Soils and green leafy vegetables irrigated with wastewater may accumulate heavy metals

A study published in the IOSR Journal of Environmental Science, Toxicology and Food Technology revealed that agricultural lands and green leafy vegetables that were irrigated with wastewater may accumulate high levels of heavy metals including copper, lead and zinc as well as nickel, chromium and cadmium.

• As part of research, a team of health experts from India’s premiere universities examined five agricultural fields in the city of Katihar in the eastern part of the state of Bihar.
• The researchers then collected soil samples from each field and used atomic absorption spectroscopy to analyze the presence of heavy metals in samples.
• The scientists then selected five green leafy vegetables – including mustard, coriander and spinach as well as bathua and cabbage – that were treated with wastewater. Parts of the plants such as shoots, roots and leaves were washed, air dried and crushed to detect traces of heavy metals.
• The experts then assessed the people’s vegetable intake, heavy metal exposure and potential adverse effects following contaminated produce.
• The results showed that both soil and vegetable samples showed heavy metal contamination that exceeded safety levels. According to the researchers, the vegetable’s leaves and shoots showed significantly high levels of copper, nickel and chromium.
• The research team inferred that the higher concentrations of metals in the vegetables’ leafy parts might be due to higher transpiration rates from the soil to the plants, which played a central role in the growth and moisture content of the vegetables.
• The experts observed that the highest transfer factor values were seen in zinc, cadmium and lead. The scientists added that vegetable samples that contained high concentrations of lead, copper and nickel were not safe for consumption.

The experts stressed on the importance of routine monitoring of heavy metal concentrations in wastewater, soil and other food sources to effectively mitigate the risk of excessive heavy metal buildup in the food chain.

Journal reference: 

Arbind Kumar and Seema. ACCUMULATION OF HEAVY METALS IN SOIL AND GREEN LEAFY VEGETABLES, IRRIGATED WITH WASTEWATER. IOSR Journal of Environmental Science, Toxicology and Food TechnologY. 2016; 10: 2 DOI: 10.9790/2402-1010020819