Microbiological and Physicochemical Analysis of Therapeutic Peat from Baikalsko Deposit, Radomir Municipality
Key Findings
- Bulgarian therapeutic peat from Baikalsko deposit (1.5-2.0 m depth) has 80% moisture, 16% dry matter, 0.5% ash
- Humic acid content 26% (dissolved form) — high for therapeutic peat
- Organic carbon 36.75%, total nitrogen 3.16%
- Water-holding capacity 1354 g/100g, swelling degree 6.80 — excellent peloid properties
- Heat capacity 4.02 J — suitable for thermotherapy
- pH 6.80 (near neutral), total mineralization 460 mg/l
- Dominant cation is calcium (90.03 mg/l), followed by magnesium (9.00 mg/l) and sodium (6.95 mg/l)
- Iron 1.07 mg/l in liquid phase
- Heavy metals all below detection or trace levels — As 0.009 mg/l, Pb <0.010, Cd <0.003, Cr <0.005 mg/l
- Microbiological results comply with Bulgarian Ordinance 14 for resort resources
Official laboratory analysis from the Bulgarian Ministry of Health’s National Specialized Hospital for Physical Therapy and Rehabilitation (Sofia). Samples were taken from the therapeutic peat deposit in Baikalsko village, Radomir municipality (Pernik Province), submitted by the deposit operator in late 2024.
Microbiological analysis
Four samples were tested — two solid peat (1.5 m and 2.0 m depth) and two overlying liquid samples. Microbial counts ranged 1,350–18,350 per g/ml. Coliform and clostridia titers were within acceptable ranges, and all results comply with Bulgarian Ordinance 14 regarding resort resources.
Physicochemical properties — solid phase
The peat presents as a dark brown, odourless mass. Key properties: 80% moisture, 16% dry matter, 0.5% ash (very low, indicating high organic content), 26% humic acids in dissolved form, 36.75% organic carbon, and 3.16% total nitrogen. Water-holding capacity of 1,354 g/100g and swelling degree of 6.80 indicate excellent peloid quality. Heat capacity of 4.02 J is suitable for thermotherapy applications.
Chemical properties — liquid phase
The brine is of hydrogencarbonate-calcium type, with total mineralization of 460 mg/l and near-neutral pH (6.80). Dominant ions are HCO₃, calcium, magnesium and sodium. Iron is present at 1.07 mg/l. All tested heavy metals (arsenic, lead, cadmium, chromium) are below detection limits or at negligible trace levels, confirming safety for therapeutic use.
Significance
Establishes a documented, independently-tested chemical and safety profile for a Bulgarian therapeutic peat deposit — one of the few peer-institution lab analyses available for Bulgarian balneological peat.