1, 2, chromium 3 and 4

This is like the story of good old movies. A good and a bad guy from the same family; The Chromium family, their compounds are good and bad. Where are they in our lives? Their existence and use dates back to about 2000 years of human civilization.

Chromium is a naturally occurring element. Out of all their compounds, the commonly occurring valence states are chromium metal Cr (0), trivalent chromium Cr (III) and hexavalent chromium Cr (IV). We need to dig out about 4 kg of chromium ore from earth to realize 1 kg usable chromium.

We use chromium compounds to fight corrosion, as tanning salts in leather industries and others, as an important constituent in metal alloys (metal alloys alone account for 85% of chromium usage), in wood preservation, cement manufacturing.
Abundantly used in today’s surface coating applications incl. chrome plating, paint and pigment applications (the brilliant yellow paint has to be made from high concentrations of chromium compounds) and in few anodizing process.
They were an essential compound in those infamous magnetic recording tapes and photography films: Progressive new technologies at least replaced these tapes and films with new mass storage devices and image sensors.
So, what is so special about these chemical compounds?

Hexavalent Chromium Cr (IV), a class I carcinogen, is one of the most celebrated chemical in recent times. Thanks to the sustainable status shift companies are aiming at. Even the ‘Erin Brokovich’ movie plot was built on Cr (IV) health effects based on a true story, where an industry’s waste water with high concentrations of Cr (IV) percolates in to ground water and lead to acute sufferings of people in and around that locality. In 1996, this company paid $333 million to the people living around its setup in a law suit.

Cr (IV) is readily reactive and soluble in water. It is still an essential alloy constituent in stainless steel and is/was used widely by those hundreds of leather tanneries of Kanpur and Vaniyambaadi in India (legally as well as illegally). People obviously love that shiny/silver finish of chrome plated products/parts. But researches say that their compounds are genotoxic even in small traces, exposure and inhalation can easily cause lung cancer and damages in kidneys and intestine. Occupational hazard is indefinitely high; certain leather tanneries no more employ young people and women, but still employ people.

Well, controversially, trivalent chromium Cr (III) is an essential mineral for human metabolism, a trace amount of it is necessary for maintenance of good health since it helps our body to utilize sugar, fat and protein. Cr (III) sounds necessary, isn’t it? Even then in many literatures, it is carefully denoted as ‘less toxic’ (than Cr (IV)), but not as ‘safe’ entirely. Continual exposure can lead to mentionable health effects and allergic situations.
Most of the literatures and research reports on Cr (III) never seem to take a firm stand on any side of good or bad affects and effects of it, hence concluded ‘less bad’ usually.

There are nearly about 20 different chromium compounds which have to be restricted / stopped in use. The new revised Hazardous waste act, 2008 enforced by Ministry of Environment and Forests, India limits hexavalent chromium only up to 50mg/kg in regulation. There are other better benchmarks which recommend complete avoidance of Cr (IV) usage until and unless it is highly necessary for technical performance in some cases, but it is essential to keep such products in closed loop of manufacture, use and recovery.
New environment regulations and measures led many to adopt Cr (III) as an effective alternative to Cr (IV) at least in surface coating applications (chrome plating etc).

# There are researches on, to discover possible absorption and removal of Cr (IV) through bacteria and other micro-organisms.
# EU norms (2006) prohibit marketing of new electrical and electronic equipments containing Cr (IV) at a concentration greater than 0.1% by weight.
# Arc welding of stainless steel is extremely dangerous.
# Trivalent chromium compounds are bluish-black.
# Hexavalent chromium compounds are yellow-orange-brown.

It is difficult to get convinced on this whole chromium chronology, all depends on its oxidation state and acidity around, chromium compounds can change from trivalent to hexavalent and vice-versa through various reactions and consequences in the environment and inside human/animal body. We still have to settle for one Cr (III) which is less toxic and obviously not 100% safe.

Teflon Tale

Smart Teflon non-stick cook wares, what is that about them?
They help us to cook fast, saves energy and makes the whole process hassle free. Apart from this proverbial applications Teflon products are also used in apparels, automotive fabrics, exterior coatings, home furnishings, upholstery, sealants, cables and in semiconductor manufacturing.

Our fellow non-stick cook wares are usually coated with PTFE (Polytetrafluroethyelene) fluropolymer and sometimes with other fluropolymers over metal surface. We might be ingesting these fluropolymers along with the food we cook on them. Do we have PTFE on our daily menu?

PTFE has a melting point above 300 degrees and it will start to fume out above 250 degrees, usually we don’t cook at these temperatures knowingly, but broiling and use of fat/oil, frying meat etc can very well happen at these temperatures. Even though the raw material manufacturer doesn’t recommend these practices, how many of us are aware of this; when we can get a plenty of non-stick frying pans in this country. These degraded fumes are lethal to birds (claims the Teflon manufacturer) and can lead to flu-like symptoms in humans.

Well, then we have this PFOA (Perflurooctanic acid), also known as C8 used to make PTFE which is a likely carcinogen. Till date, PFOA don’t have any practical alternative. It can accumulate in human blood, has a very long half life in humans and does not break down in the environment. PFOA is used only during manufacture of PTFE and a traceable amount of it remains in the finished product, how bad is that traceable amount is a question mark.

In 2004, a renowned company in US settled 300 million dollars in a law suit filed by the residents living around its chemical plant producing PTFE, for contaminating the drinking water in that locality. Access to literatures, analysis reports on PTFE and PFOA are very limited. These chemicals are still undergoing rigorous safety reviews across various countries and organizations.

And to conclude, we still don’t know how bad PTFE and PFOA are.

PVC! - a known culprit

Vinyl chloride, a class I carcinogen is the monomer used to produce PVC. Humans have high probability of acquiring cancer due to vinyl chloride exposure. As a matter of fact 13% of death in this world happens because of cancer.

PVC is not bio-degradable like many other polymers. It is cost prohibitive to recycle PVC in a safe way, because of the number and types of additives used in its production. Less than 1% of PVC is recycled across the world. Its contents can leech out in to the environment at any point of their life cycle.

Phthalates are used as plasticizers to soften PVC, their content usually range from 1 to 40% in proportion with other additives. It can be found in soft toys, medical equipments like tubes & blood bags, cosmetics, surface coatings etc. Phthalates can leech out during use, causes liver and kidney damage and reproductive system damages.

PCB (Polychlorobiphenyl) is added as a stabilizing additive in flexible PVC. Dioxins and PCBs are produced as by-products when PVC is produced or burned. Production of PCB is completely banned in many countries since 1970 because of its adverse health effects. Dioxins can persist in the environment and can travel long distances.

Phthalates, PCB and Dioxins are identified as potential endocrine disrupters and carcinogens.
PVC is declared as ‘contaminant’ even before 10 years in many countries. Still many Indian majors are strategizing their timelines to phase out hazardous substances.

PVC is a commonly used insulation on electrical wires, used abundantly in construction applications, medical applications, automobile interiors, many forms of cards (smart cards, credit cards etc), and in clothing and footwear to name a few.