Cleanup of Obsolete Pesticides Burial in Sherobod, Jami District, Khatlon Region, Tajikistan
Project dates: 2019-2020
Number of people at risk: 1,000 residents
Source of pollution: Burial of obsolete pesticides, DDT
Project implementers: NGO "Peshsaf", Environmental Protection Committee
Total cost: $50,000, the project was funded by European Commission, the assessment was co-funded by USAID and some travel costs were covered by Trust for Mutual Understanding.
The project was implemented in 2019-2020 by current EHPMI member CSO Peshsaf with the financial and organizational support of the EU/ Blacksmith Initiative UK and the Environmental Protection Committee under the Government of the Republic of TajikistanProject dates: 2019-2020Number of people at risk: 1,000 residentsSource of pollution: Burial of obsolete pesticides, DDTProject implementers: NGO “Peshsaf”, Environmental…
DDT – General Information
The term DDT refers to p,p’-dichlorodiphenyltrichloroethane. DDT, prepared by the reaction of chloral with chlorobenzene in the presence of sulfuric acid, was first made in 1874; and its insecticidal properties were discovered in 1939 by a Swiss chemist, Paul Hermann Müller. DDT (dichloro-diphenyl-trichloroethane) is considered one of the first of the modern synthetic insecticides.
DDT is applied as a dust or by spraying its aqueous suspension. The term DDT is also applied to commercial products consisting predominantly of p,p‘-DDT, but also containing smaller amounts of other compounds. All DDT isomers are tasteless, almost odorless solids.
DDT is a non-systemic contact insecticide with a broad spectrum of activity. Growers used DDT on a variety of food crops in the United States and worldwide. Some of the crops were beans, cotton, soybeans, sweet potatoes, peanuts, cabbage, tomatoes, cauliflower, brussel sprouts, corn, and other crops. DDT was also used in buildings for pest control.
It was banned in several countries in the early 1970s because of ecological considerations, and many other countries have more recently restricted or banned its use except when it is needed for the protection of human health. Despite a ban on sales, organochlorines may still be found in storage in many countries such as Tajikistan; thus, exposure is still possible. DDT is still used in some countries for the control of vectors that transmit yellow fever, sleeping sickness, typhus, malaria and other insect-transmitted diseases.
DDT was designated as a persistent organic pollutant (POP) in 1997 by the Governing Council of the United Nations Environment Programme. Pesticide applicators are exposed primarily to p,p‘-DDT, whereas it is the p,p‘-DDE metabolite to which the general population is exposed in the diet or drinking-water.
DDT and its metabolites are persistent in the environment and resistant to complete degradation by microorganisms, although photochemical degradation does occur. The persistence of DDT is substantially lower in tropical climates than in temperate ones (a few months compared with years). DDT and its metabolites are readily adsorbed onto sediments and soils, which can act both as sinks and as long-term sources of exposure. Because of its strong tendency to be adsorbed onto surfaces, most DDT that enters water is and remains firmly attached to soil particles. If it does find its way into water, it is gradually lost by adsorption onto surfaces.
In soils, DDT is immobile under aerobic conditions with a mean half-life ranging from 2 to 15 years. DDT is metabolized by microbial systems in soils and is broken down into DDE and DDD. Significant degradation has been demonstrated in soils under anaerobic conditions, while little or no degradation was observed under aerobic conditions. Biodegradation, however, is highly variable and influenced by the populations of required microorganisms. Various amendments to soils such as energy and carbon sources, were shown to increase degradation under anaerobic but not aerobic conditions. DDT has been shown to readily degrade in certain flooded soils. DDT is apparently co-metabolized by microorganisms and is not used as a sole carbon source. Products of biodegradation include DDD and DDE and occasionally DBP (4,4′-dichlorobenzophenone).
The physical and chemical properties of DDT and its metabolites enable these compounds to be taken up readily by organisms from the surrounding medium and from food. In aquatic organisms, uptake from water is generally more important, whereas food is the major source for terrestrial fauna. High lipid solubility and low water solubility lead to the retention of DDT and its stable metabolites in fatty tissue. In general, organisms at higher trophic levels tend to contain more DDT-type compounds than those at lower ones. These compounds can be transported around the world in the bodies of animals, as well as in ocean and air currents.
In the United States, populations of bald eagles and other raptors crashed when DDT thinned their eggs, killing their embryos. The pesticide, known for accumulating in food webs and persisting in soil and river sediment, was banned in the United States in 1972. Studies in animals have also shown that oral exposure to DDT can cause liver cancer.
DDT is classified as “moderately toxic” by the US National Toxicology Program (NTP) and “moderately hazardous” by WHO, based on the rat oral LD 50 of 113 mg/kg. Indirect exposure is considered relatively non-toxic for humans. The International Agency for Research on Cancer (IARC) classified DDT as Group 2A “possibly carcinogenic to humans”. EPA has determined that DDT, DDE, and DDD are probable human carcinogens as of January, 2015.
Current concerns surrounding DDT are that it is an endocrine disruptor. Endocrine disruptors are chemicals that can interfere with endocrine (or hormone) systems at certain doses. These disruptions can cause cancerous tumors, birth defects, and other developmental disorders. Any system in the body controlled by hormones can be derailed by hormone disruptors. A wide and varied range of substances are thought to cause endocrine disruption. Chemicals that are known endocrine disruptors include diethylstilbestrol (the synthetic estrogen DES), dioxin and dioxin-like compounds, polychlorinated biphenyls (PCBs), DDT, and some other pesticides.
Pesticides in Tajikistan
Before the collapse of the Soviet Union, pesticides and other chemicals were actively used in Tajikistan’s agriculture. The application of different pesticides was often done without proper adherence to the existing rules and standards and without consideration of the climatic conditions in different areas.
The range of pesticides used in Tajikistan included the following POPs: aldrin, dieldrin, heptachlorine, endrin, hexachlorinebenzene, toxaphene, chlordane, DDT, endosulphane, and lindane. On average, about 14 thousand tons of pesticides were brought to Tajikistan every year. The share of DDT constituted from 33 to 80% of the total volume of pesticides. About 90 thousand tons of DDT were brought to Tajikistan during the period of active use of this insecticide.
In 1970, by the decree of the Minister of Health of the Soviet Union, application of DDT was banned in agriculture and, in 1987. DDT was banned for use to control vector-borne diseases. In the 1980s and through the beginning of 1990s, the use of other pesticides-POPs was also banned. Despite the ban, the remaining pesticides were still used, though in much smaller volumes.
Currently, the threat of obsolete pesticides to the health of people and the environment in Tajikistan still exists. During the Soviet time, the amount of pesticides brought to Tajikistan exceeded actual application needs by 1.5-2 times. As a result, excessive volumes of pesticides were accumulating in multiple storages and distribution centers of “Tajikselkhozkhimiya” Republican Service. Because there were so large volumes of unused pesticides, various violations occurred: pesticides were distributed to individuals for uncontrolled use in their gardens, some pesticides were dumped in municipal landfills or secretly buried. In the 2000s and because of small supplies of pesticides to Tajikistan, the existing volumes of obsolete pesticides were used again in agriculture. People particularly preferred using DDT and excavated the waste chemical from the Vakhsh polygon, where more than 9 thousand tons of DDT were buried. The customs of Tajikistan registered some cases of illegal import of DDT, including the case of bringing 7 tonnes of DDT from Uzbekistan.
Today, agriculture is an important part of Tajikistan economy, generating about 24.2% of GDP (2015). The total area of land used for growing various crops exceeds 900 thousand hectares. Much attention was also paid to the agricultural sector while Tajikistan was part of the USSR. In Tajikistan there were significant areas of agricultural land for growing crops, especially cotton, and millions of rubles were spent on building infrastructure, as well as providing the industry with agrochemicals and pesticides. The development of agriculture, and, above all, cotton growing, in Tajikistan was closely linked to the widespread use of pesticides to control agricultural pests, plant diseases, and weeds.
Site Description
The village of Sherobod is located in Khatlon Region, the most densely populated part of the Republic of Tajikistan.
In the late 1980s, about 100 meters from the outskirts of the village, more than 20 tons of pesticides (bags and metal containers) of the former “Ilyich” state farm were buried. According to local residents, the pesticides were buried to a depth of 4 meters, the total area of the pollution zone was more than 160 square meters.
Until 1995, the inhabitants of the village of Sherobod did not know about the pesticides buried in this area. The pesticides were discovered by accident during the road construction. Some local residents started digging out pesticides to sell and use, which is both illegal and dangerous for health and environment. The burial and the adjacent area are currently used as a pasture for livestock. The distance to the residential area is 100 meters. About 50 children go to school on the road that runs along the burial place.
Shahlo Subhonova, activist of the Jami District: “This place was shown to us by local residents. Until 1991, the airport was located in the northern part of the Shurchosoy River. As soon as the civil war began, the airport was abandoned and the pesticides were buried near the river. If not for the road construction, no one would have known about it”.
Site Assessment
The site was initially assessed in March 2019. The project team found soil with yellow coloration near the bank of the river and took samples.
The soil samples were analyzed for concentrations of DDT, DDE, DDD, and lindane by the certified laboratory of the Agrophysics Science Institute, St-Petersburg, Russia. The maximum concentration of DDT in soils exceeded the baseline values of Tajikistan (0.1 mg/kg) by 22,450 times. The regional soil level (RSL) for residential soil (1.9 mg/kg) was exceeded by 11,815 times, for industrial soil (8.5 mg/kg) – by 2,641 times.
In November 2019, the project team did the Detailed Site Assessment (DSA) of the site in Sherobod. More extensive soil sampling was conducted as part of DSA to estimate the volumes of contaminated materials and propose risk reduction alternatives. The map of the DDT contamination is shown below.
The area contaminated with DDT in Sherobod was estimated about 300 square meters and the estimated volume of contaminated soil and pesticides was 200 cubic meters.
Preparing for Remediation
The project team met with Head (Hakim) of District Administration and local administration to discuss the findings of the conducted assessments and the feasibility of risk reduction activities. The local administrators expressed support for the assessment activities and promised to help with the coordination and implementation of future risk reduction measures. The project team also interviewed local residents to find out about the contamination distribution patterns and known health impacts.
On 24th of September 2019, the project team conducted public hearings in Dusti Jamoat of Sherobod Village to inform the authorities and local residents about the results of the DSA, existing health risks and options for remediation of the area. Peshsaf NGO and Farodis NGO informed the public about the upcoming project. Hussein Yorov, the Chairman of the Mahalla Committee of Sherobod Village, spoke with words of support to the project team. A total of 40 people took part in the public hearings. All of them voted in favor of the implementation of the risk reduction project.
Project team developed an alternative analysis matrix to choose the best course of actions to reduce health risks at the site.
The following alternatives were considered:
A. No action;
B. Repackaging of obsolete pesticides and removal to Hazardous Waste Storage;
C. Repackaging and safeguarding obsolete pesticides on site;
D. In site treatment of obsolete pesticides through biodegradation;
E. Biodegradation of pesticides in bioreactors (mobile plants);
F. In situ treatment of obsolete pesticides through destruction with special equipment (Burning pesticides in special modular plants);
G. The burning of pesticides in cement kilns.
The possibility of implementing of each alternative was assessed on a 5-point scale according to the following parameters: Risk reduction effectiveness; Sustainability; Logistical feasibility; Potential risks of work; Compliance with regulations and/or accepted practices; Stakeholder acceptance; Anticipated costs.
Repackaging of obsolete pesticides and removal to Hazardous Waste Storage was chosen as the preferred course of action. This alternative was supported by the Committee for Environmental Protection.
Cleanup Process
The cleanup started on January 16th, 2020. At the first day the Safety Manager Umidjon Ulugov and Community Trainer Lyudmila Bobritskaya held one more practical training for workers on handling hazardous materials.
The project team marked the site with a signal tape and prepared all the necessary equipment. Heavy machinery (excavator and trucks) were used for digging and loading contaminated materials, which reduced the potential exposure of workers. During the five days from January 16th to January 21st, the total of 15 trucks were loaded with contaminated soil and transported to the Vakhsh Polygon, the specially designated area for storing obsolete pesticides in Tajikistan.
The burials were opened carefully. First, the top layer of soil above the obsolete pesticide was removed and put onto a platform (which was made from a plywood plate and covered with a 200 micron-thick plastic film).
The obsolete pesticides were carefully removed and slowly poured into the UN Big Bags (special soft containers for hazardous materials). The project team repackaged a total of 16 Big Bags with obsolete pesticides. The Big Bags were labeled so that later it would be possible to identify their origin.
The repackaged pesticides were moved to Vakhsh polygon and placed in special cells.
Workers filled the pit with clean soil. The soil was provided from a nearby source by local authorities. The project team brought 15 trucks (approximately 200 cubic meters) of clean soil.
In total, 255,000 kg of highly contaminated soil were removed and 9,500 kgs of pesticides were extracted and repackaged at the site. The list of found obsolete pesticides included: DDT 75% – 2,765 kg, DDT 25% – 2,250 kg, DDT 12% – 3,650 kg, Fenturan – 835 kg.
Education and Awareness
In January-February 2020, Farodis NGO and Peshsaf NGO with support of Blacksmith Initiative conducted an information campaign for local residents living near the contaminated area.
Farodis and Peshsaf distributed journals “Objects of Toxic Pollution” (Issue 1, Issue 2, Issue 3), booklets “What Are Pesticides?” and wall calendars in the Khukumat, Jamoat and Mahalla (local administration units) and among the local residents.
Project consultant Bobritskaya Lyudmila Sergeevna: “This site did not seem to be the most polluted and the burials were there for many years. But this stream flows directly into the Kafernigan River and then to the transboundary Amu Darya River. Thank God that during all this time there were no major landslides, otherwise it would have all fallen into the river. The cleanup removed that risk for good.”
Post Remediation Assessment
In order to control the quality of the cleanup, the project team took soil samples to analyse for organochlorine pesticides. The results indicated that in all samples the DDT concentrations did not exceed 1.9 mg/kg, Regional Screening Level for Residential Soil, the United States Environmental Protection Agency (US EPA). It means that DDT health risks for people in the area were reduced to internationally acceptable levels.
The Maximum Allowable Concentration adopted in Tajikistan is 0.1 mg/kg for DDT and in some samples the concentrations were above this value, though below 1.9 mg/kg. Since cleaning up the area to achieve compliance with MSA is impractical, the project team concludes that no further clean up action or long-term pollution controls system are necessary in the area.
The map of the DDT concentrations in soil before and after cleanup is shown below.
Link to project description at PE website: Tajikistan (Sherobod): Obsolete Pesticide Cleanup