INTRODUCTION:According to the report from 2010, Mongolian water consumption was 550 million cubic meter andapproximately 9.1% of the total Mongolian population obtain their water from inadequate hygiene waterresources - springs and rivers. Due to non-hygiene water usage has caused water-born communicableand non communicable diseases among the population. In the last years there has been issue of pollutionof one of the Mongolia’s more representative river Selenge and its following rivers -Kharaa, Orkhon andit is necessary to evaluate water pollution of these rivers.GOAL:To determine water chemical and biological pollution of Kharaa and Orkhon river and to evaluate waterqualityMaterials and MethodsWe collected water, sediments and macro invertebrates sample from three points of river -upstream,midstream, downstream and for Kharaa river the samples were collected from Tunkhel, Mandal andBayangol soum, fo Orkhon river the sequence was Orkhontuul, Orkhon, Khushaat soum. Samples werecollected June, August, October of 2011, 2013.In water sample, we determined physic-chemical 15 parameters including temperature, pH, total dissolvedsolids, conductivity, smell, color, hardness, sulfate, chloride, nitrate, nitrite, ammonia, dissolved oxygen,biological oxygen demand and mercury using their standard methods. Macro invertebrate samples werecollected to evaluate water quality and we determined mercury in sediments and macroinvertebratesamples to evaluate mercury contamination.RESULT:Physic-chemical results of the water showed that water of Kharaa, Orkhon rivers were classified lowmineralized, soft water and nutrient pollution indicators for ‘slightly polluted’category. For dissolved andbiochemical oxygen, they were belong to the category of ‘pure water’.There were no correlation between 2012 and 2013 results and mercury in water, sediments and macroinvertebrates were qualified standard value.CONCLUSION:According to research results water quality of Kharaa, Orkhon river was good and have less pollution andit is possible to use in household consumption after proper cleaning and disinfection.

Backround Peutz–Jeghers (PJ) syndrome is a rare autosomal dominant disorder characterized by a mucocutaneous pigmentationon on oral mucosa and multiple hamartomatous polyps located in the digestive tract except esophagus. PJ syndrome can be diagnosed in early childhood by a characteristic pigmentation and family history of polyposis. However, it is often diagnosed first as a polyp in the small intestine that causes obstruction and intussusception and is often treated with a bowel resection. If diagnosed in young childhood, an effective non-invasive method is to resect the polyps by tying off the blood supply to the polyps, that is the method named ischemic polypectomy, before they grow to the point of obstruction using a endoscopy. PJ syndrome is rare in Mongolia, but in severe cases, small intestine polyps are treated only surgically. Double-balloon-endoscopy (DBE) has been performed at the Mongolian- Japanese Hospital since 2023, making it possible to diagnose and treat the syndrome endoscopically. Our patient, a 15-year-old boy, had a mucocutaneous pigmentation that had been previously undiagnosed and was first diagnosed with intussusception at the age of 13. He had undergone 4 endoscopic procedures for upper and lower gastrointestinal polyps at the National Center for Maternal and Child Health successfully. In our hospital, we found endoscopically multiple hamartomatous polyps of various sizes between 1-3 cm, and a 3 mm diameter tumor that filled 3/4 of the intestinal lumen was treated by ischemic polypectomy. After the procedure, there were no early or late complications related to the procedure. The child's condition improved, the main complaints subsided, and he continues his daily life normally. However, follow-up DBE is required.