Water from household laundry has been estimated to make up about 2% of the total volume flowing into municipal wastewater treatment plants (WWTPs). Records of the chemicals used in the manufacture of textiles/clothing and analyses of both washed clothes and laundry wastewater indicate that a large number of environmentally harmful substances can potentially reach treatment plants. These substances, including fibers and micro plastics fromlaundry, may contribute to the pollution of sewage sludge used for fertilization of arable land, or pollute the receiving waters downstream of wastewater treatment plants.
Textiles are one of the groups of consumer goods that the Environmental Objectives Committee proposed (SOU 2012: 38) be subject to a government mandate regarding the use of hazardous chemicals, environmental risk reduction measures and voluntary eco-labeling. The government has also decided (Ds 2012: 23) on interim measures aimed at removing toxic material from the environment, including providing information on hazardous substances in clothing. The Swedish environmental objectives system also includes the so-called "Generation target", that states that material life cycles should be as free as possible from hazardous substances and that consumption of goods should produce as few health and environmental problems as possible, including in all the countries where they were manufactured. The Generation target means that the Swedish government needs to take into account environmental and health impacts that Swedish consumption may cause in other countries. The EU Waste Framework Directive (2008/96 / EC) defines a waste hierarchy that puts the recycling of old products, such as clothing, before the recycling of waste. This study may inform those working on developing such directives.
Aim
The purpose of this study was to examine the extent to which laundering of five types of clothing (cotton t-shirts, cotton jeans, work trousers, fleece sweaters and weatherproof jackets) contributes to the presence of toxic pollutants in sludge and effluent water from a representative sample of treatment plants.
Experimental
The choice of clothing was based on the study "Kartläggning av kemikalieanvändning i kläder" (Swerea IVF, Report 09/52) and were purchased in Umeå during January 2014.
The different categories of clothing were washed twice in a washing machine, without drying them in between and all wastewater was collected from the washer. Immediately after washing, samples of this water were transferred into 2 L glass containers and were analyzed for 126 compounds by three different laboratories (Miljökemiska Laboratoriet, Umeå Universitet, Svenska Miljöinstitutet (IVL) och Stockholms Universitet (ACES)).
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Results
The results show that the main types of chemicals that were released when the clothing was washed, regardless of the type of clothing, were process and functional chemicals. This was expected since functional chemicals are added to the garment and are usually not chemically bonded to the fabric, whilst the process chemicals should not be present in the final product at all. Chemicals belonging to the group unwanted chemicals were released in very small amounts to the wastewater whatever type of clothing washed.
The functional chemicals represented 30 % of the analyzed target compounds but accounted for up to 99% (for t-shirts) of the release when the clothing was washed. The lowest contribution of functional chemicals to the total release of chemicals was from weatherproof jackets. Process chemicals dominated those released from weatherproof jackets (90%) and fleece sweaters (72%); for working pants, the contribution was 41%. The unwanted chemicals were present in much lower amounts in the laundry wastewater than the functional and process chemicals: they represented 1% or less of the chemicals detected.
T-shirts is estimated to release the largest amount of chemicals (469 kg functional chemicals, 0.5 kg process chemicals and 0.07 kg unwanted chemicals) based on the yearly net supply and the first two washing cycles. Fleece sweaters released the least amount of chemicals; 1.8 kg functional chemicals, 2.9 kg process chemicals and 3 g unwanted chemicals.
Phthalates, DINCH (a phthalate substitute), bisphenols, formaldehyde, and organophosphates were the groups of chemicals estimated to be released in largest amounts from the five types of clothing included in the study, contributing 47%, 25%, 12%, 12%, and 3%, respectively, to the total amount.
Based on the yearly net supply of clothing included in this study, the estimated release of textile fibers varies between 100 kg for fleece sweaters up to 8,500 kg for t-shirts. T-shirts released 0.85 mg fibers per kg, jeans released 0.46 mg/kg, weatherproof jackets 0.02 mg/kg, working pants 0.07 mg/kg and fleece sweaters 0.1 mg/kg.
Discussion
Phthalates and organophosphates were estimated to be released in large amounts (302 kg and 7.6 kg) contribute with 50% and 5% respectively to the amounts found in effluents from wastewater treatment plants. Chlorophenols and perfluorinated compounds were estimated to be released in very low amounts (430 g and 300 g respectively). This is however still more, 167% and 223% respectively, than what is found annually in the effluents and sewage sludge of all Swedish WWTPs.
The estimated contribution to sewage sludge for the different compound classes was far higher than the calculated contribution to effluent. The estimation produced a contribution figure of over 100% for some compound groups. Short chain chloroparaffins and chlorophenols were estimated to contribute to the amount found in sewage sludge to such a large degree that it exceeded what is actually found in the sewage sludge. Chlorophenols are distributed between both effluent and sewage sludge, but reference data was only found for sludge, so this could be the reason for the overestimation of the amount that ends up in the sewage sludge. It can also not be excluded that the selection of clothing was not representative of what is on the market.
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Conclusions
Chemicals that are banned according to legislation such as Reach should, in principle, not be present in clothing. Even so, they are sometimes found during inspections of manufacturing facilities and analyses of clothing. This is a large problem since the use of a chemical can be banned in some countries but not in others. Arylamines are, for example, forbidden within the EU, but one of those 4,4'-diaminodiphenylmethane could still be detected in all types of clothing. Now, the clothing that we wear comes from all over the world, and it is difficult to find information on which chemicals have been used in its production since that can take place in many different countries. This tractability needs to be improved.
In this study, we detected 72 out of 126 compounds that are non-naturally occurring compounds, in the laundry wastewater. Among the compound groups that could not be detected were anilines, triclosan, triclocarban, and siloxanes.
The compounds released in large amounts into the laundry wastewater in this study were the process chemical bisphenol S (BPS), and the functional chemicals phthalates (DBP, BBP, DINP, DIDP), DINCH, organophosphates (TPP, TCEP, TCPP, TEHP, TBEP) and formaldehyde. Considering the net supply of new clothing to Sweden, the estimated annual contribution of the release of such compounds from new clothing being washed for the first time will be substantial.
Even though some of these chemicals will be degraded during the treatment process in the WWTP, many of them will end up in effluent or sewage sludge and, to different degrees, contribute to the compounds that risk ending up in WWTPs or where nutrients are recycled from sewage sludge.
Future work
To obtain a better picture of the volume of chemicals flowing to the WWTPs and, potentially, the environment, originating from the laundering of clothing, it would be of interest to study the release of chemicals from a broader range of clothing types. It would also be interesting to include analysis of the fabric to see what proportion of chemicals are released during laundry, and what proportion remain and are then potentially released during later washing or enter the textile waste stream.
It would also be of great interest to carry out non-target analysis on both the textiles and the wastewater to form an even broader picture of which chemicals are present in the textiles and the wastewater.