Overview
This study measured lead, cadmium, copper, and chromium by flame atomic absorption spectroscopy in water samples drawn from six source types in Diyala Governorate, Iraq: the Diyala River, the Khirisan River, municipal tap water, bottled drinking water (two unnamed companies, ozone-sterilized), filtered tap water, and three groundwater wells. The authors report copper concentrations within WHO and Iraqi drinking-water limits across all source types, while lead, cadmium, and chromium concentrations substantially exceeded WHO and Iraqi standards in multiple source types — most prominently 109× the WHO Pb limit in Diyala River water, 274× the WHO Cd limit in well water (the source’s stated multiplier; strict arithmetic 0.820/0.003 = 273.3×), and roughly 20× the WHO Cr limit in well water and filtered tap water. The reported concentrations are extraordinarily high for drinking-water FAAS measurements and are reported without LOD/LOQ, reference-material recoveries, or QA/QC documentation, so the page is treated as B-tier regional contextual evidence rather than as defensible per-sample occurrence data.
Key numbers
The paper reports concentrations as mean ± SD (mg/L); each sample was re-analyzed three times. No per-source sample counts are stated in the methods.
Lead (Pb), mg/L (Fig. 6, p. 474):
| Source | Concentration (mg/L) | Multiple of WHO/Iraqi limit (0.010 mg/L) |
|---|---|---|
| Diyala River | 1.089 ± 0.006 | 109× |
| Khirisan River | 0.137 ± 0.008 | 14× |
| Tap water | 0.380 ± 0.011 | 38× |
| Bottled drinking water | 0.534 ± 0.003 | 54× |
Lead concentration ordering reported by the authors: Diyala River > bottled drinking water > tap water > Khirisan River.
Cadmium (Cd), mg/L (Fig. 7, p. 474):
| Source | Concentration (mg/L) | Multiple of WHO/Iraqi limit (0.003 mg/L) |
|---|---|---|
| Diyala River | 0.133 ± 0.002 | 44× |
| Khirisan River | 0.140 ± 0.012 | 47× |
| Tap water | 0.130 ± 0.001 | 43× |
| Filtered tap water | 0.630 ± 0.013 | 210× |
| Bottled drinking water | 0.205 ± 0.009 | 68× |
| Well water | 0.820 ± 0.010 | 274× (per source; strict arithmetic = 273.3×) |
Cadmium concentration ordering reported by the authors: well water > filtered tap water > bottled drinking water > Khirisan River > Diyala River > tap water.
Chromium (Cr) — total chromium by Flame AAS (Fig. 8, p. 474):
| Source | Concentration (mg/L) | Multiple of WHO/Iraqi limit (0.050 mg/L) |
|---|---|---|
| Diyala River | 0 (below detection per Fig. 5) | — |
| Khirisan River | 0 (below detection per Fig. 5) | — |
| Tap water | 0 (below detection per Fig. 5) | — |
| Bottled drinking water | 0 (below detection per Fig. 5) | — |
| Filtered tap water | 0.970 ± 0.004 | 19× |
| Well water | 1.010 ± 0.014 | 20× |
The authors interpret the elevated Cr in groundwater and filtered tap water as deriving from war-remnant weapons, soil pollution, and waste incineration. Flame AAS measures total Cr; no speciation between Cr(III) and Cr(VI) is performed, so the values are read as total Cr despite the authors’ Cr(VI)-framed discussion.
Copper (Cu), mg/L (Fig. 9, p. 474):
| Source | Concentration (mg/L) | WHO limit (2.000 mg/L) | Iraqi limit (1.000 mg/L) |
|---|---|---|---|
| Diyala River | 0.039 ± 0.002 | within | within |
| Khirisan River | 0.030 ± 0.003 | within | within |
| Tap water | 0.006 ± 0.003 | within | within |
| Bottled drinking water | 0.014 ± 0.008 | within | within |
The authors attribute the low Cu concentrations to the low copper background of Iraqi territory overall.
WHO and Iraqi drinking-water limits cited (Table on p. 471):
| Heavy element | WHO (mg/L) | Iraqi standard IQS 417 (mg/L) |
|---|---|---|
| Cd | 0.003 | 0.003 |
| Cr | 0.050 | 0.050 |
| Cu | 2.000 | 1.000 |
| Pb | 0.010 | 0.010 |
Methods (brief)
Water samples were collected between August 2016 and February 2017 in sterile plastic tubes from six source categories in Diyala Governorate: Diyala River (4 locations in Baquba), Khirisan River (3 locations in Buhriz and Huider), refinery drinking water (Al-Hadd Al-Akhder village, Huider, Baquba), bottled drinking water from two unnamed companies (Baquba; ozone-sterilized), filtered tap water, and three groundwater wells (Baquba, Al-Abara, Buhriz). All samples were re-analyzed three times. The paper does not state a per-source sample count or LODs.
Concentrations were measured by flame atomic absorption spectroscopy on an Aurora Instruments Ltd. 1200 (Canada 2004) instrument. Lead, cadmium, copper, and chromium hollow cathode lamps were operated at 5 mA with a 0.2 nm slit width. Air-acetylene flame; fuel flow 1.5 L/min. The methods statement that “wavelengths for all lamps were set at 217 nm resonance line” is preserved as-written from the source; 217 nm is the conventional Pb wavelength, while Cd (228.8 nm), Cu (324.7 nm), and Cr (357.9 nm) are measured at distinctly different wavelengths, so this is either a writing error or a methodological problem the source does not address.
No reference materials, LOD/LOQ values, recovery percentages, blank corrections, or other QA/QC documentation are reported. Concentrations are reported as mean ± SD (mg/L) at one decimal of standard deviation.
Limitations
- Total sample size not stated; per-source counts not derivable from the methods.
- Wavelength reporting inconsistency (217 nm stated for all four lamps; not the conventional wavelengths for Cd, Cu, Cr); not addressed by the authors.
- No LOD/LOQ, no reference-material recoveries, no QA/QC documentation.
- Reported drinking-water concentrations for Cd in well water (0.820 mg/L) and Pb in Diyala River (1.089 mg/L) are extraordinarily high for FAAS without sample dilution discussion; sample-matrix and detection-limit effects are not addressed.
- Cr values are total Cr by Flame AAS; the discussion frames contamination as hexavalent Cr from war remnants but provides no speciation evidence.
- Cu and Cr values reported as 0.000 mg/L in Fig. 5 are read here as below detection rather than literal zero; the source does not state an LOD.
- Sampling design is opportunistic (selected locations within Baquba and surrounding municipalities) rather than randomized or stratified.
- Bottled drinking water aggregated across two unnamed companies; per-company values not reported.
Implications
- Certification: This page is regional context for the Diyala Governorate water-pollution signal, not occurrence data suitable for HMTc bottled-drinking-water threshold work. The reported bottled-water Pb of 0.534 mg/L would, if defensible, place the matrix at 54× the WHO limit; the page’s B-tier grade and the unaddressed methodological issues mean this value should not drive any HMTc bottled-water threshold without independent corroboration.
- Courses: Useful as a case study in the difficulty of interpreting peer-reviewed contamination data when methodology is thinly reported (no LODs, no QA/QC, no per-source sample counts), and as documentation of post-conflict water-infrastructure deterioration in Iraq.
- App: Geographic context for Iraq-origin bottled drinking water; not a defensible per-product occurrence input.
- Microbiome: Not applicable.
Related evidence
Update history
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