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7
WQ.184/2019
WRITTEN QUESTION TO THE MINISTER FOR THE ENVIRONMENT
BY SENATOR K.L. MOORE
ANSWER TO BE TABLED ON TUESDAY 30th APRIL 2019
Question
Will the Minister indicate the number of boreholes which are used for residential water consumption; and publish the results of any water-sampling tests undertaken by the Official Analyst, indicating in particular the number of samples tested per year for the past 5 years and the number of results that showed nitrate levels of below 40 mg/l; below 50 mg/l; above 50mg/l; and above 70 mg/l?
Answer
The Water Resources (Jersey) Law 2007 requires that all boreholes and wells used by homes in the Island are registered with the Government of Jersey Environmental Protection team. There are approximately 3393 homes supplied with drinking water by registered or licenced private water supplies (boreholes, wells and surface water)[1].
The Jersey Official Analyst Laboratory has confirmed that the following number of water sample tests have been submitted by households for nitrate analysis in the past 5 years.
Year | Total Number of Samples[2] |
2014 | 235 |
2015 | 256 |
2016 | 269 |
2017 | 206 |
2018 | 239 |
2019 | 107 (up to April 2019) |
The States of Jersey Official Analyst does not compile an annual breakdown of the specific results, as the results are supplied to the individual householders who commissioned the tests. However, for 2018, the Analyst has provided the following additional specific breakdown in relation to boreholes and wells sampled.
Number of samples | Percentage of samples | |||||||||
Number of samples | Below | Above | Below | Above | ||||||
40 mg/l | 50 mg/l | 50 mg/l | 70 mg/l | 40 mg/l | 50 mg/l | 50 mg/l | 70 mg/l | |||
192[3] | 107 | 123 | 69 | 33 | 56 | 64 | 36 | 17 | ||
In addition, the Environmental Protection team has previously compiled results from the Official Analyst records between 2008 and 2014.
Number of samples | Percentage of samples | |||||||||
Number of samples3 [4] | Below | Above | Below | Above | ||||||
40 mg/l | 50 mg/l | 50 mg/l | 70 mg/l | 40 mg/l | 50 mg/l | 50 mg/l | 70 mg/l | |||
491 | 226 | 266 | 225 | 134 | 46 | 54 | 46 | 27 | ||
Nitrate concentration in groundwater changes gradually over time so the two data sets are broadly comparable.