The Thin End

We are more aware than ever before that microplastics (plastic particles under 5 mm) are an abundant type of debris found in salt and freshwater environments.  They can be readily ingested along with food and enter the 'food' chain.   It is not yet clear what harm if any the ingestion of microplastics has in the food chain, although some studies have found depressed growth and lethargy. In a Limnology & Oceanography Letters study, researchers demonstrated the transfer of microplastics through the food chain between microscopic prey and larval fish that live in coastal ecosystems. They also found that microplastic ingestion interferes with healthy growth in fish larvae. The investigators also looked at the effects of a common pollutant (the pesticide DDT) that attaches to microparticles in coastal waters. Organisms were not able to detect or discriminate against ingesting microparticles with high levels of DDT. "Even short exposure to high levels of micropl...

A new study suggests exposure to residues persisting in the environment from pesticides banned fifty years ago is associated with autism. The new study provides the first biomarker-based evidence in humans that maternal exposure to DDT residues in the food chain may increase the risk of autism in their children. DDTs (organochlorines) were widely banned as pesticides from the late 1970s,  but residues persist in the food chain. These persistent organic pollutants can be transferred from the mother across the placenta to the fetus, resulting in fetal blood concentrations ranging from 30% to 50% of levels found in maternal blood.   The investigation ,  published online in the American Journal of Psychiatry, was derived from the Finnish Prenatal Study of Autism, a large national birth cohort with maternal serum specimens from early pregnancy tested for levels of the organochlorine DDT (dichlorodiphenyl-trichloroethane) and its metabolite DDE (dichlo...