Layout of the STEIH industrial wastewater treatment plant.
Published on 01/07/2021
The lindane remediation site was located along the left bank of the Rhine in the border region of Switzerland, France and Germany in the village of Huningue, next to Novartis Headquarters in Basel.
The site was originally owned by the former French agricultural chemicals company Produits Chimiques Ugine Kuhlmann and was used in producing the pesticide lindane. Sandoz AG bought the land in 1974. In 1978, Sandoz constructed an industrial wastewater treatment plant for the neighboring chemical and pharmaceutical companies in the industrial zone of Huningue Sud.
Ugine Kuhlmann had begun producing lindane in 1947, and was one of many companies that provided the marketplace with the then popular pesticide.
About lindane
Lindane is the name given to the chemical compound hexachlorocyclohexane (C6H6Cl6), also known as HCH, which was first synthesized in 1825 by Michael Faraday. In 1884, HCH was discovered to be a mix of different isomers. In fact, there are eight known isomers, all of which correspond to the formula C6H6CI6, but whose chlorine and hydrogen atoms are arranged differently around the carbon ring. It was not until the early 1940s, when the chemicals industry was searching for new pesticides that researchers focused on HCH and its impact on insects.
Global lindane usage peaked during the 1960s and the beginning of the 1970s. Lindane was widely applied as a broad-spectrum insecticide for agricultural and nonagricultural purposes, including the treatment of seeds and soil, and of animals to control ectoparasites. Lindane was also used as a wood preservative, along with, for example, polychlorinated biphenyl (PCB). Eva C. Voldner and Yi-Fan Li estimate that from 1948 to the early 1990s, global lindane production totaled around 720,000 tonnes.
In 1987, the International Agency for Research on Cancer, which is part of the World Health Organization (WHO), classified lindane as “possibly carcinogenic to humans” (Category 2B).
It was not until 2007 that the European Union banned the use of lindane as an insecticide, as stipulated in Regulation (EC) No. 850/2004. In 2009, HCH was also included as a persistent organic pollutant (POP) for elimination of usage in the Stockholm Convention, an international environmental treaty ratified by the majority of states across the globe.
In 2015, WHO classified the β-isomer, which has the greatest toxicity after chronic exposure, as “carcinogenic to humans” (Category 1). Chronic exposure is highest globally among agricultural workers and pesticide users. Lindane is now banned or restricted in most countries. Lindane medications, however, are still available in the United States, where the compound is approved as a second-line treatment for skin parasites, primarily scabies and lice.
Lindane was typically produced by chlorination of benzene in the presence of ultraviolet light, using high-pressure mercury lamps to form α-HCH (70 %), β-HCH (12 %), γ-HCH (10 %) and δ-HCH (7 %). After neutralization with an alkali solution and distillation of the remaining benzene, a white crystalline residue remained, referred to as crude HCH.
Odor emissions
In the early 1950s, it was found that potatoes treated with HCH tasted and smelled of chemicals, earning them the name “hexa-potatoes” as stated in the American Potato Journal. Consequently, the production process was changed. Instead of using all the isomers, some of which caused malodor, only the γ isomer, which had insecticidal properties, was used.
However, the new production process led to 8 to 12 times more waste isomers of HCH, creating challenges for the proper management of these wastes.
Production waste
From the 1950s, Ugine Kuhlmann tried to reuse some of the waste. Discarded isomers were used for conversion to 2,4,5-trichlorophenoxyacetic acid, a herbicide, and 2,5-dichloro-4-bromphenol-oxyphosphoric acid, an insecticide. In the 1960s, the company also started to produce 1,2,4-trichlorobenzene (TCB).
Nonetheless, the new production process still generated large amounts of waste. In the late 1960s and early 1970s, Ugine Kuhlmann stored tonnes of HCH waste at the site – unprotected and visible to all, and disposed of HCH waste onsite. From today’s perspective, efforts to manage and dispose of the waste material were unacceptable.
It was already known to the French authorities – shortly before Ugine Kuhlmann stopped its production in 1974 – that the company had buried material in a 4-meter-deep pit of 2,500 square meters, which was covered with asphalt (the “HCH pit”). Waste was also mixed as an additive in concrete and used for road construction in the Alsace region. Between 1965 and 1970, lindane waste was deposited in landfills in the municipalities of Sierentz, Wintzenheim and Huningue in the Haut-Rhin department and Hochfelden in the Bas-Rhin department of Alsace, France, according to the French Basol database of contaminated sites.
Public perception
Meanwhile, public awareness of chlorinated pesticides and their effects on humans and the environment was increasing, inspired by Rachel Carson’s Silent Spring. The book first appeared in 1962 in the United States and was translated into German under the title Der stumme Frühling in 1963.
In the early 1970s, the United States issued an import ban on Swiss cheese after lindane was detected in some products. Systematic measurement of cow’s milk carried out in the northwestern area of Switzerland subsequently showed that some of the samples from milk producers exceeded the HCH limits set by WHO. Consequently, a ban on the use of this milk in Switzerland was issued in the autumn of 1972.
As part of the systematic measurements, the Basel Cantonal Laboratory detected HCH isomers within a radius of 30 kilometers of Ugine Kuhlmann’s factory. In September 1972, the Swiss newspaper National-Zeitung reported on the connection between the HCH contamination and production in Huningue, which was followed up in the French daily L’Alsace Saint-Louis. HCH was detected not only in Switzerland but also in the neighboring communities of Weil am Rhein in Germany as reported by the National-Zeitung, and a ban on the use of this milk was put in place in Germany during 1973.
When Ugine Kuhlmann ceased production in 1974, Sandoz built an industrial wastewater treatment plant on the grounds of the former production site. The plant was used to treat the industrial wastewater of Sandoz and several of the neighboring chemical and pharmaceutical companies, including BASF and TFL France.
During the construction of the wastewater treatment plant, the French authorities demanded that three groundwater monitoring wells be installed to monitor groundwater flow and contamination around the HCH pit, which was located below one of the plant’s parking lots.
The monitoring showed that the groundwater was contaminated with HCH isomers, which necessitated further studies as well as immediate containment measures. In 1992, a hydrological and hydrochemical study was carried out by the Bureau de recherches géologiques et minières (BRGM). In 1994 and 1995, additional areas of the site were investigated by Antea, a consultancy. The investigators found that the HCH contamination extended beyond the initial target area around the HCH pit.
Demands for remediation
On February 16, 1996, a report from the Regional Directorate for Industry, Research and the Environment (Direction régionale de l’industrie, de la recherche et de l’environnement, DRIRE), was sent to the Prefect of the Upper Rhine (Le Préfet du Haut-Rhin), highlighting the groundwater pollution. On June 20, 1996, the Prefect of the Upper Rhine issued an order stating that the existence of residual deposits of lindane waste was likely to damage the soil and subsoil and that Ugine Kuhlmann must be considered responsible for the pollution. According to the order, remediation work was to be started within six months of receipt.
On September 5, 1996, the wastewater treatment plant operator, Sandoz, submitted a report describing the means of containment of the HCH pit. Shortly after this, on December 23, 1996, Ugine Kuhlmann went into liquidation and the French authorities demanded that the liquidator carry out additional containment work. As this did not occur, the Prefect of the Upper Rhine requested funds from the French Environment and Energy Management Agency (Agence de l’environnement et de la maîtrise de l’énergie, ADEME) to manage the contaminated groundwater while Sandoz voluntarily continued to monitor and treat it.
In October 2000, ADEME commissioned Gester, a consultancy, to carry out an assessment of the situation on the basis of existing data and also to collect groundwater samples.
Start of initial remediation measures
Over the years of operation of the industrial wastewater treatment plant, the layer of asphalt and concrete over the HCH pit eroded and cracks started to appear. At the end of 2002, work was carried out to repair the parking lot to improve waterproofing and rainwater drainage with the aim of limiting water infiltration into the ground.
As part of these efforts, groundwater pumping was implemented, which lowered the mobile HCH pollution in the water and prevented the water from flowing in the direction of the groundwater to the Rhine. As a consequence of these measures, groundwater monitoring showed that concentrations were below the limits for the α- and γ-isomers of HCH, but varied by up to several tens of μg/liters for the β- and δ-isomers.
Due to lower volumes of incoming wastewater, Novartis in 2011 began an engineering project to divert the untreated water to the modernized wastewater facility ProRheno in Basel. Subsequently, the wastewater treatment plant in Huningue was shut down in December 2012.
At the same time, the area of the former St. Johann Rhine harbor had been decontaminated and transformed into a beneficial public riverside zone, including a bike path connecting Switzerland and France. In preparing for the shutdown of the industrial wastewater treatment plant, Novartis discussed the idea of remediating the site despite not being the actual polluter and carried out detailed site investigations to further assess the soil and groundwater contamination.
