How do we know which plastic container is safe?

[clowntrigger]

Hi Guys

I know that certan plastic container or pail cannot be used to hold seawater as some of them will leach toxin into the water, so how to differentiate that? I am thinking of getting a Toyogo brand container to mix my seawater as these rectangular container are huge and will meet my 10% water changes that my tank need. Also thinking of those sell by Ikea, any comments?

[Tanzy]

Some containers have a 'food safe' logo. It looks like a fork and a knife. Usually underneath.

[Achilles Tang]

I use the biggest Toyogo containers to help me mix my saltwater.... in fact I use two of these at one time... and they still hardly fill up half my tank!

Check out the product reviews on this shortly!

[Achilles Tang]

Oops I didn't reply your question exactly!

The toyogo container mentioned has the plastic recycling code/resin ID code of 5, indicating that it's PP (polypropylene).

PP is used to make auto parts, appliance parts, pipes, toys, medical tubing, margarine tubs, syrup bottles and trash bags.

Many drinking straws are made of PP.

I guess it should be food grade.

[Achilles Tang]

Here's more info on PP:

PP (Polypropylene)

Chemical Resistance General: Very Good

Stress-Crack(^1) Resistance: Excellent

Maximum Service Temperature: 220&176;F/104&176;C

Brittleness Temperature: 32&176;F(^2)/0&176;C

Impact Resistance(^2): Fair

Abrasion Resistance: Good

Rigidity: Good

Easy to Clean: Good

Translucent: No

Outdoor Use: No

Can Be Welded (Hot Gas): Yes

Food Grade Acceptability: (Natural, Unpigmented): Yes(^3)

Color (Natural, Unpigmented): Off White

Advantages: good resistance to many organic chemicals; less expensive than comparable stainless steel tanks

Applications: weldable PP fittings available; plating and pickling lines; etch tanks for processing silicon wafers

Do Not Use With: strong oxidizing agents, aromatic or chlorinated hydrocarbons, subfreezing temperatures

[Achilles Tang]

Worried about plastics being food grade?

Check this out!

Plastics 101: A Glossary of Terms

COMMON PLASTICS

ACRYLONITRILE-BUTADIENE-STYRENE (ABS) is a hard plastic used to make pipes, windows, refrigerator door liners, radio cases, telephone housings, and boat and auto parts. The production of ABS uses a number of hazardous chemicals, including butadiene and styrene (suspected human carcinogens) and acrylonitrile (a probable human carcinogen). ABS requires the use of antioxidants (see "additives," below).

BIOPOLYMERS are biologically derived polymers. They are produced through the transformation of agricultural or marine feedstocks (e.g. starch and cellulose), or by harnessing the enzymes found in nature. As such, they are based on renewable sources rather than the non-renewable fossil fuels used to make most plastics. In addition to being non-toxic, the processes used to create biopolymers minimize energy consumption and waste generation, and their degradation products can be re-used (methanol, methane) or composted into soil. Biodegradable plastics can still be petroleum-based and should not be mistaken for bio-based plastics. Although many bioplastics are still in the developmental stage, emerging applications include packaging, computer storage media, and medial implant devices. The Greenpeace credit card is one example of a biopolymer.

CHLORINATED POLYVINYL CHLORIDE (CPVC) is produced through the chlorination of PVC, which improves its heat resistance. CPVC is used in hot water piping in building construction. CPVC presents many of the same problems as PVC: It produces dioxin throughout its lifecycle and leaches chemical additives (see "additives," below).

COPOLYMER is two or more different polymers chemically linked together. It differs from an alloy or blend, which is a mixture of two or more polymers.

ETHYLENE VINYL ACETATE (EVA) is a copolymer of polyethylene and vinyl acetate. Vinyl acetate is made from acetic acid. EVA is used to make plastic film and sheeting, overhead projector sheets, toys and other items.

POLYCARBONATE (PC) is used to make products such as compact disks (CDs), glass lenses, and food can linings. PC is normally made from the polycondensation of phosgene (a highly toxic gas derived from chlorine) and Bisphenol A (a chemical known to cause endocrine disruption in rats at very low doses). New production processes using alternatives to Bisphenol A may provide a significant improvement in PC's environmental profile in the future.

POLYETHYLENE (PE) is the most common commodity plastic in the world. PE does not require the addition of chemical softeners, unlike flexible PVC. PE products sometimes do, however, contain UV and heat stabilizers, antioxidants and flame retardants. PE is used to make bottles, films, sheets, detergent containers and electrical cabling. The density of PE is determined by the type of polymerization conditions under which the resin is made. High Density Polyethylene (HDPE) is Code 2 in the Society of Plastics Industry's resin identification code and is commonly used in milk jugs, garbage bags and liquid detergent bottles. Low Density Polyethylene (LDPE) is Code 4 of the SPI's resin identification code, and is found in common items such as bread bags, grocery bags and squeezable bottles for mustard and other products.

POLYETHYLENE TEREPHTHALATE (PET). Produced from dimethyl terephthalate and ethylene glycol, PET is used to make packaging (e.g. soft drink bottles), photographic film, magnetic recording tape, and textiles. PET often contains additives such as UV stabilizers and flame retardants. PET does not require chemical additives in order to be flexible. The phthalate (the softener) used in PET is bound in the polymer itself, and does not readily leach out of PET products. The Danish Technical Institute compared PET to PVC and found that PET poses less risk to workers and the environment.

POLYOLEFIN is a generic term for POLYETHYLENE (PE) and POLYPROPYLENE (PP) plastics. The raw materials for these plastics include ethylene and propylene, which are petroleum-based (and therefore not sustainable in the long run), highly flammable and explosive, but relatively harmless to the environment when compared to PVC. The petroleum used to make these resins can generate dioxins due to the use of chlorine catalysts in the production process. The burning of these plastics generates volatile compounds, including formaldehyde and acetaldehyde, both suspected carcinogens.

POLYPROPYLENE (PP) is one of the most rapidly growing commodity plastics. PP is used to make auto parts, appliance parts, pipes, toys, medical tubing, margarine tubs, syrup bottles and trash bags. Many drinking straws are made of PP. PP is Code 5 in the Society of Plastic Industry's resin identification code and appears as the number 5 in the recycling symbol.

POLYSTYRENE (PS) is the third or fourth most common plastic. Its production involves the use of benzene (a known carcinogen) and styrene (a suspected human carcinogen). Although PS requires far fewer chemical additives than PVC (see "additives," below), it can still pose significant hazards. During a fire, burning PS can release toxic chemicals including styrenes and polyaromatic hydrocarbons (PAHs). Relatively difficult to recycle, PS is used to make styrofoam cups, egg cartons, foam meat trays and insulating foams, as well as hard items such as cups, aspirin bottles, lawn chairs and toys. PS is Code 6 in the Society of Plastics Industry's resin identification code and appears as the number 6 in the recycling symbol.

POLYTETRAFLUOROETHYLENE (TFE) is commonly referred to by its Dupont trade name of Teflon. TFE gives off a highly poisonous gas when it is heated at too high a temperature. TFE is used in "no-stick" frying pans, valve and pump parts, wire insulation, heat cables and aerospace parts.

POLYURETHANE (PU) is used primarily to make insulation and foam for carpet underlay, auto cushions and other products. The production of PU consumes about 11 percent of the world's entire chlorine production, involves the use of hazardous intermediates, and creates numerous hazardous byproducts. PU production has been linked to occupational health problems including asthma, heart disease and reduced sperm quality. The burning of PU releases a number of hazardous chemicals into the environment, including isocyanates and hydrogen cyanide.

POLYVINYL CHLORIDE (PVC) is commonly known as vinyl. It is made from vinyl chloride, a known human carcinogen. PVC is the second most common plastic and the only widely used plastic with a high chlorine content. Because of its chlorine content, PVC is responsible for the spread of dioxins and other persistent organic pollutants (POPs) in the environment. PVC requires the use of more chemical additives (see "additives," below) than any other common plastic, and it is the least recycled of all common plastics. PVC is used to make packaging, toys, I.V. bags and tubing, pipes, siding, flooring, wall covering, wiring and many other items. PVC is Code 3 in the Society of Plastics Industry's resin identification code and appears as the number 3 in the recycling symbol.

POLYVINYLIDENE CHLORIDE (PVDC) is similar to PVC, but an additional chlorine atom is attached to the carbon atoms on the polymer chain. PVDC is used to make food wraps (e.g. Saran Wrap), upholstery and car cover seats.

COMMON ADDITIVES USED IN PVC AND OTHER PLASTICS

Additives are chemicals that are added to the polymer to give the plastic the qualities desired in the final product. PVC products, for example, always contain additives. Some types of PVC contain more additives than the polymer itself. Because they are not chemically bonded to the polymer in PVC, additives routinely leach out of the plastic. Listed below some of the more common additives used in PVC.

ADIPATES are a family of plasticizers that are often used to replace phthalates (see "phthalates," below). DEHA, the most common adipate, is a teratogen (causes birth defects) and causes reproductive effects in animal studies. It has also been documented to cause liver tumors in mice.

ANTIOXIDANTS are additives used to reduce oxidative degradation, which means that they are used to prevent discoloration during processing. Examples include phenolics, such as butylated hydroxy toluene, and organophosphites.

BISPHENOL A (also known as 2,2-bis(4-hydroxyphenyl)propane). Although it is better known as a component of polycarbonate plastic, this chemical is also used as an antioxidant in PVC. Since it is used as an additive in PVC and not as a polymer ingredient, Bisphenol A can leach out of the plastic at a faster rate from PVC products than from polycarbonate products.

CHLORINATED PARAFFINS (CPs) are used as both plasticizers and flame retardants. These chemicals are highly toxic, persistent in the environment, and are known to build up in the food chain. The largest use of CPs is in PVC products (e.g. cables). CPs are also used as cooling lubricants in metal processing, and as flame retardants in rubber and other products. Chlorinated paraffins are a probable human carcinogen, and have been demonstrated to cause reproductive impairment (including miscarriages) in rabbits and other animals. CPs also generate dioxin when they burn in fires. In 1995, European chlorinated paraffin producers announced a voluntary agreement to phase out short-chain chlorinated paraffins. U.S. producers (Dover Chemical, Occidental and Keil Chemical) have announced no such plans.

FLAME RETARDANTS are chemicals that are added to plastics to lower their ignition potential and rate of combustion. Examples include toxic and persistent compounds such as brominated hydrocarbons (PBBs) and chlorinated paraffins (see above). More environmentally acceptable flame retardants include aluminum and magnesium hydroxides, antimony trioxide and phosphate esters.

HEAT STABILIZERS are used primarily in PVC to reinforce chlorine bonding and counter disintegradation at high temperatures. Examples of heat stabilizers used in plastics include lead, barium/cadmium metal salts, and organotins. Stabilizers can comprise up to 5 percent of the weight of PVC products.

LEAD and CADMIUM are heavy metals that are used as stabilizers in PVC products, including toys. They can also be found in pigments that are added to various kinds of plastic.

NONYL PHENOL is used as a surfactant in PVC and PS in conjunction with antioxidants, stabilizers and plasticizers. It has been found to affect reproduction in aquatic organisms. One study found that PVC films contained the most nonyl phenol of any of the common food packaging tested. Nonyl phenols are described as "endocrine disruptors" because they interfere with the natural function of the endocrine system.

ORGANOTINS are commonly used as stabilizers in PVC products including pipes, siding and windows. Studies conducted in Canada document organotin leaching from PVC drinking water pipe. Tributyl-tins, once used as biocides in ship anti-fouling paints, have been shown to cause ###### changes in shellfish and harm to dolphins. 155 countries have proposed a ban on organotins. Mono- and di-organotins (the only types used as PVC heat stabilizers) have been linked to teratogenicity (ability to cause birth defects) in animals and toxic effects on the immune system. The Swedish government has announced its intention to phase out organotins.

PHTHALATES. The most common plasticizers (see "plasticizers," below) are a family of chemicals known as phthalates. Some of the most widely used phthalates include DEHP, DINP, and BBP. Ninety percent of all phthalates are used as PVC plasticizers. Phthalates are also used in inks, silicons and other minor applications. According to the Danish EPA, phthalates are "the most abundant man-made environmental pollutants" in the world. Phthalates are known to cause liver and kidney damage, reproductive damage and in some cases (DEHP, DINP) cancer. Major phthalate manufacturers include Exxon and Aristech.

PLASTICIZERS are compounded with PVC resin to make a final product flexible or soft. PVC uses more plasticizers than any other plastic. Plasticizers occupy space and physically separate the PVC molecular chains from one another, thus allowing more chain movement and flexibility. Many plasticizers are also flammable, which means they require the addition of flame retardants.

ULTRAVIOLET (U.V.) STABILIZERS are commonly used in PVC, polyethylene, polypropylene, polystyrene, ABS and polyesters to prevent degradation from U.V. radiation. PVC stabilizer formulations can contain stabilizers from more than one group. Examples include inorganic metal salts, particularly of lead and barium; metal soaps or other salts of organic acids, particularly of barium, cadmium, lead, calcium, magnesium, zinc, lithium, aluminum and sodium; organotin compounds; and epoxy compounds.

[Phang]

So much infor......

So which plastics are suitable for marine????

[Achilles Tang]

As long as it's food grade, it will be saltwater-safe.

high-density polyethylene (HDPE) is the best food-grade plastic around.

[Phang]

According to the above mentioned,

PVC does leak out substances that are harardous ....

then what about the pipings used for tanks.....

most pipings are made from PVC right????

[Achilles Tang]

Yeah... that did look scary.

But I think PVC is safe for aquaria use... as I haven't heard of any problems all these years arising from PVC piping usage.