Using Worms to Clean Wastewater Helps Tomato Growth and Reduces Metal Absorption

Jim Crocker
16th July, 2024

Using Worms to Clean Wastewater Helps Tomato Growth and Reduces Metal Absorption

Image Source: Natural Science News, 2024

Key Findings

  • The study by the University of Agriculture Peshawar found that using vermicompost in soil significantly reduced heavy metal concentrations in tomato plants irrigated with wastewater
  • Tomatoes grown in soil with 25% vermicompost had the lowest levels of harmful metals like cadmium, chromium, copper, and lead
  • Vermicompost not only improved plant growth and yield but also made the soil safer by reducing the bioavailability of heavy metals
Heavy metals pose a significant threat to the environment due to their persistence, toxicity, and ability to accumulate in living organisms. The University of Agriculture Peshawar recently conducted a study assessing the impact of vermicompost on heavy metal bioaccumulation in tomato plants irrigated with wastewater[1]. This research offers a promising solution to mitigate the harmful effects of heavy metals in agricultural practices, particularly in regions where wastewater is often used for irrigation. The study involved a controlled experiment using plastic bags filled with 5kg of growing media, which consisted of garden soil mixed with varying levels of vermicompost (0%, 5%, 15%, and 25%). The pots were irrigated with wastewater from different industries, including pharmaceutical and plastic industries, as well as sewage water from the Hayatabad Industrial Estate in Peshawar. Tap water was used as a control. The results demonstrated that vermicompost significantly influenced tomato plant growth and reduced the concentration of heavy metals. Heavy metals such as cadmium (Cd), chromium (Cr), copper (Cu), and lead (Pb) were found in lower concentrations in tomatoes grown in soil amended with 25% vermicompost. Specifically, the study recorded minimum concentrations of Cd (2.48 mg kg^-1), Cr (1.27 mg kg^-1), Cu (4.10 mg kg^-1), and Pb (0.62 mg kg^-1) in these conditions. In contrast, maximum concentrations of these metals were observed in plants irrigated with sewage water, highlighting the detrimental impact of wastewater on crop safety and quality. This study aligns with earlier findings that underscore the dangers of using wastewater for irrigation. For instance, research has shown that vegetables irrigated with wastewater accumulate significant amounts of heavy metals, posing serious health risks to consumers[2]. Moreover, heavy metals can disrupt plant growth and biochemical processes, as seen in studies involving tomato plants irrigated with sewage water containing high metal concentrations[3]. The current study expands on these findings by demonstrating that vermicompost can effectively mitigate heavy metal bioaccumulation. Vermicompost, the product of the vermicomposting process involving earthworms and microbes, has been shown to improve soil properties and detoxify industrial wastes[4]. This detoxification occurs due to the strong metabolic systems of earthworms and the involvement of gut microbes, which reduce the bioavailability of heavy metals in the soil. In the context of the present study, vermicompost application at 25% significantly enhanced plant growth and yield while reducing the bioavailability and bioaccumulation of heavy metals. These results suggest that incorporating vermicompost into agricultural practices can be a viable strategy to improve crop safety and productivity, particularly in regions where wastewater irrigation is prevalent. The implications of these findings are substantial. Given the increasing problem of environmental pollution by heavy metals[5], the use of vermicompost offers a sustainable and effective method to protect crops and, by extension, human health. The study recommends avoiding wastewater irrigation due to the high levels of heavy metals and advocates for the application of vermicompost to reduce heavy metal bioaccumulation and enhance productivity. In summary, the research conducted by the University of Agriculture Peshawar provides compelling evidence that vermicompost can play a crucial role in mitigating heavy metal contamination in crops. By improving soil properties and reducing the bioavailability of heavy metals, vermicompost not only enhances plant growth and yield but also ensures safer food production. This study, along with previous research, highlights the importance of sustainable agricultural practices in addressing the challenges posed by environmental pollution.

AgricultureEnvironmentPlant Science

References

Main Study

1) Vermi-remediation impacts on growth and metals bioaccumulation in tomato irrigated with wastewater.

Published 13th July, 2024

https://doi.org/10.1016/j.chemosphere.2024.142848

Related Studies

2) Accumulation of heavy metals in edible parts of vegetables irrigated with waste water and their daily intake to adults and children, District Mardan, Pakistan.

https://doi.org/10.1016/j.foodchem.2012.09.058

3) Biochar increased photosynthetic and accessory pigments in tomato (Solanum lycopersicum L.) plants by reducing cadmium concentration under various irrigation waters.

https://doi.org/10.1007/s11356-017-9866-8

4) Bioremediation and detoxification of industrial wastes by earthworms: Vermicompost as powerful crop nutrient in sustainable agriculture.

https://doi.org/10.1016/j.biortech.2018.01.003

5) Heavy metal pollution in the environment and their toxicological effects on humans.

https://doi.org/10.1016/j.heliyon.2020.e04691


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