Nwankwoala et al. 2022 - Port Harcourt groundwater and wastewater metals

Nwankwoala, Osayande, and Uboh measured Pb, Fe, Hg, As, and Cd in groundwater and industrial wastewater from Trans-Amadi, Port Harcourt, Nigeria. This is upstream groundwater/wastewater and source-attribution evidence, not mineral-water product occurrence: the authors connect elevated groundwater lead to industrial and municipal waste inputs in a non-mineralized urban-industrial area.

Key numbers

The study collected 14 samples in August 2011: 10 borehole groundwater samples and 4 industrial wastewater samples. Borehole locations were Nkpogu, Ordinance, Rivoc Road, GTC (By Zoo), Nwuke Street, Eastern By-Pass, Odili Road, Amadi-Ama, Abuloma, and Oginigba. Wastewater samples were WWBR from breweries, WWCM from ceramics, WWPE from plastics, and WWTX from textiles.

Table 1 reports heavy-metal concentrations in mg/l. Groundwater Pb values were 0.050 at Nkpogu, <0.001 at Ordinance, 0.150 at Rivoc Road, <0.001 at GTC, 0.050 at Nwuke Street, 0.100 at Eastern Bye-pass, 0.100 at Odili Road, 0.050 at Amadi-Ama, <0.001 at Abuloma, and 0.075 at Oginigba. Wastewater Pb values were 0.150 at WWBR, 0.075 at WWCM, 0.150 at WWPE, and 0.050 at WWTX. The WHO permissible limit printed in the table is 0.01 mg/l for Pb.

Table 1 reports total iron values in mg/l: 0.161, 0.063, 0.160, 0.065, 0.226, <0.010, 0.065, <0.010, 0.065, and <0.010 across the 10 groundwater samples; wastewater values were 0.903 at WWBR, 26.741 at WWCM, 1.226 at WWPE, and <0.010 at WWTX. The WHO permissible limit printed in the table is 0.05 mg/l for total iron.

For Hg, Table 1 reports <0.001 mg/l in all groundwater samples, <0.001 mg/l in WWBR, <0.0025 mg/l in WWCM, <0.001 mg/l in WWPE, and <0.001 mg/l in WWTX. The printed WHO permissible limit is 0.001 mg/l. For As, Table 1 reports <0.001 mg/l in all 10 groundwater samples, <0.001 mg/l in WWBR, <0.005 mg/l in WWCM, <0.013 mg/l in WWPE, and <0.001 mg/l in WWTX. The printed WHO permissible limit is 0.01 mg/l.

For Cd, Table 1 reports <0.002 mg/l in all 10 groundwater samples, 0.003 mg/l at WWBR, 0.004 mg/l at WWCM, 0.003 mg/l at WWPE, and 0.003 mg/l at WWTX. The printed WHO permissible limit is 0.003 mg/l.

Table 2 reports study-wide ranges and means: Pb <0.001-0.150 mg/l, mean 0.071 mg/l; total Fe <0.010-26.741 mg/l, mean 2.120 mg/l; Hg <0.001-<0.0025 mg/l, mean 0.000 mg/l; As <0.001-0.013 mg/l, mean 0.001 mg/l; and Cd <0.002-0.004 mg/l, mean 0.001 mg/l.

The abstract states that geochemically significant Pb and Fe prevailed in about 70% of functioning domestic water-supply wells in Trans-Amadi, while industrial effluent liquid wastes were characterized by traces of Hg and As with relatively high Pb and Fe. The conclusion states that higher Pb concentrations in all Trans-Amadi locations indicate lead pollution from highly industrialized areas.

Methods (brief)

Groundwater samples were collected from boreholes after pumping wells continuously for at least five minutes. Samples were collected in clean 1.5 L plastic containers, corked immediately, transported in ice-packed coolers, and analyzed within 24 hours. The authors measured Pb, total Fe, Hg, As, and Cd using flame atomic absorption spectrophotometry with a Perkin Elmer A3100. The paper reports total elemental metals; As is not speciated into inorganic arsenic, and Hg is not speciated into methylmercury.

Implications

Certification: These are groundwater and wastewater values, not mineral-water, bottled-water, or product occurrence data. They should not enter product threshold pools.

Courses: Useful for source-attribution and water-pathway teaching because the authors attribute elevated Pb in groundwater to industrial and municipal liquid wastes, recharge by meteoric water, and urban waste materials rather than to proven geologic Pb mineralization.

App: Context only. The paper supports local water-pathway and exposure context, not product-level contamination estimates.

Wiki pages this source may touch

• irrigation-and-soil-amendments
• source-attribution-environmental-burden-apportionment
• lead
• iron
• mercury-total
• arsenic-total
• cadmium

Verification notes

Recovered from skip:not-food-occurrence under the 2026-06-10 inclusion-by-default rule. The old skip treated “not mineral-water product occurrence” as exclusionary, but the paper is in-scope a3 groundwater/wastewater pathway and source-attribution evidence.

Numbers were checked against the extracted PDF text, especially the abstract, Methods, Table 1, Table 2, and conclusion. Units are preserved as mg/l. The paper reports total arsenic and total mercury only, so this page uses tAs and tHg and does not infer iAs or MeHg.

Page history

The five most recent substantive edits to this page. 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.