To safeguard the quality of the sediment at the bottom of water bodies and thus protect public health, the EPA has included sediment management in the Soil and Groundwater Pollution Remediation Act（土壤及地下水污染整治法）. Several subsidiary regulations also have been strictly enforced. However, sediment management and the associated legal infrastructure are still in their infancy in Taiwan. Thus the EPA is diligently improving the relevant legal framework. To improve sediment management, the EPA will focus on integrating and compiling all information collected by various ministries related to sediment along with sediment risk assessment capacity building.
Sediment quality is directly related to environmental and ecosystem protection. The Soil and Groundwater Pollution Remediation Act states that sediment quality is to be regularly monitored for four types of water bodies: rivers, lakes, reservoirs and drainage/irrigation channels. Although allowing sediment to build up at the bottom of water bodies does not pose a direct threat to human health, the long-term accumulation in sediment of pollutants from industrial activity has the potential to harm human health, since pollutants can have a magnified impact as they pass into living organisms in the food chain. Suitable management of polluted sediment that could directly or indirectly affect the quality of freshwater food is thus necessary.
In the past, polluted sediments have posed threats of different degrees to human health in Taiwan. A survey of polluted sediments in irrigation channels showed that many local factories had discharged wastewater that entered directly into agricultural irrigation channels, and in addition, effluents from hidden pipes also drained into such channels, resulting in produce being contaminated through polluted sediment. In 2001, a major incident involving farmlands in Yunlin County（雲林縣） becoming contaminated with heavy metals from polluted sediments clearly demonstrated the need for sediment quality management.
Legal framework for sediment management
Amendments to Article 6 Paragraph 6 of the Soil and Groundwater Pollution Remediation Act announced on 3 February 2010 added the formulating, classified management and restriction use of the sediment quality indicators. The EPA has since announced a series of regulations – such as the Regulations Governing Classified Management and Use Restrictions of Sediment Quality Indicators（底泥品質指標之分類管理及用途限制辦法） and the Regulations Governing Submitting Sediment Test Reports for the Reference of Industry Competent Authorities（目的事業主管機關檢測底泥備查作業辦法）– as well as administrative guidelines such as the Guidelines for Writing Assessment Reports for Sediment Environmental Impact, Health Risks, Techniques, and Economic Benefits (底泥之環境影響與健康風險、技術及經濟效益評估報告撰寫指引) and the Guidelines for Writing Sediment Remediation Plans (底泥整治計畫撰寫指引). In January 2014, the EPA also began requiring industry competent authorities to submit reports on testing they have conducted on water bodies under their jurisdiction.
The most important sediment management work is the establishment of sediment quality determination criteria. Since sediments of different water bodies have varying impacts upon the environment, sediment effects on human health and the ecosystem cannot be determined by a single set of benchmarks. The EPA therefore consulted sediment management strategies of more advanced nations to formulate a set of quality indicators for preliminary screening of polluted sites. If the screening indicates that sediment and organisms might be contaminated, further risk assessments will be applied to determine the pollution potential followed by drawing up a suitable management or remediation plan.
At present, sediment quality survey and related technologies in Taiwan are still in the early stages of development, whereas in the US and EU, sediment management strategies are far more advanced. For example, for a report for the US Congress, the US EPA spent a considerable amount of resources and manpower to collect about 4.6 million data entries from more than 50,000 sites during the 1980s and 1990s. The US EPA later used the data to establish a sediment quality screening methodology and sediment screening benchmarks. In contrast, as of June 2015, Taiwan had only accumulated approximately 20,000 sediment quality data entries. Thus, after referring to the experience and methodologies of advanced nations and incorporating local environmental data, the EPA formulated the Regulations Governing Classified Management and Use Restrictions of Sediment Quality Indicators.
The aforementioned regulations have three main components: items and benchmarks; classified management; and use restrictions of the sediment quality indicators. The indicator items include heavy metals, pesticides, and organic compounds such as polycyclic aromatic hydrocarbons (PAH), dioxins, and plasticizers. For classified management, the sediment quality is graded as one of three grades. The industry competent authority will determine the improving measures and restrictions to be implemented according to the sediment quality grade to ensure environmental safety.
To fully implement the above regulations, the EPA – as authorized by Article 6 Paragraph 7 of the Soil and Groundwater Pollution Remediation Act – has formulated the Regulations Governing Submitting Sediment Test Reports for the Reference of Industry Competent Authorities. The regulations stipulate that industry competent authorities must conduct regular sediment quality testing in all of the water bodies within their jurisdictions at least once every five years, and must submit test reports from the previous year to the EPA by 31 March at the latest.
Sediment quality management strategies
To protect environmental quality and safeguard public health, the EPA is continuously implementing sustainable sediment quality management and developing technologies that fit local environmental characteristics. The EPA’s sediment management has two major priorities:
• Building a comprehensive regulatory infrastructure for sediment management
• Integrating sediment data obtained by various ministries
2) Technology Development
Building local capacities for sediment risk assessment and selection of remediation sites.
Implemented sediment management measures
A general introduction to the regulatory approach to building a comprehensive sediment management system has been mentioned above. Some of the more specific measures being taken include:
1) Integrating sediment data obtained by various ministries
In the past, Taiwan’s sediment survey program lacked systematic survey data. Following the EPA’s announcement of the aforementioned regulations and administrative guidelines, industry competent authorities must now test and report on sediment quality every six months. This will lead to the gradual accumulation of data on domestic sediment quality. Through data categorization, reordering and reduction, the continuously updated data fed into policymaking support systems will give government agencies a better understanding of changes and trends in sediment qualities. Linked with other environmental monitoring data, the computer modeling of water bodies can support decisions regarding suitable times to remove sediment or to conduct other management measures that may pose a threat to public health with better administrative effectiveness.
2) Local sediment remediation risk management capacity building
The EPA is currently rolling out its sediment pollution risk assessment platform that allows for input from experts in related disciplines and combines data on the physical and chemical composition of sediment; environmental, ecosystem, and public health risks; economic cost-benefit assessments; sediment remediation techniques; and data platform building. The sediment pollution platform has been established with the following objectives in mind:
a) Assist in the sustainable management of sediment and development of assessment, management and remediation technology
b) Build a foundation for local capacity building
c) Establish an international cooperation mechanism to promote exchanges for sediment-related technologies and management
In the future, the EPA will seek local and international cooperation in promoting exchanges on sediment-related technology in order to cultivate local research talent and accelerate domestic sediment research, with the hope that Taiwan can become a regional hub for sediment R&D. The EPA is also working with environmental enterprises to apply some of the promising research results in sediment remediation and risk assessment methodologies. The EPA believes that cooperation between government, industry, and academia is the most effective way to solve the problems of polluted sediment.
Expected Benefits and Overall Outlook
Since the amendments to the Soil and Groundwater Pollution Remediation Act in 2010, the phase-in of additional regulations and working principles has rounded out Taiwan’s sediment management system. Pollution survey and assessment technologies have also been developed to meet the requirements of a more complex system. Regular sediment monitoring, which will begin in the near future, should also create a new market for related products and services. However, rapid growth will also create problems in terms of personnel capacity building and technology development and promotion, all of which need to be addressed by the EPA. The EPA expects that the goals of sustainable sediment management and developing local technology will be reached through the establishment of a sediment management system, developing pollution assessment related technology and personnel capacity building.
Excerpt from Environmental Policy Monthly, 18 (7)
- Environmental Protection Administration, R.O.C.(Taiwan)