For the prevention of soil and groundwater pollution, local competent authority must carry out regular testing, pollution investigation and verification of public petition for soil and groundwater quality in the area of under jurisdiction. Therefore, Taichung City Government Environmental Protection bureau (herein referred to as EPB) to control soil and groundwater pollution quality constantly, commissioned AECOM Taiwan Corporation (herein referred to as the team) to perform " Year 2013 Soil and Groundwater Pollution Investigation and Verification project "( herein referred to as the Project). According to the contract, it is required to submit the Project final report (draft) before November 15th,2013 and submit the formal final report (approved version ) based on EPB’s comments.
The project contract amount of work were adjusted based on the progress of sites improvement schedule, the application of change order were submitted respectively on May 10th and November 20th,2013 The applications were approved by EPB on June 28th and November 27th,2013. All work items were accomplished according to the planned schedule.
The investigation of high pollution potential areas, agricultural land and area around suspected sources of pollution was based on Article 6 of the Soil and Groundwater Pollution Remediation Act. For those areawith the pollutant concentrations below the Soil Pollution Control Standards but exceed the Soil Pollution Monitoring Standards the monitoring were conducted continuously.
Total 214 lots farmlands that exceeded the Soil Pollution Control Standards(agricultural food crops) in 2011 and 2012 were investigated. The results indicated there were 50 lots of agricultural land exceed the Soil Pollution Control Standards and total area was about 8.1 hectares. It is recommended to carry out detail investigation to promote the future pollution improvement after official public announcement. Using previous survey results as a basis to calculate the average difference between heavy metal concentration in the monitoring of agricultural land. It was found that concentration of copper, chromium, lead and nickel pollutant hadthe highest average increment in the first trunk of Jan-Tsuo-Yuan canal, were 10.7 mg/kg, 25.6 mg/kg, 2.5 mg/kg and 21.4 mg/kg respectively. As a result, the team concluded that an external contamination flows into agricultural land continuously.
The team completed groundwater sampling work, total 156 monitoring wells during the dry and wet season. According the sampling results, groundwater concentration exceeded Pollution Control Standards at land lot No.377 Jingmei section Beitun district, chlorine contamination area in Tanzi district and Beitun district, Aerospace Industrial Development Corporation (AIDC) in Xitun district, Wang Tian plant Sinon Corporation in Dadu district, large storage tank area at port of Taichung, Feng-fu gas station of Taiwan Youni Corporation and Shigang gas station of Formosa Oil Corporation. Therefore, It is recommended that in addition to monitor groundwater constantly, EPB enhance the supervision of improving sites improvement to speed up the releasing of sites earlier.
For the wells inspection and maintenance portion of works, annual inspection were conducted twice, 15 monitoring wells down-hole video inspection, 51 monitoring wells exterior maintenance work, 7 temporary wells were abandoned at Guangzheng road of Dali district, . Standard monitoring well located at Xia Tian dike (L00040) was also abandoned in Wurih district. A new standard monitoring well (L00173) was installed in Taiping Nursery of Houli district. Based on the results of inspections this year, it is recommended EPB to have priority of maintenance work of well cement platform, warning pillar and protective casing pipe next year to provent contamination leaking into monitoring wells and pollute groundwater directly.
Inventory of seven region’s residentail wells and total 30 wells sampling work was conducted this year, concentration of trichlorethylene exceeded drinking water standard at 4 residential wells in Tanzi district and Beitun district. EPB had requested management unit to prohibit the use for drinking purposes.
The team has designed a the classification system for the control sites, increase 1.5 times the frequency of inspections for the 28 first degree sites and enhanced sites inspection at specific milestones, for example when contaminated soil off-site treatment to confirm operations and schedule executed in accordance with the approved plan. In addition, follow-up control measures were proposed for each site to facilitate EPB’s administrating process control.
The verification of 13 sites whose contamination improvements were completed was conducted. Following 4 sites are not meet the improvement goal and need to perform the improvement work continuously: Houli gas station of Shan-Loong transporttion corporation, land lot no.176-140 Jan-Tsuo-Yuan section, Taichung Elementary School, Yung-Zip Chemical Corporation; The results of verification indicated Jin-wan Gas Station, Shueinan airport (O and H zone), Tai-Fu industrial company, Taiwan Aisin Elite MFG corporation, land No.98 Shi-Nan-Shi section of Wurih district, Taichung port gas station of Di-Wa corporation, Cheng-He corporation, land No.893 Jung-He section of Longjing district, land No.53 Jan-Tsuo-Yuan section could meet the improvement objectives.
The review of underground storage tank system reportingwere completed on June and October, 2013 and 320 gas stations and 317 gas stations were reviewed respectively. It is100 percent of the reporting and review rate. If reporting data was abnormal during review, Clarification and correction was requested by phone immediately. The tracking of reporting data correction was accomplished.
For the assistance of administration, the team had assisted EPB to executive 6 emergency investigation initiated by public petitions, total funding for the implementation is NT$ 751,000 dollars, NT$49,000 dollars left. Additionally, the team completed ”Explanation Session of Soil and Groundwater Pollution Remediation Act”on June 14, 2013,and“Explanation Session of Underground Storage Tank System Regulations Guidance“ on August 21, 2013. Total number of participants are 310 and meet the contract requirements. Besides, the team assisted EPB to held “Brownfield Redevelopment and Green Remediation International Workshop” on October 24, 2013, to promote environmental technologies exchange with domestic and foreign experts, environmental agencies, and industrial circles.
The strategy of promoting integrated management of soil and groundwater contamination, the team used the geographic information system to integrate the relevant information of soil and groundwater in Taichung city. Accomplished input of 4,219 data provided by EPB this year. In addition, the team converted GIS system file format to KML format, therefore EPB could use with a PC or tablet computer by importing the data in Google Earth. Moreover, the team completed the potential pollution classification system and proposed the response strategies and the initial plan of action management.