Phytoavailability, human risk assessment and transfer characteristics of cadmium and zinc contamination from urban gardens in Kano, Nigeria

Abstract

Zinc and Cd accumulation by vegetables in our soils is mainly a metabolically controlled process. Such accumulation can contaminate the ecosystem but under our conditions intake and ingestion of these metals will likely have to occur over a prolonged period to experience health hazard.

Accumulation of soil‐borne aluminium, iron, manganese and zinc in plants cultivated in the region of Moanda (Gabon) and nutritional characteristics of the edible parts harvested

“…The BCF, also referred to as the ‘bioconcentration factor’, an index of the ability of a vegetable to accumulate a particular metal as a function of its concentration in the soil, was calculated as…”

“…As a rule, the greater the value of the THQ is above unity, the greater the level of concern is. The method of estimating risk using the THQ is based on the equation …”

“…The BCF, also referred to as the 'bioconcentration factor', an index of the ability of a vegetable to accumulate a particular metal as a function of its concentration in the soil, was calculated as 24 BCF = metal concentration in consumed fresh part of plant (mg kg −1 )/metal concentration in soil (mg kg −1 ).…”

Fractionation and mobility of cadmium and zinc in urban vegetable gardens of Kano, Northern Nigeria

“…In the Kwakwaci and Gada soils, in con- trast, the organically bound fraction was the most important one, followed by the carbonate bound fraction. In these soils, Cd bioavailability has been reported (Abdu et al 2010) thereby representing potential phytotoxic and human health hazards (Udom et al 2004). The relatively high percentage of mobile and more labile fractions (26% to 42%) of Cd observed in these soils is an indication of its anthropogenic source.…”

Human bioaccessibility and absorption by intestinal cells of potentially harmful elements from urban environmental matrices

“…Details of this procedure are described in ANNEX C. The residual fraction was calculated as the difference between the pseudo-total concentration extracted by the 3051A method (USEPA. 2007) and the sum of the F1, F2 and F3 fractions (Abbad & Torres 2002;Abdu et al 2011Abdu et al , 2012Puga et al 2016). The residual fraction is associated with the elements strongly adsorbed to the crystalline matrix, mainly by specific adsorption, suggesting predominantly a geogenic origin (Patinha et al, 2015b).…”