If you're tempted to upgrade your iPhone next week if, as expected, Apple unveils its new model, Sue Williams has a word of advice. Don't.

"I really hope people will think do they need a new device," says Williams, whose documentary Death by Design examines the human and environmental costs of creating our latest tech gadgets and disposing of our old ones.

"If you think of the harm that chucking out your old one does, do you really need a new one? It's been so built in to the system that every two years there's going to be a new model and you've got to get it, but I would just say why when your current one is working fine."

Reuters A new documentary reveals the environmental costs of creating our latest tech gadgets and disposing of our old ones.

Williams is no Luddite. She's speaking to me from New York, iPhone 6 close at hand, Macbook on the desk in front of her.

"I'm as addicted as anybody else, I love my phone, I couldn't manage my life without it," she says.

But she delayed upgrading from her iPhone 4 as long as possible, even learning how to replace the battery herself.

"I was really scared, it felt like I was operating on a human body, but it's actually really easy," she says.

"The hardest thing is finding a screwdriver that will open the body."

It was only when the letter S on her keyboard stopped working and she could no longer type her own name that she gave in.

Williams spent five years making her film, which ranges from cancer clusters in New York (the result, her film claims, of a chemical spill at a nearby IBM plant) to poisoned rivers and worker suicides in China. A lot of it is not new to anyone who has paid attention to this stuff, but it is brought together in a way that makes a compelling argument: those shiny objects we crave come at a much higher price than we like to acknowledge.

"They're so beautifully designed, such beautiful objects, that it's so hard to imagine they're full of all this toxic stuff we don't want to get inside of us," she says.

The film came about almost by accident. She met Chinese environmental activist Ma Jun and was seriously impressed by his work, documenting waterways polluted by factory waste. She initially thought she might make a film about him - and he does feature prominently - but "as he started analysing the data he started realising a lot of the polluters were working for the electronics companies". And she realised that was the subject she was looking for.

Apple is not, of course, the only company turning a blind eye to the shortcomings of its supply chain.

"They're the richest, shiniest, and most gorgeous brand in the world, so you can't ignore them," she says, "but Samsung and the others aren't doing any better."

Perhaps the most shocking footage of the film - and in some ways the most depressing - is of the piles of e-waste being burnt, bashed and pulled apart in villages in China just down the road from the plants where the components were manufactured. The scenes are positively medieval, the toxins being released - including lead and cadmium - positively lethal.

"I'm just like the people in my film - I have a drawer full of electronics and I don't know what to do with them," Williams admits.

"The whole e-waste situation is so extraordinarily complicated and murky. Even if I schlepped something up 75 blocks to the quarterly e-waste recycling fair, I don't where it's going to end up. It can go anywhere - they have no control over where it goes once it leaves their hands."

She's not arguing against technology or innovation - she just wants us to slow down on the rampant consumption, the compulsion to upgrade, and to focus a little more on what that costs us, and the planet.

"It's been such an exciting period, the digital revolution, led by these wonderful geniuses like Steve Jobs that no one has really taken the time to look at how they are made and unmade," she says.

"It's been a celebration of the technology and this heroic entrepreneurship. But when I started to take the lid off I found it wasn't so pretty underneath.