The end for lindane

A new European Commission report recommends suspending the use of the persistent organochlorine insecticide lindane because of severe health effects and environmental data gaps. It is now being discussed secretly by regulators across Europe - a process that does not involve public interest groups. The Pesticides Trust [now PAN UK] has seen a leaked copy of the report and is concerned that the findings have not been adequately addressed by Europe as a whole. David Buffin reports.

The Austrian authorities have produced a monograph covering the health and environmental effects of lindane on behalf of the European Union under Council Directive 91/414/EEC. Although the document is complete, it remains a draft until disclosure by all EU Member States. It could take at least a year before the final decision that will be binding across the European Union. This decision may differ from the original suspension suggestion from the Austrians, especially as countries still widely using lindane such as France and Italy will be part of the debate. This process will take too long and prevent speedy action. In the UK alone over the next year, as much as 76,000 kg may be unnecessarily used posing a continued threat to people and the environment.
    It is surprising to see how little adequate data supports the continued approval of lindane. But it was a pesticide developed in the 1940s, at a time when far less attention was paid to detailed experimentation required to prove a chemical was safe. The report suggests there are at least seven data gaps that urgently need attention. Of particular concern is the lack of adequate carcinogenicity data.
    The Austrians conclude that there is not enough certainty with current data on lindane. On 21 December 1998 they recommended suspending its use across the EU pending the submission of further data.
    At about the same time the Pesticides Trust [now PAN UK] and Pesticides Action Network (PAN) Europe wrote to the Ministers of Agriculture, Health and Environment in all EU Member States expressing concern about lindane. Public interest groups are not consulted during the review process and slow action over lindane will further fuel anxieties with the present regulatory mechanisms.

What does the report say?
The report summarises a number of health and environmental concerns raised by the continued use of lindane.

Health effects
Carcinogenicity studies in mice indicate that exposure to lindane increased the incidence of liver and lung tumours. Despite these suggestions, the report says none of the mouse cancer studies were fully adequate because of deficient experimental design and insufficient documentation on the results. As a result, it is not possible to establish a clear idea of the No Observed Effect Level (NOEL) or a No Observable Adverse Effect Level (NOAEL). Lindane should be classified 'category 3 of carcinogenic substances' and labelled with the risk phrase 'possible risk of irreversible effects' under Directive 67/548 EEC, the report recommends.
    Data from published literature suggests that lindane can have effects on female hormone levels, and can also affect sexual behaviour in female rats.
    Results from published postnatal studies showed that oral dose levels of greater than or equal to 10 mg/kg body weight/day cause behavioural changes in developing rats.
    In addition, adverse effects on the brain function in developing rats were observed at relatively low levels. No clear NOELs/NOEALs could be established.
    Rat neurotoxicity studies show that a single dose of 30 mg/kg body weight can cause convulsions.
    Lindane induces increased irritability and impairs spontaneous and conditioned behaviour in rats. Effects on behaviour (aggression, hyperactivity) and excitability have also been reported in a study for dermal toxicity in rats. A clear NOAEL has not been established for these lindane-induced effects.
    Studies have demonstrated that lindane increases liver enzyme activities. In other rat and mice tests, effects on the immune system were observed. Again neither NOEL nor NOAEL levels could be established for immunotoxicity because of adverse reactions seen at all dose levels tested.
    Epidemiology studies examined in the report included toxic effects on blood, on genes, and association with cancer or birth defects. None of the studies provided causal links because of either insufficient details of dose or exposure to lindane or because exposure to other chemicals (mostly other organochlorines) occurred simultaneously.

Fate in the environment
Lindane is highly volatile and stable in the air. Since release to the atmospheric environment cannot be controlled, the report concludes lindane has the potential to contaminate 'sensitive areas'. Surface and soil applications of lindane are now rare in Europe as most application is for seed treatment. This should mean less lindane escapes into the atmosphere, although no accurate predictions can be made because no experimental data are available for this application method.

Wildlife
Birds may be exposed to lindane by eating contaminated seeds, or after soil treatment. The report concludes that the number of grains which represents no hazard for birds could not be calculated. The hazard for birds feeding on treated shoots could not be assessed because of the lack of residue data.
    Seed and soil treatment can take place during bird breeding seasons. Birds can absorb lindane, and this may threaten reproduction, although the effect on breeding success and foetal survival is unclear.
    There is also a potential for small mammals such as mice and voles to pick up hazardous amounts of lindane from contaminated feed (after seed and soil treatment). But it is difficult for the researchers to draw conclusions because of the lack of data.
    No tests of the acute toxicity of lindane to aquatic organisms are available
    Results of a study on bluegill sunfish showed very high levels implying lindane had accumulated through the food chain.

Numerous data gaps
The report complains of a lack of scientific information about the impact of lindane. Some of the major studies required are:

• a new carcinogenicity study
• the relationship between hormonal disruption and exposure to lindane
• developmental toxicity in rat
• the levels of lindane exposure which change behaviour
• the effect on the immune system
• chronic toxicity to birds and small mammals
• levels of lindane which poison fish and other aquatic species.

Conclusion
Lindane use must not continue in the absence of data to allay these concerns. The Austrian rapporteurs suggest that lindane should be temporarily suspended from the market until all the data gaps have been submitted and assessed.
    For some time, the Pesticides Trust [now PAN UK], as part of PAN Europe, has been calling for a ban on the use and production of lindane across Europe. This pesticide was developed in the 1940s when cheap and relatively hazardous chemicals were considered acceptable. Lindane is already banned in Sweden and Denmark, and it is now time for the rest of Europe to follow suit.

European Commission, Review of Lindane, December 1998.

[This article first appeared in Pesticides News No. 43, March 1999, page 3]