We have been dealing with the “forever chemical” it seems like, well, forever. I awoke yesterday to my newsfeed telling me that we now have the “everywhere chemical.” The CNN story, Synthetic chemical in consumer products linked to early death, study finds, identifies a list of pollutant sources which sounds similar to that of PFAS, such as stain-resistant products and food packaging, but more ubiquitous, as in personal care products, children’s toys and furniture. What had me sit up in bed was the assertion that geezers such as me are at risk of an early death through our exposure to this chemical.
What is this bad thing? You may have guessed the chemical is phthalates, or phthalate acid ethers, or PAEs. Like PFAS, PAEs comprise a large collection of manufactured organic chemicals, in widespread use, with a wide variety of properties. They are all seemingly persistent in the environment and they all seem to be suspect of altering hormone activity in humans, shockingly sperm count in young men and gonad development in fetuses, and now we learn of resulting in premature deaths in older people.
The article in Science Digest, which seems heavily influenced by a university press office at NYU, seems a bit “breathless.” It says: “the new results add to mounting evidence of societal costs related to continued heavy exposure to the chemicals. For example, past research has linked more than 10,000 deaths a year to lowered testosterone levels in adult men attributed to phthalate exposure. These deaths cost Americans nearly $9 billion in lost economic productivity.” My cynical mind hears “send us more money for research,” and I think, “but, won’t extreme heat, intense storms and novel pandemics likely do the far greater damage to humanity?”
For those of us in the biosolids profession, we nonetheless need to take note of this unfurling issue. We have seen how PFAS has emerged as a “crisis,” though in truth PFAS has been here with us for over 4 decades with little obvious impacts. Before PFAS, we had PBDE flame retardants, dioxin incinerator emissions, and PCB oil “crises.” If we can forecast phthalates to be next crisis in line, we can get a jump on the issue. We can draw on recent synoptic overview of human exposures (Human health impacts of exposure to phthalate plasticizers: An overview of reviews) and on early studies of their flow, removal and fate in wastewater treatment systems (Flow of sewage sludge-borne phthalate esters (PAEs) from human release to human intake: Implication for risk assessment of sludge applied to soil and Fate of four phthalate plasticizers under various wastewater treatment processes). Moreover, we need to be sure we provide a context for the relative contribution of biosolids-borne phthalates to other sources of exposure (Isolation of Phthalates and Terephthalates from Plant Material – Natural Products or Contaminants? and Consumer Product Chemicals in Indoor Dust: A Quantitative Meta-analysis of U.S. Studies). With phthalates, we would do well to get a jump on understanding the risks.
The good news is that we can look forward to improved capabilities of the EPA to assess risk and fate of micropollutants such as phthalates. This is in the four recently announced research projects, one which will be directed by the Water Research Foundation. The EPA Is also updating its biosolids screening tool and risk assessment model, the basis for judging the need to propose new regulatory standards, and is seeking a science advisory group to provide oversight.
How concerned should we be that biosolids-borne phthalates will be subject to regulation? If human health and environmental risks are posed by phthalates in biosolids, the studies and models by EPA are the best way of determining those risks. During this process, scientists will continue examining other pathways of phthalate exposure, such packaging, cosmetics, and furniture. My guess is that phthalates that flow from consumer products, to sewers, to biosolids, to soils, to crops, and then back to food will be shown to be so diluted and diffuse as to result in vanishingly smaller risks to humans than other, more direct exposure pathways. So for the time being, I can certainly commit myself today to eating less biosolids.