Identification of Technosols formed from industrial dust in the area of Yazd city (Central Iran) by ground-based radiometry

Abstract

Intensive industrial development in the form of metallurgical plants and quarries for mining of mineral resources in the vicinity of the city of Yazd resulted in significant dustiness of the ground layer of atmosphere and accumulation of industrial dust on the soil surface. At the locations of alloy steel production facilities, dust composition was dominated by particulate matter less than 1 μm (PM1), while near sand quarries, dust particles less than 10 μm (PM10) were predominant. The dust from these sources also differs in chemical composition (iron/silicon content ratio, pH). Registration with a pyranometer with a dark green filter with transmittance at a wavelength of 550 nanometers with a time interval of 20 seconds at a speed of 30 km/h during the movement along the specified routes allowed authors to identify zones with a stable increased content of particles of different sizes in the near-surface atmosphere. Sampling soil pits in these zones confirmed the presence on their surface of layers of dust deposits with a thickness of more than 5 cm, which allows them to be attributed to Technosols in accordance with the WRB soil classification. The soil map of the research area was compiled at a scale of 1 : 25 000 with the reflection of Technosols participation in the soil patterns. According to the map, more than three quarters of the study area are soil complexes including Technosols. Arid climatic conditions of the region lead to the accumulation of dust on the soil surface, which are practically not transformed and not removed from the soil, which results in their degradation and deterioration of the environmental conditions. Dust accumulation on the soil surface affects the state of vegetation cover of the region, which serves as a basis for indirect satellite indication of dusting zones. The method of revealing the dust layer on the soil surface based on the assessment of dustiness of the near-surface atmosphere using pyranometer can serve as a good complement to remote sensing methods.