Karen hill tribe representatives from Klity Creek in Thong Pha Phum district of Kanchanaburi filed a petition with the environment minister on Friday calling for faster action to clean up the creek, which is heavily contaminated with lead.
The Supreme Administrative Court ordered the clean-up work to begin four years ago but little has been achieved so far by the Pollution Control Department (PCD), they claimed.
Kamthorn Srisuwanmala, who represents Karen people affected by lead contamination, said the local people are frustrated by the slow rate of progress.
So far, two dykes have been built to hold back lead-contaminated sediment, but no plans have been put forth to show how the rest of it will be removed, he said.
"The department must accelerate its efforts as we still drink and use the water from the contaminated creek," he said, adding that department officials have visited locals frequently about the issue.
Mr Kamthorn and a group of about 20 Karen people petitioned Natural Resources and Environment Minister Gen Surasak Karnjanarat on Friday to press their demand.
They also lodged another petition at Government House.
A ministry representative said he received their letter and that the process to hire a contractor for the clean-up work is taking time, which has led to the delays.
Mr Kamthorn said residents have heard rumours that a bidder has already been selected but that the government has not yet agreed terms with them, which prompted them to come forward and ask the department to accelerate its efforts.
The department should expedite the work or risk facing a penalty for violating the court order, according to Surapol Kongchanthuek, director of the Karen Studies and Development Centre.
Locals have already informed the court of the long delays, Mr Surapol said.
Klity Creek was contaminated by water illegally discharged from a nearby lead factory operated by Lead Concentrate Co. The Department of Mineral Resources ordered the closure of the company in 1998, the same year the contamination was exposed.
In 2002, the 22 victims affected by consumption of the water filed complaints with the Central Administrative Court against the PCD for being too slow to clean up the creek. The Supreme Administrative Court in 2013 ordered the department to rehabilitate the creek and compensate the Karen who lodged the complaint.