DDT was first evaluated in 1966 and has been reviewed several times since. The JMPR in 1993 and 1994 proposed Extraneous Residue Limits (ERLs) for carrots, eggs, meat and milks and confirmed the previous temporary ERL proposed for cereal grains. The 1995 CCPR was informed that additional data on meat were available from Australia, New Zealand and the USA and decided to keep the proposal for meat (1 mg/kg) at Step 3 pending the evaluation of these data by the 1996 JMPR. The 28th (1996) Session of the CCPR advanced all ERLs except that for meat to Step 8. The existing CXL for meat, 5 mg/kg (fat), was converted to a temporary limit in 1993.
No information was supplied by governments on registered or recommended uses of DDT on crops or animals. Some countries allow its limited use for public health applications.
The Meeting received national residue survey data on DDT in meat from Australia, Germany, New Zealand, Norway, Thailand, the UK and the USA.
The British annual report on residue monitoring for 1994, further data on dairy products from New Zealand and on commodities of plant origin from Norway and Spain were also provided. Information on residues and dietary intakes of DDT was made available by Global Environment Monitoring System - Food Contamination Monitoring and Assessment Programme (GEMS/Food) of WHO. Because no request was made for these data by the CCPR however, the Meeting could not conclude that a complete database was available to support re-evaluations of ERLs for commodities other than meat and proposed to postpone such evaluations to a later periodic review.
Definition of the residue: Sum of p,p'-DDT, o,p'-DDT, p,p'-DDE and p,p'-TDE (p,p'-DDD). The residue is fat-soluble.
Meat. Residues of DDT and its metabolites in most of the many samples analysed were at very low levels, but in some samples of meat fat were higher than the proposed ERL of 1 mg/kg. From Australia, results of 91,747 analyses of meat fat were available from 1989-1994, and 51 samples (0.06% of the total) of which 29 were beef, 1 deer, 1 horse, 13 sheep and 7 pork, contained residues above 1 mg/kg. In 3 samples the residues were higher than 5 mg/kg.
In Germany, 1653 samples of fat of meat were analysed in 1993. Only 1 sample of sheep fat and 2 samples of bacon (0.2% of the total number) contained residues in the ranges 1.1-2 and 2.1-5 mg/kg respectively.
Analyses of 1568 and 28,640 meat fat samples were available from Norway (1990-1994) and Thailand (1993-1994) respectively. All residues were lower than 1 mg/kg.
In the USA, 31 (0.08%) of 38,420 meat fat samples from 1991-1994 contained residues higher than 1 mg/kg (4 samples with residues above 5 mg/kg).
In UK monitoring in 1994 74 samples of lamb fat were analysed and none contained residues exceeding 1 mg/kg.
In a monitoring programme in New Zealand, from July 1990 to June 1994 analysis of a total of 4682 samples of meat fat from lambs, sheep, calves, cattle, pigs, deer and goats showed residues above 1 mg/kg in 1.6%, above 2 mg/kg in 0.43%, and above 5 mg/kg in 0.04% of the samples. In a separate survey of 403 lambs from a region with a history of DDT use 33%, 18% and 3% of the fat samples contained residues above 1,2 and 5 mg/kg respectively.
The following Table shows the distribution of DDT residues higher than the proposed ERL of 1 mg/kg.
|
Animal |
No. of samples |
Distribution of DDT residues in % |
||
|
>1 mg/kg |
>2 mg/kg |
>5 mg/kg |
||
|
Lambs |
965 |
1.9 |
0.2 |
- |
|
Adult sheep |
548 |
2.2 |
0.7 |
- |
|
Adult bovines |
739 |
0.68 |
- |
- |
|
Suckling calves |
1211 |
2.5 |
0.82 |
0.08 |
|
Pigs |
925 |
1.1 |
0.43 |
0.11 |
|
Deer |
227 |
0.88 |
- |
|
|
Goats |
67 |
- |
- |
|
|
Lambs from a region where DDT was historically used |
403 |
33 |
17.6 |
3.2 |
In all, 162,102 samples of meat fat were analysed in Australia, Germany, Norway, Thailand, the UK and the USA, and residues above 1 mg/kg were found in 85 samples (0.05%). The samples from New Zealand belonged to a different population. Excluding the lambs from the region with a known DDT history, 1.6% of the 4682 samples analysed were higher than the proposed ERL of 1 mg/kg; 0.43% higher than 2 mg/kg and 0.04% higher than 5 mg/kg.
The GEMS/Food database for meat fat shows low levels of DDT residues in most countries, but maximum residues were found of 2 mg/kg in the former Soviet Union (1991), 4.1 mg/kg in China (1990), 7 mg/kg in Egypt (1993), 4.1 mg/kg in India (1989) and 91 mg/kg in Spain (1994). These figures are insufficient to support a revision of the proposed ERL, because some relevant information (e.g. number of samples analysed, explanation of extreme values) is not given.
