Overview
This short paper reports ten elements measured by AAS in waterleaf and lettuce leaves from three farms near Sabon Tasha, Kaduna, irrigated with water from the Kaduna River and urban drainages. Waterleaf from one farm (Juji) carried 18.80 µg/g lead, far above the other farms. Arsenic was not measured and mercury was near zero.
Key numbers
- Waterleaf lead 0.76 ± 0.02, 18.80 ± 1.14 and 0.32 ± 0.06 µg/g at the three farms; cadmium 0.25 to 0.57 µg/g (Table 1).
- Lettuce cadmium 2.61 ± 0.81, 1.68 ± 0.16 and 0.87 ± 0.35 µg/g; lead 0.47 to 0.85 µg/g (Table 2).
- Mercury 0.00 to 0.01 µg/g in waterleaf and 0.00 to 0.0019 µg/g in lettuce (Tables 1-2).
Methods (brief)
Leaves were washed, air-dried for two weeks and oven-dried at 105 °C, digested in nitric, perchloric and sulfuric acids and analyzed by AAS. No detection limits, blanks, recoveries or reference materials are reported. The DOI is not printed on the PDF.
Evidence Fitness
Very small (one vegetable sample per farm per species, as far as can be told) and without analytical quality control, on a dry-weight basis from wastewater-irrigated farms rather than retail. Some text statements conflict with the tables (lead “only detected in waterleaf”; waterleaf iron mean). Lettuce iron values below 0.5 µg/g are implausibly low. Waterleaf and lettuce are leafy proxies for collard-greens and vegetables-mixed; neither was measured.