21. Persistent Organic Pollutants

Chile: Current Situation

by Ms. Claudia Paratori

1. BACKGROUND

The need for maintaining the food supplies of the population implies prioritizing the use of pesticides for the protection of agricultural, forestal, and animal production. These compounds are utilized to combat the pests and diseases that impair production, and they can reach levels that are toxic for living things and the environment. It is for this reason that the countries, including Chile, have regulated their trade and use in their national territories.

The organochlorine pesticides generate life-threatening residues with great biological toxicity and high persistence, on the order of years, which has meant that, despite restrictions on their use and production in many countries, they continue to be detected in the environment, especially in biological matrixes. The following diagram of the ecological recycling of organochlorine residues shows the environmental dispersion paths, indicating the ways by which human beings are reached:

Of the 12 compounds identified as persistent organic pollutants (POPs), namely aldrin, chlordane, dieldrin, DDT, endrin, heptachlor, hexachlorobenzene, mirex, toxaphene, polychlorinated biphenyls (PCBs), dioxins, and furans, the majority have been utilized in Chilean agriculture for several years. Because of their extensive use and the information about them that has been amassed worldwide, the Agricultural and Livestock Service (SAG), an independent agency in the Ministry of Agriculture, has been obliged to take restrictive action that has culminated in a total ban on the use of some of these products in the country.

This ban did not cause problems, except for some of an economic nature, since numerous other pesticides (such as organophosphorus compounds, carbamates, and pyrethroids) rapidly replaced them.

In Chile, the importation, manufacture, sale, distribution, and use of the following compounds have been prohibited: DDT since 1984, aldrin since 1988, and chlordane, dieldrin, endrin, and heptachlor, since 1987. Enforcement of the bans on these products is carried out by the inspectors of the Agricultural and Livestock Service in inspections conducted at the pesticide distribution and collection points. The ban on imports of these products is enforced at the ports of entry, a task that is facilitated by Law No. 18,164 of the Ministry of Finance on Customs Legislation, which states that the above-mentioned Service must have prior knowledge of the customs destination of various materials, among them pesticides. Although in the inspections conducted by the Service at the pesticide distribution sites the presence of these products has not been detected, there has been no exhaustive country-wide inspection that would assure that none of them remain, either in warehouses or agricultural sites.

On the other hand, the compounds hexachlorobenzene, mirex, and toxaphene are not used in Chile. Thus, there has been no request to register them with the Agricultural and Livestock Service and they have not been imported, manufactured, or marketed in the country.

The use of the polychlorinated biphenyls (PCBs) in electric transformers is prohibited.

No information is available on dioxins and furans.

2.STUDIES ON PERSISTENT ORGANIC POLLUTANTS

A) National Commission on the Environment

In 1997 the National Commission on the Environment (CONAMA) prepared the study "Evaluation of the National Sector with Respect to the Management and Handling of Chemical Substances," with the objective of obtaining a national analysis that would provide a basic understanding of the chemical substances manufactured, imported, exported, utilized, handled, and/or prepared in the country, their specific uses, and the populations and environmental resources that are potentially affected by them. Information on pesticides and polychlorinated biphenyls, among other products, was obtained from various public and private agencies.

In regard to pesticide compounds, which include organochlorine compounds, the study provides:

• A pesticide compound list, with the Chemical Abstracts Service (CAS) and United Nations (UN) numbers, risk classifications, and glossary.
• The pesticide registry of the Agricultural and Livestock Service (SAG), updated to July 1997, with 914 products; this includes the trade name, active ingredient, formulation, concentration, manufacturer, country of origin, registrant, and number and date of registry.
• A list of 512 pesticide products for agricultural use, in order of toxicity and use.
• A list of active ingredients in pesticide formulations, with their respective oral LD₅₀ and toxicity.
• A list of the volume of imports and exports of pesticide compounds between 1993 and 1996.
• Information on the origin and destination of pesticide compounds, by company.

This study demonstrates that in order to establish the scope and validity of the existing information on the organochlorine pesticide compounds it is necessary to set up a list of the substances considered most relevant, with nomenclature and/or common coding based on internationally accepted criteria, control of the information in order to eliminate typographical errors, and a system for coordinating both public and private institutions that permits safe and confidential access and transfer of the information, when necessary, among the institutions involved in the management and handling of the chemical substances.

The following table shows the volume and type of inputs imported by the Chilean agricultural sector between 1994 and 1996, according to information from the Office of Agrarian Studies and Policies (ODEPA) of the Ministry of Agriculture:

Table I: Imports of Inputs for the Agricultural Sector, 1994, 1995, and 1996

(Source: Office of Agrarian Studies and Policies - ODEPA)

2. Public Health Institute of Chile

In 1982 the Public Health Institute of Chile (ISP) conducted a study to detect residues of the organochlorine pesticide DDT in breast milk, human adipose tissue, and cow’s milk, using gas chromatography with electronic capture detection (GC-ECD). A second objective of the study was to report on the levels of pollution reached in order to be able to establish the application strategies to correct this problem of pollution and chronic toxicity to xenobiotic substances in the future.

The results of the study demonstrate the presence of metabolites of DDT, p,p´-DDT, o,p´-DDT, p,p´-DDD, and p,p´-DDE in 100% of the samples (60 samples in total, 32 of which correspond to cow’s milk and 28 to breast milk and/or female adipose tissue). The results are summarized in Table II.

(1) Ministry of Health, Exempt Resolution No. 1.450, 1983.

As can be seen in the table, until 1982 there was significant contamination by DDT residues in Chile, especially of food with a high lipid content, such as cow’s milk and breast milk. As a result, the importation, manufacture, sale, distribution, and use of DDT have been prohibited since 1984.

This Institute presented the results of a study to determine the presence of organochlorine compounds in cow’s milk and butter to the First Chilean Congress of Epidemiology. See Table III.

1. No. exceeding the limit: number of samples that exceed the maximum tolerances of pesticide residues in food for domestic consumption, set through the Exempt Resolution No. 1,450, of 1983, Ministry of Health. These values are presented in Table VII of this document.
2. Noncompliance: percentage of the 4,150 samples that exceed the maximum pesticide residue tolerances for food for domestic consumption.

This table shows that in the samples of cow’s milk and butter, noncompliance with the Resolution limiting the concentration of organochlorine compounds fell from 29% to 7%, which shows that the national ban on DDT in 1984, aldrin in 1988, and chlordane, dieldrin, endrin, and heptachlor in 1987 have had significant effects in the short term on food products and, thus, on human health.

3. School of Public Health, School of Medicine, University of Chile

   The School of Public Health conducted a study in 1989 to determine the level of contamination by hexachlorobenzene, lindane, and DDT and their metabolites in human adipose tissue and breast milk in 47 pregnant women. Table IV presents a summary of the results obtained.

   Table IV: Concentrations of Organochlorine Pesticides

   in Adipose Tissue and Breast Milk

   Matrix	Pesticide [ppm]
   	Hexachloro-benzene	Lindane	DDT
   Adipose tissue
   Average	NA(1)	NA	NA
   Minimum concentration	0.018	0.000	0.078
   Maximum concentration	1.270	0.091	3.670
   No. of cases without detected levels	0	33	0
   Breast milk
   Maximum permissible limit [mg/kg]	0.5	0.2	1.25
   Average	0.008	0.005	0.052
   Minimum concentration	0.000	0.000	0.004
   Maximum concentration	0.031	0.051	0.186
   No. of cases without detected levels	7	16	0

   NA: data not available.

   In this study, similar to one conducted in 1979, a comparison of DDT levels in breast milk and adipose tissue was made, revealing a reduction in human contamination, which is attributable to the ban on this compound since 1984. However, there still are appreciable concentrations in humans, deposited mainly in adipose tissue and breast milk, which represents an additional source of risk for the newborn.

4. Agricultural and Livestock Research Institute

Between 1981 and 1990 the Agricultural and Livestock Research Institute (INIA), an agency of the Ministry of Agriculture, explored the presence of persistent organic pollutants, specifically organochlorine pesticide residues (lindane, DDT and its metabolites, aldrin, dieldrin, heptachlor epoxide, and chlordane), in food, soils from Regions IV to XI of the country, and water. In addition, it conducted some controlled experiments to determine the capacity of plants to absorb molecules of organochlorine pesticides and their entry into the food chains. The identification of the organochlorine compounds was carried out using gas chromatography with electron capture detection (GC/ECD). However, because these pesticides were not used after the ban imposed in 1984, the Institute considered it inappropriate to continue with this line of research. This Institute has the physical infrastructure and specialized personnel to conduct research to determine the environmental dispersion of persistent organic residues and their maximum tolerable levels.

This study shows that the highest percentage of pesticide occurrence is found in the northern area of the country (Region IV, 83%), and the lowest, in the southern area (Region XI, 27%). With regard to the identity of these compounds, the most ubiquitous pesticides were lindane (present in all regions), dieldrin, and DDT (absent in Region XI); those found least often were heptachlor epoxide, metabolites of DDT, and chlordane.

Some of the results obtained in the above-mentioned study on food for human consumption, exportable fruits, recycling of organochlorine pesticide residues (OPRs) in areas devoted to cattle and poultry production, and radicular absorption of OPRs, are presented below:

1. Food for Human Consumption

• Edible oil samples contaminated with pesticide residues were not evident.
• The meat samples analyzed contained residues of lindane (100%), heptachlor and heptachlor epoxide (87%), dieldrin (48%), chlordane (26.7%), and DDT and its metabolites (23%). The concentrations of the residues of lindane and DDT and its metabolites were lower than those labeled dangerous under international standards. On the other hand, heptachlor and its metabolite, dieldrin, and a -chlordane exceed the maximum residue limits (MRLs) by 20.0%, 6.6%, and 16.0%, respectively.
• The samples of wheat flour analyzed contained traces of OPRs (lindane, aldrin, dieldrin, p,p´-DDE, and chlordane), all much lower than the MPRLs established in the Codex Alimentarius (1987).
• Lindane and dieldrin were found in samples of eggs from the Metropolitan Region; however, the values were under the MRLs in Chile (Ministry of Health, 1982) and those established by FAO/WHO (1987).

1. Exportable Fruits

• The organochlorine pesticide residues proved to have low percentages of occurrence, with levels between 50 and 500 times lower than the respective maximum permissible limits (MPRLs). The residues found correspond to dieldrin, aldrin, and lindane.
• OPRs were not detected in apples.
• Organophosphorus pesticide residues were more evident in table grapes, apples, and nectarines than were those of organochlorines, showing a higher percentage of occurrence, a greater range of products, higher residual concentrations, and wider geographical coverage.

1. Recycling of Organochlorine Pesticide Residues in Cattle-raising Areas

• Found in the highest percentages were DDT and its metabolites (37%), heptachlor and its epoxide (32%), and endrin (3%).
• The OPRs were found most often in perirenal fat (75%) and soils (57%), and to a lesser extent in pastures (32%).
• Testing for OPRs in the perirenal fat of cattle demonstrated the persistence of this residue mainly in Metropolitan Regions VII, IX, and X.
• Of the pesticides, lindane had the highest occurrence (56%), together with aldrin/dieldrin (46%), which reflects their widespread use in agriculture and livestock production and their persistence.

1. Recycling of Organochlorine Pesticide Residues in Poultry Production Systems in the Metropolitan Region

• In poultry, lindane and aldrin/dieldrin occur in the highest percentages, which is similar to the results obtained in meat and perirenal fat in cattle.
• The high presence of lindane and aldrin/dieldrin in food ingredients and concentrates leads to the assumption that this would be the most common way of entry into poultry.

1. Radicular Absorption of Organochlorine Pesticide Residues

• The potential capacity for radicular absorption of dieldrin was studied for three species: rye grass, clover, and wheat. Proportionality was verified between the levels of dieldrin in the nutrient solutions and in the leaves, in accordance with linear functions perfectly defined for every species, which demonstrates the presence of the phenomenon of radicular absorption.
• The radicular absorption of dieldrin will depend on the organic matter in the soil, the plant species, and exposure time.

3. Institute of Nutrition and Food Technology

The Institute of Nutrition and Food Technology (INTA), together with the National Commission on the Environment (CONAMA), conducted the study "Screening of Pesticide Residues in Habitually Consumed Fruits and Vegetables in Chile," in which 30 pesticides were analyzed in each of 546 fruit and vegetables samples. Although the pesticides analyzed correspond mainly to organophosphorus compounds, pyrethroids, and carbamates, and not organochlorine compounds, this study provides background concerning the frequency of occurrence of pesticides in food samples and thus serves as a good basis for determining the presence of other compounds that persist in the environment. The highest percentages of occurrence are presented in Table V.

Number of samples with residues out of a total of 546 fruit and vegetables samples.

These results demonstrate that, in addition to the organochlorine compounds indicated in the list of POPs, there are other pesticide compounds that are found as residues in food. Thus it is appropriate to follow up those residues found most frequently and in higher concentrations, such as chlorpyrifos, ethyl parathion, diazinon, and methamidophos.

3. REGULATION

The Official Chilean Standard NCh 409/1.Of84 establishes the physical, chemical, radioactive, and bacteriological requirements for drinking water from any supply system and sets the maximum permissible concentrations of certain pesticides, shown in Table VI.

4. LEGISLATION ON PESTICIDE COMPOUNDS

A) Ministry of Agriculture

Legal regulation of pesticides in Chile begins with Law No. 15,703 of 1964 and Decree No. 567, which empower the Ministry of Agriculture, through the Division of Agriculture and Fishing and the Department of Agricultural Defense, to regulate the manufacture, formulation, distribution, and application of pesticides, which include the organochlorine compounds. In 1980 Decree-Law No. 3,557 for Agricultural Protection repeals previous legislation and empowers the Agricultural and Livestock Service (SAG):

1. To collect pesticide samples at any stage of their marketing and to confirm that their composition corresponds to what is indicated on their labels.
2. To authorize a use different from the one specified on the pesticide label.
3. To prohibit the utilization or sale of contaminated products.
4. Through Exempt Resolution published in the Official Journal, to regulate, restrict, or prohibit the manufacture, importation, sale, and use of pesticides.
5. To provide warnings as necessary for aerial or ground application of pesticides.
6. To order the seizure of pesticides that are considered dangerous.

The Ministry of Agriculture, through Resolution No. 1,117 of 1984, establishes the toxicological classification of pesticides for agricultural use, breaking it down into four categories according to the lethal and acute oral and dermal doses, based on WHO recommendations. Through Resolution No. 1,179 of 1984, it regulates the information that should be contained in the text and the colored band identifying the toxicological classification on pesticide labels.

Category Toxicological classification Band color

1. Extremely toxicred
2. Highly toxicyellow
3. Moderately toxicblue
4. Slightly toxicgreen

Each label should be written in Spanish and in specified locations, identify the product and list the precautions and instructions for its use.

Since July 1997, the Agricultural and Livestock Service has a had registry listing 914 agricultural pesticides, corresponding to 437 active ingredients and 61 registrants or companies. The information on the products includes the following:

• For active ingredients
  • Identity
  • Physical and chemical properties
  • Analytical methods
  • Safety
  • Toxicology
  • Environmental impact
  • Ecotoxicology
• For formulated products
  • Composition
  • Physical and chemical properties
  • Application
  • Proposed containers
  • Toxicology
  • Environmental impact
  • Ecotoxicology

B) Ministry of Health

The Ministry of Health, through Exempt Resolution No. 1,450 of 13 December 1983, sets the maximum tolerances for pesticide residues in food for domestic consumption, in the form indicated in Table VII.

In accordance with the Sanitary Code this Ministry has the power to authorize the manufacture and importation of toxic or hazardous substances for sanitary and domestic use.

It should be emphasized that in Chile the most commonly eaten fruits are, in descending order of consumption: apples, pears, peaches, nectarines, grapes, oranges, limes, and bananas; for vegetables the order is: tomatoes, lettuce, potatoes, cabbage, celery, beets, and carrots. It is significant that 70% of the pesticides imported by Chile are utilized in the production of fruits and vegetables; this should be taken into account when utilizing a pesticide product that is highly persistent in the environment.

Click to view: Table VII: Maximum Pesticide Tolerances in Food for Internal Consumption [mg/kg]

5. CONCLUSIONS

1. In Chile the importation, manufacture, sale, distribution and use of the following compounds have been prohibited: DDT since 1984; aldrin since 1988; and chlordane, dieldrin, endrin, and heptachlor since 1987.
2. Despite the reduced use of PCBs, at present a large quantity exists as waste in the country, generated by the ban on their use in electric generators. Through the Basel Agreement a company has currently been entrusted with storing and exporting this waste for treatment, with the cost covered by the company generating the waste.
3. In Chile there are no programs for analyzing dioxins and furans.
4. The studies to determine organochlorine pesticide residues in cow’s milk, breast milk, adipose tissue, and butter demonstrate that these compounds are contaminants. They also show the significant impact of the regulatory measures instituted to protect human health.
5. The country has a comprehensive information system on imports of pesticide products, which is handled entirely by the Agriculture and Livestock Service.
6. It is necessary to establish a registry of other persistent organic products, which should include products of the total or partial chemical, biological, or photochemical degradation of organochlorine compounds, since they occasionally produce metabolites that are of equal or greater toxicity than the original compounds and persist longer in the environment.
7. The search for alternatives to the use of organochlorine pesticides, such as the comprehensive management of crops and pests, should be promoted.
8. The study of organochlorine pesticide residues in food for human consumption demonstrates the persistence of these in varying quantities, depending on the food and the pesticide in question.
9. A comprehensive information system should be established, coordinated by a single agency at the interinstitutional level, covering the national, regional, and sectoral areas. Data entry, management, and control should be uniform, and data on imports, exports, production, use, and disposal of pesticide compounds should be updated periodically.
10. Public and private institutions need to be made aware of the need for them to contribute institutional information on persistent organic compounds.
11. The proper management of organochlorine pesticide products requires a clearly defined policy, efficient legislation, and an institutional structure capable of responding to the demands stemming from the risks to health and the environment. To this end the following aspects of the management of organochlorine pesticide compounds should be considered: marketing, control, transportation, storage, registration process, toxicological categories, certification of applicators, and final disposal of products and containers.
12. The promotion of research on persistent organic compounds stimulates the scientific development of the country and contributes to the identification of other potential compounds that should be characterized as persistent and to a more exhaustive study of those already identified as such.
13. In Chile there are public and private laboratories that have the necessary analytical techniques and trained personnel for the identification of organochlorine compounds.

6. BIBLIOGRAPHY

1. Proyecto "Evaluación del Sector Nacional Relacionado con la Gestión y Manejo de Sustancias Químicas" – Informe Final; CICA Ingenieros Consultores – CONAMA/BIRF; December 1997.
2. "Análisis y Desarrollo de una Propuesta para una Política sobre Manejo Seguro y Racional de Sustancias Químicas" – Informe Final; AMBAR Consultoría e Ingeniería Ambiental – CONAMA, December 1997.
3. Triviño A., Iván; "Contaminación de leche materna, tejido adiposo de mujeres y leche de vaca por plaguicidas de alto poder residual", Boletín del Instituto de Salud Pública de Chile; Vol. XXIII, Nºs 1 y 2, 90 – 99 (1982).
4. Serra, I.; Triviño, I.; Orellana, M.; Bustamante, J.; Ruiz, G.; "Niveles de contaminación actuales con plaguicidas organoclorados en tejido adiposo de embarazadas chilenas y en leche materna"; Escuela de salud Pública, Facultad de Medicina, Universidad de Chile.
5. Proyecto de Investigación Fundación Fondo de Investigación Agropecuaria –FIA- e Instituto de Investigaciones Agropecuarias –INIA; "Fuentes de Contaminación por Pesticidas Organoclorados y Metales Pesados en Áreas Agrícolas de las Regiones IV a XI"; Informe Final; 1990.
6. "Screening de residuos de pesticidas en frutas y hortalizas de consumo habitual en Chile", Proyecto en elaboración, CONAMA – INTA, 1997.
7. Norma Chilena Oficial NCh 409/1.Of84, Instituto Nacional de Normalización, Agua Potable – Parte 1: Requisitos, 1984.

http://irptc.unep.ch/pops/POPs_Inc/proceedings/Iguazu/PARATORI.html