Trace zinc and copper concentrations in roadside vegetation and surface soils: a measurement of local atmospheric pollution in Alice, South Africa

Evaluating Potential Ecological Risks of Heavy Metals of Textile Effluents and Soil Samples in Vicinity of Textile Industries

The present study pertains to assessing the heavy metal (Cd, Cr, Co, Cu, Pb, and Zn) contents of untreated and treated effluents of two textile industries and agricultural soil samples in the vicinity of these industries located in Ludhiana, Punjab (India). The genotoxicity of the effluents samples was estimated using Allium cepa root chromosomal aberration assay. The exposure of Allium cepa roots to untreated effluents from both industries resulted in the reduction of mitotic index (MI) and increase in chromosomal aberrations in the root tip meristematic cells when compared to those that were exposed to the treated effluents indicating the significant genotoxic potential of untreated effluents. Risk characterization of soil sample was carried out by calculating the potential ecological and human health risks of heavy metals. The hazard index was observed to be less than 1, indicating there was no potential health risk of heavy metals in soil samples. Furthermore, bioaccumulation potential studies on plant species grown in the vicinity of these industries have shown that bioaccumulation factor (BAF) varied as Ricinus communis L. > Chenopodium album L. > Cannabis sativa L. with Co and Pb having maximum and minimum values, respectively.

Heavy Metal Levels in Vegetables Cultivated in Pakistan Soil Irrigated with Untreated Wastewater: Preliminary Results

Unfortunately, vegetables are commonly cultivated with untreated wastewater and consumed by human beings who often ignore their harmful impacts on health. The industrialization and urbanization in developing countries have led to the release of increasing amounts of heavy metals (HM) into the environment. Regular monitoring of metal concentration levels in contaminated soils and edible plants is essential to prevent their excessive build-up in the diet and food chains. This study aimed to determine the concentration and accumulation of selected HM in the soil-plant system from a field located in D.I. Khan, Pakistan. Thereby, determinations of copper (Cu), lead (Pb), cadmium (Cd), chromium (Cr), iron (Fe), nickel (Ni), and cobalt (Co) were assessed in the soil of the field as well as in the roots, stems, leaves, and grains of ridge gourds (RG) and sponge gourds (SG). The gourds were irrigated with untreated wastewater and removed from the soil when completely matured. Their parts were then separated and digested for HM analyses, which were performed by atomic absorption spectrophotometry. Mean HM concentrations of each gourd were compared to each other within the same vegetable or between the vegetables. Intra-analyses depicted a similar quantitative distribution of HM in the RG or SG parts. Independently of the gourds’ variety, Fe and Pb were the most concentrated HM, and Pb was particularly concentrated in grains. Mean concentrations of Pb and Co in these vegetables were found to be toxic, since they exceeded the safe limits recommended by the Food and Agriculture Organization/World Health Organization (FAO/WHO). Inter-analyses of HM concentrations performed between RG and SG parts revealed that the mean concentration of Pb was significantly higher in roots of SG compared to that of RG. Nevertheless, mean Cr concentrations were significantly higher in all parts of RG compared to that of SG. The concentrations of Co were insignificantly different between the parts of these two vegetables. Also, the assessment of hyperaccumulation factors demonstrated that these gourds are hyperaccumulators, improper for dietary intake and commercialization, but might be useful for phytoremediation. Taken together, our data shed light on the urgent need for developing sustainable agriculture in Pakistan.

Risk of Lead Exposure from Transport Stations to Human Health: A Case Study in the Highland Province of Vietnam

Lead (Pb) is a heavy metal that negatively affects human health. Many studies have shown the relationship between lead exposure and various human activities, of which automobile service stations with gasoline emissions are considered the main cause. However, a limited number of studies have specifically considered lead exposure from automobile stations in Vietnam, as well as its impact on human activities and the surrounding natural resources. The objective of this study was to assess the possible risks of lead exposure to the surrounding agricultural and non-agricultural farms of a bus station located in the center of Dalat city, Lamdong province, Vietnam. To address this objective, 45 samples were collected from the soil, irrigated water resources, and vegetable crops of areas both close to and far away from the bus station. These samples were tested using the atomic absorption spectrometry technique. Our findings demonstrated higher lead concentration levels from all three types of samples collected from areas near the bus station. Of which, soil and water samples showed higher than normal exposure values of lead, but these were still under the allowed limits established by the Vietnam standard. Different from the soil and water, vegetable samples surrounding the bus station presented greater lead contamination than the permitted limit. High risk quotient (RQ) indexes were detected to point out that accumulative consumption of leaded vegetables over time could cause lead poisoning and harm human health. This study not only provides significant inferential evidence of the risk of lead exposure to agricultural activities and human health in Vietnam, but also delivers a real-life example for a real-world context.

Environmental exposure of road borders to zinc

The emissions of zinc along roads originating from tyre wear, corrosion of safety fence and other traffic-related sources have been quantified and validated by measured long-term loads in road run-off and airborne solids (drift) for 29 published case studies. The distribution pattern over the road border at various distances from the edge of the paved surface is assessed on the basis of 38 published case studies with measured concentrations in soil. For the impact assessment, the road border is differentiated into a zone that is part of the "technosphere" and the "target zone" beyond that technosphere that can be considered as part of the receiving environment. The "technosphere" of the road includes the central reservation, the hard and the soft shoulder or, if one or both shoulders are not present, the so-called obstacle "free zone" that is defined by road engineers. Pollution within the technosphere may require appropriate management of solid disposal and isolation from groundwater to prevent further distribution of pollutants to the environment. In the target zone along regional roads, the zinc load is about 4 mg/m(2) year and this is of the same order of magnitude as that of atmospheric deposition in areas beyond the influence of roads (background). In the target zone along highways, the zinc load is increased in comparison to the background deposition. The average load of about 38 mg/m(2) year is similar to that in fertilised agricultural land. Because most of the emitted zinc stays in the technosphere, the total amount entering this target zone along highways is limited. From the 140 tons of zinc per year that is released from tyre wear in The Netherlands, 64 tons is emitted in the urban area, 6.5 tons reaches to the target zones of all roads and only 1.1 tons of zinc will enter the target zone along highways. This amount will be further decreased by the application of porous asphalt in the near future. The emission from safety fence corrosion does not enter the target zone. Only in special cases, such as bridges, crossings and squares the release of zinc from these sources may enter the aquatic environment by the discharge of run-off.

A survey of trace metals in vegetation, soil and lower animal along some selected major roads in metropolitan city of Lagos

The concentration of trace metals (Cd, Cu, Pb and Zn) in a total of 144 samples of grass, soil and lower animal (earthworm, Lybrodrilus violaceous) were collected and analysed for their metallic content. Levels of cadmium ranged from 0.01-0.07 microg g(-1); 0.01-0.12 microg g(-1) and from trace-0.05 microg g(-1) dry weight for plant, soil and animal samples respectively. Mean concentration of copper ranged 0.10-1.48 microg g(-1); 0.10-2.90 microg g(-1) and 0.01-0.08 microg g(-1) for samples in similar order as above. The levels of Pb varied from 0.01-0.14 microg g(-1); 0.02-0.23 microg g(-1) and from trace-0.07 microg (g-1) while that of Zn ranged from 0.19-1.80 microg g(-1); 0.51-3.35 microg g(-1) and 0.01-0.08 microg g(-1) also in the same order of samples as mentioned above. Levels of metals in soil samples were higher than the background levels with the exception of Zn but lower than European Union (EU) limits. The results generally revealed the presence of metals in plant and animal samples and metal dynamics up the food chain is highly possible. Acceptable recoveries of the spiking experiment validate the experimental protocol.