the resistome (i.e., collection of resistance traits in the microbiological community). Unfortunately, the bacteria’s survival mechanisms, via co-selective pressures, can affect their susceptibility to antibiotics. This review highlights the complexity of estuarine environments, using two key contaminant groups (metals/toxic elements and polyaromatic hydrocarbons), through which a variety of possible chemical and biological pollutant stressors can promote the emergence and dissemination of antimicrobial resistance. We find compelling divers to call on more focused research on historically disrupted ecosystems, in propagating AMR in the real world

Oil spill problems and sustainable response strategies through new technologies

Crude oil and petroleum products are widespread water and soil pollutants resulting from marine and terrestrial spillages. International statistics of oil spill sizes for all incidents indicate that the majority of oil spills are small (less than 7 tonnes). The major accidents that happen in the oil industry contribute only a small fraction of the total oil which enters the environment. However, the nature of accidental releases is that they highly pollute small areas and have the potential to devastate the biota locally. There are several routes by which oil can get back to humans from accidental spills, e.g. through accumulation in fish and shellfish, through consumption of contaminated groundwater. Although advances have been made in the prevention of accidents, this does not apply in all countries, and by the random nature of oil spill events, total prevention is not feasible. Therefore, considerable world-wide effort has gone into strategies for minimising accidental spills and the design of new remedial technologies. This paper summarizes new knowledge as well as research and technology gaps essential for developing appropriate decision-making tools in actual spill scenarios. Since oil exploration is being driven into deeper waters and more remote, fragile environments, the risk of future accidents becomes much higher. The innovative safety and accident prevention approaches summarized in this paper are currently important for a range of stakeholders, including the oil industry, the scientific community and the public. Ultimately an integrated approach to prevention and remediation that accelerates an early warning protocol in the event of a spill would get the most appropriate technology selected and implemented as early as possible-the first few hours after a spill are crucial to the outcome of the remedial effort. A particular focus is made on bioremediation as environmentally harmless, cost-effective and relatively inexpensive technology. Greater penetration into the remedial technologies market depends on the harmonization of environment legislation and the application of modern laboratory techniques, e.g. ecogenomics, to improve the predictability of bioremediation

The legacy of industrial pollution in estuarine sediments : spatial and temporal variability implications for ecosystem stress

The direct impacts of anthropogenic pollution are widely known public and environmental health concerns, and details on the indirect impact of these are starting to emerge, for example affecting the environmental microbiome. Anthropogenic activities throughout history with associated pollution burdens are notable contributors. Focusing on the historically heavily industrialised River Clyde, Scotland, we investigate spatial and temporal contributions to stressful/hostile environments using a geochemical framework, e.g. pH, EC, total organic carbon and potentially toxic elements: As, Co, Cr, Cu, Ni, Pb and Zn and enrichment indicators. With regular breaches of the sediment quality standards in the estuarine system we focused on PTE correlations instead. Multivariate statistical analysis (principle component analysis) identifies two dominant components, PC1: As, Cr, Cu, Pb and Zn, as well as PC2: Ni, Co and total organic carbon. Our assessment confirms hot spots in the Clyde Estuary indicative of localised inputs. In addition, there are sites with high variability indicative of excessive mixing. We demonstrate that industrialised areas are dynamic environmental sites dependant on historical anthropogenic activity with short-scale variation. This work supports the development of ‘contamination’ mapping to enable an assessment of the impact of historical anthropogenic pollution, identifying specific ‘stressors’ that can impact the microbiome, neglecting in estuarine recovery dynamics and potentially supporting the emergence of antimicrobial resistance in the environment

Co-selection of antibiotic resistance in Gram-negative bacteria caused by pollution legacy in the Clyde estuary

Antimicrobial resistant bacteria can become harboured in sediments of postindustrial estuaries. Subsequently, their resistance traits could be enriched by pollutants deposited in the sediments. Recent evidence strongly suggests this may pose hazards that not only affects the health care sector, but could also impact tourism and the aquaculture industries. The River Clyde, UK was chosen for this study due to its extensive industrial history, and three sites were chosen to sample from representing different levels and types of industrial activities—two highly polluted and one relatively “pristine” site

Potential risks of antibiotic resistant bacteria and genes in bioremediation of petroleum hydrocarbon contaminated soils

Bioremediation represents a sustainable approach to remediating petroleum hydrocarbon contaminated soils. One aspect of sustainability includes the sourcing of nutrients used to stimulate hydrocarbon-degrading microbial populations. Organic nutrients such as animal manure and sewage sludge may be perceived as more sustainable than conventional inorganic fertilizers. However, organic nutrients often contain antibiotic residues and resistant bacteria (along with resistance genes and mobile genetic elements). This is further exacerbated since antibiotic resistant bacteria may become more abundant in contaminated soils due to co-selection pressures from pollutants such as metals and hydrocarbons. We review the issues surrounding bioremediation of petroleum-hydrocarbon contaminated soils, as an example, and consider the potential human-health risks from antibiotic resistant bacteria. While awareness is coming to light, the relationship between contaminated land and antibiotic resistance remains largely under-explored. The risk of horizontal gene transfer between soil microorganisms, commensal bacteria and/or human pathogens needs to be further elucidated, and the environmental triggers for gene transfer need to be better understood. Findings of antibiotic resistance from animal manures are emerging, but even fewer bioremediation studies using sewage sludge have made any reference to antibiotic resistance. Resistance mechanisms, including those to antibiotics, have been considered by some authors to be a positive trait associated with resilience in strains intended for bioremediation. Nevertheless, recognition of the potential risks associated with antibiotic resistant bacteria and genes in contaminated soils appears to be increasing and requires further investigation. Careful selection of bacterial candidates for bioremediation possessing minimal antibiotic resistance as well as pre-treatment of organic wastes to reduce selective pressures (e.g., antibiotic residues) are suggested to prevent environmental contamination with antibiotic-resistant bacteria and genes

Antibiotic resistance patterns in soils across the Scottish landscape

The environment disseminates antimicrobial-resistance genes; however, it remains challenging to distinguish whether human activities exacerbate antimicrobial resistance or what is natural. Here, we quantified ~300 resistance-related genes in 200+ Scottish soil samples. Location or land use does not explain gene differences, but nutrient levels reduce gene richness. Elevated levels of metals increased gene richness, and selenium increased transposase levels. Rainfall and persistent organic pollutants also increased transposase relative abundance, possibly promoting conditions conducive to the horizontal transfer of antimicrobial-resistance genes. Selenium and polychlorinated biphenyls were primary factors in gene abundance, while polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and pH influenced gene diversity. Polychlorinated biphenyls are derived from anthropogenic activities, highlighting human activities’ potential impact on gene prevalence. This is the first national-scale, high spatial resolution dataset of antimicrobial-resistance genes in Scottish soils and provides a novel resource on which to build future studies

Toxicological response and bioaccumulation of strontium in Festuca rubra L. (red fescue) and Trifolium pratense L. (red clover) in contaminated soil microcosms

Potentially toxic elements (PTE) from industrial activities remain a global concern for their environmental hazards. In particular, strontium is found in drinking water and food, primarily from contamination from the nuclear industry, petroleum extractions, fireworks, and electronics. Its carbonate form is bioavailable and closely resembles calcium; thus, it has become a health concern, and . Pphytoremediation has often been considered for Sr2+. We toxicologically determined Sr2+ tolerance in Festuca rubra (red fescue) and Trifolium pratense (red clover), and their ability to bio-accumulate strontium was compared to the sorption capacity of the soils. These plants were chosen for their ubiquity and as primary colonisers in soils. Experimentally uncontaminated farm soils from Lanarkshire, Scotland, were used, along with two common plants. Further, seed-germination and plant-growth assays demonstrated that strontium chloride exposures impact both species (0-40mM;

Rhodococcus strains from the specialized collection of alkanotrophs for biodegradation of aromatic compounds

The ability to degrade aromatic hydrocarbons, including (i) benzene, toluene, o-xylene, naphthalene, anthracene, phenanthrene, benzo[a]anthracene, and benzo[a]pyrene; (ii) polar substituted derivatives of benzene, including phenol and aniline; (iii) N-heterocyclic compounds, including pyridine; 2-, 3-, and 4-picolines; 2- and 6-lutidine; 2- and 4-hydroxypyridines; (iv) derivatives of aromatic acids, including coumarin, of 133 Rhodococcus strains from the Regional Specialized Collection of Alkanotrophic Microorganisms was demonstrated. The minimal inhibitory concentrations of these aromatic compounds for Rhodococcus varied in a wide range from 0.2 up to 50.0 mM. o-Xylene and polycyclic aromatic hydrocarbons (PAHs) were the less-toxic and preferred aromatic growth substrates. Rhodococcus bacteria introduced into the PAH-contaminated model soil resulted in a 43% removal of PAHs at an initial concentration 1 g/kg within 213 days, which was three times higher than that in the control soil. As a result of the analysis of biodegradation genes, metabolic pathways for aromatic hydrocarbons, phenol, and nitrogen-containing aromatic compounds in Rhodococcus, proceeding through the formation of catechol as a key metabolite with its following ortho-cleavage or via the hydrogenation of aromatic rings, were verified

Heat recovery potential and hydrochemistry of mine water discharges from Scotland's coalfields

Prospective and operational mine water geothermal projects worldwide have faced challenges created by mine water chemistry (e.g., iron scaling, corrosion) and high expenditure costs (e.g., drilling or pumping costs) among others. Gravity fed or actively pumped drainages can be cheaper sources of low-carbon mine water heating when coupled with adequately sized heat exchanger and heat pump hardware. They also provide valuable chemical data to indicate mine water quality of associated coalfields. Field collection of temperature and flow rate data from mine water discharges across the Midland Valley of Scotland, combined with existing data for Coal Authority treatment schemes suggest that mine water heat pumps could provide a total of up to 48 MW of heat energy. Chemical characterisation of mine waters across the research area has created a valuable hydrochemical database for project stakeholders investigating mine water geothermal systems using boreholes or mine water discharges for heating or cooling purposes. Hydrochemical analytical assessment of untreated gravity discharges found that most are circumneutral, non-saline waters with an interquartile range for total iron of 2.0 - 11.6 mg/L. Stable isotope analysis indicates that the discharges are dominated by recent meteoric waters, but the origin of sulphate in mine waters is not as simple as coal pyrite oxidation, rather a more complex, mixed origin. Untreated gravity discharges contribute 595 kg/day of iron to Scottish watercourses; thus, it is recommended that when treatment schemes for mine water discharges are constructed, they are co-designed with mine water geothermal heat networks

Heat recovery potential and hydrochemistry of mine water discharges from Scotland’s coalfields

Prospective and operational mine water geothermal projects worldwide have faced challenges created by mine water chemistry (e.g., iron scaling, corrosion) and high expenditure costs (e.g., drilling or pumping costs) among others. Gravity fed or actively pumped drainages can be cheaper sources of low-carbon mine water heating when coupled with adequately sized heat exchanger and heat pump hardware. They also provide valuable chemical data to indicate mine water quality of associated coalfields. Field collection of temperature and flow rate data from mine water discharges across the Midland Valley of Scotland, combined with existing data for Coal Authority treatment schemes suggest that mine water heat pumps could provide a total of up to 48 MW of heat energy. Chemical characterisation of mine waters across the research area has created a valuable hydrochemical database for project stakeholders investigating mine water geothermal systems using boreholes or mine water discharges for heating or cooling purposes. Hydrochemical analytical assessment of untreated gravity discharges found that most are circumneutral, non-saline waters with an interquartile range for total iron of 2.0 - 11.6 mg/L. Stable isotope analysis indicates that the discharges are dominated by recent meteoric waters, but the origin of sulphate in mine waters is not as simple as coal pyrite oxidation, rather a more complex, mixed origin. Untreated gravity discharges contribute 595 kg/day of iron to Scottish watercourses; thus, it is recommended that when treatment schemes for mine water discharges are constructed, they are co-designed with mine water geothermal heat networks