Plastic fish?

Might the law of “unintended consequences” save certain fish from extinction?

A significant amount of synthetic clothing fibers have been found inside fish caught off the Northern California coast and ending up on local dinner plates, according to a new study by environmental scientists at UC Davis. About a quarter of the 64 fish purchased at fish markets in Half Moon Bay and Princeton and analyzed for the study turned out to have bits of synthetic clothing in their guts, said lead researcher Chelsea Rochman, of the UC Davis School of Veterinary Medicine.
“A significant amount of synthetic clothing fibers have been found inside fish caught off the Northern California coast and ending up on local dinner plates, according to a new study by environmental scientists at UC Davis.
About a quarter of the 64 fish purchased at fish markets in Half Moon Bay and Princeton and analyzed for the study turned out to have bits of synthetic clothing in their guts, said lead researcher Chelsea Rochman, of the UC Davis School of Veterinary Medicine.”   — http://www.sfgate.com

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A quarter of fish sold at markets contain man-made debris
A quarter of fish sold at markets contain man-made debris

Plastic debris litters aquatic habitats globally, the majority of which is microscopic (< 1 mm), and is ingested by a large range of species. Risks associated with such small fragments come from the material itself and from chemical pollutants that sorb to it from surrounding water. Hazards associated with the complex mixture of plastic and accumulated pollutants are largely unknown. Here, we show that fish, exposed to a mixture of polyethylene with chemical pollutants sorbed from the marine environment, bioaccumulate these chemical pollutants and suffer liver toxicity and pathology. Fish fed virgin polyethylene fragments also show signs of stress, although less severe than fish fed marine polyethylene fragments. We provide baseline information regarding the bioaccumulation of chemicals and associated health effects from plastic ingestion in fish and demonstrate that future assessments should consider the complex mixture of the plastic material and their associated chemical pollutants. Introduction  Small plastic debris is ubiquitous in the aquatic environment, contaminating coastal1,2, deep-sea3, near-shore1 and open-ocean1,4,5 pelagic habitats. Global trends suggest that accumulations are increasing in aquatic habitats1,5, consistent with trends in plastic production— increasing 560 fold in just over 60 years6. Production trends in combination with increasing environmental accumulations may lead to greater hazards for wildlife.  Hazards associated with plastic debris include physical components of the material7,8,9, chemical ingredients7,10,11 and sorbed environmental chemicals7,10 (e.g. persistent bioaccumulative and toxic substances (PBTs)12,13 and metals14). Upon ingestion, microscopic plastic fragments can translocate into the tissues of mussels15 and cause increased granulocytomas and decreased lysosomal membrane stability9. Based upon the UN Globally Harmonised System, > 50% of plastics are associated with hazardous monomers, additives and chemical byproducts11 (e.g. the carcinogenic polyvinyl chloride (PVC) monomer is the building block for the PVC11 piping that transports our drinking water). PBTs, found on recovered plastic debris globally12, bioaccumulate in foodwebs10 and are linked with several adverse effects including endocrine disruption16, decreased fish populations17 and reduced species evenness and richness18.  A concern often raised, that remains poorly understood, is the extent that chemicals associated with plastic debris, via environmental sorption12,13 or the manufacturing process10,11, bioaccumulate in animals as a consequence of ingestion. Evidence from laboratory studies include the bioaccumulation of polybrominated diphenyls (PBDEs), a flame-retardant added to plastics, in crickets via ingestion of polyurethane foam19 and greater concentrations of polychlorinated biphenyls (PCBs) in lugworms fed polystyrene with sorbed PCBs20. In nature, plastics with sorbed chemicals are found globally from coastal areas to the remote habitats of the subtropical gyres12. Evidence from observational studies in nature have found that birds with plastic in their stomachs have greater concentrations of lower chlorinated PCBs in their tissue than those that do not21 and similar congener patterns of PBDEs in their tissues as those found on the ingested plastic22. Of greater concern, is the hazards to wildlife health when they are exposed to the complex mixture of plastic material and plastic-associated chemicals (including the chemical ingredients and those sorbed from nature)23.  The physical and chemical hazards outlined above combined with the ingestion of plastic by a large range of aquatic organisms across multiple trophic levels24 and the evidence that supports chemical transfer from plastics to wildlife19,20,21,22 prompted us to measure the bioaccumulation of chemicals and adverse health effects from plastic-ingestion in fish. Fish, one of the largest and most diverse groups of animals and of great ecological- and commercial- importance25, are useful as sensitive indicators of effects associated with stressors in aquatic habitats26. Furthermore, plastic particles are reported in the gut content of several species of fish globally including from pelagic habitats27,28, estuaries29,30,31, and bays32.  Using Japanese medaka (Oryzias latipes), a widely accepted model fish species33,34, we achieved baseline information regarding the bioaccumulation of PBTs and associated health effects in fish via a chronic dietary exposure to low-density polyethylene (LDPE) plastic. Polyethylene has a greater affinity for organic contaminants than other mass-produced polymers13, comprises the largest component of plastic production globally (29%6) and is one of the most common polymers recovered as aquatic debris35. Fish were exposed to three treatments: a negative control (no LDPE), a virgin-plastic (LDPE virgin pre-production plastic) and a marine-plastic treatment (LDPE deployed in an urban bay). Medaka were exposed to 10% plastic (by weight) mixed into treatment diets and sprinkled at the top of each tank. Diet and plastic dissociated at the surface and thus fish were exposed to plastic similar to the way they are in the wild (i.e. floating in the water column). As such, this translates to 8 ng of plastic per mL of water. Maximum concentrations reported in the North Pacific Subtropical Gyre are 300 ng/mL5, and thus the concentrations of plastic used in this experiment may be considered environmentally relevant. Our chemical analyses targeted polycyclic aromatic hydrocarbons (PAHs), PCBs and PBDEs (see Figure 1 for a schematic diagram). All accumulate on plastic debris in marine habitats12. In addition, PBDEs are additives on several plastics36 and PAHs are a likely byproduct of plastic manufacturing37. Anthropogenic debris in seafood: Plastic debris and fibers from textiles in fish and bivalves sold for human consumption  Scientists say atmospheric releases of hormone-disrupting chemicals may be a big source of of pollution in streams and lakes. After studying water quality near industrial sites permitted to release toxic chemicals into the air, the researchers said they found unexpectedly high levels of BPA in water around those factories.