What’s in the millions of tonnes of sludge sprayed on UK farmland? The answer won’t make you happy | George Monbiot

If humanity has an epitaph, it might read something like this: “Knackered by the things we missed.” It is true that several existential threats are widely known and widely discussed. But some of the greatest dangers we face appear on almost no one’s radar.

How often have you thought about this one: spreading sewage sludge on farmland? I would guess very few would include it in their top civilisational hazards. Despite the best efforts of a handful of us, it trundles on, unknown to most. Surprising as it may seem, new research suggests that it could help call time on us.

In principle, we should return human waste to farmland, as it is rich in nutrients. But thanks to years of regulatory failure, this waste in many countries is now contaminated with a vast range of toxins. Some come from runoff into the sewers: from roads, building sites, homes and commercial premises. But what we are now discovering is that a great volume of contaminants is introduced deliberately.

At some sewage farms, you can witness tanker lorries queueing to offload liquid waste. In return for a fee to the water company, they can pour this effluent into the “head of the works” (the top of the sewage processing chain). Whistleblowers from the Environment Agency report that these loads are scarcely tested. The testing that does occur is often for chemicals that may damage the sewage equipment, rather than those that may poison people and ecosystems. The fees appear to create an incentive for water companies to turn a blind eye.

Many of these tankers are delivering leachate from landfill sites, containing a dense cocktail of pollutants, including per- and polyfluoroalkyl substances (Pfas, or “forever chemicals”), other persistent organic compounds, pharmaceuticals and a thick sludge of microplastics. Some tankers come from, well, who knows where? The lack of adequate testing looks like an open invitation to organised crime, which, thanks to a total failure of enforcement, has now cornered much of the UK’s hazardous waste disposal market. Altogether, whistleblowers estimate, in England about 1m tonnes a year of liquid effluent is dumped under this system into sewage works.

Where do these toxins go? Some of them, especially the soluble compounds, will wash through the sewage plant and into our rivers and the sea. Some will be trapped in the sludge. Where does the sludge go? About 87% of it is sold or given to farmers and spread on their land as fertiliser.

What does this fertiliser contain? Good question. It is tested (if at all) only for fluoride, heavy metals and bacteria. No tests are conducted for the vast majority of potential contaminants. From the government’s own, suppressed research, we know that it is likely to contain such toxins as polycyclic aromatic hydrocarbons, dioxins, furans, benzo(a)pyrene, polychlorinated biphenyls and phthalates, many of which bio-accumulate in the soil. A study published this month by the James Hutton Institute found that after four years of sewage sludge spreading, microplastic levels in the fields it tested rose by up to 1,450%. It also discovered that there was little reduction in the soil of microplastics dumped 22 years ago: once they arrive, they don’t leave.

An investigation by the Ends Report last year found forever chemicals in the sewage sludge being sold to farmers at levels up to 135 times higher than those considered safe by scientists. Almost all the sludge samples it took had concentrations above the risk threshold. For such reasons, Switzerland and the Netherlands have banned sludge spreading.

The new research I mentioned at the beginning shows how microplastics absorbed by plants could severely inhibit photosynthesis, and therefore crop production. All the major sources of microplastics in farmland soils arise from breathtaking negligence. In some places, trailer loads of microplastic have been spread deliberately by farmers to make the soil more friable. Some have been introduced to the soil in the form of pelleted fertilisers, coated with polyurethane, polystyrene, PVC, polyacrylonitrile or other synthetic polymers. Some may now come from oxo-degradable plastic sheeting. Oxo-degradable polymers are ordinary plastics mixed with compounds which ensure they shatter into microplastics after a while, allowing farmers to plough them in when they have done their job. Such plastics are banned in the EU, but remain legal in the UK. Good old Brexit, eh?

But the major source of microplastics in fields is likely to be sewage sludge spreading. What are the combined impacts on crops of microplastics and the many other toxic compounds in contaminated sewage sludge? Again, no one knows.

At no point in the chain is adequate routine testing conducted: not of the contents of the tankers before they discharge into the sewers; not of the sludge dispatched to farms; not of the fields receiving repeated applications; not of the crops, meat and milk coming from those fields. But of one thing we can be sure: like the chemicals themselves, the impacts will accumulate over time.

If comprehensive testing of farmland is ever conducted, we could discover that large areas are now too toxic for safe food production. Even the government’s own research warns that the cumulative effects of these pollutants could render the soil “no longer … suitable for supporting crop growth”. We have to face this issue just as the global food system looks dangerously fragile.

The legal campaign Fighting Dirty, which three of us set up, sought to oblige the Environment Agency to set a date for the proper regulation of the sewage sludge being spread on farmland. We lost our case, partly on the grounds that the Environment Agency had no duty to act without government direction, yet no such direction had been issued. The judge also decided that contaminated sludge spreading could not be regarded as “a matter of imperative urgency”, because the Environment Agency was not treating it as such. Perhaps they make sense in law, but these grounds look to me like circular reasoning.

We discovered from the court papers that the agency had pressed repeatedly for a “ministerial steer”, but was not receiving one, and that better regulation is being impeded by resistance from the water companies and the waste industry. Life is just full of surprises.

The case revealed a massive loophole in the law, which the government still has failed to close. I’ve been told that officials at the Department for Environment, Food and Rural Affairs were crowing over the result: three cheers for mass contamination!

Perhaps another epitaph would read, “Some of us tried, but no one in power would listen.” A more concise version would be, “RIP FFS.”