A joint
announcement detailing restrictions to carbaryl use in the UK was made by the
Ministry of Agriculture Fisheries and Food (MAFF) Pesticide Safety Directorate
and the Health and Safety Executive (HSE) on 7 November. Carbaryl will no longer
be approved for non-professional uses; will be available for medical uses only
by prescription; and professional use is subject to restrictions designed to
limit operator exposure.
The decision follows an assessment by the government's
Committee on Carcin-ogenicity (COC), based on manufacturer's test data (not
made available to the public), which concluded that carbaryl should be
considered a potential human carcinogen.
Carbaryl's use as an insecticide in the treatment of head
lice was the most widely reported aspect following the announcement. It is one
of several such insecticides including lindane, permethrin and d-phenothrin. The
problems of domestic use of pyrethroids have been raised in Germany, with
regulators concerned about carcinogenicity (PN29, p. 3).
As a result of the COC findings the Department of Health
restricted carbaryl-based head lice treatments to prescriptions only. The Chief
Medical Officer advised health professionals to recommend treatments based on
malathion, permethrin and other synthetic pyrethroids. He also referred to the
Bug Busting programme promoted by Community Hygiene Concern (see PN29, p. 17).
Carbaryl's new prescription only status may not reduce its use, but may
increase the burden on doctors-and the overall health bill.
Carbaryl has played a role in lice treatment rotation
programmes aimed at avoiding louse resistance. The new restrictions may disrupt
this programme, or result in increased use of other treatments such as those
containing lindane.
In the public health sector carbaryl's main recent uses
have been in wasp nest destruction and ant control. MAFF and HSE advise using
alternative products based on synthetic pyrethroids, organophosphates or other
carbamate insecticides. Recommended replacements for carbaryl in the control of
mites, lice and insects in poultry houses include alpha-cypermethrin (WHO class
II toxicity, highly toxic to bees), dichlorvos (WHO class Ib toxicity,
cholinesterase inhibitor, eye and skin irritant, classed as a possible human
carcinogen by IARC and EPA and on the UK Red List) and fenitrothion (WHO class
II toxicity, cholinesterase inhibitor and on the UK Red List).
In its role as a lumbricide (worm killer) on turf, carbaryl
will continue to be approved for use by professionals, subject to the
conditions. According to the Sports Turf Research Institute (STRI) carbaryl is
the least effective lumbricide currently in use. Carbendazim (a fungicide) and a
mixture of lindane (organochlorine insecticide classified as a probable human
carcinogen by the US EPA and a possible human carcinogen by IARC, on the UK Red
List, an endocrine disruptor and toxic to wildlife) with thiophanate methyl (a
fungicide classed as a possible human carcinogen by the US EPA) are more
effective and far more widely used. STRI has done some research into alternative
worm control strategies, but work has been interrupted because of breaks in
funding.
In UK agriculture, carbaryl is used on apples as a thinning
agent and insecticide. In 1992 it was the seventh most extensively used
pesticide by weight, on top fruit with 20.56 tons being applied over an area of
15,087 ha(1). This use will be subject to new conditions which will be stated on
product labels.
Carbaryl-new restrictions
Applications must only be made using vehicles with a closed cab-open vehicles are no longer permitted;
a low level induction bowl or closed systems must be used for transferring the product to the spray tank;
coverall, apron and gloves must be worn when handling the concentrate-previous approvals also require a face shield to be worn;
coverall must be worn during application;
coverall and gloves must be worn when handling contaminated surfaces;
the latest time of treatment to top fruit is three weeks before harvest-this period was previously seven days.
Carbaryl is also used
in veterinary medicine on products such as pet flea collars. The Veterinary
Products Committee is considering restricting these uses.
The UK authorities reacted swiftly and decisively to restrict
the use of carbaryl in the wake of the report from the COC. A number of
questions arise from this decision, such as:
should products which are officially acknowledged to be potential carcinogens be labelled as such?
will carbaryl's ban as a consumer product affect its status within the Prior Informed Consent (informing the importer) procedure?
should the authorities be recommending the use of other hazardous pesticides in place of carbaryl, or should they use this opportunity of heightened awareness to reduce reliance on pesticides and promote alternatives? (MD)
1. Pesticide Usage Survey Group, Pesticide Usage Survey Report 115: Orchards and Fruit Stores in Great Britain 1992, MAFF 1994. See also Pesticide Usage Survey Group, Pesticide Usage Survey Report 120: Hardy Nursery Stock in Great Britain 1993, MAFF 1995.
[This
article first appeared in Pesticides News No. 30,
December 1995, page 5]