In 1898, Marie and Pierre Curie discovered radium. Claimed to have restorative properties, radium was added to toothpaste, medicine, water, and food. A glowing, luminous green, it was also used in beauty products and jewelry. It wasn't until the mid-20th century we realized that radium's harmful effects as a radioactive element outweighed its visual benefits. Unfortunately, radium isn't the only pigment that historically seemed harmless or useful but turned out to be deadly. That lamentable distinction includes a trio of colors and pigments that we've long used to decorate ourselves and the things we make: white, green, and orange. Our story begins with white. As far back as the 4th century BCE, the Ancient Greeks treated lead to make the brilliant white pigment we know today. The problem? In humans, lead is directly absorbed into the body and distributed to the blood, soft tissues, and mineralized tissues. Once in the nervous system, lead mimics and disrupts the normal functions of calcium, causing damages ranging from learning disabilities to high blood pressure. Yet the practice of using this toxic pigment continued across time and cultures. Lead white was the only practical choice for white oil or tempera paint until the 19th century. To make their paint, artists would grind a block of lead into powder, exposing highly toxic dust particles. The pigment's liberal use resulted in what was known as painter's colic, or what we'd now call lead poisoning. Artists who worked with lead complained of palseys, melancholy, coughing, enlarged retinas, and even blindness. But lead white's density, opacity, and warm tone were irresistible to artists like Vermeer, and later, the Impressionists. Its glow couldn't be matched, and the pigment continued to be widely used until it was banned in the 1970s. As bad as all that sounds, white's dangerous effects pale in comparison to another, more wide-spread pigment, green. Two synthetic greens called Scheele's Green and Paris Green were first introduced in the 18th century. They were far more vibrant and flashy than the relatively dull greens made from natural pigments, so they quickly became popular choices for paint as well as dye for textiles, wallpaper, soaps, cake decorations, toys, candy, and clothing. These green pigments were made from a compound called cupric hydrogen arsenic. In humans, exposure to arsenic can damage the way cells communicate and function. And high levels of arsenic have been directly linked to cancer and heart disease. As a result, 18th century fabric factory workers were often poisoned, and women in green dresses reportedly collapsed from exposure to arsenic on their skin. Bed bugs were rumored not to live in green rooms, and it's even been speculated that Napoleon died from slow arsenic poisoning from sleeping in his green wallpapered bedroom. The intense toxicity of these green stayed under wraps until the arsenic recipe was published in 1822. And a century later, it was repurposed as an insecticide. Synthetic green was probably the most dangerous color in widespread use, but at least it didn't share radium's property of radioactivity. Another color did, though - orange. Before World War II, it was common for manufacturers of ceramic dinnerware to use uranium oxide in colored glazes. The compound produced brilliant reds and oranges, which were appealing attributes, if not for the radiation they emitted. Of course, radiation was something we were unaware of until the late 1800s, let alone the associated cancer risks, which we discovered much later. During World War II, the U.S. government confiscated all uranium for use in bomb development. However, the atomic energy commission relaxed these restrictions in 1959, and depleted uranium returned to ceramics and glass factory floors. Orange dishes made during the next decade may still have some hazardous qualities on their surfaces to this day. Most notably, vintage fiestaware reads positive for radioactivity. And while the levels are low enough that they don't officially pose a health risk if they're on a shelf, the U.S. EPA warns against eating food off of them. Though we still occasionally run into issues with synthetic food dyes, our scientific understanding has helped us prune hazardous colors out of our lives.
1898., Marie i Pierre Curie otkrili su radij. Mislilo se da ima okrepljujuća svojstva, pa se radij dodavao u paste za zube, lijekove, vodu i hranu. Zbog sjajne, svijetle zelene boje, korišten je u kozmetičkim proizvodima i nakitu. Tek smo sredinom 20.-og stoljeća shvatili da štetni učinci radija, radioaktivnog elementa, premašuju njegove vizualne prednosti. Nažalost, radij nije jedini pigment u povijesti koji se činio bezopasnim ili korisnim, za kojeg se ispostavilo da je smrtonosan. U te žalosne značaje spada i trio boja i pigmenata koje već dugo koristimo za ukrašavanje sebe i predmeta koje pravimo: bijela, zelena, i narančasta. Naša priča počinje s bijelom. Još u 4. stoljeću pr. K., stari Grci su koristili olovo za stvaranje sjajnog bijelog pigmenta. U čemu je problem? Kod ljudi je olovo izravno upijeno u tijelo i raspoređeno po krvi, mekanom, i mineraliziranom tkivu. U živčanom sustavu olovo oponaša i ometa uobičajene funkcije kalcija, što nanosi štete u rasponu od poteškoća u učenju, pa sve do visokog krvnog tlaka. Ipak se navika korištenja tog otrovnog pigmenta zadržala kroz vrijeme i kulture. Olovna bijela bila je jedini praktični izbor bijele uljane boje ili tempere sve do 19.-og stoljeća. Kako bi napravili boju, umjetnici bi samljeli komad olova u prah izloživši se otrovnim česticama prašine. Zbog slobodnog korištenja pigmenta došlo je do tzv. slikareva kolika, što danas zovemo trovanjem olovom. Umjetnici koji su radili s olovom žalili su se na paralize, melankoliju, kašalj, povećane mrežnice, pa čak i sljepoću. Ipak, gustoća, neprozirnost i topla nijansa olovne bijele bile su neodoljive umjetnicima poput Vermeera i, kasnije, impresionistima. Sjaj mu je bio nenadmašiv, pa je pigment naširoko korišten sve do njegove zabrane u 1970.-ima. Koliko god to loše zvučalo, opasne posljedice bijele blijede u usporedbi s drugim, šire rasprostranjenim pigmentom, zelenom. Dvije sintetičke zelene, Scheeleova i Pariški zelena, predstavljene su u 18. stoljeću. Bile su puno vibrantnije i sjajnije od dosadne zelene napravljene od prirodnih pigmenata, pa su brzo postale popularniji izbor boje, uključujući i boje za tekstile, tapeta, sapuna, ukrasa za torte, igračaka, slatkiša, te odjeće. Ove pigmente izgrađuje spoj koji se zove bakrov hidrogen arsenat. Kod ljudi izloženost arsenu može oštetiti funkciju i način komuniciranja stanica. Visoke razine arsena u tijelu izravno su povezane s rakom i srčanim bolestima. Kao posljedica toga, radnici u tvornicama tekstila u 18. st. često su bili otrovani, a žene u zelenim haljinama rušile bi se zbog izlaganja svoje kože arsenu. Stjenice navodno nisu živjele u zelenim sobama, a neki misle da je Napoleon umro od sporog trovanja arsenom uzrokovanog zelenim tapetama u njegovoj spavaćoj sobi. Izrazita toksičnost zelene boje ostala je skrivena do 1822. kad je objavljen recept za arsen. Sto godina kasnije, prenamijenjen je kao insekticid. Sintetička zelena vjerojatno je najopasnija često korištena boja, ali barem nije radioaktivna, poput radija. Premda jedna druga boja je - narančasta. Prije Drugog svjetskog rata, bilo je često da proizvođači keramičkog posuđa koriste uranijev oksid kao glazuru u boji. Spoj je stvarao sjajne crvene i narančaste pigmente, koji bi bili privlačni atributi, da nije bilo radijacije. Naravno, o radijaciji nismo znali ništa sve do kasnog 19. stoljeća, a kamoli o poveznicama s rakom, o kojima smo saznali puno kasnije. Tijekom Drugog svjetskog rata Američka vlada zaplijenila je sav uranij zbog izrade bombi. Međutim, odbor za atomsku energiju oslabio je ta ograničenja 1959., vrativši ostatak uranija u tvornice keramike i stakla. Narančasto posuđe napravljeno u sljedećem desetljeću još danas nosi neke opasnosti na svojoj površini. Značajno je da starinsko posuđe za zabave često radioaktivno. Razine su dovoljno niske da ne predstavljaju zdravstveni rizik ako su na polici, ali američki EPA savjetuje da se iz njih ne jede. Iako se katkad susrećemo sa problemima sintetičke boje za hranu, naše razumijevanje znanosti pomoglo je ukloniti opasne boje iz naših života.