India was one of the first countries to implement a public health program to address iodine deficiency through salt iodization in 1950s.
Published Aug 23, 2024 | 7:00 AM ⚊ Updated Aug 23, 2024 | 7:00 AM
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Recently, a study conducted by Toxics Link—an Indian environmental research and advocacy organisation— showed that not even packaged salt and sugar are free from microplastics.
The organisation in India tested for the presence of microplastics in salt and sugar, revealing that all Indian brands—whether large or small, packaged or unpackaged, sold online or in local markets—contain ‘microplastics’. Microplastics are defined as tiny plastic particles measuring less than 5 millimetres (0.2 inches) in length.
India was one of the first countries to implement a public health program aimed at addressing iodine deficiency disorders through salt iodization in the 1950s. In 1962, the Government of India launched the National Goiter Control Programme (NGCP) to provide iodized salt to areas with high rates of goitre. Over time, iodized salt became a staple in Indian kitchens, symbolising a commitment to health.
However, recent research uncovered an even more alarming finding: higher concentrations of microplastics were detected in iodized salt. These microplastics appeared as multicoloured thin fibres and films.
The study tested ten varieties of commonly used salts, including table salt, rock salt, sea salt, and local raw salt, as well as five sugar samples purchased both online and from local markets. Except for two salt samples and one sugar sample, all others were branded. Of the ten salt samples tested, three were packaged iodized salts, three were rock salt samples (including two organic brands), two were sea salts, and two were local brands.
Salt, an integral part of most food items, plays an essential role in maintaining various ion levels in the human body and also acts as a preservative. Additionally, salt finds applications in diverse industries, including cosmetics, personal care products, and pharmaceuticals. It is extracted from various sources, such as saline lakes, saline rocks, and saline wells.
The study found that the abundance of microplastics (pieces per kilogram of dry weight) varied across different salt samples, ranging from 6.71 to 89.15 pieces per kilogram of dry weight.
The highest concentration was found in an iodized salt sample (89.15 pieces per kilogram of dry weight), while the lowest concentration in an organic rock salt sample (6.70 pieces per kilogram of dry weight). Among the samples, packaged iodized salt brands exhibited higher contamination levels compared to the others. Overall, high concentrations of microplastics were found in iodized salt samples, whereas rock salt samples generally had lower microplastic content, with the exception of one inorganic sample.
The colour, size, and shape of microplastics are crucial in understanding their environmental and health impacts. Different colours indicate their origins, with black plastics often linked to food packaging and transparent ones to disposable bags.
Colours also reveal their degradation through photoaging, affecting aquatic life, as certain fish prefer ingesting red, green, and yellow microplastics. Size matters too; smaller microplastics (0.1-1 mm) are more easily transported and ingested, posing greater risks to both humans and animals.
The shape, such as fibres from clothing, influences how microplastics spread in air, water, and soil, highlighting their contamination potential. The primary types of microplastics identified in the three iodized salt samples were films and fibres. Fibrous forms were the predominant shape observed in tested local salt samples, accounting for 91.11 percent of all shapes among the two samples. The four types of microplastics found in the rock salt samples were fibres, pellets, films, and fragments.
In the iodized salt samples, a total of five colours were identified. White was the most common, constituting almost 38.53 percent, followed by transparent at 33.02 percent, blue at 14.67 percent, red at 8.25 percent, and black at 5.5 percent.
The study revealed varying levels of microplastic contamination in different sugar samples. Among the five tested sugar samples, the highest concentration of microplastics was found in the range of 68.25 pieces per kilogram to 11.85 pieces per kilogram.
The majority of microplastics were in the 0.1-0.3 mm size range. Fibers were the predominant type of microplastic found in the sugar samples, constituting 95.65 percent of the total. This was followed by pellets and films. A total of seven colours of microplastics were identified in the sugar samples, including transparent ones.
Mr Ravi Agarwal, Founder Director, Toxics Link in a statement said, “The objective of our study was to add to the existing scientific database on microplastics so that the global plastic treaty addresses this issue in a concrete and focused manner. The aim is also to trigger policy action and attract the attention of researchers for possible technological interventions to reduce the exposure risks to microplastics.”
Researchers suggest several potential sources for microplastic contamination in iodized salt:
“The study is critically significant as microplastics (MPs) are being discovered in various parts of the human body, including the lungs, blood, and digestive system,” the study said. This raises significant health concerns due to their potential toxicological impact and ability to contribute to inflammation and other health issues.
“Although the precise health effects of these small particles and their associated chemicals have yet to be fully proven, the pervasive presence of MPs underscores the urgent need for comprehensive research into their long-term health implications,” said the study.
While the exact health impacts of these tiny particles and their associated chemicals are not yet fully understood, their widespread presence highlights the urgent need for extensive research into their long-term effects. Emerging studies suggest that microplastics may increase the risk of conditions such as oxidative stress, which can cause cell damage, inflammation, and cardiovascular disease.
Animal studies have also connected microplastics to fertility issues, various cancers, disruption of the endocrine and immune systems, and impaired cognitive functions like learning and memory. In one of the most recent studies—a preprint paper still under peer review and posted online by the National Institutes of Health—researchers discovered a particularly alarming accumulation of microplastics in brain tissue samples.
An autopsy examination of livers, kidneys, and brains revealed the presence of microplastics in all these organs, with 91 of the brain samples showing significantly higher concentrations—about 10 to 20 times more than the other organs. Among 24 brain samples collected in early 2024, microplastics made up approximately 0.5 percent of the tissue’s weight on average. The study described the brain as “one of the most plastic-polluted tissues yet sampled.”
Other health risks of microplastics
Exposure levels
The Food Safety and Standards Authority of India (FSSAI) in a statement said that while the report underscores the global prevalence of microplastics, it also emphasises the need for more robust data to fully understand the implications for human health and safety, particularly in the Indian context.
“As the food safety regulator of the country, FSSAI is committed to ensuring that Indian consumers have access to safe and healthy food. While global studies have highlighted the presence of microplastics in various foods, it is imperative to generate reliable data specific to India,” it said in a statement. In response to it, FSSAI launched a project to tackle the growing concern of microplastic contamination in food.
FSSAI said that recognising microplastic pollution as an emerging threat that requires immediate attention, the project – “Micro-and Nano-Plastics as Emerging Food Contaminants: Establishing Validated Methodologies and Understanding the Prevalence in Different Food Matrices” – was started in March this year to develop and validate analytical methods for detecting micro and nano-plastics in various food products, as well as assess their prevalence and exposure levels in India.
The primary objectives of the project include developing standard protocols for micro/nano-plastic analysis, conducting intra- and inter-laboratory comparisons, and generating critical data on microplastic exposure levels among consumers.
“This project will help understand the extent of microplastic contamination in Indian food and guide the formulation of effective regulations and safety standards to protect public health. The findings from this project will not only inform regulatory actions but also contribute to the global understanding of microplastic contamination, making Indian research an integral part of the global effort to combat this environmental challenge,” said the FSSAI in statement.
This study is being implemented in collaboration with leading research institutions across the country, including the CSIR-Indian Institute of Toxicology Research (Lucknow), ICAR-Central Institute of Fisheries Technology (Kochi), and the Birla Institute of Technology and Science (Pilani).
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Toxic link highlights the urgent need to address microplastics (MPs) in food and their presence in the human body through coordinated actions:
Apart from Salt and Sugar, microplastics have infiltrated various food items, raising significant concerns about human exposure. Here are key findings on different food products contaminated with MPs:
