A Comparative Health Risk Assessment for Exposure to
Heavy Metals in some Industrial Areas
By: Eng.Mohamed Tayel
Ecology is a confluence of all the science point of political or social, economic or psychological or creative as a science that carries the impact on all life and human Style all its components properties.
It has given the political, economic and regulatory environment science a priority in the study and research to build strategies and preparing plans as an essential element may lead to failure if you do not take into consideration, leading to further development and discoveries of those theories related to the environment, climate and pollution became an essential science policy such as geography and climate science and the environment … etc.
Despite all the importance attached to the old environment and the definition of their importance and impact of science, but it has been handled in recent centuries, such theories can be overcome in light of what happened from a huge boom and rapid growth of science and technology. It has packed the so-called new world order or globalization and the free market to the innovation and marketing of these developments and discoveries successive according goals are to extend its influence and control and profit only, oblivious to the negative impact on human life, which has led to significant environmental problem resulted in the phenomena and the concerns that many of what we hear recently, including global warming and the expansion of the ozone layer and natural disasters such as floods, earthquakes and the steady increase of environmental pollution … etc.
Realized recently regimes and governments specifically developed nations over the existing danger. Only experts and specialists is the environmental pollution of the most important issues of the day the issue. The most recent studies illustrate this by warning by researchers that the level of intelligence when millions of people could be affected negatively as a result of environmental pollution and the spread of toxic substances in the air.
Due to the rapid industrial development and increased environmental pollution problems in their entirety from the pollution of air and water, soil and other forms of pollution, risks become clear. Atmospheric air pollution is considered the most important problems of human exposure on a regional or global level. The problem of atmospheric air pollution has got recently a great deal of interest to evaluate the risks to living organisms.
Alexandria is one of the major industrial cities as they contain 40% – 50% of the industry to the level of the Arab Republic of Egypt, and industrial activities vary city to the petroleum, petrochemical, chemical, iron, steel, cement , fertilizer and paper industry… etc., and the city of exposed to atmospheric pollution as a result of these various industrial activities as well as the construction of buildings and real estate in addition to the high density of traffic activities, and are considered heavy metals such as cobalt and Chromium, Copper, Iron, Lead, Zinc, Magnesium, Manganese and Nickel … etc. one of the main air pollutants resulting from the various activities and thus are pollutant levels at places of influence resulting from several different sources.
The current study provided data for the concentration of heavy metals in the total suspended particles and some plants including (crops, fruits and medical plants) and the soil in which the plants grow. Assessment of health risks and effects on different age groups as well as the cancer risk were achieved.
Monitoring sites and sample collection
Three areas have been identified for monitoring where represent activities in the city as follows:
(The first industrial zone (Abu Qir), Residential Area (Abis) and Second Industrial Zone (Amreya))
Total suspended particulate samples collected every season of the year and plants and soil samples during winter and summer seasons.
Tools and measuring devices
Uses the volume sampler device to collect Total suspended particulate samples were collected on the filter type Whatman GF / A glass microfiber filter within 24 hours. Plant collecting samples from cultivated and the dominant vegetation in the monitoring and dried and also soil samples assembling at a depth of 15 cm the bottom of the plants have been digesting all samples using acids to convert samples to liquid solution.
The heavy metals, such as Co, Cr, Cu, Fe, Pb, Zn, Mg, Mn and Ni were determined by using Atomic Absorption Spectroscopy (AAS). In addition, health risk assessment and cancer risk associated with different exposure pathways (ingestion, dermal and inhalation) was calculated by some mathematical equations.
The results showed and illustrated the following:
- Concentration of heavy metals in TSP and health risk assessment
The maximum concentration of TSP was attained during spring at Abu Qir site. Regarding Abis site, the maximum concentration of TSP was attained during winter. During summer, the maximum concentration was at Amreya site
In comparison, the mean concentration of TSP exhibited values significantly lower than the air quality limits (230µg/m3) as stipulated by the Egyptian environmental law 4/94 and amendment law 9/2009.
The dominant elements in TSP were Zn, Mg and Fe and the minimum concentrations were noted for Cu, Pb, Mn, Cr, Ni and Co. Heavy metals were arranged in the following order Zn> Mg> Fe> Cu> Pb> Mn> Cr> Ni and Co during monitoring period at all sites
Chronic daily exposure dose (CDD), Hazard quotient (HQs) and Hazard index (HI) and cancer risk were calculated to different ages group (infant-toddler-child-teen-adult) through (ingestion-dermal-inhalation ) pathways.
Chronic daily exposure dose (CDD) of heavy metals in TSP less than reference doses. RfD, the value of HQ and HI were less than 1 in safe side. HQ due to inhalation of dust particles is lower than the other two exposure pathways. It is unlikely that this exposure route would pose a higher risk than ingestion. Among the different oldness groups, the greater of exposure could be arranged as toddler > child > adult > teen > infant. High risk locations could be arranged as Abu Qir > Abis >Amreya location.
Carcinogenic metal risk assessment caused by Co, Cr, Pb and Ni on basis of inhalation and ingestion exposure pathways .toddler expose to high cancer risk in Abu Qir and Amreya sites. Total cancer risk index was calculated as 2.60, 33.21, 25.93, 3.29, 17.57 and 17.57 per year for infants, toddler, child, teen and adults respectively. Among the different oldness groups, the greater of exposure could be arranged to cancer risk as to toddler > child > adult > teen > infant.
- Concentration of heavy metals in study species and health risk assessment
Studied plant species in monitoring sites
|Winter||Urtica dioica||Vicia faba||Salix Alba||Trifolium alexandrinum||Morus alba||Triticum aestivum|
|Summer||Ficus carica||Psidium guajava||Arctium lappa||Pluchea odorata||Ficus carica||Zea mays|
Co is an essential element with concentrations in plants are cited to be as low as 0.1–10 mg/kg dry weight, not detect in Urtica dioica, Vicia faba, Salix alba, Morus alba, Triticum aestivum and Ficus carica (Amreya) during summer season. Cr not detect to all study species at the three sampling sites while Cu concentrations was in normal range for all study species.
Fe is essential for plant growth Where Fe concentrations were found to be lower than the normal range in winter season for U. dioica, V. faba, S. alba, Trifolium alexandrinum and M. alba study species, the concentration for other species lay in the normal range; Pb was detected in the study species during summar with concentrations higher than normal range, and did not detected during winter for related study species except V. faba and Zn concentration were in the normal range for all the investigated species except Vicia faba and Morus alba where attained concentrations above the normal during winter season.
Mg concentrations were above normal range for all study species; Mn concentrations were in normal range for all study species except only for Trifolium alexandrinum which attained values below the normal range and Ni concentrations were not detected in summer season for all study species and were detected in winter season with normal range except for Morus alba was higher than the normal range.
For children, chronic daily exposure dose were below the reference dose except Fe and Pb which exceed the reference dose. Explicitly, Fe was higher than RfD for Ficus carica at Abu Qir site, Arctium lappa and Pluchea odorata at Abis site in summer season while Pb achieved higher doses than RfD for Vicia faba and Ficus carica and Psidium guajava in winter season at Abu Qir site, for Arctium lappa and Pluchea odorata at Abis site as well as Ficus carica and Zea mays at Amreya site in summer. For adult, results shown that all heavy metals daily dose were below the reference dose except Pb where Pb were higher than RfD for Vicia faba, Ficus carica and Psidium guajava at Abu Qir site, Arctium lappa at Abis site and Ficus carica and Zea mays at Amreya site in summer.
The HQ values of all heavy metals, in all study species were < 1.0 except Fe and Pb which exceed (> 1.0) because CDD for child and adult for study species that exceed reference dose. HI may be used as indicators for ingesting of metals via consuming plants were calculated by summation of HQ of all heavy metals for each plant. The highest HI of heavy metals was recorded in Ficus carica for children. HI range of heavy metals for all plants were between 1 to 5, indicated that there was no risk from the intake of plants. HI values for child were lower than 5 in winter season and higher than 5 in summer season and for adults HI values were lower than 5 in winter season and higher than 5 in summer season except Amreya region was lower than 5
Carcinogenic risk assessment which indicates the risk caused by Pb through ingestion pathways showed that cancer risk for children and adults was above 10−6 for all studied species except Trifolium alexandrinum. For U. dioica, S. alba, M. alba and T. aestivum it was shown that no carcinogenic risks for Pb because it was not detected. Psidium guajava attained the high cancer risk index (85.81 and 57.16 per year) for child and adult, respectively, during summer at Abu Qir site. The total cancer risk index was calculated as 421.67 and 280.88 per year for children and adults respectively. Among the different oldness groups, the greater of exposure could be arranged to cancer risk as child > adult.
- Metal transfer factor (MTF) and soil chemical and physical properties
By measuring the physical and chemical properties of the soil it was found that the soil to areas of measurement was Loamy Sand and alkaline. MTF measured values less than 1 for all the heavy elements in plant species. This means that the plants absorb elements and accumulated the heavy metals. Exception of the Pb in Vicia faba, Psidium guajava, Pluchea odorata and Ficus carica (Amreya) species, values of Zn in Morus alba and Ficus carica (Amreya) and values of Mg in Salix alba and Ficus carica (Abu Qir) were > 1 which indicates that plant accumulates the heavy metals.
- Concentration of heavy metals in soil and health risk assessment
The mean metal concentrations of measured heavy metals in the soils ranged within the normal ranges but Cr was very low compared except soil underneath of Ficus carica (Abo Qir site), Psidium guajava and Arctium lappa.
Chronic daily exposure dose of metals (CDD) for the three exposure pathways ingestion, dermal and inhalation to agricultural soils was calculated, for child and adult age groups, heavy metals high risk appears to be through ingestion route of exposure and inhalation route of exposure which significant compared with the dermal routes of exposure. High risk locations could be arranged as Abu Qir > Abis >Amreya location. HI of ingestion exposure pathway was 1.13 for child to soil underneath Ficus carica Abu Qir site and HI of sum of ingestion, dermal and inhalation pathways were 1.15 for child to soil underneath Ficus carica.
Conclusively, the underlying study highlight on the importance of health risk assessment in daily heavy metal exposure which simultaneous can result in sub threshold exposures to several metals that could result in adverse health effects. Thus intentional attempts should be directed to preserve the public health.
- 1.Urgent and detailed future studies for heavy metal release in industrial areas with different activities should be evaluated.
2.Great attention should be directed to human health either directly or indirectly to avoid the harmful effect of overdoses of heavy metals in industrial areas.
3.Excessive consideration should be paid to the edible and medicinal plants growing in the polluted areas.
4.There are no limits and a clear threshold for heavy metals in Egyptian law respecting TSP, plants and soil. So, there is a need for strict governmental rules to regulate the problem.
5.Extensive study should be carried out for other study species in Alexandria city especially near industrial areas.