Total Ni concentration in settleable dust on rooftops of houses at a mineral processing industry: case study of ZIMPLATS , Zimbabwe

Author

Phiri, Brian.

Title

Total Ni concentration in settleable dust on rooftops of houses at a mineral processing industry: case study of ZIMPLATS , Zimbabwe

Abstract

Background: Nickel (Ni) is a potentially toxic trace element which can cause harmful respiratory effects, skin allergies, and carcinogenicity. It can enter the human body through the air, water, food, or tobacco smoke or direct contact with products that contain Ni such as coins, jewellery, and stainless steel.
Objectives: To measure the amount of settleable dust on rooftops of houses (low, medium and high-density suburbs) at Zimplats mining area. To determine the concentration of total Ni in settleable dust on rooftops of houses at Zimplats mining area. To determine the variation of settleable dust and Ni concentration in settleable dust across different suburbs at Zimplats mining area. The amount of settleable dust and the concentration of total nickel (Ni) in it, and the variation of settleable dust and Ni concentration in settleable dust across different locations were determined at a mineral processing industry, using Zimplats, Zimbabwe as a case study.
Methods and materials: at Zimplats mining area. Dust particles were collected from rooftops of 60 houses (low, medium and high-density) from between 10 and 25 January 2024. Dust samples were collected using sterile polypropylene containers. Collected samples were quantified using gravimetric method. The total Ni concentration in the collected dust was determined using the Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) method. The variation of total Ni in dust samples within and across types of suburbs was determined using Analysis of Variance (ANOVA). Total Ni concentrations in settleable dust were compared with the threshold limit value in clean air using a one sample t-test.
Key findings: The findings revealed that dust concentrations were highest in medium density suburbs (average 0.0056 mg/m³), followed by low density suburbs (average 0.0042 mg/m³), and lowest in high density suburbs (average 0.0038 mg/m³). The differences in Ni concentration between low and medium density suburbs (0.07 mg/kg) and low- and high-density suburbs (0.04 mg/kg) was statistically significant (p-value < 0.05). The difference in Ni concentration between medium and high-density suburbs (-0.03 mg/kg) was not statistically significant (p-value > 0.05). One-Sample T-Test results (not shown here) indicated that the average Ni concentrations in all three suburbs (low, medium, and high density) were significantly higher than the expected Ni concentration in clean air.
Conclusion: the study found that dust and Nickel (Ni) concentrations in settleable dust varied significantly across residential areas surrounding the Zimplats mine. While all suburbs had Ni concentrations exceeding clean air standards, medium density areas had the highest levels of both dust and Ni. These findings suggest potential health risks for residents and highlight the importance of ongoing monitoring and dust mitigation strategies, particularly in areas closest to mining operations.

Date

May 2024

Publisher

BUSE

Keywords

Settleable dust,

Nickel concentration

Residential suburbs,

ZIMPLATS mining area

Air quality,

Supervisor

NIL