Although I currently work most often in the Contaminated Lands sector, one of my greatest concerns as an environmental scientist is not contamination, but habitat destruction. The changes which have been wrought on the surface of planet Earth in the last 12,000 years or so since agriculture started and humans began converting complex ecosystems into simple monocultures, are literally changing the Earth’s land-surface, its atmosphere, and its water. The complete and unprecedented devastation of habitats is now well documented and thoroughly researched.
But a recent newspaper article drew my attention back to chemical pollution. The research summarised in this newspaper article found that sediments and wildlife in Antarctica were contaminated with a potentially toxic flame retardant called hexabromocyclododecane. As outlined in a previous blog post on Murrang Earth Science’s site, I also learnt recently that phthalates are now found in water systems all over the world. Does this mean man-made chemicals are now found everywhere? Even in pristine ecosystems? The aim of this blog was to find out.
Man-made chemicals are now being detected in areas remote from their origin, even after water dilutes their concentration many times. N,N-diethyl-3-toluamide (more commonly known as the insect repellent DEET), clofibric acid (a drug used to regulate blood lipids), and caffeine, for example, were all found in seawater collected from a number of locations within the North Sea. Clofibric acid was also found in both shallow and deep groundwater within Germany, entering the water system after being excreted into the sewage system by humans. Some clofibric acid remained after the sewage was treated and discharged into rivers, where it then moved with river water before recharging aquifers downstream.
Research has found man-made chemicals in even the most pristine of European catchments and drinking water supplies. Caffeine, for example, was identified in 95% of European rivers (even in places like Switzerland, where sewage is treated to a very high level using advanced technology). Benzotriazole and tolyltriazole (used as aircraft deicers and anti-icer fluid, and as silver protection in dishwasher detergents), and caffeine were also identified in remote parts of northern Europe.
You might think that we would be able to source some good clean water if we just climbed far enough above the cities which are producing these chemicals, but you would be wrong. Low-brominated polybromodiphenyl ethers (PBDEs), endosulfans, hexachlorocyclohexanes (HCHs), and hexachlorobenzene (HCB) were found in all samples collected from the snow pack of the High Tatra Mountiains of Slovakia and the concentrations of these chemicals increased with increasing altitude. This is despite the low-brominated PBDEs found in these mountains having low volatility, being very hydrophobic, and having origins remote to the mountains studied. This means man-made chemicals are not just being washed through catchments with rivers and groundwater and into the sea, they are being transported in the clouds.
With no industry to speak of, transport of chemicals to the Artic has long been and continues to be a problem despite a number of these chemicals being banned. The production of a number of persistent organic pollutants was banned under the Stockholm Convention, and has successfully resulted in decreased concentrations of these pollutants in the Arctic. The concentration of other chemicals such as polycyclic aromatic hydrocarbons, however, has increased.
Perhaps what worries me even more is the contamination of the environment with antibiotics. Up to 95% of the antibiotics excreted by humans and animals are excreted in an unaltered state. These antibiotics are entering the aquatic environment, even after water is treated within sewage treatment plants. Antibiotic resistant genes from bacteria are also entering out water systems, and are now found in chlorinated drinking water, river water, and even within algae.
It’s not as if drinking bottled water rather than reticulated (ie tap) water will help as plastic leaches a number of chemicals. This exposes drinkers to higher concentrations of some chemicals than they would otherwise be exposed, or to chemicals they would otherwise not have consumed in tap water. Chemicals found in higher concentrations in (PET) bottled water than in tap water include antimony, phthalates, bisphenol A (BPA), formaldehyde and acetylaldehyde, 4-nonylphenol, and triclosan. Sometimes drinking bottled water is safer than reticulated water due to improper treatment of the reticulated water in developing nations for bacteria, pathogens and other potentially disease causing organisms. It is very rarely the case that reticulated water is unsafe in the developed world.
One cannot drink water eat food or breathe the air without some exposure to organic chemicals in this modern world. The fact that we have not previously been able to measure these chemicals or that they are in such small concentrations does not mean they are any less toxic. An amount of polonium equivalent to less than a grain of salt is enough to kill an adult human. The same amount of say sodium-chloride (ie a grain of salt) isn’t enough to do anything at all. Even though we are just now developing the methods to measure some chemicals in the environment, their small concentrations still have the potential to have significant impacts.
We can no longer avoid these chemicals, as they are borne across the Earth in the wind, are rained into our rivers from the clouds, and transported through the seas. While we know a little about the effects of some of these chemicals on their own, we certainly know very little about the effects of mixtures of these chemicals. I personally feel like the world would be a healthier and more sustainable place if their production was prevented in all but the most necessary of circumstances. Preventing their production and changing our means of inhabiting Earth may seem like an impossible task. Huge and transformation of the world’s economy occurred during and after World War Two, however, proving that rapid change can occur if only there is a will to do so.