Defining species sensitivity of invertebrates to industrial pollutants and pesticides through traits analysis

Chemical risk assessment for pollution control relies on data derived from tests performed on a limited number of species to predict the impact of pollutants on all species in an ecosystem. To address this uncertainty, environmental managers often need to incorporate an arbitrary ‘safety factor’ (usually division of a toxicity metric, such as an LCx, ECx or NOEC by 100 or 1000) to account for species sensitivity difference (among other factors) when deriving safe chemical concentrations. This is a naive approach. To improve the scientific basis for incorporating species differences into risk assessment, the capacity to provide a prediction of the actual sensitivity of an untested organism based on a limited number of measurements in a variety of tested invertebrate species would be a huge step forward.

This PhD project will seek to understand the different characteristics that make species sensitive to pollutant exposure. The student will use existing and novel approaches in comparative physiology to understand how different species characteristics, including physiological and ecological traits, affect species sensitivity within an “Adverse Outcome Pathway” (AOP) context. The project will use a range of experimental and data analysis and bioinformatic methods to address the sensitivity of different aquatic invertebrate species to two chemical classes: namely, 1) Non-polar “narcotic” organic chemicals focussing on persistent hydrocarbon molecules that characterise oil pollution; 2) Pesticides affecting nervous system function focussing on organophosphates and also neonicotinoids which are of current concern for their effects on bees and freshwater invertebrate communities. Comparing species responses for chemical classes with different non-specific (hydrocarbons) and specific (pesticide) modes of action will allow the student to tease apart the separate contributions made by different uptake, internal distribution and biochemical characteristics on species sensitivity. This will allow the objectives to be addressed.

Objective 1: Assess the sensitivity of aquatic invertebrate species from four taxa (crustacean, insects, annelid, mollusc) to a compound from each of the three different chemical classes (one hydrocarbon, one organophosphate insecticide, one neonicotinoid insecticide).

Objective 2: Quantify chemical uptake to determine parent compound and metabolite concentrations at the target site (e.g. nervous system) of the different species.

Objective 3: Model and measure pollutant interactions with putative receptors using gene sequencing, alignment, homology modelling and experimentally validated molecular docking studies.

Objective 4: Incorporate uptake rates, receptor analysis and species ecological traits into a system that links hydrocarbon and pesticide exposure to toxic effects experienced by the organism.

Organisation of the project. Main supervision will be by experts in ecotoxicology, Dr D. Spurgeon, Dr E. Lahive, based at CEH Wallingford in Oxfordshire, with co-supervision by an expert in molecular ecology, Prof. P. Kille, based at Cardiff University - the University from which the degree will ultimately be awarded. Additionally Dr S. Marshall from CASE partner Unilever will provide supervision in the risk assessment and interpretation aspects. The work on the PhD can be organised according to the specific needs of the student. However, it is anticipated that the individual would begin work at CEH Wallingford based in Oxfordshire, with a block of time spent later in the project working in the Cardiff laboratory learning molecular ecology skills and data analysis methods. During the project an industrial placement with a partner organisation (e.g. CASE partner UNILVER) can be undertaken. During this placement the student will undertake a specific piece of work linked to their project from which they can gain a greater knowledge of the impact of their research.

Applicant profile: This project would ideally suit a student with a background in biological sciences with an active interested in areas such as biochemistry, physiology, molecular biology or bioinformatics. Students who have previous experience in conducting laboratory based studies using invertebrate or aquatic species, especially within projects that have used methods for downstream biochemical or molecular biology analysis of samples, would be particularly suited. In all cases, applicants must have either obtained, or be about to obtain, a 2.1 degree or higher or have a 2.2 degree, with a Masters qualification. Substantial relevant post-graduate experience may also be sufficient in certain cases. Please contact the supervisors for more information if you are concerned about eligibility.

Application procedure: To apply please send your CV and a covering letter stating your suitability for the project and motivation to undertake a PhD by email to lead supervisor Dr D. Spurgeon ([Email Address Removed])