Manual of Countermeasures to Prevent Groundwater Pollution by Nitrated/Nitrite nitrogen

1. Background and Objectives

Public water and groundwater pollution by nitrate nitrogen and nitrite nitrogen is caused by a variety of sources, and effective measures vary accordingly in each region. In addition, the mechanism of such pollution is significantly complex.

Pollution control, therefore, requires countermeasures to be taken which reflect the natural and social characteristics of the area, the conditions of the pollution and its sources, in addition to the implementation of the controls on water discharge and ban on the infiltration into ground under the Water Pollution Control Law.
Effective measures also require the prefectures and cities designated in the Water Pollution Control Law (hereinafter referred to as 鍍he prefectures・ to formulate the plan for countermeasures to be taken in each region and to implement them in cooperation with related public and private organizations.

This manual describes the procedures for conducting surveys and taking measures to control nitrate/nitrite nitrogen pollution in public waters and groundwater
The procedures in the manual follow the measures presented by the Water Quality Division and Soil and Agricultural Chemical Division of the Central Environmental Council and are based on the case studies accumulated, scientific knowledge and other available information.

2. Procedures for Surveys and Countermeasures

Nitrate/nitrite nitrogen are generated in the process of the nitrogen cycle in the natural environment as well as in human activities.
Surveys to identify the sources and polluted areas of nitrate/nitrite nitrogen pollution must be carried out, bearing this fact in mind, and effective measures to reduce the pollutant load must be discussed and implemented.
The procedures adopted when conducting surveys and taking countermeasures can be divided into four stages:

(1) From Identification of Pollution to Investigation to Delineate the Areas and Identify the Pollution Sources

When pollution of public waters or groundwater is found, appropriate emergency measures, such as announcing people to refrain from drinking groundwater, must be taken in the first place.
Surveys conducted in the period during recognition of pollution and planning of measures include identification of the spread of the pollution and concentration distribution, hydrological and hydro geological conditions, identification of possible sources of the nitrogen load, and identification of the cause.
These studies must serve as a basis for the planning of measures and promotion procedures.

(2) Planning and Promotion of Measures

In planning and promotion of countermeasures, environmental division in charge of the prefectures must set and clearly indicate specific goals and countermeasures for pollution reduction for each pollution source, after thorough discussions with departments in the administrative organization responsible for domestic wastewater management, agriculture and livestock farming, water supply systems and others, agriculture cooperatives, residents・associations, employees・organizations, and other groups.

It is also important that all the stakeholders participate in the promotion of countermeasures by taking their respective role. Even at the stage where all possible causes of pollution have still not been identified, if the source of the nitrogen load and pollution are related to some degrees, pollution reduction measures must be taken promptly along with the identification of the actual cause of pollution.

(3) Evaluation of the Progress of Pollution

After the measures are implemented, the progress of the measures must be reviewed to determine whether the goals for pollution reduction and environmental improvement have been achieved.

(4) Re-planning and Implementation of Another Countermeasures in the Case of No Improvement

When it appears that the environmental conditions have not been improved as planned, its reasons must be identified along with the options to promote new measures to improve the situations.
The new measures for the next step must be implemented to ensure ongoing improvement of the environment.

3. Conducting the Survey

(1) Identification of Pollutantsand Polluted Areas

The results of the series of surveys, including 田ontinuous monitoring survey・conducted by the prefectures carried out according to the articles of the Water Pollution Control Law and water source monitoring data conducted by water supply enterprises or water quality surveys conducted by local governments, must be compiled and analyzed to obtain the latest information on public water and groundwater pollution by nitrate/nitrite nitrogen.

When pollution is found, the investigation of the groundwater or public waters in and around the polluted area, as well as investigations in the areas surrounding polluted wells must be implemented in order to obtain as much information as possible on polluted aquifers, polluted watersheds, concentration distribution of nitrate and nitrite/nitrate nitrogen and other factors.

An efficient way to identify the polluted areas and concentration distribution is to use simplified measuring methods in the first place to obtain an overview of the nitrate/nitrite nitrogen pollution and then to conduct the precise investigations and analyses stipulated in the national guidelines.

Especially in the investigation of groundwater quality, the wells monitored must be carefully chosen to maximize its outcome.
To this end, the information on the location of monitoring wells must be obtained from the local government or other organizations, as well as through interviews at the site.

Information on the flow of groundwater and hydrology of the aquifers must also be taken into consideration when making decisions. When the aquifer which supplies water to the polluted well is identified, the wells acquiring water from same aquifer should be also investigated. When the aquifer supplying water to the polluted well is not identified, the wells whose aquifers are known should be selected from the wells in the areas surrounding and be investigated in order to identify the polluted aquifer. Then the wells fed on that aquifer should be investigated.

It is preferable to select other aquifers as well in order to confirm no pollution. When nitrate /nitrite nitrogen pollution is identified, the organizations responsible for the water supply system must notify the stakeholders in order to prevent any adverse effect on human health by way of drinking the polluted water. The owners of the wells must be informed of the pollution if the groundwater is used for drinking or household use and the water supply enterprises must be also informed.

(2) Information Gathering.

Information must be collected and analyzed to get the overview on hydrology, hydrogeology, land use, and distribution of pollution sources in the designated area by taking into consideration of geography and groundwater flow of the area where the pollution has been found and its surroundings, groundwater recharging area, and public water catchment area.
Interviews and field studies must be conducted, too, if necessary.
The information collected from these documents must be appropriately organized in appropriate ways, such by mapping and so on.
Special attention must be paid when the polluted well is of a deep well, since the pollution sources may be located at a significant distance upstream from the polluted area. In addition, in some cases the pollution can be caused by the land used in the past.
The data on he history of the land use of the land, therefore, should also be collected.

As nitrate/nitrite nitrogen can be generated from nitrogenous compounds in the environment,.
To learn the amount of nitrogen supply, data on the following, must be obtained.
Although it is preferable to obtain the data for the amounts of applied fertilizers, discharged water and its nitrogen content by carrying out the investigation,
In the case with no monitoring data in existence, figures per unit and other necessary data should be obtained which are necessary for the calculation of the amount of nitrogen supply should be obtained from literature and other sources.

Commercial Facilities Data on treatment, amount, nitrogen concentration and other factors of the wastewater in factories and commercial facilities, business establishments where water containing nitrogen is discharged.

Species and types of livestock, number of animals, rearing system, amount of animal waste generation of livestock excrement, conditions of animal excrement treatment for different treatment methods, level of nitrogen in animal excrement

Number of people using the sewage systems, rural sewage treatment systems, domestic wastewater treatment tanks, and other domestic wastewater treatment systems, as well as wastewater nitrogen concentrations in these systems; nitrogen concentration in miscellaneous domestic wastewater when a flush toilet wastewater treatment tank is used; conditions of underground seepage infiltration treatment;

The size of agricultural farmland, types of crops, annual quantity of fertilizer applied, nitrogen content of the fertilizers, fertilization standards for the fertilization, nitrogen intake of the crop, fertilizer application methods, timing of fertilization, type of fertilizer, amount and quality of wastewater from cultivation facilities

Nitrogen concentration in groundwater that is considered to be free from anthropogenic influences (amount of nitrogen derived from deposition, plants, animals, and microbes in soil), amount of precipitation and nitrogen concentration in precipitation, seepage percolation rate of precipitation

(3) Identification of Pollution Sources

By reviewing the results of monitoring surveys and information gathered above, the factors, including concentration distribution of nitrate/nitrite nitrogen, location and distribution of the sources of nitrogen load, amount of nitrogen supply for each pollution source, groundwater flow, groundwater recharging area and river flow, should be analyzed to identify the cause of pollution. In the analyses, the following items must be checked if applicable.

In order to understand the distributions of nitrate/nitrite nitrogen, it is preferable to analyze the composition of wastewater and fertilizers and other items, in addition to the concentration of nitrate/nitrite nitrogen.

4. Area to be Controlled

The area to take specific measures shall be the area related with the nitrate /nitrite nitrogen pollution where the EQS for nitrate/nitrite nitrogen has been met or is not likely to be met.

The area where to take specific measure must be determined based on the results of monitoring investigations, information gathering and pollution source analyses, and by comprehensive analysis of the distribution of nitrate/nitrite nitrogen concentrations, location and distribution of the sources of nitrogen load, catchment area of the public water area, groundwater flow, and groundwater recharging area.

In order to promote the pollution reduction measures accounting for the local conditions, other information may be taken into consideration when determining the area. For instance, several polluted areas can be combined into one to take same measurement.
Municipal borders, the area of a district covered by an agricultural association and the area covered by the sewage treatment system can be accounted for the determination of the controlled area.

The followings are the items to be considered when the area to be controlled is determined.

(1) When the nitrate/nitrite nitrogen concentration is increasing in a groundwater basin area or the pollution is found in the whole area or scattered throughout the area, the entire groundwater basin should be covered.
The groundwater recharging area of the polluted aquifer must also be carefully taken into consideration.

(2) When the polluted area is isolated in a plateau, the polluted area shall be designated as the area to be controlled.
However, several plateau areas share a number of common factors, including specific methods for pollution reduction (e.g., when several plateaus separated by a valley or river are located in close proximity and they share similar land use and the same kind of sources of nitrogen load), the whole region that includes these plateaus should be treated as one area to be covered.

(3) When the pollution take places in an alluvial fan or ocean front, the determination to designate the whole area or part of the area must be made based on the continuity of the pollution derived from the concentration distribution of nitrate/nitrite nitrogen and other substances, estimated distribution of the sources of nitrogen load, groundwater flow and other information. When the pollution take places in an aquifer close to the surface, the source of the nitrogen load is likely to be within the polluted area where the or in the surrounding area.
On the other hand, when the pollution take places in an deeper aquifer layer, the geographical structure and groundwater flow of a wider area must be analyzed along with the conditions of the groundwater recharging area in order to make an appropriate determination.

(4) When the pollution is found in public water, the area to be covered must be determined by reviewing the distribution of nitrate/nitrite nitrogen concentrations, volume and nitrate/nitrite nitrogen concentration of the water flowing into the area (e.g., rivers, public waterways and discharge from factories and commercial facilities), and land use and geographical conditions of commercial facilities.
In such cases, careful attention must be paid to the distribution of ammonia nitrogen concentrations, as well as the volume of water discharged from factories and commercial facilities.

(5) When nitrate/nitrite nitrogen pollution is found both in public water and groundwater and the pollution of these water bodies is considered to be caused by one nitrogen load source, the area related both with the public water and groundwater should be preferably treated as one area.

(6) When the pollution is a point-source pollution limited to a narrow area, the individual control over the point-source should be discussed (rather than designation of the controlled area).

5. Planning of the Countermeasures

A coordinating organization (e.g., liaison group and coordinating group) of all the stakeholders in the area designated shall be established to promote sharing the information on the range of pollution, cause of pollution, area to be covered, and others. The reduction target assigned for each source and countermeasures to be taken to achieve the target are also discussed by the organization members.
Promotion of the countermeasures, review of the progress and determination to continue or revise the countermeasures are also on the agenda of the organization.

(1) Members of the Coordinating Organization

The coordinating organization should consists of members selected from the local government officials in the area who are in charge of such subjects as environmental management, domestic wastewater treatment, agriculture and livestock and water supply systems, as well as those from agricultural associations, residents・associations, employers・organizations, experts and so on.
Members should be selected to reflect the he conditions and surces of the pollution in the area.

(2) Establishment and Operation of Coordinating Organizations

Establishment, convocation of meetings, discussion on opinions and other administrative tasks on of the coordinating organizations are carried out under the leadership of the environmental division of the local governments.
When the area is located across the borders of prefectures, the coordination and cooperation among the concerned local governments is essential and may take the flexible measures. In some cases, a government may be chosen to take the leadership based on the geographical and other conditions of the area. Existing organizations may be used for the purpose.

(3) Items to be Discussed and Reviewed in the Coodinating Organizations

6. Promotion of the Measure

(1) Planning

Based on the results of discussion at the coordinating organization, the prefecture. lays down the plan for promotion of measures to control nitrate/nitrite nitrogen pollution. In the planning stage, reduction targets for each source, specific measures to achieve the targets, methods to evaluate the progress of the measures, and other items must be clearly indicated under the common recognition by the members with the aim to reduce the level of nitrate/nitrite nitrogen concentration below the EQS.

• Basic Philosophy of the Planning

The plan must indicate the goals and specific measures to be taken which accounts for the pollution level, geography, geology, conditions of the surrounding areas, current land use and natural and social conditions, so that the measure to control nitrate/nitrite nitrogen pollution can be implemented most effectively.
As the sources of the nitrate/nitrite nitrogen has a variety including wastewater from factories and other facilities, livestock excrement, domestic wastewater, and fertilizers used for a variety of crops. When specific measures and targets are discussed for each pollution source, knowledge from all of the governmental divisions and private organizations concerned should be accounted.
t would be preferable to include a set of action plans designed specifically for each member of the coordinated organization in order to ensure the effective implementation of the plan.
The countermeasures to reduce the nitrate/nitrite nitrogen load to the public water and groundwater must be prioritized. Purification of polluted groundwater must be discussed, accounting for the conditions of the pollution, the urgency level of the measure, current progress in of technological development and other factors.

• Contents of Plan

The plan must include the following.
a. Delineation of the area to be controlled.
b. Basic principles and goals of the measure.
c. Specific targets and procedures to reducer the load from or each pollution source.
- Factories and commercial facilities / - Livestock excrement / - Domestic wastewater / - Fertilization / - Others
d. Measures on water supply systems and wells for drinking water.
e. Methods to determine and evaluate the progress of the measure.
f. Scheme to promote the measures.
g. Others - Awareness raising and instruction for local to the industries and residents

(2) Implementation of the Measure

Below is a list of the control measures for each pollution sources.
When measures to reduce the load of nitrate/nitrite nitrogen are implemented, the most appropriate and effective methods for the case, accounting for the cause and conditions of the pollution, social and natural conditions in the region and other factors, must be selected from the list and included in the plan for promoting on of measures.
Such measures must be implemented in good coordination and cooperation among the members of the coordinating organization concerned.

• Measures for Factories and Commercial Facilities

Generation of wastewater from factories and commercial facilities and infiltration into ground of sewage and other wastewater must be treated by fully complying with the regulations stipulated in the Water Pollution Control Law. Appropriate measures must also be promoted also for facilities that are not subject to the regulations.

• Measures for Livestock Excrement

n accordance with Following the Law Concerning the Appropriate Treatment and Promotion of Utilization of Livestock Manure, appropriate measures must be taken to:

(1) comply with the management standards for livestock excrement treatment and construction standards for storage facilities,

(2) promote appropriate management of livestock excrement under the plan by the prefecture that stipulates the targets for the facility improvement and

(3) promote the use of such facilities. These measures, in accordance with the Law, are effective in to reducing the pollution by livestock excrement. The comprehensive measures in accordance with the Law must be fully taken and improvement of facilities must be prioritized. Other measures to meet the regional needs should be promoted.

• Measures for Domestic Wastewater

In order to reduce the pollution load from domestic wastewater, the framework of the domestic wastewater measures based on the Water Pollution Control Law must be promoted.
In addition, improvement of treatment facilities for domestic wastewater, such as sewage systems, installation of domestic wastewater treatment tanks, and proper maintenance and management of treatment tanks must be promoted.

The revision of the Law for Combined Household Wastewater Treatment Facility (on June 2, 2000) obligates installation of a combined household wastewater treatment tank that treats both raw sewage and general wastewater from households when new buildings are constructed. The revision also stipulates the regulations to promote switching of the existing flush toilet wastewater treatment tanks to combined household wastewater treatment tanks. Such promotion must be continued.
Also, installation of combined household wastewater treatment tanks equipped with a nitrogen removal function should be encouraged.

The proper discharge of the wastewater must be ensured in some regions, where groundwater is polluted because of the insufficient installment of drainage canal for household wastewater, allowing the wastewater to infiltrate into the ground.

• Measures for Fertilization

When instructions for proper management of soil, including fertilization standards, stipulated by the prefecture, are not observed, appropriate measures must be taken to promote the compliance with the instructions for proper management of soil, including fertilization standards.
Even when the fertilization standards are met, the soil management must be examined and procedures for the improvement must be discussed if t groundwater is pollution by fertilizes.

To this end, a variety of measures based on the Guideline for the Control of Soil Management Pollution Concerning Related Nitrate/nitrite nitrogen must be taken. Such measures may include re-evaluation of the current soil management, strict enforcement of appropriate fertilization methods based on the analyses on the soil and crops, promotion of proper fertilization based on the specific quality properties of organic materials such as compost, promotion of new fertilization techniques, including the use of controlled fertilizer application, and examination of the current systems of cultivation systems.

(3) Evaluation of Progress

Once implementation of the measure is initiated, the progress of the measure must be evaluated based on the information on the implementation of the measure for each pollution source, quality of the public water or groundwater in the area and other factors.
The methods used to obtain information on the progress must be included in the plan for promotion of measures to control nitrate/nitrite nitrogen pollution from the beginning to obtain accurate information.

• Obtaining Information for Implementation of the Reduction Measures

Progress in the improvement facilities, volume of nitrogen application, volume of nitrogen treatment and other factors are studied for each specific target and measures that are described in the plan for promotion of measures to control nitrate/nitrite nitrogen pollution. Each stakeholder who takes the specified measures should be instructed to collect and keep the records to evaluate the implementation of the measure.

• Obtaining Information on the Water Quality

The points should be selected as monitoring sites where changes in of the quality of the public water or groundwater, as well as on the effectiveness of the measures, can be monitored. The selection should be made based on the results of the investigation to delineate the polluted area, information and analyses of pollution causes, while taking into consideration of the location and distribution of the sources of the load, groundwater flow, river flow and other information. The monitoring items shall be nitrate/nitrite nitrogen.
Other items, such as water quality properties at the source of the load, may be also selected if necessary.

(4) Determination to Continue or Revised

he coordinating organization shall evaluate the progress and discuss continuation of the implementation or initiation of new measures and/or revision of the reduction targets. Based on the results of discussion, either continuous implementation of the existing measures and/or implementation of a new measure shall be carried out.

7. Information Disclosure

Information on the water quality, targets of the measure, current progress of implementation and others are disclosed to the public Awareness raising programs must be carried out and information must be provided for the businesses and, residents in the area and other people concerned in an appropriate manner so that they can share the accurate information. This is important if the measures are to be promoted and to prevent damages caused by rumors.

Flow Chart of the Regional Measures Concerning Nitrate/nitrite nitrogen Pollution