Apple iPhone 5, 4S among most environmentally friendly phones, study finds

The study published by iFixit on Wednesday was based on a chemical analysis study performed by HealthyStuff.org, which sought to discover what hazardous chemicals are found in popular smartphones.

Researchers performed an X-ray fluorescence spectrometric analysis of 36 devices, assigning each a rating on a scale of 0 to 5, lowest being best, and ranked the products by chemical, component and "overall." The process consisted of chemical analysis testing for 12 common hazardous chemicals, such as bromine, mercury, and lead; component testing constituted a breakdown by case, screen, solder, circuit board and other vital parts; and finally an overall assessment of each device.

While Apple's iPhone 2G came in with the worst score, maxing out the ratings scale at 5.0, the newer iPhone 4S and iPhone 5 handsets were found to be of "low concern," at 2.69 and 2.75, respectively. Also deemed environmentally responsible were the LG Remarq, Motorola Citrus, and Samsung's Captivate and Evergreen. Overall, the Citrus contained the least toxic chemicals, and was awarded a score of 2.56.

Sitting at the other end of the spectrum was the Nokia N95, Motorola W233 Renew and Palm m125, each retaining a score of 4.5 or below.

Out of the 36 tested units, 6 were of "low concern," 24 were of "medium concern" and 6 scored poor "high concern" ratings.

Looking at the rankings, a definite improvement from manufacturers can be seen as the poor-performing handsets are mainly older models like the iPhone 2G and Samsung's SCH-U410 from 2007.

It should be noted, however, that phones which scored high ratings overall weren't top performers in every category.

"The 'low concern' Samsung Reclaim had a 'high concern' proportion of arsenic," iFixit writes. "Twenty-four of the phones (nearly 70%) had a 'high concern' proportion of copper."

Major cellphone manufacturers, while making strides, shouldn't "rest on their laurels," the report said, as "many toxics remain" in discarded handsets.

"There is a trend of less toxics overtime, it looks like—especially for Apple. That’s good, but it’s not good enough."