Effects of salinity on the transformation of heavy metals in tropical estuary wetland soil

In this study, a survey for the spatial distribution of heavy metals in Shouguang reed wetland of China was conducted. Samples were collected from water and soil in two parts of the wetland: treatment wetland and natural wetland. The elements including K, Ca, Na, Mg, Al, Fe, As, Cr, Pb, Zn, Mn, Hg were analyzed. The changes of their contents along the flow direction were investigated and the contents in treatment wetland and natural wetland were compared. The data indicates that the contents of nutrient and heavy metals decrease along the flow direction. The soil in Shouguang is saline-alkali. The nutrient elements are enriched, while the heavy metals are in low concentrations. The content of the nutrient and heavy metal in treatment wetland is higher than that in natural wetland. The removal rate of the element is Fe(68.6%), Al(45.8%), K(44.7%), Na (25.7%), Ca(23.1%), Mg(22.8%), Pb(90.45%), Zn (87.83%), Cd(71.16%), Mn(56.75%), Cr(40%). The Hg and Cd are undetected. Contents of As, Cr, Pb ,Zn and Mn in soil are highest in top layer. With the depth increasing, the concentration of heavy metal decreases.

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Microbiology and Heavy Metal Content of Wetlands Impacted by Crude Oil Pollution in Rivers State, Southern Nigeria

Microbiology Research Journal International ◽

10.9734/mrji/2021/v31i230296 ◽

2021 ◽

pp. 53-63

Author(s):

Mebom Princess Chibuike ◽

N. David Ogbonna ◽

Williams Janet Olufunmilayo

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Metal Concentration ◽

Microbial Population ◽

Soil Depth ◽

Heavy Metal Concentration ◽

Soil Samples ◽

Population Diversity ◽

Wetland Soil ◽

Subsurface Soil

Wetland soils constitute vast, under-exploited and sometimes undiscovered ecologies in many countries of the World, including Nigeria. A total of 54 wetland soil samples including surface and subsurface soil at depths of 0-15 cm and 15-30 cm were collected using a sterile hand auger for a period of three months between August and October and subjected to standard and analytical microbiological procedures. The wetland soil samples were further subjected to atomic absorption spectroscopy (AAS) to check for presence and concentration of heavy metals. Results obtained showed that apart from heterotrophic bacterial and fungal counts, hydrocarbon utilizing bacteria (HUB) counts were higher in the surface soil ranging from 12.06±3.43bX107 cfu/g at Iwofe to 6.19±2.67aX107 cfu/g at Chokocho while subsurface soil had HUB ranging from 8.91±6.67aX103 cfu/g at Eagle Island to 4.93±3.95aX103cfu/g at Chokocho. Heavy metals such as Fe, Pb, Cd and Ni were recorded in concentrations above FEPA permissible limit in the surface and subsurface soil across the three wetlands. The heavy metal concentration in each wetland however, decreased with an increase in soil depth. According to literatures, elevated levels of heavy metals in soils decrease microbial population, diversity and activities. However, the microbial population in this study increased with increasing heavy metal concentration which indicates that the microbes can tolerate or utilize heavy metals in their systems; as such can be used for bioremediation of heavy metal polluted soils.

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Evaluation of the impact of anthropogenic activities on wetland soil qualities: A case study of Isoko South Area of Delta State, Southern Nigeria

Global Journal of Earth and Environmental Science ◽

10.31248/gjees2021.099 ◽

2021 ◽

Vol 6 (2) ◽

pp. 58-66

Author(s):

A. N. Ogbaran ◽

◽

I. E. Joseph-Akwara ◽

Keyword(s):

Heavy Metals ◽

Soil Depth ◽

Anthropogenic Activities ◽

Cadmium Concentration ◽

Contamination Factor ◽

Pollution Load Index ◽

Soil Samples ◽

Reference Station ◽

Wetland Soil ◽

The Impact

This research was carried out to evaluate the impact of dumpsite and farming methods (anthropogenic Activities) on wetland soil qualities. Soil samples were collected from three strategic locations in Irri and Uzere communities at Delta State of Nigeria, and a reference station (control) about 5 km away from the study site. The sampling was done at the end of the rainy season (September, 2020), when the flood water had started rescinding, at two soil depths (5 to 10 cm and 45 to 50 cm). The concentration of iron, nickel, copper and cadmium concentration of the soil samples were determined with the Atomic Absorption Spectrophotometer (AAS), according to procedures approved by ASTM International. Results obtained from the chemical analysis revealed irregular concentration and distribution of the heavy metals within the studied area. Regardless of the sampling depth, the highest heavy metal concentrations were observed around the active dumpsite. Ranking order of the heavy metals’ concentrations in all the sampling locations was Fe ˃ Cu ˃ Ni ˃ Cd. It was observed from the results that the profile concentrations of the heavy metals increased with an increase in the soil depth. Using the contamination factor to assess the heavy metals contamination of the wetland, the results showed that the area ranged from moderate to considerable level of contamination, while pollution load index reveled that wetland soils were moderately polluted with the heavy metals. In terms of the soil pollution, the overall results revealed that area closed to the wastes dumpsite (site 1) was heavy polluted with the heavy metals

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