Background and Objectives
Wood vinegar, a valuable by-product derived from the pyrolysis of biomass, has gained widespread usage in various industries such as agriculture, food processing, pharmaceuticals, and environmental management. This is largely due to its rich and diverse organic composition, which offers numerous benefits, including its ability to enhance soil health, control pests, and even serve as a preservative in food. However, despite these advantages, concerns about the safety of wood vinegar have been raised, primarily due to the potential presence of harmful metallic elements, particularly heavy metals. These metals can pose serious health risks, especially when used in agricultural or environmental applications, where they can accumulate in soil and crops, affecting both plant growth and human health. Heavy metals such as lead (Pb), cadmium (Cd), and copper (Cu) can be toxic even at low concentrations, and their presence in wood vinegar may limit its safe usage. On the other hand, essential metals like iron (Fe), zinc (Zn), and manganese (Mn) are crucial for various biological processes and may enhance the efficacy of wood vinegar in agricultural practices. The objective of this study is to identify and quantify both the essential and toxic metals present in different commercial wood vinegar samples. In doing so, it also aims to investigate how factors such as the geographical origin of the product and the type of feedstock used in its production affect the concentration of these elements.
Methodology
To achieve these objectives, samples of commercial wood vinegar were collected from a range of producers in East Azerbaijan Province, along with other regions in Iran. This geographical diversity was chosen to account for potential variations in metal content resulting from differences in local environmental conditions and feedstock sources. In total, several wood vinegar samples from various production processes were obtained, ensuring a representative analysis. The elemental analysis of the samples was conducted using advanced techniques including Atomic Absorption Spectroscopy (AAS), Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), and ion exchange chromatography. These methods were selected for their high sensitivity and precision in detecting and quantifying both essential and toxic metals. Specifically, the study focused on nine elements: copper (Cu), iron (Fe), zinc (Zn), lead (Pb), cadmium (Cd), cobalt (Co), manganese (Mn), potassium (K), and calcium (Ca). These metals were chosen because of their relevance to both plant nutrition and potential toxicity in agricultural and environmental applications. The collected data were subjected to statistical analysis to evaluate any significant differences in metal concentrations based on the type of wood feedstock used (e.g., hardwood vs. softwood) and the geographical location of the producer. This approach allowed the researchers to identify patterns and relationships between metal content and the production conditions, which could inform recommendations for safer and more effective use of wood vinegar.
Results
The results of the study revealed considerable variability in the metal content of the different wood vinegar samples, with some products containing alarmingly high concentrations of toxic metals like lead and cadmium. In particular, several samples exceeded the safe limits for heavy metal concentrations that are considered acceptable for agricultural and environmental use. This poses a significant risk to soil health, crop safety, and ultimately human health, as these metals can accumulate over time and enter the food chain. Interestingly, the type of feedstock used in the production of wood vinegar had a marked impact on the concentration of essential metals. For instance, samples derived from hardwoods contained higher levels of iron and manganese, which are critical for plant growth and development. These metals play vital roles in enzymatic processes, photosynthesis, and nutrient uptake. On the other hand, samples produced from softwoods tended to have lower concentrations of these essential elements, which may affect the overall effectiveness of the wood vinegar as a soil amendment or plant growth enhancer. Geographical location also appeared to influence the elemental composition of the wood vinegar. Producers in different regions showed varying levels of metallic elements, suggesting that environmental factors such as soil composition, climate, and local pollution could contribute to differences in the final product. This variation further underscores the importance of considering both the raw materials and production conditions when assessing the safety and effectiveness of wood vinegar for agricultural applications.
Conclusion
The findings of this study highlight the critical need for comprehensive elemental profiling of wood vinegar to ensure its safe use in agricultural and environmental applications. The presence of toxic metals such as lead and cadmium in certain samples poses a potential risk to soil health, crops, and human consumers. Therefore, it is essential to establish strict quality control measures and regulatory standards to limit the concentration of harmful metals in commercial wood vinegar products. Moreover, the study emphasizes the importance of optimizing production processes to enhance the presence of beneficial elements like iron and manganese while minimizing the risk of contamination by toxic metals. By understanding the relationship between feedstock type, production conditions, and metal content, producers can make more informed decisions to improve the quality and safety of wood vinegar. In conclusion, this research provides valuable insights into the factors that affect the metal composition of wood vinegar, offering a scientific basis for the development of guidelines and policies that will help regulate and promote the safe and effective use of this product in sustainable agriculture.Top of Form
Author Contributions
Conceptualization, F.R. and A.N.; methodology, F.R. and A.N.; software, T. K.; validation, M. F.; formal analysis, M. F.; investigation, F.R. and A.N., M. F. and T.H.; resources, F.R. and A.N.; data curation, M. F. and T. K.; writing-original draft preparation, F.R. and A.N.; writing–review and editing, F.R. and A.N.; visualization, T. K.; supervision, A.N.; project administration, F.R. and A.N.; funding acquisition, A. N. All authors have read and agreed to the published version of the manuscript.
Acknowledgements
This paper is published as a part of a MSc thesis supported by the University of Tabriz, Tabriz, Iran. The authors are thankful to the University of Tabriz for financial supports.
Data Availability Statement
Data is available on reasonable request from the authors.
Conflict of interest
The authors declare no conflict of interest.
Ethical considerations
The authors avoided data fabrication, falsification, plagiarism, and misconduct.