2006-2017: Grafton (New South Wales) – Cryptosporidium

Drinking water repeatedly contaminated with pathogens in rural NSW towns

9 October 2017: http://www.abc.net.au/news/2017-09-06/drinking-water-contaminated-with-pathogens-in-nsw-towns/8875464

NSW Health documents obtained by the ABC reveal areas where deadly pathogens are regularly detected at dangerous levels in unfiltered drinking water pumped from rivers, lakes and dams.

The water safety reports, obtained after a lengthy freedom-of-information battle, also show more than 100,000 NSW residents were issued protective boil-water alerts in the last five years.

Grafton, Kempsey, Scone, Jindabyne and Bega are cited as the five worst-performing areas, with repeated “contamination incidents” triggering “potential health risks”.

Around Grafton, a population of 40,000 are at risk from cryptosporidium, a parasite that causes gastrointestinal illness.

Residents have faced 10 boil-water alerts since 2006, issued “in response to the inability of the water supply system to manage risks”.

The documents say faecal contamination from cattle, and even swimmers along the lower Clarence River catchment, is the parasite’s source.

Similar problems plague the Bemboka River catchment, near Bega, with four boil-water alerts issued by Bega Valley Council in 10 years.

Deadly bugs originate in “onsite sewerage system discharges”, “failures and presence of septic systems” and from dairy farms upstream.

The documents say “chlorine-resistant pathogens” — not killed by chemical treatments — are a threat to more than 40,000 people.

Around Kempsey, the risk identified is cyanobacteria — a toxic blue-green algae that can shut supply for 15,000 residents.

Grazing dairy cattle and raw sewage discharges near the Steuart McIntyre Dam trigger algae outbreaks here.

Alarmingly, the documents say “all pathogen groups” including e. coli are present in Kempsey water, and that a further “vulnerability assessment” should be undertaken.

In the Upper Hunter, more than 6,000 residents in Scone, Murrurundi and Aberdeen are rated at “very high risk” from dangerous pathogens flowing from an abattoir and septic tanks in the catchment.

The alpine towns of Jindabyne and Barry Way also face a “moderate risk from the presence of cryptosporidium” as well as toxic “blue-green algae” in their catchment.

Livestock faeces, and sewage, including from the Perisher ski resort are blamed.

The documents also identify other communities with one-off water concerns.

Last year boil-water alerts were issued in Dubbo, as well as villages including Toomelah, Gravesend, and Jubullum.

In the Upper Hunter, more than 6,000 residents in Scone, Murrurundi and Aberdeen are rated at “very high risk” from dangerous pathogens flowing from an abattoir and septic tanks in the catchment.

The alpine towns of Jindabyne and Barry Way also face a “moderate risk from the presence of cryptosporidium” as well as toxic “blue-green algae” in their catchment.

Livestock faeces, and sewage, including from the Perisher ski resort are blamed.

The documents also identify other communities with one-off water concerns.

Last year boil-water alerts were issued in Dubbo, as well as villages including Toomelah, Gravesend, and Jubullum.

ABC report on Grafton’s water quality incorrect: CVC

https://www.nvi.com.au/story/5260767/breaking-ecoli-detected-in-tambar-springs-drinking-water/

UPDATE 12:30: Clarence Valley Council have issued an official response to the claims made in the ABC article, stating that council has always been open about water quality issues.

Clarence Valley Council works and civil director, Troy Anderson, said the information provided to the ABC saying Grafton had 10 boil water alerts since 2006 was incorrect.

“There have been no boil water alerts for Grafton in that time – none,” he said. “The last time we are aware of where Grafton had a boil water alert was in 1967 when a water main burst during flooding.

“There have been alerts for some areas outside of Grafton, but there have been none since 2013 when re-chlorination started on the Lower Clarence supply.

“A number of these related to stand-alone water supplies that were not connected to the main Clarence Valley water supply.

“One related to the discovery of a live possum in the reservoir at Maclean and another  the discovery of a dead snake in the Copmanhurst reservoir. These were a number of years ago and in each case council has taken action to prevent similar incidents from recurring.

“Additional treatment barriers would not have prevented any of the boil water alerts that have occurred as re-contamination occurred after the treatment process.

“We note from NSW Health publications there have been no reported cryptosporidium outbreaks from water supplies anywhere in NSW, however it has been identified as a risk.

“When council prepared its drinking water management plan in 2014 the cryptosporidium risk, as outlined by NSW Health, was identified. Council has included $2.7m in this year’s budget for additional treatment barriers primarily to address this risk.

“Council has been completely open about all water quality issues – as it needs to be. All incidents, the reasons for them and the measures put in place are published online at www.riskedge.com.au/incident-register

“People should have no concerns about the quality of the Clarence Valley water supply.   ”

We do weekly testing and immediately notify the public of any issues.

“It should also be noted the ABC article reported the water supply was taken from the Clarence River. That is not correct. We take our supply from the Nymboida River.”

UPDATE 11.30AM: RISK Edge has detailed accounts of all water issues in the Clarence Valley from 2009 to 2015.

Issues range from village operators checking on plants after power outages, operational issues and incidents involving the transportation of chlorine. There has been no report of  cryptosporidium in the Clarence Valley’s water system recorded on Risk Edge.

Risk Edge does detail a boil-water alert in Maclean after the discovery of E Coli.

“Due to the distance from the chloramination point the town historically had very low chlorine residuals,” the report said.

“Following an E. coli detection during routine sampling, around 200 residents in a very defined area of the top part of Maclean fed by the “Lookout Reservoir” were advised to boil water from 21st December 2012 until 7th January 2013.”

“In recent years, Cryptosporidium has come to be regarded as one of the most important waterborne human pathogens in developed countries. Over 30 outbreaks associated with drinking water have beenreported in North America and Britain, with the largest infecting an estimated 403,000 people (Mackenzieet al. 1994). Recent research has led to improved methods for testing water for the presence of humaninfectious species, although such tests remain technically demanding and relatively expensive.

Cryptosporidium is an obligate parasite with a complex life cycle that involves intracellular development in the gut wall, with sexual and asexual reproduction. Thick-walled oocysts, shed in faeces are responsible for transmission. Concentrations of oocysts as high as 14,000 per litre in raw sewage and 5,800 per litre in surface water have been reported (Madore et al. 1987). Oocysts are robust and can survive for weeks to months in fresh water under cold conditions (King and Monis 2007).

There are a number of species of Cryptosporidium, with C. hominis and C. parvum identified as the main causes of disease (cryptosporidiosis) in humans. C. hominis appears to be confined to human hosts, while the C. parvum strains that infect humans also occur in cattle and sheep. C. parvum infection sare particularly common in young animals, and it has been reported that infected calves can excrete up to 10 billion oocysts in one day. Waterborne outbreaks of cryptosporidiosis have been attributed to inadequate or faulty treatment and contamination by human or livestock (particularly cattle) waste.

C. hominis and C. parvum can be distinguished from one another and from other Cryptosporidium species  by a number of genotyping methods. Infectivity tests using cell culture techniques have also been developed. Consumption of contaminated drinking water is only one of several mechanisms by which transmission (faecal-oral) can occur. Recreational waters, including swimming pools, are an important source of cryptosporidiosis and direct contact with a human carrier is also a common route of transmission.Transmission of Cryptosporidium can also occur by contact with infected farm animals, and occasionally through contaminated food.” ADWG 2011