Early-Life Exposure to Formaldehyde through Clothing

Natural coagulants from chestnut shells: A sustainable approach for textile wastewater treatment

The textile industry contributes to 2-10% of global greenhouse gas emissions, water extraction, and biodiversity loss, consuming 93 billion cubic meters of water annually with low reuse rates. Coagulation/flocculation is commonly used for industrial wastewater treatment, typically using conventional coagulants. Recently, interest in natural alternatives, particularly tannin-based coagulants, has grown. Given Portugal's role as a major chestnut producer and textile exporter, this study developed chestnut shell-based coagulants for textile wastewater treatment. Ethanolamine (ETA) and diethanolamine (DEA) were tested in the Mannich reaction, but only ETA produced a coagulant with a positive zeta potential and higher charge density. Five coagulants (CE_1-CE_5) were synthesized using different ETA/tannin and formaldehyde (FA)/tannin ratios. Lower ETA concentrations (7.5 mol L-1) produced the coagulant with the highest charge density and zeta potential. Further testing of FA/tannin ratios (3.5, 6, and 7.5) showed that lower FA levels reduced color removal efficiency and increased toxicity. Comparing synthetic and real textile effluent performance, natural coagulants showed superior color removal, while FeCl3 was more effective for organic matter and nitrogen removal. All coagulants removed phosphorus, with CE_2 achieving nearly 70% removal. Toxicity tests revealed that only CE_5 inhibited V. fischeri bacteria by over 70%. Formaldehyde leaching into treated water was minimal (0.17-0.3 mg L-1), below WHO limits (2.6 mg L-1), but concentrations in sludge were higher, especially in CE_3 and Tanfloc. These findings highlight chestnut shells as a promising source for producing natural, effective coagulants.

Enzymatic Cleanup of Formaldehyde in Aqueous Solutions

Numerous methods have been developed to address gaseous formaldehyde pollution, but most of them cannot be applied directly to eliminate the pollution of formaldehyde in aqueous solutions. Formaldehyde in aqueous solutions can be leached from formaldehyde-containing solid materials (e. g., food, wood, clothes, resins) and absorbed from gaseous formaldehyde by water. Here we developed an enzymatic cleanup technique - the reconstitution of an enzyme cocktail consisting of three coenzyme-free oxidoreductases (i. e., formaldehyde dismutase, methanol oxidase, and formate oxidase) and catalase for the complete oxidation of formaldehyde. This enzyme cocktail catalyzed the reaction of formaldehyde and ambient dioxygen into carbon dioxide (CO2) and water, which was demonstrated by the stable isotope tracer technique. Significant levels of formaldehyde were detected from aqueous solutions leached from the squid, pomfret, fabric, and curtain in the market. When this enzyme cocktail was applied to treat the leachates of contaminated samples above, formaldehyde was eliminated with degradation ratios of up to 100 %. This enzymatic cleanup technique, featuring excellent biosafety (for example, degradable catalysts and non-immunogenicity), independence from light, high degradation ratios, and no special equipment required, could be widely used to treat contaminated food, drinking water, and formaldehyde-containing leachate.

Clothing as a potential exposure source of trace elements during early life

In recent years, the interest in determining the chemical composition of textile products has increased among the scientific community and regulatory agencies, driven by toxicological issues and environmental concerns. Chemical elements are naturally present in clothing as natural fibers or intentionally added during manufacture. Some of them show physical-chemical properties that allow their absorption through the skin. In addition, chronic situations increase the dermal exposure capacity. Because of age-specific behavioral characteristics and underdeveloped physiological function, children may be especially sensitive to exposure to trace elements. This study aimed to analyze the levels of twenty trace elements in 120 clothing items commercialized in Spain. Textile products for pregnant women and children <36 months old were included. The potential health implication of this dermal exposure in early life was also evaluated. Aluminum, zinc, and titanium showed the highest concentrations, with median levels of 27.6, 5.6, and 4.2 mg/kg, respectively. Since chromium is employed as a metal complex dye in synthetic fibers, high levels of this element were found in black polyester. Dermal exposure to titanium, which is a ubiquitous element in clothes made of synthetic fibers, was associated with a hazard quotient (HQ) higher than the threshold value (HQ > 1), with values of 1.13 for pregnant women and 1.22 for newborns. On the other hand, HQ values of other elements and cancer risks were lower than the recommended values. Assessing early-life exposure to toxic elements can help to identify potential sources and to prevent or reduce human exposure, mainly in vulnerable groups.

Non-regulated aromatic amines in clothing purchased in Spain and Brazil: Screening-level exposure and health impact assessment

The staggering amount of chemicals in clothes and their harmful effects on human health and the environment have attracted the attention of regulatory agencies and the scientific community worldwide. Azo dyes are synthetic dyestuffs with widespread use in textile industries, currently classified as emerging pollutants of great health concern to consumers. These compounds may release one or more aromatic amines (AAs) after reductive cleavage of their azo bounds. Twenty-two AAs have already been regulated due to their carcinogenic effects. However, since information on their potential toxicity is not currently available, several AAs have not been still regulated by the European Union. Considering this gap, the present study aimed to assess the levels of forty non-regulated AAs in 240 clothing items from Spain and Brazil. The potential impact on the health of vulnerable population groups after dermal exposure to those garments was also evaluated. In Brazil, at least one AA was detected in the clothes, while in samples obtained in Spain, only two of them showed values below the limit of detection for AAs. In 75 clothes, at least one of the measured AAs was higher than the hazardous threshold (30 mg/kg), which can mean risks to human health since these compounds are suspected to be mutagenic. Aniline, the most common AA, showed a high detection rate (82%) in clothes, with significantly higher concentrations in items commercialized in Brazil (0.35 vs. 0.17 mg/kg; p = 0.032). Moreover, o-aminobenzenesulfonic and p-phenylenediamine, suspected mutagenic, were found at relevant concentrations in several clothes, mainly made of synthetic fibers. In this study, the hazard index associated with exposure to AAs through clothing was low (0.006-0.13) for all the population groups of both countries in the medium-bound scenario. However, its value was close to 1 for Brazilian pregnant women (0.998) when the maximum concentration value was considered under an upper-bound scenario. The risk of exposure to non-regulated AAs may be underestimated since only dermal exposure was considered for risk assessment. Moreover, the co-occurrence of other carcinogenic and non-carcinogenic substances present in skin-contact clothes should mean an additional source of potential risk.

Dermal exposure to bisphenols in pregnant women's and baby clothes: Risk characterization

Textile manufacturing consists of a multiple-step process in which a wide range of chemicals is used, some of them remaining in the final product. Bisphenols (BPs) are non-intentionally added compounds in textiles, whose prolonged skin contact may mean a significant source of daily human exposure, especially in vulnerable groups of the population. The present study aimed to determine the levels of bisphenol A (BPA) and some BP analogs (BPB, BPF, and BPS) in 120 new clothes commercialized in Spain for pregnant women, newborns, and toddlers. In addition, exposure assessment and risk characterization were also carried out. Traces of BPA were found in all the samples, with a median concentration of 7.43 ng/g. The highest values were detected in textile samples made of polyester. Regarding natural fibers, higher concentrations of BPs were observed in garments made of conventional cotton than in those made of organic cotton, with a significant difference for BPS (1.24 vs. 0.76 ng/g, p < 0.05). Although toddlers have a larger skin-area-to-body-weight ratio, pregnant women showed higher exposure to BPs than children. Anyhow, the non-carcinogenic risks associated with BPA exposure were below the unity, even under the upper-bound scenario. However, risks could be underestimated because other exposure routes were not considered in this study. The use of BPA has been restricted in some food-related products; therefore, BPA should also be regulated in the textile industry.

Screening of regulated aromatic amines in clothing marketed in Brazil and Spain: Assessment of human health risks

Azo dyes used in textile products contain aromatic amines (AAs), which may be released into the environment after skin bacteria cleavage the azo bond. In Europe, 22 carcinogenic AAs are regulated. Unfortunately, no information is available in many non-European countries, including Brazil. This study aimed to determine the concentrations of 20 regulated AAs in clothes marketed in Brazil and Spain. Generally, higher levels of regulated AAs were found in samples sold in Brazil than in Spain, which is linked to the lack of regulation. Sixteen AAs showed concentrations above 5 mg/kg in samples commercialized in Brazil, while 11 exceeded that threshold in Spain. Regulated AAs with levels above 5 mg/kg were more found in synthetic clothes of pink color. Concentrations in clothing were also used to evaluate the dermal exposure to AAs in 3 vulnerable population groups. The highest exposure corresponded to 2,4-diaminoanisole for toddlers in Brazil and 4,4-oxydianiline for newborns in Spain. Non-cancer risks associated with exposure to 4,4-benzidine by Brazilian toddlers was 14.5 (above the threshold). On the other hand, 3,3-dichlorobenzidine was associated with potential cancer risks for newborns and toddlers in Brazil. Given this topic's importance, we recommend conducting continuous studies to determine the co-occurrence of carcinogenic substances.