Agriculture, mining, landfills, construction, and electronic waste are all major sources of land pollution. These activities introduce heavy metals, synthetic chemicals, and plastic debris into soil, where contaminants can persist for decades and enter the food chain. Between 2015 and 2019, the global proportion of degraded land rose from 11.3 to 15.5 percent, affecting an estimated 3.2 billion people according to United Nations tracking data.
Agricultural Chemicals
Farming is one of the largest contributors to land pollution worldwide. Phosphate fertilizers, liming materials, and bio-fertilizers all release heavy metals into soil over time. Years of repeated application cause these metals to accumulate, gradually reducing soil fertility and stunting plant growth. The problem compounds: as soil quality drops, farmers often apply even more fertilizer, accelerating the cycle.
Pesticides add a second layer of contamination. Insecticides contain families of synthetic chemicals like organochlorines and organophosphorus compounds, while herbicides and fungicides carry their own toxic profiles. Some of these chemicals, including chlordane, dieldrin, and hexachlorobenzene, are classified as persistent organic pollutants because they resist breakdown and linger in soil for years or even decades. Even pesticides applied at recommended doses, such as chlorpyrifos and endosulfan, have been shown to disrupt natural nitrogen cycling in soil. Glyphosate-based herbicides pose additional risks to the microbial communities that keep soil healthy.
Microplastics in Farmland
A less obvious but increasingly significant source of land pollution is plastic contamination in agricultural soil. Plastic mulching films, irrigation tubing, and greenhouse covers are widely used in modern farming. Over time, these materials fragment into tiny particles through sun exposure and physical wear. During application and removal, mulch films frequently break apart, leaving small plastic remnants buried in the ground.
Sewage sludge is another major route. Wastewater treatment plants process human waste into nutrient-rich material called biosolids, which farmers spread on fields for their nitrogen and phosphorus content. These biosolids carry microplastics from the wastewater stream directly into cropland. Wastewater used for irrigation introduces even more. Once embedded in soil, microplastics are extremely difficult to remove and can alter soil structure, water retention, and the behavior of other pollutants.
Landfills and Municipal Waste
Landfills concentrate household and commercial waste in a single location, creating a cocktail of pollutants that can seep into surrounding land. As waste decomposes, it produces leachate, a liquid that carries dissolved contaminants outward and downward. Landfill leachate contains heavy metals like cadmium, mercury, zinc, chromium, lead, nickel, and arsenic, along with ammonia nitrogen, chlorinated salts, and organic compounds that are toxic to plants and aquatic life.
One particularly concerning group of chemicals found in leachate is absorbable organic halogens. These substances bind halogen elements to organic molecules, creating compounds that are especially harmful to ecosystems. Laboratory testing of leachate from active landfills has confirmed it is phytotoxic, meaning it can kill or severely damage plants on contact. Even when leachate doesn’t visibly escape a landfill’s containment, the sheer volume of waste and the long timescales involved make eventual leakage a persistent risk.
Mining and Industrial Activity
Mining operations expose deep layers of rock and soil to the surface, releasing heavy metals like arsenic, chromium, cadmium, copper, and mercury into the surrounding environment. These metals spread through dust, runoff, and direct contact with waste rock piles. Contamination from past mining activity can persist long after operations shut down, requiring remediation efforts that take years. One common approach uses biochar, a charcoal-like material made from heated waste wood, to absorb metals and improve soil structure so plants can gradually reestablish and stabilize the site.
Industrial manufacturing adds its own pollutants through improper storage, accidental spills, and deliberate dumping of chemical byproducts. Construction sites generate sediment runoff loaded with chemicals and nutrients that wash into surrounding land. Improperly stored hazardous materials and illegal dumping further concentrate toxic substances in soil.
Electronic Waste
Discarded electronics are a growing source of land pollution, particularly in developing countries where informal recycling operations dismantle devices without proper safety measures. E-waste contains heavy metals including arsenic, chromium, cadmium, copper, and mercury. It also carries halogenated compounds, a class of flame retardants and insulating chemicals used in circuit boards and plastic casings. When e-waste sits in landfills or is burned in open-air processing, these substances leach directly into soil.
The scale of the problem is increasing as electronics become cheaper and more disposable. Smartphones, laptops, televisions, and batteries all contain combinations of toxic materials that require specialized handling. In countries where disposal infrastructure is limited, e-waste often ends up in unlined dumps where rain carries its contaminants deep into the ground.
Deforestation and Soil Erosion
Removing vegetation strips land of its natural protection against degradation. Burning vegetation for land clearance, a common practice in agricultural expansion, destroys soil biodiversity and organic carbon while weakening the physical structure that holds soil together. Without root systems and organic matter, soil loses its ability to retain water and resist erosion, making it vulnerable to wind and rain that carry topsoil and nutrients away.
The numbers are staggering. Roughly 480 million hectares of cropland worldwide show signs of human-induced degradation, with nutrient depletion, loss of organic carbon, erosion, and salt buildup as the primary symptoms. Salinization alone has degraded an estimated 82 million hectares of rain-fed cropland and 24 million hectares of irrigated cropland. Once salt concentrations rise past a threshold, the land becomes unsuitable for most crops without expensive remediation.
How Land Pollution Affects Health
Soil contaminants reach people primarily through the food chain. Plants absorb heavy metals from polluted soil, and those metals concentrate as they move up through animals and into the human diet. The cardiovascular system appears especially vulnerable. A large meta-analysis covering more than 348,000 participants found that exposure to arsenic, lead, and cadmium is associated with increased risk of coronary heart disease and overall cardiovascular disease.
Each metal causes harm through slightly different pathways. Cadmium damages blood vessel walls and promotes the buildup of arterial plaque. A South Korean national health survey of over 10,600 adults found that high blood cadmium levels were associated with roughly 2.4 times the odds of stroke and about 1.5 times the odds of high blood pressure. Lead triggers inflammation and disrupts heart-rate regulation. A Chinese study of over 4,200 patients found elevated blood lead linked to 1.5 times the odds of developing arterial plaques.
Arsenic exposure, even at low to moderate levels, has been tied to increased mortality. A U.S. study of 3,600 adults found that arsenic exposure was associated with a 28 percent increase in the risk of death from cardiovascular causes. Separate research in England and Wales linked arsenic exposure from rice consumption to elevated cardiovascular disease risk at the population level. These findings underscore that land pollution is not just an environmental issue. It is a direct threat to human health, carried invisibly through the food people eat every day.