Heavy Metals Availability at Industrially Contaminated Soils in NSW, Australia

Frank

2011

JANS

Pot and field trials were conducted at the Faculty of Agriculture, University of Benin to determine the influence of Pb on some agronomic characters of Telfairia occidentalis and some chemical properties of soil. Completely randomized and randomized completely block designs were used in greenhouse and field trials respectively. In the greenhouse trial, lead nitrate (Pb(N0 3 ) 2 ) was applied at rates of 0, 50, 100 and 200 mg per 5 kg sieved and air-dried soil obtained from a depth of 0-15 cm. The pot rates equivalent to 0, 20, 40 and 80 kgha -1 were used in the field trial. Results indicated that the soil used was texturally sandy loam and an ultisol as demonstrated by its low base saturation. The pH, organic carbon, Effective Cation Exchange Capacity (ECEC), Exchangeable acidity, N, K, Mg, Ca, Na, Fe, Mn, Zn, free Fe and Al oxides, Amorphous Fe and Al oxides content of the soil decreased inconsistently. The organic carbon however increased in the field while the available P appreciated in the entire trials. The Pb content of the soil increased with the levels of Pb treatments when compared with the control throughout the trials. The N, P, K, Mg, Ca, Na, Fe, Mn and Zn content of shoot and root as well as their uptake also decreased consistently with increasing Pb treatments. In addition, the Pb content as well as uptake by the shoot and root also increased consistently with increased rates of the Pb applied in the trials with the minimum levels of the Pb content and uptake recorded at the control treatments. The crude protein content decreased with increased heavy metal treatments in both root and shoot with the control having the highest crude protein content. The highest crude protein percentage was recorded in the shoot compared to the root. A decrease in the dry matter yield with increased Pb treatments in shoot and root was recorded in the trials. Results also showed that the Pb influenced the height, collar girth, leaf area and number of leaves with control treatments higher than other treatments at final harvest. The manifestation of anthocyanin pigmentation in 200 mg Pb and 80 kg Pb ha -1 treatments revealed the negative influence of the Pb on the phosphorus uptake by Telfaria occidentalis.

Uptake of lead by futed pumpkin (Telfairia occidentalis Hook F.) in an ultisol

Frank

2011

JANS

Fate of some heavy metals in soils: a review

Frank

2011

JANS

This review revealed that heavy metals are naturally components of the soil orchestrated by weathering processes and that the abundance of these metals in our soil environment nowadays is due to numerous anthropogenic activities. These heavy metals are in two major categories namely the essential and non-essential ones. The essential heavy metals are needed in trace amount by living things for their physiological processes. But at higher concentration, it is hazardous in plants and animals. On the other hand, the non essential ones are dangerous to plants and animals even at low concentrations. This write-up further showed that soil pH, organic carbon, available P, oxides, effective cation exchange capacity, moisture content, oxidation-reduction state of the metals, ion exchange and sorption capacity of the metals are some of the soil factors influencing the fate and availability of the heavy metals. At lower levels of these soil factors, heavy metal ions are rendered free in the solution thereby making them available to plant and underground water. However, the most prominent soil factor influencing availability of these metals is the Soil pH. Raising some of these soil factors to appropriate levels have been discovered to reduce the availability of the heavy metals to mankind.

Influence of cadmium on early growth of fluted pumpkin (Telfairia occidentalis Hook F.) and nutrient uptake in an ultisol

Ekhomun

2011

JANS

Abstract:The greenhouse and field trials were conducted at the University of Benin, Benin City, Nigeria to determine the influence of Cd on the growth, dry matter yield and nutrient uptake by fluted pumpkin (Telfairia occidentalis). Four levels of Cd(NO 3 ) 2 treatments namely 0, 50, 100, 200 mg per 5 kg soil equivalent to 0, 20, 40, 80 kgha -1 were used in the greenhouse and field trials respectively. The completely randomized and randomized complete block experimental designs were used in the greenhouse and field trials respectively. Results indicated that increased application of Cd decreased the height, number of leaves, leaf area, stem girth and dry matter yield of the plant. The nutrients content and uptake also decreased with the increase in the supply of the Cd. Higher Cd concentrations and uptake were recorded in the root of the treated plants when compared to the control treatments. The nutrients and oxides components of the soil decreased at various levels of the Cd application. These decrease in soil nutrient components were however not consistent. However, the Cd content of the soil increased with increased Cd treatments.