Pollutants banned for over 30 years linger in UK rivers – our wildlife is the evidence:
Banned and disused chemicals from our more industrial past continue to poison wildlife in rivers throughout the UK. But since these pollutants tend to exist in low concentrations in water and sediments, their modern influence is somewhat hidden. Animals accumulate chemicals over longer periods of time though, and in new research, we've discovered how these toxic relics are funneled through food chains to contaminate entire ecosystems.
[...] Pollution in many UK rivers decreased from the late 1970s and early 1980s onwards thanks to improvements in waste treatment and regulation of toxic chemicals. Initially, biodiversity recovered and river birds like the dipper returned to urban streams as their prey of fish and aquatic insects rebounded.
But improvements weren't universal or long-lived. Recent assessments found that only 14% of English rivers have a good ecological status, with conditions only slightly different from those that would be expected with no human disturbance. None of these rivers had sufficiently low levels of chemical pollution to be granted good chemical status. The situation was slightly better in Wales and Scotland, although conditions in these rivers were also well below targets.
[...] Research in 2014 showed that industrial flame retardants, such as PCBs and PBDEs, that were still present in rivers were accumulating in the eggs of dippers. The concentrations of these chemicals were high enough to explain the reduced weight and poor body condition of newborn chicks.
[...] In rivers with the highest concentrations of PCBs and PBDEs, the invertebrate prey was dominated by freshwater shrimp, which are good at tolerating pollution but make a nutritionally poor meal for dippers. In these rivers, dippers accumulated more toxic chemicals in their eggs as they were having to eat a greater number of this low-quality and highly contaminated prey. As pollution caused the abundance of invertebrate prey to shift in urban rivers, the effect on dippers further up the food chain slowly unfurled.
Journal References:
(1) Fredric M. Windsor, M. Glória Pereira, Charles R. Tyler, and Stephen J. Ormerod. Biological Traits and the Transfer of Persistent Organic Pollutants through River Food Webs [open], Environmental Science & Technology (DOI: 10.1021/acs.est.9b05891)
(2) Ian P. Vaughan, Steve J. Ormerod. Large‐scale, long‐term trends in British river macroinvertebrates, Global Change Biology (DOI: 10.1111/j.1365-2486.2012.02662.x)
(3) Christy A. Morrissey, David W.G. Stanton, Charles R. Tyler, et al. Developmental impairment in eurasian dipper nestlings exposed to urban stream pollutants, Environmental Toxicology and Chemistry (DOI: 10.1002/etc.2555)
(Score: 2) by Runaway1956 on Sunday October 11 2020, @08:41AM (3 children)
Chemicals banned 30 years ago are still in the rivers. Does that mean that the bans were ignored? Or does it mean the chemicals are that persistent? We might suspect a little of each, is what I think.
Remember DDT? Regulations banning DDT for various applications started as early as the 1950's, but it was still around when I was in high school. The old people who believed in the stuff didn't just throw it away, they stocked up while they still could and continued using it for years. ("No, boy, that isn't DDT, stop reading the label and put it in the blower like I told you!")
“I have become friends with many school shooters” - Tampon Tim Walz
(Score: 3, Insightful) by rleigh on Sunday October 11 2020, @01:40PM
I suspect it's mostly persistence. There will have naturally been some stockpiling, but that effect will be limited once substances are no longer manufactured or sold.
I imagine in 20-30 years, we'll all be reading about Roundup/glyphosate doing pretty much the same thing long after it is banned entirely.
(Score: 0) by Anonymous Coward on Sunday October 11 2020, @03:24PM
In the case of DDT, persistance might play a role (it is a chloro-carbon after all), but let's not forget that it's not banned everywhere. There are countries in the world where it is still in use, and as you already know, chemicals know no border.
(Score: 0) by Anonymous Coward on Sunday October 11 2020, @08:19PM
Oh yes....the great british farmer is a well-known hoarder of these naughty banned chemical thingies....
TBT based anti-fouling paint?, every boat-club & marina has a supplier..
PCBs, we have a story about gallons of them, central London, late 90s..
DDT?, It's amazing how much 'new old stock' shows up.
And then there's things like a place not a million miles from where I'm typing this, 25 square miles of land contaminated with all sorts of fun shit associated with munitions manufacture, slowly leaching into the ecosystem...even though manufacture ceased decades ago, the streams are weirdly coloured still..there'll be no official sampling being done there....or, more precisely, it will get done but the results will never be released.
Mine's was the house where, through the 70s-90s my father kept some lindane handy, in a couple of old lemonade bottles, under the sink in the kitchen.
(Score: 1, Offtopic) by VLM on Sunday October 11 2020, @02:31PM
In "The Old Days" the standard answer was stirring up sediment and plowing and tilling fields and so forth to expose fresh stuff.
Just interesting to see how once a historical hypothesis is disproven, its human nature to sometimes pretend it doesn't exist.
Once the 1984 "we've always been at way with Eastasia" history rewriting squads are done, in like 2050 someone will probably re-discover the hidden hypothesis of "stirring up sediment" and we can memory hole today's food chain concentration story.