Updated: Oct 18, 2021
I recently attended the launch of the Centre for Anthropogenic Pollution Impact and Management. I was joined by a whole bunch of people who work with pollution in one way or another. Delegates included people who work with specific chemicals such as methyl tert-butyl ether (MTBE) and poly- and per-fluorinated alkyl substances (PFAS), people who work with turning waste products into new commodities, and people who work to remediate fuel spills.
An interesting outcome of the conversations we were having is that when we tried to articulate the problem that pollution presents to society, we fell short. We didn’t have a clear answer. Of course, there is not just one way in which pollution is affecting people and the environment. There are many.
In this blog, I present research that illustrates the impacts of pollution on the environment and the urgency of this problem.
It is known that close to 800 chemicals are considered to be capable of disrupting the endocrine system. The levels of endocrine disrupting chemicals in humans and wildlife are related to how much a chemical is used. Despite this, few of these 800 chemicals have been investigated in tests capable of constraining what their effects actually are. For example, over the last 50 years, male sperm counts have been dropping by an average of 1 to 2% per year in North America, Europe, Australia and New Zealand — a total of 50 to 60%. Up to 40% of young men in Northern Europe are considered to have a low sperm count. However, demonstrating a clear link between a chemical with endocrine effects in individuals and population-level declines or other effects has been challenging. This is because of the difficulty in isolating the effects of a chemical from the effects of other stressors and ecological factors.
Polychlorinated biphenyls (PCBs) were largely banned from use more than 40 years ago. Despite this, a decline in the concentration of these chemicals in wildlife has not occurring and it’s driving some populations of cetaceans (whales and dolphins) to extinction. In the Gulf of Mexico, for example, orcas numbered a mere 277 in the early 1990s. Despite efforts to protect cetaceans and fisheries since then, the Gulf of Mexico orca population now numbers just 22. In the United Kingdom the situation is no different, with the orca population there unable to produce any offspring for the last 25 years. These reproductive failures have been caused by PCBs, with reproductive effects occurring when concentrations reach 9 mg/kg or more in cetacean blubber. Cetaceans in the United States and the United Kingdom are being found with blubber PCB concentrations of 900 to 1300 mg/kg.
Pod of orcas, with a number of such pods seeing reproductive failure due to PCB exposure. Shutterstock photo ID: 1453755992, photo by Willyam Bradberry
Forty to ninety percent of the North-west pacific salmon populations have been dying prior to spawning for a number of decades. Early this year, it was discovered that a chemical called 6PPD-Quinone (N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine-quinone) is driving this decline. The exposure of salmon to 6PPD-quinone occurs when pulses of storm water carry this chemical, produced when the antioxidant 6PPD is ozonated and shredded from car tyres as they wear, into waterways. While it’s likely this pollutant has impacted fish populations all over the world, assessment of such impacts as not yet been published.
Permethrin is a type of pyrethroid insecticide widely used to control insects in agricultural feed lots in United States. Peterson et al. (2020) investigated the potential impact of permethrin contaminated dusts from feedlots on honeybees in the United States. They found there was enough contaminated dust being generated at these feedlots to kill 1 billion honeybees, every day.
Anti-coagulant rodenticides (ARs) are used as rodent poisons across Australia. These poisons can either kill rodents slowly (first generation ARs such as warfarin or coumatetralyl) or more rapidly (second generation ARs such as brodifacoum, bromadiolone , difenacoum, difethialone, or flocoumafen). While the first generation ARs are considered to break down in the bodies of larger predatory birds, the secondary ARs are not. As a result, 78% of boobook owls in southern Western Australia were found to have consumed rodents with ARs. Of these, nearly one in five had consumed lethal doses of ARs.
As the examples of pollution highlighted above show, we put a lot of effort in to constraining the effects of pollution. It takes wizards (colloquially known as analytical chemists) to develop recipes (methods) that can accurately measure chemical concentrations. It takes lots of time to complete studies in a way that ensures the effects of a chemical are truly due to the chemical and not something else (i.e. appropriate experimental design). And, banning a chemical can have serious economic impacts — not just to manufacturers but to users of that chemical (imagine if lead had been banned from use in cars without a viable replacement?). This is all to say that it takes a lot of effort from a lot of people to ensure chemical regulation is undertaken appropriately.
One of my key concerns is that regulations are not keeping up with the pollution being generated by society. That’s not to say regulations are having no effect — research undertaken in New York, USA, found that the health of 33% of the rivers investigated had improved over a 40-year period as a result of regulations (13% of rivers, conversely, declined in health over this period). However, overall concentrations of man-made pollutants are still increasing at locations in Thailand, Brazil, China, and the United States of America. Even the concentration of pollutants such as PCBs and DDT, banned for a number of decades, are still increasing in some places. In a summarising this issue, Martin (2021) states:
“New contaminant discoveries have occurred slowly, either accidentally or due to hypothesis driven ideas of individuals, rather than through any systematic, unbiased, or coordinated approach. While there are international frameworks and networks for systematic monitoring of existing contaminants, there are still no ongoing initiatives to screen in a coordinated way for new persistent contaminants emerging from today’s source regions.”
Literally millions (look at the bees alone) of organisms are dying every day as a result of pollution release, and many other organisms are losing their ability to breed and reproduce. If we know pollution is a realised threat to species, and that regulations are not preventing this threat from being manifested, what can we do? Martin (2021) made an attempt at answering this question and identified two main actions:
Make an increase in efforts aimed at preventing future persistent contaminants from circulating globally a priority for our field [environmental chemistry and toxicology] today.
More sustainable chemical use is needed and the development of less hazardous chemicals by industry should be incentivised.
I propose a third action. Vast improvements in environmental health and outcomes can be achieved by individual people acting collectively, as has been seen with meat consumption and climate change. If, on top of enhanced regulatory efforts and research focus, we all act to minimise the use of chemicals in every part of our lives, the results would surely be enormously beneficial.