Concern over the potential environmental health impacts of phthalates in soft plastic fishing lures among recreational anglers could create consumer demand for more informative labels or different plasticizers.
A survey of about 200 recreational anglers in Germany, part of a paper published in Science of the Total Environment, found that people often lose soft plastic fishing lures, raising issues about what happens to that material.
"Per day, [anglers] lose about one of those lures," Markus Brinkmann, a co-author of the paper and the director of the Toxicology Centre at University of Saskatchewan, told Plastics News in an interview. "That's quite a bit if you look at how common recreational angling is now."
Participants surveyed said they were concerned about the potential ecological impacts and wanted ingredients in the lures to be labeled. Respondents also supported legal restrictions on ingredients in soft plastic lures.
The study, which included a chemical analysis, found that soft plastic lures that are often made of PVC may leach persistent, water-soluble plastic additives.
"Soft plastic fishing lures are becoming more prevalent and really popular among recreational anglers nowadays," Brinkmann said. But there's "no knowledge … what kinds of chemicals can leach from those numbers and then also what might be the toxicological implications of that."
The research team, split between Canada and Germany, purchased 16 different soft plastic lures popular among recreational anglers in Europe and North America, cut a small piece from them and incubated those pieces in water samples to leach over 61 days.
Researchers at Toronto Metropolitan University investigated the types of compounds that leached from the samples. The University of Saskatchewan then received those extracts and tested them for "potential hormone-like effects," Brinkmann said.
The targeted screening found that 10 of the 16 soft plastic lures leached compounds like phthalates and other plastic additives, including dimethyl phthalate (DMP), diethyl phthalate (DEP), benzyl butyl phthalate (BBP) and di-n-butyl phthalate (DnBP).
DEP was detected most frequently in eight lures, followed by BBP in two lures, DMP in two lures and DnBP in one.
The extract from one lure with comparatively low phthalate and plastic additive levels was active in a bioassay, the abstract of the study said, "indicating high endocrine-disruptive potential, presumably due to unknown additives that were not among the target substances of the methodology used in this study."
In simpler terms, the sample showed some leaching of estrogenic chemicals that mimic female hormones, Brinkmann said. "When leached into the water body, [those chemicals] can have all sorts of downstream implications for fish populations … that can have feminizing effects on male fish."
"A lot of plastic products do contain those estrogenic chemicals … in other consumer products like teething rings for babies for example, plastic water bottles," he said. "The same goes with plastic packaging."
Researchers initially expected "that it would take quite a bit of time for those compounds to leach out," Brinkmann said. "But … as soon as three days or so, you got significant increases in those leached chemicals, and then after just a handful of days, some of them were actually already at their final leached concentration."
"Lures that you lose while you go fishing might sit there in the sediment for quite a long period of time," he said. "A slow and constant release of low concentrations of those compounds [creates] a certain risk that fish are … exposed to problematic concentrations.
"[Lures] are made to look like fish and a lot of, in particular, predatory fish would eat those," Brinkmann added. "There are some pictures circulating on the internet from the angling community with lake trout, pike and other species with bellies full of plastics. That certainly also has some implications, not necessarily toxicity. But it takes up space in their stomach and would slowly starve them, essentially."
"Some of those compounds that we have looked at, in particular the phthalates, are fairly well known to have all sorts of human health implications," he said. "This is something that goes potentially beyond the ecosystem impacts of those plastic lures but also the handling [of them]."