Crypto regulations could leave labs with a big bill

New Drinking Water Inspectorate (DWI) regulations designed to extend protection of water supplies from Cryptosporidium could place an increased burden on environmental testing laboratories, leaving them out of pocket at the same time.


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The new regulations amend the Water Supply (Water Quality) Regulations 1989 on the quality of water intended for human consumption. From 1 October, water undertakers will be required to carry out risk assessments to establish whether there is a significant risk from Crypto oocysts in water supplied from their WTWs for human consumption.

Where it is established that there is such a risk then the relevant undertakers must use a process for treating the water to ensure that the average number of oocysts per 10l of water is less than one.

The potential problem lays with the third tranche of the regulations which requires undertakers to verify compliance with the 1 oocyst/10l limit by ensuring that water leaving their WTWs is continuously sampled for Crypto oocysts.

According to DWI, “the analysis of collection devices for the purposes of this regulation shall be carried out at an approved laboratory using approved equipment and approved analytical systems and methods.”

Current DWI-approved testing methods are based on concentration, purification and labelling/detection. Concentration can be achieved using sedimentation, flat membrane filters or membrane cartridge filters. These allow the filtration of high volumes of water and the collection of low oocyst concentrations. Since the concentration process typically traps a large amount of debris, a purification step is needed to separate out the oocysts. In the new regulations, DWI has approved immuno-magnetic separation (IMS) for this purpose.

Following concentration and purification, any oocysts present in the sample are labelled using a specific anti-Crypto monoclonal antibody linked to a fluorescent conjugate. Current approved methods use microscopic analysis of labelled samples that are deposited onto a slide well prior to manual analysis using fluorescent microscopy.

But, on average, one operator can only be expected to examine eight slides in a four-hour shift. Laboratories are worried that the volume of samples to be analysed to demonstrate compliance with the 1 oocyst/10l limit could put pressure on staff, unless funds are set aside for investment in training and recruitment.

Peter Whittle, technical director of Hyder Laboratories and Sciences, said: “The new regulations could result in significant costs. Some of the larger labs could be looking at additional running costs in the region of £500,000 to £2M/year.” And, where labs are receiving samples from vulnerable sites, costs could be even higher.

Laboratory managers are also concerned about the clause in the new regulations which requires approved laboratories to designate a room or rooms specifically for the receipt, preparation and analysis of samples of Cryptosporidium oocysts. According to the new rules, other analysis may be carried out in the designated room or rooms, but sufficient controls must be in place.

This kind of set up – comparable to a police forensic lab – is unprecedented in the water industry and is likely to involve modifications to existing labs or construction of completely new ones.

Manufacturers of alternative detection methods have indicated that they will push for DWI approval of their products. Automated testing which can take less than 10 minutes to perform – compared to 2 hours for manual testing – would enable water companies and labs to streamline control procedures.

Mike Brailsford, director of sales and marketing at Chemunex, said: “By automating detection, one operator can run 12 samples per hour. With manual microscopy, this volume of samples could take up to six hours to analyse.”

DWI has said that currently approved testing methods are not set in stone. Owen Hydes, DWI’s deputy chief inspector, told Water & WasteTreatment: “We will recognise new developments and the regulations do specify what a lab would need to do to get another method approved.”

Validation studies would need to demonstrate that the alternative method under consideration has superior performance, or similar performance, to the approved method.

© Faversham House Ltd 2022 edie news articles may be copied or forwarded for individual use only. No other reproduction or distribution is permitted without prior written consent.

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