Krasnopyorova et al. 2024 — Trace elements in Almaty surface water and human health risk
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.