Children and young adults from areas in Mexico with highly polluted air suffer Alzheimer’s-like effects, study finds. Surprising changes were found in the brains of 43 young people who died in accidents. The findings, by a team of researchers from the U.S., Canada and Mexico, build on a growing body of research suggesting that air pollution exposure can affect the brain. Environmental Health News, Journal of Alzheimer’s Disease

Two U.S. senators express concerns about possible delays in a rail safety upgrade. California Democrats Dianne Feinstein and Barbara Boxer, in a letter  to the Federal Railroad Administration, called for a progress report on the installation of Positive Train Control, which is designed to prevent train wrecks by overcoming human error. Following a report by FairWarning, the senators said they were “deeply concerned” about possible delays in the system beyond the 2015 deadline. Congress, spurred by a deadly train wreck in Chatsworth, Calif., passed a law in 2008 mandating PTC on rail lines carrying passengers or extremely hazardous materials.

Industry and government investing millions to find “perfect wash” for bagged salads to curb food contamination. Food companies in the Salinas Valley, the nation’s salad bowl, have intensified efforts to improve cleaning techniques in response to crises such as the 2006 E. coli outbreak resulting from tainted spinach. It killed five people and sent 100 more to the hospital in the worst food poisoning outbreak linked to leafy greens in U.S. history. California HealthCare Foundation Center for Health Reporting

Microscopic plastic debris from washing clothes could be entering the food chain, researchers say. An international group of scientists identified the potential hazards of “microplastics” in synthetic clothing, which releases up to 1,900 tiny fibers every time a garment is washed. The research team took samples from 18 beaches around the world and found microplastics at every site. The substances, researchers say, are being eaten by animals, bringing the debris into the food chain. BBC, Australian Broadcasting Corp., Environmental Science & Technology

Scientists warn of the impact of water and air pollution from nitrogen fertilizers. The fertilizers have been crucial in boosting food production around the world for decades. But scientists who studied the issue for the European Union have calculated that it suffers economic damage of somewhere from $90 billion to $400 billion per year from the resulting pollution. That is more than double the value that nitrogen fertilizers add to European farm income. Public Radio International

California regulators move to put more pollution-free cars on the road. The ground-breaking action by the state’s Air Resources Board requires auto manufacturers to offer more zero-emission or very low emission cars — such as battery electric, hydrogen fuel cell and plug-in hybrid vehicles — starting with model year 2018. The board also strengthened future emission standards for all new cars. The goals are, by 2025, to slash smog-forming pollutants from new vehicles by 75 percent and reduce emissions that contribute to global warming by one-third. Los Angeles Times

California governor fired regulator who balked at relaxing environmental rules for oil extraction. Gov. Jerry Brown pushed late last year for easing standards for underground injection, a method of flushing oil from old wells. Derek Chernow, then head of the Department of Conservation, replied that the move would violate environmental laws. One week later, Chernow and a deputy were fired, and replaced with officials who agreed to speed reviews of injection projects. Los Angeles Times

Environmentalists dispute Obama’s assessment of shale gas. Activists said the president’s portrayal, in last week’s State of the Union address, of natural gas as a clean source of energy is misleading. They charged that the controversial drilling technique known as fracking is tainting drinking water and causing other pollution. Bloomberg

Recalls: hard-cooked eggs, 18th Street Deli julienne salads, Ellison Meat beef sirloin, Aunt Jemima Frozen Pancakes, Mazda Tribute SUVs, Britax child safety seats, Cephalon Treanda cancer drug , Aveeno baby lotion

Compiled by Stuart Silverstein