Phytoremediation of Arsenic (As), Lead (Pb), and Mercury (Hg) Contaminated Soil Using Sunflower (Helianthus annuus L.)

Phytoremediation is a cost-effective and environment-friendly approach to remediate or clean our environment using plants by accumulating contaminants. Helianthus annuus L., commonly named sunflower is known to be a hyperaccumulator of heavy metals from the soil. This study focuses on using sunflowers for the phytoremediation of heavy metal-contaminated soil, specifically Arsenic (As), Lead (Pb), ad Mercury (Hg). The researcher collected soil samples in the months of March – April 2024 at the Catarman Sanitary Landfill located at Sitio Banihit, Catarman, Northern Samar, and were analyzed for pH, Nitrogen (N), Phosphorous (P), and Potassium (K) test using a Soil Test Kit (STK) from the Bureau of Soils and Water Management – Department of Agriculture, and detected the presence of As, Pb, and Hg using qualitative analysis. The analysis showed that the soil is slightly acidic, has low nitrogen, high phosphorus, and sufficient potassium, that is an indication of heavy metal contamination, and is good for metal uptake and accumulation in plant. The researcher planted sunflower using the collected soil samples. Leaves were extracted after one (1) month and two (2) weeks, and tested for physical properties in terms of pH, density, and solubility. Results showed that sunflower leaves extract is slightly acidic with an average pH of 6.94., density of 1.00 g/ml, and shows a polar property. The plant sample was also analyzed using Colorimetric analysis for Arsenic, Flame AAS for Lead, and Cold Vapor AAS for Mercury. Findings revealed that the concentration of these three (3) heavy metals are below the detection limit. But in small concentrations, exposure to these heavy metals still poses a great threat to living organisms. Using sunflower plants of about four (4) months of more could further be tested for possible detection of considerable amount of heavy metal uptake.