Latvia’s Inčukalns acid tar ponds to be cleaned up thanks to EU support

Located in Latvia’s Inčukalns County, around 35 km north-east of the capital, Riga, the two Inčukalns acid tar ponds are among the country’s most polluted Soviet-era waste dumping sites. To remedy this, the second phase of a two-phase, EU-funded environmental remediation project is now underway.

Additional tools


The main element of phase two is the installation of a monitoring system to help ensure the quality of the groundwater in the area around the ponds meets legislative requirements.

After the completion of the project, which is scheduled for December 2023, the Latvian State Environmental Service will maintain the site for at least five years and continue to monitor environmental quality in the area for at least 30 years, to ensure the long-term sustainability of the remediation works.

Dangerous levels of contamination

The northern and southern Inčukalns acid tar ponds are near one of Latvia's main rivers, the 460 km-long Gauja, which rises in the Vidzeme highlands and subsequently forms part of the Latvian-Estonian border, before flowing into the Gulf of Riga at the village of Carnikava.

Between the 1950s and the 1980s, during the Soviet occupation of Latvia, the ponds – which were originally sand quarries – were used as dumping sites for waste from Riga's pharmaceutical and fragrance industries. Much of the waste contained a mixture of used lubricating oils and sulphuric acid tar from a lubricating oil processing plant. Other waste from medical and perfume oil production was also disposed of there.

As the quarries had no lining, either at the bottom or on the sides, the acid tar filtered into the soil and contaminated the groundwater. Today, the level and distribution of the contamination from both ponds presents a danger to human health and the environment.

A healthier environment

Over both phases, the aims of the project are twofold: to prevent the further spread of the pollutants, especially the contamination of groundwater by infiltration of waste acid tar; and to clean up the sites so that they no longer pose any risk to public health or the environment and can be used for economic purposes.

Phase two will ensure the completion of the works which began under phase one and the full attainment of all project objectives. Implemented during the 2007-2013 programming period, costs under the first phase that were eligible to be covered by EU funding instruments totalled over EUR 27.6 million. In excess of EUR 19.3 million was made available for that phase through the European Regional Development Fund.

Thousands of tonnes of material from the ponds has already been purified, often by being mixed with wood shavings, and removed from the area. Among other things, this material can be processed for use in the production of clinker, which acts as a binder in cement.

Total investment and EU funding

Total investment for the project “Historically contaminated sites ‘Inčukalns acid tar ponds’ remediation works – phase II” is EUR 29 699 997, with the EU’s European Regional Development Fund contributing EUR 24 869 085 through the “Growth and Employment” Operational Programme for the 2014-2020 programming period. The investment falls under the priority “Environment and resource efficiency”.

Draft date