A recently published study revealed that fertilizers and pesticide application to cropland are now the primary sources of sulfur to the environment. Historically, the coal-fired power plants were the most significant contributor of reactive sulfur to the environment, but synthetic agricultural inputs now replace it.

Acid Rain

Acid rain, the form of precipitation that contains an increased level of nitric and sulfuric acid, made headlines in the 1960s and 1970s when scientists associated degradation of forest and aquatic ecosystems in the northeastern US and Europe to fossil fuel emissions from industrial centers. 

Acid rain has devastating ecological effects, especially on bodies of water like the lakes, streams, wetlands, and others. It makes the waters more acidic that results in increased aluminum absorption from the soil, and are eventually carried into lakes and streams. Acid rain is lethal to crayfish, clams, fish, and other aquatic animals. 

Although some species can tolerate acidic waters, the effect of some species affects many more throughout the food chain. It can also affect non-aquatic species such as birds.

The documented effects of acid rain in the 1970s  prompted the crafting of the legislation Clean Air Act and its amendment regulated air pollution, decreasing sulfur levels to low levels. 

READ: Reducing Emissions of Carbon Dioxide Is Not as Easy as It Seems  

The Study

According to Eve-Lyn Hinckley of the University of Colorado and the lead author, the study indicates that "sulfur applications to croplands in the US are ten times higher than the peak sulfur load in acid rain. No one has looked comprehensively at the environmental and human health consequences of these additions."

The research team analyzed trends of sulfur application in various essential crops in the US, corn in the Midwest, sugarcane in Florida, and wine grapes in California. The study revealed that areas like while New England had declining trends in response to recovery from historic atmospheric deposition, sulfate export from agricultural fields is increasing. 

Sulfur

Sulfur is an essential plant nutrient. It is a stable, naturally occurring element that exists in geologic form. It is released into the environment through mining, fossil fuel extraction, and synthesis of fertilizers and pesticides. 

The element reacts quickly, causing harm to health, and the cycling of toxic metals endangers people and wildlife. 

Sulfur is commonly used in commercial fertilizers to improve the production and health of crops. It poses harmful effects to agricultural soils and downstream waters

READ ALSO: Large Carnivores Less Likely to Attack Cattle With Painted Eyes on Their Rumps  

Trends is Sulfur Application

Agricultural application of sulfur increases the formation of methylmercury in waters which then drains of farmlands. Methylmercury is a potent neurotoxin that bioaccumulates. Fishes and small invertebrates pose a high concentration in fish and a much higher level in humans and wildlife that eats the contaminated fish.

Researchers believe that the trends will continue to increase in many croplands, including China and India.

More Studies on Sulfur

There is so much research that highlights the understanding and regulation of nitrogen and phosphorous fertilizers which causes eutrophication, fish kills, and proliferation of harmful algal blooms. 

The researchers believe that further studies should be done to investigate the implications of high sulfur use in agriculture, environment, and health and to collaborate with farmers to assess how to optimize the use of sulfur.

READ NEXT: Fukushima Wastewater Contaminants at Risk of Being Released into the Ocean