Overview
This study measured 26 trace elements in surface water from four rivers flowing through Almaty City, Kazakhstan — Bolshaya Almatinka, Malaya Almatinka, Esentai, and Kargalinka — across four seasons in 2023 (n=64 samples, 16 sites). The four rivers are the primary sources of drinking water for Almaty. The study applied non-carcinogenic (Hazard Quotient, HI) and carcinogenic risk (CR) assessments using both dermal and ingestion exposure pathways.
Key numbers
- Total elements measured: 26, including As, Be, Co, Cd, Cu, Li, Mo, Ni, Pb, Se, U, Hg, Al, Ba, Cr, Fe, Mn, Sr, V, Zn.
- Carcinogenic risk elevated above acceptable threshold (CR > 10^-4) for As, Ni, Cr, U, and Pb at multiple sampling sites.
- Two sites near urban thoroughfares showed CR in the 10^-2 range — two orders of magnitude above the US EPA acceptable threshold of 10^-4, indicating a substantive carcinogenic risk from drinking-water exposure at those sites.
- As, Ni, Cr, and U were the dominant contributors to carcinogenic risk; Pb and Cd contributed at lower but non-trivial fractions.
- Non-carcinogenic HI exceeded 1 for several metals at specific sites, primarily driven by Ni, Al, and Mn.
- Seasonal variation documented across all elements; spring (snowmelt) and summer showed distinct concentration profiles versus autumn and winter, consistent with runoff and dilution dynamics.
- Method detection limits and blank corrections applied; concentrations near MDL flagged in the source.
Methods (brief)
Analytical methods: ICP-MS (ELAN-9000, Perkin Elmer) for trace elements at sub-ppb levels; ICP-AES (OPTIMA-8000) for major elements. Sampling protocol: 16 fixed sites across 4 rivers, 4 seasonal campaigns (March, June, September, December 2023). Health risk assessment: US EPA framework (USEPA 2004) using standard ingestion and dermal exposure factors. Speciation: none — total element concentrations. Limitation: surface water measurements; downstream treatment plant performance not characterized in this study.
Implications
Certification: Drinking water is a non-trivial route of heavy metal dietary exposure; Almaty-area As, Ni, U, and Cr levels in raw source water are relevant context for supply-chain water sourcing decisions. Not directly usable for food matrix contamination_profile. Courses: Useful for modules on water-borne heavy metal exposure routes and the distinction between regulatory MCLs and health-protective thresholds; CR at 10^-2 for two sites illustrates how point-of-use source matters. App: Not applicable to ingredient contamination profiles directly, but relevant to water used in food production if Kazakhstan supply chains are being assessed. Microbiome: Not applicable.
Wiki pages updated on ingest
Update history
The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.
| Commit | Date | Change | Description |
|---|---|---|---|
| a8052bb | 2026-08-09 | major | 6 sections added; narrative text revised |