Environmental impact of paper

Environmental product declarations or product scorecards are available to collect and evaluate the environmental and social performance of paper products, such as the Paper Calculator, Environmental Paper Assessment Tool (EPAT), or Paper Profile.

Both the U.S. and Canada generate interactive maps of environmental indicators which show pollution emissions of individual facilities.

Issues

Pulp and paper mills contribute to air, water and land pollution. Discarded paper and paperboard make up roughly 26% of solid municipal waste in landfill sites.

Pulp and paper generate the third largest amount of industrial air, water, and land emissions in Canada and the sixth largest in the United States. In 2015, the industry released 174,000 tonnes of emissions to air, water and land, or 5.3% out of a total of 3.3 million tonnes of emissions released by all industries in Canada. In the United States the pulp and paper industry released about 79,000 tonnes or about 5% of all industrial pollutant releases in 2015

Worldwide, the pulp and paper industry is the fifth largest consumer of energy, accounting for four percent of all the world's energy use. However, the entire paper and printing sector contributes less than 1% to the global greenhouse gas inventory due to the very high use of renewable energy, mostly biomass.

The pulp and paper industry uses more water to produce a ton of product than any other industry.

The de-inking process during paper recycling is also a source of emissions due to chemicals released in the effluent. The European Recovered Paper Council has developed a "deinkability scorecard" which identifies the printed paper products which have the best recyclability when they are deinked.

Much of the wood harvested in North America goes into lumber and other non-paper products. In the U.S., 36% of the timber harvest is used for paper and paperboard and in Canada 21% comes directly from harvested trees. The rest comes from sawmill residues (55%) and recycled paper (24%).

Deforestation is often seen as a problem in developing countries, but also occurs in the developed world. Woodchipping to produce paper pulp is a contentious environmental issue in Australia. In the 1990s, the New Zealand government stopped the export of woodchips from native forests after campaigning by environmentalists.

Over 6.5 million trees were cut down to make 16 billion paper cups used by US consumers for coffee alone in 2006, using 4 billion US gallons (15,000,000 m³) of water and resulting in 253 million pounds (115,000 tonnes) of waste. Overall, North Americans use 58% of all paper cups, amounting to 130 billion cups.

Air pollution

The National Emissions Inventory in the U.S. and the Air Pollutant Emission Inventory (APEI) in Canada compile annual statistics on emissions of air pollutants that contribute to smog, acid rain, greenhouse gases and diminished air quality including particulate matter (PM), sulphur oxides (SO_x), nitrogen oxides (NO_x), cadmium, lead, mercury, and persistent organic pollutants (POPs) such as dioxins and furan, hexachlorobenzene (HCB), and polycyclic aromatic hydrocarbons (PAH). In addition, the Toxics Release Inventory (TRI) is a publicly available database maintained by the EPA's TRI Program that tracks the management in the U.S. of certain toxic chemicals that may pose a threat to human health and the environment.

In the U.S., total industrial releases of toxic waste into the air were 690 million pounds (313,000 tonnes) in 2015 and pulp and paper accounted for 20%. Of the releases to air by the pulp and paper industry, 60% were methanol, which is not a persistent, bioaccumulative, and toxic (PBT) chemical and is not a carcinogen. Several PBTs are emitted by the pulp and paper industry at measurable levels, including lead, hexachlorobenzene (HCB), dioxins, furans and polycyclic aromatic hydrocarbons. In Canada emissions of these chemicals by the industry were less than 2% of total emissions in 2015. In the U.S., the pulp and paper industry accounted for 22% of total HCB emissions but other PBT emissions were under 2% of national totals.

There are other important releases to air by the pulp and paper industry. Fine particulate matter (PM_2.5) consists of particles 2.5 microns in diameter or less, which can penetrate the respiratory system and have a serious effect on health. The pulp and paper industry in the U.S. and Canada is responsible for roughly 10% of the industrial releases of PM_2.5. However, the majority of PM_2.5 in the air comes from non-industrial sources such as residential wood combustion, construction, and dust from unpaved roads; when these sources are taken into account, the pulp and paper industry in North America produced only about 0.5% of the total in 2014.

Nitrogen oxides (NO_x) sulfur oxides (SO_x) and carbon dioxide (CO₂) are all emitted during pulp and paper manufacturing. NOx and SOx are major contributors to acid rain, and CO₂ is a greenhouse gas responsible for climate change. In 2014, the pulp and paper industry in North America was responsible for about 0.5% of the total SO_x and NO_x releases from industrial and non-industrial sources.

Water pollution

Wastewater discharges from a pulp and paper mill contain solids, nutrients and dissolved organic matter such as lignin. They also contain alcohols, chelating agents and inorganic materials like chlorates and transition metal compounds. Nutrients such as nitrogen and phosphorus can cause or exacerbate eutrophication of fresh water bodies such as lakes and rivers. Organic matter dissolved in fresh water, measured by biological oxygen demand (BOD), changes ecological characteristics. Wastewater may also be polluted with organochlorine compounds. Some of these occur naturally in the wood, but chlorine bleaching of the pulp produces far larger amounts. Recent studies underline appropriate pre-treatment of the wastewater (e.g. coagulation) as a cost-effective solution for the removal of Chemical Oxygen Demand (COD) and the reduction of the pressure on the aquatic environment.

In Canada, the pulp and paper industry released 5% of the total industrial waste disposed of to water in 2015. In 2014, 97.5%, 99.9% and 99.8% of effluent samples from pulp and paper mills met regulatory requirements for toxicity tests on fish, biochemical oxygen demand, and total suspended solids, respectively.

The pulp and paper industry also produces important emissions of heavy metals. In Canada, for example, this industry is the third source of lead (Pb) emissions to water In the U.S., the pulp and paper industry is responsible for 9% of industrial releases to water. In 2015, the pulp and paper sector was ranked first in the amount of toxic weighted pound equivalents (TWPE) discharged to water by industry. Over 92% of this TWPE came from hydrogen sulphide, dioxin and dioxin-like compounds and manganese (Mn) and manganese compounds. Seven pulp and paper facilities accounted for 80% of the hydrogen sulphide discharged, and five facilities accounted for 93% of the dioxin discharged out of a total of 226 facilities. The last time the EPA reviewed Mn and Mn compounds (2006) it concluded that discharges were below treatable levels. Levels of discharge have not changed significantly since that time.

Discharges can also discolour the water, making it ugly. This has happened in the Tarawera River in New Zealand, which became known as the "black drain".

Paper waste

Discarded paper and paperboard make up roughly 26% (or 67 million tons) of the 258 million tons of solid municipal waste generated in 2014 and over 14% of the 136 million tons solid municipal waste that ended up in landfills in 2014. Paper waste, like other wastes, produces the additional hazard of toxic inks, dyes and polymers that might be carcinogenic when incinerated, or commingled with groundwater by traditional burial methods such as modern landfills. Paper recycling mitigates this impact, but not the environmental and economic impact of the energy consumed by manufacturing, transporting and burying and/or reprocessing paper products.

Wood pulping process

Chlorine and chlorine-based materials

Chlorine and compounds of chlorine are used in the bleaching of wood pulp, especially chemical pulps produced by the kraft process or sulfite process. In the past, plants using elemental chlorine produced significant quantities of dioxins, persistent and very toxic organic pollutants. From the 1990s onward, the use of elemental chlorine in the delignification process was substantially reduced and replaced with ECF (Elemental Chlorine Free) and TCF (Totally Chlorine Free) bleaching processes. As a result, dioxin production was also significantly reduced.

In 2005, elemental chlorine was used in 19–20% of kraft pulp production globally, down from over 90% in 1990. 75% of kraft pulp used ECF, with the remaining 5–6% using TCF. A study based on U.S. Environmental Protection Agency (EPA) data concluded that "Studies of effluents from mills that use oxygen delignification and extended delignification to produce ECF (elemental chlorine free) and TCF pulps suggest that the environmental effects of these processes are low and similar." Most TCF pulp is produced in Sweden and Finland for sale in Germany, all markets with a high level of environmental awareness. In 1999, TCF pulp represented 25% of the European market.

TCF bleaching, by removing chlorine from the process, reduces chlorinated organic compounds to background levels in pulp mill effluent. ECF bleaching can substantially reduce but not fully eliminate chlorinated organic compounds, including dioxins, from effluent. While modern ECF plants can achieve chlorinated organic compounds (AOX) emissions of less than 0.05 kg per tonne of pulp produced, most do not achieve this level of emissions. Within the EU, the average chlorinated organic compound emissions for ECF plants is 0.15 kg per tonne.

However, there has been disagreement about the comparative environmental effects of ECF and TCF bleaching. On the one hand, paper and chemical industry-funded studies have generally found that there is no environmental difference between ECF and TCF effluents. On the other hand, an independent peer-reviewed study has found that, comparing conventional, ECF and TCF effluents before and after secondary treatment, "TCF effluents are the least toxic."

Sulfur, hydrogen sulfide and sulfur dioxide

Sulfur-based compounds are used in both the kraft process and the sulfite process for making wood pulp. Sulfur is generally recovered, with the exception of ammonia-based sulfite processes, but some is released as sulfur dioxide during combustion of black liquor, a byproduct of the kraft process, or "red liquor" from the sulfite process. Sulfur dioxide is of particular concern because it is water-soluble and is a major cause of acid rain. In 2006 the pulp and paper industry in Canada released about 60,000 tonnes of sulfur oxides (SOx) into the atmosphere, accounting for just over 4% of the total SOx emission from all Canadian industries.

A modern kraft pulp mill is more than self-sufficient in its electrical generation and normally will provide a net flow of energy to the local electrical grid. Additionally, bark and wood residues are often burned in a separate power boiler to generate steam.

Air emissions of hydrogen sulfide, methyl mercaptan, dimethyl sulfide, dimethyl disulfide, and other volatile sulfur compounds are the cause of the odor characteristic of pulp mills utilizing the kraft process. Other chemicals that are released into the air and water from most paper mills include the following:

• carbon monoxide
• ammonia
• nitrogen oxide
• mercury
• nitrates
• methanol
• benzene
• volatile organic compounds, chloroform.

Bleaching mechanical pulp is not a major cause for environmental concern since most of the organic material is retained in the pulp, and the chemicals used (hydrogen peroxide and sodium dithionite) produce benign byproducts (water and, eventually, sodium sulfate, respectively).

However, the bleaching of chemical pulps has the potential to cause significant environmental damage, primarily through the release of organic materials into waterways. Pulp mills are almost always located near large bodies of water because they require substantial quantities of water for their processes. An increased public awareness of environmental issues from the 1970s and 1980s, as evidenced by the formation of organizations like Greenpeace, influenced the pulping industry and governments to address the release of these materials into the environment. Environmental NGO pressure was especially intense on Swedish and Finnish pulp and paper companies.

Conventional bleaching using elemental chlorine produces and releases into the environment large amounts of chlorinated organic compounds, including chlorinated dioxins. Dioxins are recognized as a persistent environmental pollutant, regulated internationally by the Stockholm Convention on Persistent Organic Pollutants.

Dioxins are highly toxic, and health effects on humans include reproductive, developmental, immune and hormonal problems. They are known to be carcinogenic. Over 90% of human exposure is through food, primarily meat, dairy, fish and shellfish, as dioxins accumulate in the food chain in the fatty tissue of animals.

Greenhouse gas emissions

Globally, 69% of greenhouse gas emissions come from the energy and transportation industries. The global print and paper industry accounts for about 1% of global carbon dioxide emissions. Recent bottom-up analysis across 30 major countries estimated that domestic paper-related sectors accounted for about 3.2% of global anthropogenic greenhouse-gas emissions over 1961–2019, and outlined net-zero pathways to 2050 centered on energy-efficiency improvements and energy-system decarbonization.

Greenhouse gas emissions from the pulp and paper industry are generated from the combustion of fossil fuels required for raw material production and transportation, wastewater treatment facilities, purchased power, paper transportation, printed product transportation, disposal and recycling.

Disposing of paper in landfill sites, and subsequent breakdown and production of methane (a potent greenhouse gas) also adds to the carbon footprint of paper products. This is another reason why paper recycling is beneficial for the environment. Paper recovery, instead of landfilling can reduce the global warming potential of paper products by 15 to 25%.

At pulp and paper mills in the U.S., the GHG emission rate expressed in tons of carbon dioxide equivalents per ton of production has been reduced by 55.8% since 1972, 23.1% since 2000, and 3.9% compared to 2010. Between 2005 and 2012, U.S. pulp and paper mill purchased energy (from fossil fuels) use per ton of production has been reduced by 8.8%.

In Canada, between 2000 and 2012, direct GHG emissions declined by 56% and total energy use by 30%. Some of this decline is due to the contraction of the forest industry but a large part is due to reduced use of fossil fuels and increased self-generation of power from renewable biomass. Bioenergy accounted for 56% of forest industry energy use in 2012, up from 49% in 2000.

Non-renewable resources

Clay or calcium carbonate are used as fillers for some papers. Kaolin is the most commonly used clay for coated papers.

Tree invasive species

Trees particularly suited for pulp production have been introduced in various regions worldwide. Some of those have now come to be recognized as aggressive invasive species. In Malaysia, the Acacia auriculaeformis and Acacia mangium are counted as invasive trees. The fast-growing and highly profitable eucalyptus must be regarded an invasive species in various part of the world.