User:Pacific raffaella/Central Valley groundwater pollution

Article Draft

Lead

Contaminated groundwater in the Central Valley of California is a growing problem due to contamination and overuse. This problem is compounded by the overdrafting of underground aquifers.

Nitrates are the most abundant pollutants in the Central Valley due to the copious amounts of agricultural runoff from the farms. The concentration of naturally occurring arsenic is also an issue. Added content: Manganese has been detected at concerning levels, posing health risks especially to young children and pregnant women due to its neurotoxic effects. End of added content. This is a public health concern as groundwater is often the primary water source in the region.

Near-term solutions to reduce pollution and overuse are often costly and hard to implement in a timely manner. Reference added to existing content

History

Groundwater has been pumped in the valley since 1850, when residents began to build pumps to help make up for the lack of surface water in the area. At the turn of the 20th century, California became as a leading agricultural producer due to its technological advances in land management, irrigation and machinery. The Central Valley had ideal economic and climate conditions for many crops and drew in wealthy landowners.

Aquifers are critical because groundwater supplies much of the water needed for agricultural purposes and serves as the only source of water for several communities throughout the valley. However, reciprocal rainfall is not always available to recharge the aquifers, and recent years have seen an increase in drying wells. This overdraft of groundwater causes numerous problems for farmers and is only made worse by climate change. Throughout the early 1900s, technology for waste management did not advance at the same speed as the growth in agriculture. Issues in groundwater contamination by nitrates come from 50 years of unregulated management of livestock waste disposal, septic systems and commercial fertilizers. Added content: With manganese now also emerging as a concern, studies have shown that elevated levels of manganese in water supplies can lead to cognitive and neurological developmental issues, with fetuses and young children being especially vulnerable. End of added content. The California Sustainable Groundwater Management Act of 2014 was the first to specify how to manage groundwater in a way that would not harm or endanger future access to clean groundwater.

...

Regulations and standards

Set by the California Department of Public Health in 1989 ([when?] has been added), the maximum contaminant level for nitrates, in CCR §63341, is 45 milligrams per liter (mg/L) for nitrate as NO3 (equivalent to 10 mg/L for nitrate as nitrogen or “N”); 10 mg/L for nitrate plus nitrite as N; and 1 mg/L for nitrite as N. Reference added to existing content. Added content: Currently, there is a secondary maximum contaminant level (MCL) for manganese, primarily based on aesthetic properties like taste and color, set at 0.05mg/L. However, health experts have raised concerns that manganese levels below this threshold could still pose risks, especially for neurodevelopment in children. End of added content. Public wells are required to test their water annually and submit the results to the Department of Health, but private wells are not required to do so. A documented 98% of the state has access to drinkable water, though some studies note that access disparities exist.

Despite modern data and methods for agricultural safety, 92 water systems in the Central Valley were attached to wells containing illegal levels of nitrates between 2005 and 2008, impacting the 1,335,000 residents in the area. Historically, programs to identify and address the impact nitrates have on communities and industries have run at around $1 million each. Added content: Meanwhile, research has identified manganese contamination in many water supplies, prompting local advocates to push for improved monitoring and regulatory limits tailored to manganese's neurotoxic effects. End of added content

...

Sources of nitrogen

Manure, fertilizer, and septic waste are the leading sources of nitrates in groundwater. Manure produces around 6.5 million tons of nitrogen, which, when not handled properly or with improper drainage methods, can contaminate soil and water sources.Reference added to existing content. Nitrogen-based soil compounds produced by crops such as legumes, are consistently a minimal source. Fertilizers add roughly 11.5 million tons of nitrogen annually in the United States. Nitrogen in fertilizers is converted to nitrates, which is the main form of nitrogen in wastewater. Nitrogen from fertilizers can also be released into the atmosphere as ammonia gas, commonly recognized as a greenhouse gas. In the U.S. 53% of nitrates originate from fertilizers, making this a priority for Californian officials. Reference added to existing content.

...

Sources of Magnesium

Added content: Manganese contamination can result from both natural geological processes and human activities such as industrial and agricultural runoff. Elevated manganese in soil and water often correlates with agricultural zones due to natural weathering of manganese-containing minerals and contamination from fertilizers. Given manganese's potential risks, officials and health agencies are now advocating for enhanced filtration methods in affected communities. End of added content.

Population impact

...

Drinking water and consuming dietary sources of nitrates/nitrites are speculated to cause increased cancer risks when the nitrate compounds react with amines and amides to form carcinogens. The exact process of how this happens is still being researched.

Added content: Manganese contamination has been linked to neurological damage in children exposed to concentrations higher than 0.1 mg/L. Exposure to manganese-contaminated water during critical developmental periods can hinder cognitive development, with studies suggesting significant long-term impacts on memory, attention, and overall learning ability. End of added content.