Behaviour and effets of environmental pollutants in marine and terrestrial animals

Environmental pollutants such as POPs (Persistent organic pollutants) are well known anthropogenic and lipophilic compounds that bioaccumulate throughout the trophic chain. As they are resistant to biological degradation and are transported on long distances, POPs are now present worldwide in the environment. Numerous studies have shown that these pollutants have harmful effects on animal and human health, such as hepatic, immune and neuro-toxicity, as well as endocrine and reproductive disruption.

The main route of contamination of mammals by POPs is through the ingestion of food. As most POPs are not easily biotransformed in the organism, these pollutants tend to bioamplify throughout the food chain, making humans or marine mammals highly contaminated. As a result of their lipophilic properties, POPs preferentially accumulate in tissues such as the liver, the skin and, mainly, the adipose tissue. They are also transferred in high amounts to the offspring through the milk.

During periods of negative energy balance, POPs can be mobilized from the adipose tissue. In addition to being a reservoir, the adipose tissue can thus also be an internal source of lipophilic pollutants for the rest of the body. Once in the bloodstream, pollutants are able to contaminate other tissues or be transferred into the milk, which can be particularly harmful.

Northern elephant seal mother-pup pair (Año Nuevo colony – © T de Tillesse)

Nowadays, numerous parameters related to the toxicokinetics (behaviour) and toxicodynamics (effects) of environmental pollutants such as POPs remain unknown. Our research projects aim at exploring (i) the mechanisms of accumulation and mobilization of POPs and other environmental pollutants in cells and tissues, (ii) the toxicokinetics of POPs and other environmental pollutants during periods of negative energy balance in whole organisms, (iii) the toxic effects of POPs and other environmental pollutants at molecular, cellular and physiological levels, and (iv) the interactions (synergies or antagonisms) between different pollutants or between pollutants and nutrients present in the diet (impact of complex mixtures on pollutant toxicokinetics and toxicodynamics). Our study models involve in vitro (cell cultures of adipocytes, hepatocytes and enterocytes – Fig. 1) and in vivo (wild marine mammals and fish – Fig. 2) approaches.

Primary cultures of rat adipocytes (Louis et al. In Vitro Cell Dev Biol 2014)