Ecological and human health risk assessment of heavy metal contamination in soil of a municipal solid waste dump in Uyo, Nigeria

Abstract

The study assessed the levels of some heavy metals in soils in the vicinity of a municipal solid waste dumpsite with a view to providing information on the extent of contamination, ecological risk of metals in the soils and human health risk to the residents in Uyo. Soil samples were collected in rainy and dry seasons and analyzed for metals (Pb, Cd, Zn, Mn, Cr, Ni and Fe) using atomic absorption spectrometry. The concentrations of heavy metals (mg/kg) at the dumpsite in rainy season were Pb (9.90), Zn (137), Ni (12.56), Cr (3.60), Cd (9.05) and Mn (94.00), while in dry season, the concentrations were Pb (11.80), Zn (146), Ni (11.82), Cr (4.05), Cd (12.20) and Mn (91.20). The concentrations of metals in the studied sites were higher than that of the control site (P < 0.05). Pollution indices studies revealed that soil samples from dumpsite and distances from 10 and 20 m east of the dumpsite were highly polluted with cadmium. Ecological risk assessment carried out showed that cadmium contributed 98-99 % of the total potentially ecological risk. No probable health risk was observed as the total hazard index of all the metals was less than one. However, children were found to be more susceptible to heavy metal contamination than adult.

Enrichment, Source Apportionment and Health Risk Assessment of Soil Potentially Harmful Elements Associated with Different Land Use in Coastal Tidelands Reclamation Area, Eastern China

“…PHEs from industrial activities and agricultural fertilization management accumulate continuously after entering the soil and migrate in different systems (such as water systems and crops), thereby entering the human body through the food chain, resulting in harm to human health [3,65]. Besides, compared with daily average exposure, non-carcinogenic risk index and carcinogenic risk index, it can be found that children are more vulnerable to PHEs in soil than adults (Figure 8), which is similar to previous research results [44,60,65]. It is mainly because the children's immune resistance is much lower than that of adults, which is more sensitive to environmental pollution.…”

“…If CR < 10 −6 , it will neglect the carcinogenic risk to human health. 10 −6 < CR < 10 −4 is considered an acceptable range and CR > 10 −4 is viewed as unacceptable [44].…”

The Role of Salicylic Acid in Plants Exposed to Heavy Metals

“…The increased amount of HM in soil leads to greater uptake by plants that can reduce plant growth, biomass, photosynthesis, crop yield, and quality in plant [57]. From a biological point of view, the top soil is the most active zone of soil that accumulates a large amount of toxic metals that poses serious concern to the environment [49,58,59].…”

Health and Ecological Risk Assessment of Exposure to Toxic Heavy Metals Found in Settled Dust in the City of Kerman, Southeast of Iran

“…The geoaccumulation index (Igeo) was distinguished into seven classes. Igeo ≤ 0, class 0, unpolluted; 0 < Igeo ≤ 1, class 1, from unpolluted to moderately polluted; 1 < Igeo ≤ 2, class 2, moderately polluted; 2 < Igeo ≤ 3, class 3, from moderately to strongly polluted; 3 < Igeo ≤ 4, class 4, strangle polluted; 4 < Igeo ≤ 5, class 5, from strongly to extremely polluted; and Igeo > 5, class 6, extremely polluted [26,27].…”

“…The following terminology were used for the potential ecological risk index: Er i >40, low potential ecological risk; 40 ≥ Er i >80, moderate potential ecological risk; 80 ≥ Er i >160, considerable potential ecological risk; 160 ≥ Er i >320, high potential ecological risk; and Er i ≤ 320, very high ecological risk and The following terminology are used for the potential ecological risk index: RI > 150, low ecological risk; 150 ≥ RI > 300, moderate ecological risk; 300 ≥ RI > 600, considerable ecological risk; and RI ≤ 600, very high ecological risk [29].…”