Explained: How Air and Water Pollutants are Linked to Blood Cancer in India

Explained How Air and Water Pollutants are Linked to Blood Cancer in India.

Explained How Air and Water Pollutants are Linked to Blood Cancer in India.

Maanal Gauri, Nainika Gupta, Nandana N

According to an article by the Financial Express, every five minutes in India, a new person is diagnosed with some type of blood cancer. Among these, acute myeloid leukemia (AML), an aggressive blood disorder characterized by an abnormal white blood cell count, has affected both rural and urban populations. General signs and symptoms of the early stages of AML mimic those of the flu or other common diseases, including fever, bone pain, and shortness of breath. According to the International Agency for Cancer Research - Cancer Tomorrow, the number of new AML cases in India was estimated to reach over 70,000 annually by 2045, making leukemia a significant national concern. However, managing AML in India remains challenging due to a limited understanding of the disease, its risk factors, and the availability of data.

In Delhi, there has been an alarming rise in deaths caused by AML. Literature has suggested that mortality rates due to AML could be linked to air quality in a region. Petrol and vehicular emissions, major contributors to the city's air pollution, release benzene, a liquid chemical known for its carcinogenic effects. The benzene level in petrol, as of 2020, is 1 percent (Bharat Stage VI). With the steady rise in vehicle usage and petroleum consumption in metropolitan cities such as Delhi, Bangalore, and Mumbai, there has been an alarming increase in benzene levels as well. While the National Ambient Air Quality Standard (NAAQS) has set a benzene limit of 5 μg/m3 since November 2009, studies consistently find benzene concentrations exceeding this threshold nationwide.

Petrol pumps, in particular, are hotspots with high concentrations of benzene, given its volatile nature which causes it to evaporate during refueling. A study done in Delhi categorized sites based on land use, and found that concentrations of benzene, toluene, and xylene (together referred to as BTX) varied across these sites, with the highest levels observed at gasoline filling stations. The presence of elevated BTX concentrations near petrol pumps indicates an increased risk to nearby residents given benzene’s carcinogenic effects.

To mitigate the health risks associated with benzene exposure in Delhi, particularly among petrol pump workers, there must be a system to continuously monitor the benzene levels. This involves installing monitoring devices at locations including petrol pumps and heavy traffic areas. In Europe, Petrol Vapour Recovery stations have been designed to prevent the emission of volatile compounds, including benzene. Stage I vapor recovery systems capture gas vapors at the nozzle during refueling, preventing their escape into the air. Stage II systems further capture any remaining vapors using suction power, ensuring minimal emissions and cleaner air around gas stations. Together, they provide a two-pronged strategy for reducing benzene exposure and environmental pollution. Although Stage I is implemented in India, the combined use of Stage I and Stage II systems can synergistically mitigate benzene exposure at petrol pumps, enhancing environmental protection.

So, problem solved, right?

Actually, not quite. Those living in urban areas clearly suffer due to their increased exposure to carcinogens through air pollution, but is it the same case in rural communities?

Well, according to the United Nations’ Food and Agriculture Organization, agriculture is the primary source of income for more than 70 percent of rural households in India. It contributes to about 17 percent of India’s GDP and employs more than half of its population. However, despite agriculture being a crucial part of the Indian economy, the increase in cropping area has been marginal compared to the increase in crop production. This growth in efficiency can be attributed to an uptick in fertilizer and pesticide use by farmers—which, though key tools for increasing crop protection and productivity, have quickly become a bane for the very same people whose livelihoods they sustain. Many studies have come forward connecting increased pesticide use to high leukemia rates.

Most farmlands in the country have faced uncontrolled and unregulated application of chemical pesticides. Uttar Pradesh, Maharashtra, and Punjab are the three biggest consumers of pesticides in India, and studies have shown that the pesticides used in these fields do not remain at the target site, but often contaminate water sources through soil percolation, air drift, or in the form of runoff. Organic pesticide residues have been detected in both surface and groundwater samples of Kanpur, UP, owing to the high agricultural activity surrounding the gangetic plain.

Another of the big hitters among plant protective agents are organochlorine pesticides, long-term exposure to which has been linked to DNA damage and the associated development of all kinds of cancers, including AML.

Most pesticide poisoning cases in India can be attributed to a dangerous organochlorine pesticide called endosulfan, the concentration of which was found to be concerningly high in the rivers at Allahabad as per a study by the Industrial Toxicology Research Centre.

Now the pesticides have even found their way into potable water, and you might be unconsciously taking in carcinogens as part of your daily diet. Apart from farm workers, infants and children are more susceptible to pesticide toxicity than other groups, making this an even more pressing issue. But how can this be remedied?

Bio-pesticides have emerged as an alternative in recent years, but they still have a long way to go before they find their way into the mainstream (pun not intended). Their usage in the subcontinent, according to the government of India, was a meager 4000 tonnes in 2020, while chemical pesticides were used over tenfold this amount.

Another promising technological intervention is the use of microorganisms for bioremediation, which involves breaking down dangerous pollutants into nontoxic compounds. Many possible options have come up for this avenue, including fungal and bacterial strains indigenous to India. A study conducted at NIT Srinagar has even demonstrated targeted pollutant purification using a bacterial strain isolated from Dal Lake.

However, benzene and pesticides are only two pieces of the whole puzzle. Even after the execution of these strategies at a large scale, the current state of the industrial complex and India’s status as a developing country means that there are many more risk factors to deal with. Despite the obvious hurdles, change always starts small, and even one step forward is a step towards healthy living. So the next time you go grocery shopping, keep in mind these implications, and make sure to buy only organic produce for lunch. Oh, and use a bicycle.

Maanal Gauri, Nainika Gupta, Nandana N are pursuing BTech at Plaksha University, Mohali.
 



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