Report to the Minister for Health and Social Services - Dispensations for water quality parameters granted under Article 9C of the Water (Jersey) Law 1972- amendment No. 2
1. Background
Under Article 9C of the 1972 Law as amended, The Jersey New Waterworks Company Ltd. may apply for dispensation for one or more water quality parameters, subject to a number of conditions including:-
- that the dispensation is necessary to maintain a supply of water for domestic purposes;
- that a supply of water for those purposes cannot be maintained in the specified areas by any other reasonably practicable means; and
- that the supply of water in accordance with the dispensation does not constitute a potential danger to human health.
Under Article 19 of the Water Law 1972 the Minister for Health and Social Services is a statutory consultee for dispensation requests from Jersey Water to the Minister of Planning and Environment. This is to ensure that in considering the implications of any dispensation the human health concerns may be addressed prior to a decision being made.
2. Issues
The current dispensation levels have been in place since 01 January 2004 (the start of the law). The Health Protection Service have previously intimated in discussions with Jersey Water and Environmental Protection that when the current dispensations run out they would not be prepared to agree to a further set of dispensations without there being in place proposals to achieve the overall compliance with the water quality parameters of the legislation.
Officers from Environmental Protection and Health Protection Services met on the 14th August 2008 to discuss the dispensations which had been received by the Minister for Planning and Environment from Jersey Water.
Table 1 Current (and proposed) levels of dispensation
Parameter | Maximum allowable concentration | Percentage of samples allowed per annum (%) |
Nitrate (and nitrite) | 70 mgl-1 | 33 |
Manganese | 100 µgl-1 | 5 |
Iron | 500 µgl-1 | 5 |
In the past Jersey Water has instigated various measures to reduce the concentration of these parameters, including:
1.1 Nitrate (NO3)
- Introduction of online monitoring at water resource sites over the past five years to enable blending of source water at critical times.
- Mixing nitrate free water from the desalination plant to dilute surface water source nitrate levels.
Considerations
Levels of nitrates in source water in the Island are proportional to rainfall. Recent wet summers have caused increased run-off from agricultural land with stream sources frequently being >50 mgl-1 (the maximum allowable concentration). In such circumstances, it is impossible to blend surface waters.
1.2 Manganese (Mn)
- Oxidation of raw water at the treatment works and removal by rapid gravity filters.
- Blending of raw waters prior to treatment.
Considerations
Manganese is mainly derived from the biological breakdown of vegetation in reservoirs during spring and autumn caused by rapid temperature inversion. Gravity filters cannot cope with this sudden shock loading and short-term peaks in manganese above 50 µg l-1 may occur.
1.3 Iron (Fe)
- Rolling programme to replace old iron and steel service pipes @2.5 km per year.
Considerations
Routine maintenance and removal of pipes disturbs iron deposits and can result in levels exceeding 200 µgl-1 for short periods of time.
- Health implication
The provisional health-based guideline value for manganese set by the World Health Organisation is 500 µgl-1 (i.e. more than the stipulated 100 µgl-1 requested in the dispensation). No health-based guideline value exists for iron.
Nitrate therefore represents the major exceedence of a health-based guideline value and the contaminant of concern with regard to this dispensation from Jersey Water. It is recognised that Jersey Water alone is unable to control the cause of nitrate in its source water and that subsequent interventions to reduce concentrations are limited.
- Long-term solutions
The use of treatment processes for the long term solution to the problem of elevated nitrates is not possible due to the large volume of heavily contaminated waste that would require disposal. In the past the company have looked at nitrate removal but this would require discharge to sea of significant volumes of very high nitrate effluent. Approximately 25% volume of throughput is lost to waste.
Long-term solutions for reducing nitrate in source water, through better land management and use, may be achieved through the implementation of Water Catchment Management Areas under the provisions of the Water Pollution (Jersey) Law, 2000 and the EU Water Framework Directive (EU 2000/60/EC).
Implementation on a pilot scale is about to commence in the Val de la Mare catchment. The work is being led by Environmental Protection, Environment Division and will be undertaken alongside the work of the Countryside Renewal Scheme operated by the Environment Division.
Officers from Health Protection Services have agreed to the current dispensations (Table 1) being extended from 01 January 2009 subject to the approval of the MInister, provided:
- that Environmental Protection and Jersey Water undertake the implementation of Water Catchment Management Areas under the provisions of the Water Pollution (Jersey) Law, 2000 and the EU Water Framework Directive (EU 2000/60/EC).
- that the end point of the dispensations directly relates to publication of a report on the outcome of a pilot project assessing the viability and contribution of Water Catchment Management Areas to the Island.
The pilot phase project for the Val de la Mare catchment was discussed and agreed. The terms of reference for this project were given as:
1) Assess the impact on water quality that a series of identified changes in land management and use can achieve.
2) Investigate the practicalities and costs of undertaking such changes.
3) Develop knowledge and working relationships necessary for island-wide implementation.
Health Protection Services agreed that this represented the optimal start for the implementation of Water Catchment Management Areas on an island-wide basis resulting in the minimisation of nitrate concentrations in source waters. This work will complement ongoing implementation of the Water Pollution (Jersey) Law 2000.
Recommendation
The Minister supports the Officer decisions and agrees to the current dispensations (Table 1) being extended from 01 January 2009, provided:
- The Minister for Planning and Environment and Jersey Water undertake the implementation of Water Catchment Management Areas under the provisions of the Water Pollution (Jersey) Law, 2000 and the EU Water Framework Directive (EU 2000/60/EC).
- The end point of the dispensations directly relates to publication of a report on the outcome of a pilot project assessing the viability and contribution of Water Catchment Management Areas to the Island.
iii. The pilot phase project for the Val de la Mare catchment is implemented as agreed along the stated terms of reference.
Stephen D Smith
Head of Health Protection Services
14 October 2008
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