Almost six hundred million pounds is the sum of money needed to set-up metaldehyde (slug pellet) treatment for drinking water in the East of England, according to Anglian Water. The company estimates it would also cost an additional £17million every year to run – amounting to a 21 per cent increase in customer bills.

The cost predictions were released recently at a meeting led by Anglian Water to share progress, learnings and concerns in tackling pesticide levels in raw water sources for drinking water. The session brought together some of the leading water companies in catchment management, Defra, industry regulators and pesticide chemical manufacturers.

The Drinking Water Directive says individual pesticide levels in drinking water must not exceed 0.1 micrograms per litre, and regulators want to know by 2017 how this limit will be met for metaldehyde. At present an outright ban on metaldehyde from 2020 is a real possibility unless UK policymakers choose to pursue a more bespoke approach.

At the event, Anglian Water presented findings from its catchment management initiatives including its Slug It Out trial – the UK’s largest ever metaldehyde-free farming trial aimed at meeting the drinking water directive. Slug It Out achieved a 60 per cent drop in levels of metaldehyde detected in reservoir tributaries last year, but it was not enough to meet the legislative limits in all areas. Severn Trent and Thames Water have also run similar trials.

The results from the three companies show that even removing 100 per cent of metaldehyde from farmland is still not sufficient to meet the drinking water legislation. The reasons for this are being investigated but it is believed the chemical takes longer to break down than previously thought, and could be coming from other sources such as domestic allotments.

Anglian Water believes more support from others including agriculture, water sector regulators and pesticide manufacturers is needed to find the best solution overall.

Domestic customers should not be financial backstop for pesticide treatment

Anglian Water’s Catchment Strategy Manager, Lucinda Gilfoyle, said:

“Through our catchment management strategy and Anglian Water farming advisors we’re working collaboratively with farmers and the agricultural sector on a range of topics, and our two sectors are working more closely and more effectively than ever before. Other water companies are doing the same as they recognise catchment management brings excellent customer benefits through reduced cost of water treatment and environmental benefits too.”

“However, the product substitution trials have proved that water catchments are all different and respond differently, and one size fits all legislation – such as a nationwide ban on metaldehyde – would not be effective. It could also place the UK agricultural industry in a worrying position where one of its most important tools in fighting pests that damage crops could be lost.”

“Water companies want to safeguard raw water quality and meet the standards, but the findings from ourselves, Severn Trent and Thames Water show blanket measures, such as an outright ban, may not deliver the necessary water quality results."

“If resolving this issue is then left to water companies alone any solution would likely need to be ‘end of pipe’. Not all pesticides can be removed by conventional treatment technology meaning end of pipe solutions can’t be relied upon as a panacea. Even if a treatment solution is technically possible on such a large scale, our cost estimates show that funding it would be hugely costly and unsustainable for customers’ bills. We strongly believe that domestic customers should not be the financial backstops for this.”

According to Anglian Water, a collaborative catchment approach across multiple business sectors provides the best option to safeguard raw water quality effectively while still enabling the agricultural sector to thrive. However, the utility said that catchment management by its very nature involves many different stakeholders and should therefore not be the sole responsibility of water companies to deliver. More organisations need to take responsibility for catchment management as an essential approach, and for regulators to mirror this in the regulation too.

The cost of treating metaldehyde

Anglian Water is the only water company to run a metaldehyde water treatment plant. The Lincolnshire site became operational in 2015 and has enabled Anglian Water to generate detailed cost predictions for installing and running similar facilities across its 27,500square kilometre region.

It is the first time this cost information has been made available and shows the scale of the bill customers would have to foot to meet the drinking water legislation on pesticide limits.

Lucinda Gilfoyle added:

“In the interests of shared learning, we released these cost predictions to highlight the level of scaling up that an ‘end of pipe’ approach to metaldehyde would mean across our region, let alone the whole UK.”

“On top of the £600million set-up costs for similar equipment across our network, it would cost £17million every year just to power, maintain and operate the equipment. In customer terms, to leave the problem of metaldehyde pollution to the water company alone to fix would amount to a 21 per cent increase in customer bills – a colossal burden which we do not believe is fair or sustainable. And treatment on this scale has never been attempted so it’s not truly known if it would be successful in all areas.”

“We are not in favour of an outright ban on metaldehyde - our Slug It Out trial has shown this would not achieve the pesticide limits either. This is why we believe catchment management is the best solution, and why a catchment-by-catchment approach to legislation is required to mirror that. It’s now in the hands of policymakers as to whether they will take heed of the trial results and learnings observed.”

As well as discussing the potential financial implications and the essential role of cross-sector collaboration in catchment management, representatives also discussed gaps in current technology, the effectiveness of catchment management approaches, agricultural awareness around water quality and the cost differences between slug control options.