Chemicals in the development of liver cancer in Tajikistan.
Study of Liver cancer in Tajikistan caused by toxic chemicals
Tech Area / Field
- ENV-EHS/Environmental Health and Safety/Environment
- MED-DIS/Disease Surveillance/Medicine
3 Approved without Funding
Institute of Gastroenterology, Academy of Sciences, Republic of Tajikistan, Tajikistan, Dushanbe
- Institute of Chemistry named after V.I.Nikitin, Academy of Sciences, Republic of Tajikistan, Tajikistan, Dushanbe
- Tufts University / Tufts University School of Medicine, USA, MA, Boston\nRobert-Koch-Institute, Germany, Berlin
Project summaryProject goal to explore the epidemiological, clinical, immunological, morphological features in patients with HCC of unclear cause, as well as to ascertain the role of chemicals (DDT, AFB1) in the etiology of primary liver cancer in Tajikistan.
Liver cancer, which is the 6th most common cancer worldwide, is characterized by a high mortality rate and ranks 3rd in overall global cancer mortality [Borzio et al., 2015 McGlynn K.A. et al., 2015]. In most countries hepatocellular carcinoma (HCC) is the predominant type of primary liver malignancies, accounting for 80-85% of all cases [Ventura, M., et al.,2004]. HCC prevalence is directly dependent on the geographic area. In countries of Central Africa and South-East Asia, HCC has the highest prevalence (> 20 cases per 100’000 population), in Greece and Italy 10-20 and in the United States 5-10 cases per 100’000 population. The HCC incidence closely correlates with the high prevalence of HBV infection in these geographic areas. Over 50% HCCs occur in Asia, where major risk factors include chronic infection with hepatitis B virus (HBV) and consumption of aflotoxin B1[Kew MC., 2013] a kind of mycotoxins.
Mycotoxins are fungal toxic metabolites which naturally contaminate food and feed. Aflatoxins (AFs) are the main toxic secondary metabolites of some Aspergillus moulds such as Aspergillus flavus, Aspergillus parasiticus and the rare Aspergillus nomius (Ali et al., 2005, Alcaide-Molina et al., 2009; Kew MC, 2013; Saad-Hussein A. et al., 2014). Aflatoxins are produced on various grains and nuts, e.g., corn, sorghum, cottonseed, peanuts, pistachio nuts, copra, cereals, fruits, oilseeds, dried fruits, cocoa, spices and beer in the field and during storage. AFs occur mainly in hot and humid regions where high temperature and humidity are optimal for moulds growth and toxins production (Ventura et al., 2004; Zollner & Mayer-Helm, 2006). Mycotoxins are known to be highly carcinogenic in liver. The highest carcinogenic potential has aflatoxin, produced by the fungus Aspergillus fungal stock flavis. Aflatoxins and other toxic substances contained in mould contaminate foods and grain crops if not correctly stored, act as carcinogens and can cause liver cancer. Tajikistan’s population predominantly consumes cereal-based foods, such as rice, corn, nuts, peanuts, and spices in their daily diet. Mycotoxigenic fungi contaminate stored food products and produce mycotoxins that pose a threat to human and animal health.
Other hepatotoxic carcinogens are synthetic chlorinated hydrocarbons and organochlorine pesticides (including DDT), which cause liver cancer in experimental animals. DDT and its derivatives are characterized by their ability to accumulate and their resistance to environmental conditions, resulting in pollution of water, soil and food from by trace amounts of DDT and its metabolites. Importantly, the human intake of DDT group pesticides with food leads to their accumulation in fatty tissues, carrying the potential risk of toxic effects over prolonged periods of time. In Tajikistan, the economic recession has led to a shortage of seeds to grow crops with the need for imports from abroad that proved susceptible to diseases and infections. This resulted in the use of large amounts of pesticides to protect the plants. In this context large quantities of illegal chemicals (about 200-500 tons) including DDT were used. The amount of pesticides used in some parts of Tajikistan during 1998-1999 ranged from 120 to 2,680 kg/ km2 and up to 4,800 kg/ km2 in cotton fields. In Tajikistan, there are three landfill disposal sites for toxic chemicals in which more than 16,000 tons of toxic substances are deposited. A major concern is the illegal import of pesticides, including those prohibited for use in agriculture, from neighbouring states. So, in 2005-2007, according to unofficial data, from the Republic of Uzbekistan for the Northern regions of Tajikistan more then 30 tons of DTT were imported. In the South of Tajikistan there are polygons with buried pesticides close to water sources, crops and fruit trees.
ISTC has approved a project “Sources of Chemical pollutions of a foodstuff produced in the Republic of Tajikistan” in 2010. Results of studies on food products produced in the fileds the Vahsh and Kanibadam pesticide burial for the period 2011-2013 years shows the high level of organochlorine pesticides such as the sum of the HCCH isomers (α β γ σ), Heptachlor, Heptachlor epoxid, α-chlordane; γ-chlordane; Endrin, Endrin aldehyde; Endrin keton; DDT with metabolites; Aldrin; Endosulfan I and II, the MRLs in meat , milk and fruits exceeds from 3.8, up to 107.7 times. Also, were identified in the same pesticides Methoxychlordane, Dieldrin content of which is not permitted by hygiene regulations GN 02/01/2701 -10. Relief of Vakhsh pesticide burial is such that rain, mud water and the excess water of the reservoir pass through the territory Vahsh burial ground, then through the village Mashal and flow into the river Vakhsh which is the main lifeline of the Vakhsh valley. Therefore, water of three water sediments bodies must be analysed for harmful substances. Kanibadam landfill is located at a height of 275 meters above the Kanibadam city at a distance of 5800 meters, the slope of the relief from the south to the north-west directed towards Kanibadam where pass two main canals (Isfarinka and Great Fergana Canal) and drilled numerous wells of different purposes.
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