Literature review of fungi in buildings and their ability to methylate chlorophenols into malodorous chloroanisoles

A source of indoor malodor in older buildings are chloroanisoles, a methylation from chlorophenols. Chlorophenols were commonly used in wood preservatives 50 years ago which were used to treat construction details exposed to high moisture loads. The methylation process requires a methylator in the form of fungi or bacteria in conjunction with adequate growth conditions for said fungi. The food industry has a history of issues with chloroanisoles contaminating different food items. There have been studies made on fungi species found in the packaging materials or surfaces in proximity and their ability to methylate various chlorophenols. Different species of fungi are present in many places, not only packaging materials but also various building materials. A literature review has been made in this study to compare fungi species able to methylate chlorophenols and their potential occurrence in wooden construction details in buildings. Two species were found to be considered strong methylators and also commonly found in wooden constructions, Aspergillus versicolor and Paecilomyces variotii. The properties of these fungi will be used for future studies of the conditions achievable in wooden constructions where the historic wood preservatives were likely used.

Digestive disorders induced by the accumulation of arsenic in the human body

Exposure to arsenic is common, but unconscious, inducing major imbalances especially in the digestive tract, lungs, skin. Contamination is achieved by exposure to arsenic in the air, soil, groundwater, food. It is noted the use of arsenic in pesticides, herbicides, paints, wood preservatives, drinking water, various foods with a wide range of consumption (seafood, rice – including rice milk, rice bran, rice cereals, rice syrup rice, rice crackers). The diagnosis of arsenic poisoning is an important step in establishing the diet and detoxification treatment, focusing on the cause, not the symptoms. We present the case of a 45-year-old patient with symptoms manifested in the digestive tract for 4 years: abdominal bloating, cramps, vomiting, weekly episodes of acute diarrhea. During these period the patient received multiple treatments depending on the symptoms, without a significant improvement, without performing specific investigations of arsenic poisoning. The personalized diet and treatment plan, used in the case of this patient, for a period of 4 months was distinguished by a total solution of the manifestations presented in the anamnesis stage.

Critical review on arsenic: Its occurrence, contamination and remediation from water and soil

With the increasing pollution in today’s world, importance is being given to solve a problem and do it in a sustainable, eco-friendly manner. Arsenic is a class-1 carcinogen and also causes many other side effects to humans, plants and animals. The utilization of arsenic as wood preservatives, pesticides, or its historical overuse by some military units for rice killing operations has led to the increase in the toxic effects of arsenic like its carcinogenicity, decreased immune response etc. Although conventional methods like coagulation, lime softening, adsorption, membrane technology are effective, they have their disadvantages like additional waste generation, causing increased pollution and are expensive. The better alternative is phytoremediation. Appropriate plants like Brassica juncea, Hydrilla verticilata, Pteris vittata L., Vallisneria natans, can be chosen based on the method of the remediation like phytoextraction, phytostabilization and phytofiltration or phytovoltalization. This review provides the list of a few plants which can be likely chosen for the purpose of both water and soil remediation. Advancements are occurring in bioremediation studies with the development of transgenic plants like transgenic tobacco, transgenic Arabidopsis thaliana for better phytoremediation. Understanding the mechanism employed by the plant for its uptake/detoxification can aid in the enhancement of the process of remediation with the external supply of phosphorus. Along with this, the proper and safe disposal of plants is crucial for the remediation process. In addition, awareness of this solution to the general public is to be made for its effectiveness.

Evaluation of Heartwood Extracts Combined with Linseed Oil as Wood Preservatives in Field Tests in Southern Mississippi, USA

Heartwood extracts of naturally durable wood species are often evaluated as alternatives to chemical wood preservatives, but field data from long-term performance testing are lacking. The current study evaluated the long-term (five-year) performance of two non-durable wood species treated with heartwood extracts of either Tectona grandis, Dalbergia sissoo, Cedrus deodara, or Pinus roxburghii alone or combined with linseed oil. Stakes (45.7 × 1.9 × 1.9 cm) and blocks (12.5 × 3.75 × 2.5 cm) cut from the sapwood of cottonwood and southern pine were vacuum-pressure impregnated with the individual heartwood species extract, linseed oil, or a mixture of each individual wood extract and linseed oil. For comparison, solid heartwood stakes and blocks of the wood species used to obtain extracts were also included in the tests. All samples were exposed for five years to decay and termites at a test site in southern Mississippi using ground contact (AWPA E7) and ground proximity (AWPA E26) tests. Results showed that extract-oil mixtures imparted higher termite and decay resistance in cottonwood and southern pine than linseed oil only or the individual heartwood species extract in both tests. However, these treatments were as not effective as to commercially used wood preservatives, copper naphthenate (CuN) or disodium octaborate tetrahydrate (DOT) in either test. Moreover, solid heartwood P. roxburghii stakes were completely decayed and attacked by termites after five years in the ground contact test. In contrast, C. deodara stakes were slightly attacked by termites and moderately attacked by decay fungi. However, T. grandis and D. sissoo stakes showed slight to superficial attack by termites and decay fungi in ground contact test. In contrast, T. grandis and D. sissoo blocks showed slight decay fungi attack in above-ground tests. However, termites did not attack T. grandis, D. sissoo, and C. deodara blocks. However, decay fungi moderately attacked C. deodara blocks, and P. roxburghii blocks were severely attacked by decay fungi and termites in the above-ground test.

Visually sorting waste wood — an exploratory study

Waste wood collected at the Vancouver landfill has been sorted based on the visibility of coatings, paints, and the green colorization of wood typically associated with wood preservatives. The sorted material was then ground and tested with an inductively coupled plasma mass spectrometry (ICP–MS) for heavy metal elements that are toxic or harmful to humans and (or) the environment. Results indicated that wood preservatives were not visually detectable but paints and coatings were. Therefore, the study demonstrated that visual sorting is not sufficiently accurate to distinguish between treated and clean or untreated waste wood.

Aleurites moluccanus (candlenut tree).

A. moluccanus is a medium-sized tree, reaching up to 20 m tall and with a diameter at breast height of 90 cm (Elevitch and Manner, 2006), growing in dense stands through much of the humid tropics. It grows on a wide range of sites and has become naturalized after planting in many areas. Best growth is observed in the open in areas with bimodal rainfall (Alambat, 1971). It tolerates drought and can stand moderately strong winds. It is propagated using seeds, which are recalcitrant. More research is needed on vegetative propagation. A. moluccanus is valued for its wood and for oil from the nuts, for which it is grown in plantations and in silvopastoral systems. The dense crown provides good shade for cattle, and it acts as a nurse crop for other agricultural crops. The wood is used for manufactures and in light construction. The oil from the seeds is used in the manufacture of paint, soap, shampoo, varnish and wood preservatives. The juice of the nuts can be taken internally to eradicate worms, while the seeds serve as a mild purgative. The seeds are also used to make palm sugar and as a flavouring. The soot from burnt seeds has been used in tattooing in Tonga (Aguilar, 1917; Alambat, 1971; Mabberley, 1997).

Determining the effect of synthetic-based varnish and impregnation on wood’s shear strength under cold climate conditions

Glue shear strength and wood preservatives play an important role in the longevity of engineered wood products. The effects of factors such as UV rays, humidity, and temperature on wooden materials are known. However, it is not known what effects sub-zero temperatures have on wood material and how wood preservatives play a role. This study determined the effects of synthetic-based varnish and impregnation on shear strength in cold climatic conditions. Variables including glue type, ambient temperature, tree type, and process type were investigated. Wood laminate test samples were produced for this purpose, and water repellent impregnation material and synthetic-based varnish were used as wood preservatives. Experimental samples were kept in a cold air cabinet at (-15 °C) and (-30 °C) temperature for 90 days. Samples kept in different temperature conditions were subjected to a pull experiment in a parallel (//) direction to the fibers under static load. As the ambient temperature decreased, the shear strength decreased (-15 °C: 8,960 N/mm2 ,-30 °C: 8,025 N/mm2 ) . When the performance of wood preservation elements were examined, it was determined that the varnish process (8,875 N/mm2) and the impregnation process (8,691 N/mm2) were not statistically significant, at 12% and 10%, respectively.

Proteomics Reveals Octyl Gallate as an Environmentally Friendly Wood Preservative Leading to Reactive Oxygen Species-Driven Metabolic Inflexibility and Growth Inhibition in White-Rot Fungi (Lenzites betulina and Trametes versicolor)

The most commonly applied wood preservatives are based on creosote, pentachlorophenol, and waterborne chromate copper arsenate, which negatively affect the environment. Thus, environmentally friendly wood preservatives are required. This study investigated the antifungal activity and mechanism of several long-chain alkyl gallates (3,4,5-trihydroxybenzoates) against white-rot fungi, Lenzites betulina and Trametes versicolor. The results revealed that octyl gallate (OG) had the best antifungal activity. Additionally, OG may have a mechanism of action similar to surfactants and inhibit ATPase activity, causing mitochondrial dysfunction and endogenous reactive oxygen species (ROS) production. Upon exposure to endogenous ROS, cells rapidly inhibit the synthesis of 60S ribosomal subunits, thus reducing the mycelial growth rate. L. betulina and T. versicolor also remodeled their energy metabolism in response to low ATP levels and endogenous ROS. After OG treatment, ATP citrate synthase activity was downregulated and glycolytic activity was upregulated in L. betulina. However, the activity of aerobic pathways was decreased and the oxidative branch of the pentose phosphate pathway was redirected form nicotinamide adenine dinucleotide phosphate (NADPH) to minimize endogenous ROS-mediated damage in T. versicolor. Taken together, these observations reveal that OG is a potent inhibitor of white-rot fungus. Further structural optimization research and pharmacological investigations are warranted.