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Man and his Pesticides
1406 mass and circulating H.P.L. values, high levels being found in multiple pregnancies and in some diabetic patients with large placentas. Conversely, H.P.L. levels fail to increase normally when fetal growth is retarded by placental insufficiency, and it has been suggested that the finding of normal values serves to exclude such a diagnosis. Other advantages of plasma-H.p.L. assays in the assessment of placental function include the narrow normal range of levels at a given period of gestation and the ease and rapidity of the assay, which enables repeated serial determinations to be performed and results to be produced within hours. On p. 1385 contributors from Siena and Lausanne record their findings in 72 healthy pregnant women and in 13 cases of threatened abortion. In the normal pregnancies placentallactogen levels in plasma rose steadily; and similar increases were noted in 5 women with threatened abortions which ultimately went to term. On the other hand, in the 8 pregnancies which ended in spontaneous abortion, the plasma levels were either barely detectable or rapidly decreased until abortion. These results are in accord with those of SAXENA and his colleagues,24 who found that the decrease in plasma-H.p.L. levels preceded abortion by periods ranging from 5 to 10 days.
Serial
determinations offer the best means of assessing when the feto-placental unit is at risk and it has been proposed that a 50% fall during late pregnancy indicates the need for prompt induction of labour or for caesarean section. 24 A decrease of this magnitude must indicate extensive placental dysfunction and, therefore, it seems desirable to improve the precision of the assay so that, if necessary, treatment can be based on a smaller fall. If this is practicable, then future management of high-risk patients would ideally be carried out in units with resources for repeated assays at intervals of hours rather than days. Even if the value of such estimations is substantiated, however, H.P.L. assays will complement and not replace tests based on urinary oestriol determinations, which provide a measure of both fetal and placental function. Thus, the cestriol measurements assess both the ability of the fetal adrenals to produce 16
from establishing the clinical value of H.P.L. assays in the assessment of placental function, much further work on this hormone is required. It is not known whether H.P.L. has any therapeutic application (for example, in the treatment of spontaneous abortion), whether or not non-primates synthesise a placental lactogen, and why the human placenta secretes a number of hormones both structurally and biologically similar to those produced by the anterior pituitary gland.
Apart
Man and his Pesticides WHEN D.D.T. (dicophane) is applied as an agricultural pesticide and becomes incorporated in the topsoil, three to six years may elapse before the D.D.T. residues fall by 50%. Sensitive chemical tests have shown that D.D.T. and other organochlorine pesticides in very low concentrations are now almost universally distributed in the environment. In Britain the advisory committee on pesticides and other toxic chemicals has conducted a further review of the risks arising from the use of persistent organochlorines * and its report1 appeared last week. It concludes that no evidence can be found to indicate that the persistence of these chemicals has adverse effects on man; but their presence, even in low concentrations, is undesirable and an attempt should be made to reduce amounts in the environment. The main changes recommended are the withdrawal of aldrin, dieldrin, and D.D.T. from use on a number of crops, the removal of D.D.T. sold in small packs to the home gardener, and the abandonment of certain uses of dieldrin and D.D.T. in food storage and in the home kitchen and larder. The Government has accepted this advice and it is hoped that these uses of organochlorine pesticides will be gradually curtailed and will cease altogether by the end of 1970. For certain other applications of these chemicals in hygiene and public health, timber preservation, and the commercial mothproofing of wool, the committee recommends further inquiries and surveys. There is no case at present for the complete withdrawal of any of the organochlorines, though the situation will remain under constant
scrutiny. The committee is particularly anxious to control the thermal vaporisers-those devices which discharge D.D.T., gamma-B.H.c. (benzene hexachloride), or a mixture of the two, and which are chiefly used as fly controllers, though they are also available for attack on food-storage pests, clothes moths, cockroaches, and aphids and mushroom flies in horticulture. Vaporisers are in operation in food premises, intensive poultry houses, calf-rearing houses, offices, shops, mills, warehouses, hospitals, and the home. They are especially attractive to those responsible for premises subject to legislation requiring more or less continuous control of insect pests. The amount of D.D.T. vaporised in thermal units is only a minute fraction of all the D.D.T. distributed in one way or another, but " the proportion of the chemical so applied that may be absorbed by man and livestock may well be higher than from other types of application ". For this reason, and because of D.D.T.’S persistence, the committee advises that D.D.T. should not be vaporised in the presence of people or animals, * Aldrin, campheclor (’Toxaphene’), chlordane, D.D.T. (dicophane), dieldrin, endosulfan, endrin, T.D.E. (’Rhothane’). B.H.C
1.
was
not
included
in
the
review.
Department of Education and Science: Further Review of Certain Persistent Organochlorine Pesticides Used in Great Britain. H.M. Stationery Office, 1969, 12s. 6d.
1407
exposed food is sold, prepared, served, or eaten. Among its remarks on other possible domestic uses of organochlorines, the report sees no need for small packs containing dieldrin, sometimes in aerosol formulations, to be offered to the public for the control of cockroaches and ants. The labelling of some of these preparations is ambiguous and implies that they might be used freely against many more visitors to the larder and the and
particularly
where
kitchen. Some of the organochlorine pesticides are to be found in many of the components of human diet in Britain, whether produced at home or abroad. But the residues identified are at consistently low levels; and there are signs that the levels of D.D.T., aldrin/ dieldrin, and B.H.c. in the British diet are declining. The levels of D.D.T. and B.H.c. are well below the maximum acceptable daily intakes recommended by the World Health Organisation, though the dieldrin figures are of the same order as the W.H.O. maximum. Recommendations implemented after an earlier review published in 1964 led to an estimated fall of about 25% in the total tonnages of aldrin, dieldrin, D.D.T., and T.D.E. used in agriculture and horticulture in Great Britain. The new measures will, it is hoped, give a further reduction of 20%. The conclusions were reached in the British context: in tropical countries where food production is vital and mortality from insect-borne disease is high, the hazards to wildlife and the presence of minute residues in human fat may rightly be regarded as
relatively unimportant. For some years misgivings have been forcefully expressed about the damage to wildlife caused by pesticides. Of the organochlorines, the committee believes that only aldrin/dieldrin and D.D.T. have significant effects on wildlife in this country. Earlier restrictions on the use of cereal-seed dressings in spring have greatly reduced the number of incidents of acute poisoning in both seed-eating and predatory birds. There is little evidence to suggest that acute D.D.T. poisoning is at all common among birds in Britain, though casualties do happen-for example, in orchards in some seasons. In the late 1940s, in this country and in North America, about the time D.D.T. was introduced on a large scale, eggshell thickness decreased and egg breakage by parent birds became commoner, especially among predators. Some falling-
off was noted at that time in the success of rearing young, but the populations of peregrine falcons and sparrowhawks remained steady until 1955, when a sharp fall was attributed to dieldrin. Other evidence exists that D.D.T. can affect eggshell thickness, egg breakage, and breeding success, but no sign has been found that it has reduced populations. In this country, residues of D.D.T. in natural waters have generally been well below the levels likely to affect survival of fish, though fish populations are seldom
studied with sufficient accuracy for the effects of chronic toxicity to be determined. Dieldrin seems to have a considerable and protracted effect on some elements of soil micro-arthropod populations, but most workers believe that the results are not important to agriculture or the general environment. But the damage done by D.D.T. to natural enemies sometimes contributes to the resurgence of certain pests and to the development of secondary pests. It was not possible to estimate reliably the cost of the committee’s proposals. Growers may have to pay a few tens of thousands of pounds more annually for alternative pesticides, which are unlikely to be as cheap as the organochlorines. (For some 110 crop uses of D.D.T., acceptable alternative pesticides already exist for about 70; and replacements for almost all the remaining 40 are under test.) Other factors have to be reckoned in the cost: capital, labour, new application techniques, and possibly increased numbers of applications. The report asks for more work on these points and on cost/benefit analysis of the insurance use of pesticides.
Annotations DEATH PENALTY AND VIOLENT CRIME
PARLIAMENT has wisely chosen to abolish the obscene and cruel ritual of hanging. Countries which abolished capital punishment some years ago have found no need to reintroduce the death penalty, and this country’s experience since capital punishment was suspended has been similarly reassuring. The
death-penalty issue has been aired thoroughly repeatedly in recent years, particularly in the periods preceding changes in the law (the and
Homicide Act of 1957, which removed the death penalty for certain classes of murder, and the Murder [Abolition of Death Penalty] Act of 1965, which suspended capital punishment for a trial period of 5 years). The arguments are well known by now,! and on grounds of rationality the abolitionists must win the day. The risk of being murdered was the same in 1968 as it was in 1957 (about 3 in a million); the 1965 Act has not led to a rise in the murder-rate.2 (The number of capital murders seems to have risen slightly since 1965, but for technical reasons it is difficult to interpret the figures for the years since the law changed.) The retentionists’ main propthat capital punishment is a unique deterrent to murder-would collapse if those backwoodsmen would base their argument on fact rather than on confusion and so-called common sense. Despite the mass of evidence accumulated in favour of abolition, however, public opinion has remained curiously 1. Lancet, Nov. 15, 1969, p. 1054. 2. Murder 1957 to 1968. H.M. Stationery
Nov. 15, 1969, p. 1054.
Office, 1969. See Lancet,
Serial
determinations offer the best means of assessing when the feto-placental unit is at risk and it has been proposed that a 50% fall during late pregnancy indicates the need for prompt induction of labour or for caesarean section. 24 A decrease of this magnitude must indicate extensive placental dysfunction and, therefore, it seems desirable to improve the precision of the assay so that, if necessary, treatment can be based on a smaller fall. If this is practicable, then future management of high-risk patients would ideally be carried out in units with resources for repeated assays at intervals of hours rather than days. Even if the value of such estimations is substantiated, however, H.P.L. assays will complement and not replace tests based on urinary oestriol determinations, which provide a measure of both fetal and placental function. Thus, the cestriol measurements assess both the ability of the fetal adrenals to produce 16
from establishing the clinical value of H.P.L. assays in the assessment of placental function, much further work on this hormone is required. It is not known whether H.P.L. has any therapeutic application (for example, in the treatment of spontaneous abortion), whether or not non-primates synthesise a placental lactogen, and why the human placenta secretes a number of hormones both structurally and biologically similar to those produced by the anterior pituitary gland.
Apart
Man and his Pesticides WHEN D.D.T. (dicophane) is applied as an agricultural pesticide and becomes incorporated in the topsoil, three to six years may elapse before the D.D.T. residues fall by 50%. Sensitive chemical tests have shown that D.D.T. and other organochlorine pesticides in very low concentrations are now almost universally distributed in the environment. In Britain the advisory committee on pesticides and other toxic chemicals has conducted a further review of the risks arising from the use of persistent organochlorines * and its report1 appeared last week. It concludes that no evidence can be found to indicate that the persistence of these chemicals has adverse effects on man; but their presence, even in low concentrations, is undesirable and an attempt should be made to reduce amounts in the environment. The main changes recommended are the withdrawal of aldrin, dieldrin, and D.D.T. from use on a number of crops, the removal of D.D.T. sold in small packs to the home gardener, and the abandonment of certain uses of dieldrin and D.D.T. in food storage and in the home kitchen and larder. The Government has accepted this advice and it is hoped that these uses of organochlorine pesticides will be gradually curtailed and will cease altogether by the end of 1970. For certain other applications of these chemicals in hygiene and public health, timber preservation, and the commercial mothproofing of wool, the committee recommends further inquiries and surveys. There is no case at present for the complete withdrawal of any of the organochlorines, though the situation will remain under constant
scrutiny. The committee is particularly anxious to control the thermal vaporisers-those devices which discharge D.D.T., gamma-B.H.c. (benzene hexachloride), or a mixture of the two, and which are chiefly used as fly controllers, though they are also available for attack on food-storage pests, clothes moths, cockroaches, and aphids and mushroom flies in horticulture. Vaporisers are in operation in food premises, intensive poultry houses, calf-rearing houses, offices, shops, mills, warehouses, hospitals, and the home. They are especially attractive to those responsible for premises subject to legislation requiring more or less continuous control of insect pests. The amount of D.D.T. vaporised in thermal units is only a minute fraction of all the D.D.T. distributed in one way or another, but " the proportion of the chemical so applied that may be absorbed by man and livestock may well be higher than from other types of application ". For this reason, and because of D.D.T.’S persistence, the committee advises that D.D.T. should not be vaporised in the presence of people or animals, * Aldrin, campheclor (’Toxaphene’), chlordane, D.D.T. (dicophane), dieldrin, endosulfan, endrin, T.D.E. (’Rhothane’). B.H.C
1.
was
not
included
in
the
review.
Department of Education and Science: Further Review of Certain Persistent Organochlorine Pesticides Used in Great Britain. H.M. Stationery Office, 1969, 12s. 6d.
1407
exposed food is sold, prepared, served, or eaten. Among its remarks on other possible domestic uses of organochlorines, the report sees no need for small packs containing dieldrin, sometimes in aerosol formulations, to be offered to the public for the control of cockroaches and ants. The labelling of some of these preparations is ambiguous and implies that they might be used freely against many more visitors to the larder and the and
particularly
where
kitchen. Some of the organochlorine pesticides are to be found in many of the components of human diet in Britain, whether produced at home or abroad. But the residues identified are at consistently low levels; and there are signs that the levels of D.D.T., aldrin/ dieldrin, and B.H.c. in the British diet are declining. The levels of D.D.T. and B.H.c. are well below the maximum acceptable daily intakes recommended by the World Health Organisation, though the dieldrin figures are of the same order as the W.H.O. maximum. Recommendations implemented after an earlier review published in 1964 led to an estimated fall of about 25% in the total tonnages of aldrin, dieldrin, D.D.T., and T.D.E. used in agriculture and horticulture in Great Britain. The new measures will, it is hoped, give a further reduction of 20%. The conclusions were reached in the British context: in tropical countries where food production is vital and mortality from insect-borne disease is high, the hazards to wildlife and the presence of minute residues in human fat may rightly be regarded as
relatively unimportant. For some years misgivings have been forcefully expressed about the damage to wildlife caused by pesticides. Of the organochlorines, the committee believes that only aldrin/dieldrin and D.D.T. have significant effects on wildlife in this country. Earlier restrictions on the use of cereal-seed dressings in spring have greatly reduced the number of incidents of acute poisoning in both seed-eating and predatory birds. There is little evidence to suggest that acute D.D.T. poisoning is at all common among birds in Britain, though casualties do happen-for example, in orchards in some seasons. In the late 1940s, in this country and in North America, about the time D.D.T. was introduced on a large scale, eggshell thickness decreased and egg breakage by parent birds became commoner, especially among predators. Some falling-
off was noted at that time in the success of rearing young, but the populations of peregrine falcons and sparrowhawks remained steady until 1955, when a sharp fall was attributed to dieldrin. Other evidence exists that D.D.T. can affect eggshell thickness, egg breakage, and breeding success, but no sign has been found that it has reduced populations. In this country, residues of D.D.T. in natural waters have generally been well below the levels likely to affect survival of fish, though fish populations are seldom
studied with sufficient accuracy for the effects of chronic toxicity to be determined. Dieldrin seems to have a considerable and protracted effect on some elements of soil micro-arthropod populations, but most workers believe that the results are not important to agriculture or the general environment. But the damage done by D.D.T. to natural enemies sometimes contributes to the resurgence of certain pests and to the development of secondary pests. It was not possible to estimate reliably the cost of the committee’s proposals. Growers may have to pay a few tens of thousands of pounds more annually for alternative pesticides, which are unlikely to be as cheap as the organochlorines. (For some 110 crop uses of D.D.T., acceptable alternative pesticides already exist for about 70; and replacements for almost all the remaining 40 are under test.) Other factors have to be reckoned in the cost: capital, labour, new application techniques, and possibly increased numbers of applications. The report asks for more work on these points and on cost/benefit analysis of the insurance use of pesticides.
Annotations DEATH PENALTY AND VIOLENT CRIME
PARLIAMENT has wisely chosen to abolish the obscene and cruel ritual of hanging. Countries which abolished capital punishment some years ago have found no need to reintroduce the death penalty, and this country’s experience since capital punishment was suspended has been similarly reassuring. The
death-penalty issue has been aired thoroughly repeatedly in recent years, particularly in the periods preceding changes in the law (the and
Homicide Act of 1957, which removed the death penalty for certain classes of murder, and the Murder [Abolition of Death Penalty] Act of 1965, which suspended capital punishment for a trial period of 5 years). The arguments are well known by now,! and on grounds of rationality the abolitionists must win the day. The risk of being murdered was the same in 1968 as it was in 1957 (about 3 in a million); the 1965 Act has not led to a rise in the murder-rate.2 (The number of capital murders seems to have risen slightly since 1965, but for technical reasons it is difficult to interpret the figures for the years since the law changed.) The retentionists’ main propthat capital punishment is a unique deterrent to murder-would collapse if those backwoodsmen would base their argument on fact rather than on confusion and so-called common sense. Despite the mass of evidence accumulated in favour of abolition, however, public opinion has remained curiously 1. Lancet, Nov. 15, 1969, p. 1054. 2. Murder 1957 to 1968. H.M. Stationery
Nov. 15, 1969, p. 1054.
Office, 1969. See Lancet,