1, 3-Butadiene (BD) is primarily used for the production of synthetic rubbers and polymers, which are found in many industrial and consumer products. BD is suspected to be both carcinogenic and genotoxic to humans. This study aims to compare occupational exposure limits (OELs) based on BDâs carcinogenic effects using threshold and non-threshold methods in industrial settings. A review of published literature was carried out to find the most suitable in vivo carcinogenic data. Selection criteria included the number of dose levels considering more than three dose level and chronic exposure through the lung route. Studies of the National Toxicology Program (NTP) and Melnick et al. met the criteria for this study. The U.S. Environmental Protection Agency (EPA)âs BMD software, version 3.2.0, was utilized to estimate BMDL10. In the threshold approach, OELs were calculated using BMDL10 divided by uncertainty factors. The margin of exposure (MOE) method was used as a non-threshold approach. In the threshold approach, an OELI of 2.3 ppm and 3.8 ppm was estimated in males and females, respectively. In the non-threshold approach, the OELII of 0.008 ppm and 0.014 ppm was calculated for males and females, respectively, which were substantially lower than those found using the threshold method. Examining and comparing the results of this study to the threshold limit values (TLVs) and carcinogenic risk values determined by the EPA revealed that the threshold values are closer to the safe workplace concentrations (concentrations where no carcinogenic effects have been detected). Consequently, the use of non-threshold approaches results in an inaccurate estimation of carcinogenic risk.

There is growing interest in using the ecosystem services framework for environmental risk assessments of chemicals, including plant protection products (PPPs). Although this topic is increasingly discussed in the recent scientific literature, there is still a substantial gap between most ecotoxicological studies and a solid evaluation of potential ecotoxicological consequences on ecosystem services. This was recently highlighted by a collective scientific assessment (CSA) performed by 46 scientific experts who analyzed the international science on the impacts of PPPs on biodiversity, ecosystem functions, and ecosystem services. Here, we first point out the main obstacles to better linking knowledge on the ecotoxicological effects of PPPs on biodiversity and ecological processes with ecosystem functions and services. Then, we go on to propose and discuss possible pathways for related improvements. We describe the main processes governing the relationships between biodiversity, ecological processes, and ecosystem functions in response to effects of PPP, and we define categories of ecosystem functions that could be directly linked with the ecological processes used as functional endpoints in investigations on the ecotoxicology of PPPs. We then explore perceptions on the possible links between these categories of ecosystem functions and ecosystem services among a sub-panel of the scientific experts from various fields of environmental science. We find that these direct and indirect linkages still need clarification. This paper, which reflects the difficulties faced by the multidisciplinary group of researchers involved in the CSA, suggests that the current gap between most ecotoxicological studies and a solid potential evaluation of ecotoxicological consequences on ecosystem services could be partially addressed if concepts and definitions related to ecological processes, ecosystem functions, and ecosystem services were more widely accepted and shared within the ecotoxicology community. Narrowing this gap would help harmonize and extend the science that informs decision-making and policy-making, and ultimately help to better address the trade-off between social benefits and environmental losses caused by the use of PPPs.

Remediation of residually contaminated soils remains a widespread problem. Biochar can immobilize polycyclic aromatic hydrocarbons (PAH). However, studies on its ability to immobilize PAH and N, S, and O substituted PAH (hetero-PAH) in real soils, and benchmarking with commercial activated carbon are missing. Here, we compared the ability of pristine biochar (BC), steam-activated biochar (SABC), and commercial activated carbon (AC) to immobilize PAH and hetero-PAH. The three carbons were tested on soils from four different contaminated sites in Austria. Different amendment rates (w/w) of the carbons were investigated (BC: 1.0, 2.5, and 5%; SABC: 0.5, 1.0, and 2.0%; AC: 1%) in batch experiments to cover meaningful ranges in relation to their performance. SABC performed better than AC, removing at least 80% PAH with the lowest application rate of 0.5%, and achieving a complete removal at an application rate of 1.0%. BC performed slightly worse but still acceptable in residually contaminated soils (40 and 100% removal at 1 and 5% amendment, respectively). The ability of BC and SABC to immobilize PAH decreased as the PAH-molar volume increased. PAH with three or more rings were preferentially removed by AC compared to SABC or BC. This can be explained by the difference in pore size distribution of the carbons which could limit the accessibility of PAH and hetero-PAH to reach sorption sites for π- π electron donor-acceptor interactions, which drive PAH and hetero-PAH sorption to carbons. Column percolation tests confirmed the results obtained in batch tests, indicating, that decisions for soil remediation can be derived from simpler batch experiments. In soil samples with 1% BC, a reduction of over 90% in the total concentration of PAH in the leached water was observed. Overall, BC and SABC were demonstrated to be valid substitutes for AC for stabilizing residually contaminated soils.

Climate impacts of elevated temperatures and more severe and frequent weather extremes like heatwaves are globally becoming discernible on nature. While a mechanistic understanding is pivotal for ecosystem management, stressors like pesticides may interact with warming, leading to unpredictable effects on freshwater ecosystems. These multiple stressor studies are scarce and experimental designs often lack environmental realism. To investigate the multiple stressor effects, we conducted a microcosm experiment for 48 days comprising benthic macroinvertebrates, zooplankton, phytoplankton, macrophytes, and microbes. The fungicide carbendazim (100 μg/L) was investigated combined with temperature scenarios representing elevated temperatures (+4 °C) or heatwaves (+0 to +8 °C), both applied with similar energy input on a daily fluctuating ambient temperature (18 °C ± 1.5 °C), which served as control. Measurements showed the highest carbendazim dissipation in water under heatwaves followed by elevated and ambient temperatures. Average carbendazim concentrations were about 50% in water and 16% in sediment of the nominal concentration. In both heated cosms, zooplankton community dynamics revealed an unexpected shift from Rotifera to Cladocera and Copepoda nauplii, indicating variations in their thermal sensitivity, tolerance and resilience. Notably, warming and heatwaves shaped community responses similarly, suggesting heat intensity rather than distribution patterns determined the community structure. Heatwaves led to significant early and longer-lasting adverse effects that were exacerbated over time with Cladocera and Copepoda being most sensitive likely due to significant carbendazim interactions. Finally, a structural equation model demonstrated significant relationships between zooplankton and macrophytes and significantly negative carbendazim effects on zooplankton, whereas positive on macroinvertebrate abundances. The relationship between macroinvertebrate feeding and abundance was masked by significantly temperature-affected microbial leaf litter decomposition. Despite the thermal tolerance of zooplankton communities, our study highlights an increased pesticide threat under temperature extremes. More intense heatwaves are thus likely to cause significant alterations in community assemblages which will adversely affect ecosystem's processes and functions.

Adsorption and transport of levofloxacin (LEV) and ofloxacin (OFL) enantiomers in a matrix containing goethite and natural organic matter (NOM) were investigated using batch and column experiments. In batch studies, competition and enantioselectivity were observed in the adsorption of LEV and OFL. Enantioselectivity upon adsorption was investigated by comparing changes in the enantiomer fraction (EF) (the ratio of LEV to the sum of LEV and OFL remaining in the solution) after and before adsorption. At pH < 7, there was hardly any selectivity in adsorption of OFL and LEV to goethite. At pH > 7, OFL showed a stronger adsorption than LEV to goethite, and this preference remained when NOM samples of Leonardite humic acid (LHA) and Elliott Soil fulvic acid (ESFA) were added. However, when Suwannee River NOM (SRNOM) was added, the preference was reversed, and LEV was adsorbed more strongly. In single systems, the presence of different types of NOM increased adsorption of LEV and OFL, especially LEV. In column studies, preloaded NOM decreased the transport of LEV and OFL through goethite-coated sand. The EF values in the effluent increased with retention time and reached the largest values (0.59–0.72) at around 1.5 pore volume (PV), and then decreased again, reaching a stable value at 5.0–30.0 PV. Both batch and column experiments showed that, fractionation of LEV and OFL occurred during adsorption and transport in the presence of NOM-goethite complexes, which would eventually affect their environmental fate

Microplastics (MPs) in soil undergo different aging processes such as photoaging, mechanical abrasion and biodegradation, leading to alterations in the surface properties of MPs. In this study, we investigated the adsorption-desorption of chlorpyrifos (CPF) on pristine and UV light-aged low-density polyethylene (LDPE) and biodegradable (Bio) MPs that were derived from plastic mulch films. We also tested the bioconcentration of pristine and aged MPs (LDPE- and Bio-MPs aged under UV light and LDPE-MPs aged in three different soils) associated with CPF by earthworms (Lumbricus terrestris). The results showed that UV-aged MPs showed higher CPF adsorption capacities than pristine MPs, with the adsorption capacities at 184.9 ± 5.3, 200.5 ± 1.8, 193.0 ± 8.7, and 215.9 ± 1.1 μg g−1 for pristine LDPE-, UV-aged LDPE-, pristine Bio- and UV-aged Bio-MPs, respectively. The desorption rate of CPF from UV-aged LDPE-MPs within 48 h was lower than the desorption from pristine ones (28.8 ± 7.7% vs. 40.0 ± 3.9%), while both pristine and UV-aged Bio-MPs showed very low CPF desorption rates. A 4-day Petri dish experiment showed that UV-aged MPs were significantly less concentrated in earthworm casts than pristine counterparts (52% and 36% lower for UV-aged LDPE- and Bio-MPs), while UV-aged MPs with adsorbed CPF were concentrated significantly more than UV-aged MPs without CPF. Interestingly, LDPE-MPs aged in soil with a high carbon, nitrogen, and carbon-to-nitrogen ratio were significantly more concentrated in earthworm casts than pristine LDPE-MPs. In conclusion, UV-aged MPs acted as stronger vectors for CPF than pristine MPs. The bioconcentration of MPs differed significantly due to microplastic aging, as well as the combined effect with CPF. Moreover, LDPE-MPs aged in soil with enriched carbon and nitrogen were significantly concentrated in earthworm casts. Further studies on the environmental behaviours of aged MPs associated with other pollutants in soil, especially soils high in carbon and nitrogen, are needed.

The Zayandeh-Rood River (Isfahan Province, Iran) is of vital importance as a water source for various purposes, but it is facing adverse effects from human activities. This study focused on the surface sediment of 21 stations along the river to assess the concentration of potentially toxic elements (PTEs) and their environmental risk using the Geoaccumulation Index (Igeo), Enrichment Factor (EF), Pollution Load Index (PLI), and Potential Ecological Risk Index (RI). The mean concentration of the PTEs (mg/kg) was ranked as follows: Cd (0.34)< As (9.73)< Pb (10.95)< Co (11.91)< Cu (31.14)< Ni (31.90)< Zn (61.33)< Cr (96.95)< V (125.09)< Mn (707.76). Positive correlation coefficients were found among all the PTEs, while their relationships with the sediment physicochemical characteristics varied considerably, indicating that various interacting factors might influence the deposition and mobility of PTEs in the river. The river was classified as having moderate to low contamination (Igeo index) and minimal-to-moderate enrichment (EF index) except for Cd and As which exhibited extremely high enrichment and strong pollution in the upstream zone, where agricultural activities dominate. Therefore, managing agricultural practices and reducing the excessive use of PTE-containing pesticides and insecticides should be a primary focus to protect the Zayandeh-Rood River from further contamination.

The purpose of this study was to evaluate the environmental and health risk of PM2.5 microns in district 10 of Tehran. Initially, data related to the year 2019 were collected and analyzed through pollutant measurement at the regional level. Based on Kriging's interpolation the corresponding raster was produced and classified according to the minimum and maximum range. Finally, according to the air quality index, the level of importance of health safety was classified and the relevant map was prepared. Through the IO technique, the location layer of sensitive and vulnerable land uses and the carbon monoxide contaminant zoning layer were mapped. Results showed that District 10 of Tehran with the average concentration of 42µg/m3 is the most polluted area in terms of this contaminant in Tehran. Also, most of the PM2.5 pollutants belong to the northern, southern and western half of the region. Also, December was the most polluted month of the year with an average concentration of 56μg/m3. From the point of view of the air quality index based on the type of pollutants, the area had 104 days of unhealthy and unhealthy days for sensitive groups. Environmental and health risk assessment of these pollutants indicates that according to William Fine method, the risk number is 105, which indicates the average risk level. Therefore, it requires corrective and emergency risk control measures.

In this study systematic random sampling was conducted. To estimate the sample size, 100 households were selected based on the population of the city using Cochran's formula. Total generated municipal solid waste was consecutively collected, weighed and separated during a week. Then, after providing the required training through face-to-face manner and brochures regarding the economic, social, cultural and environmental importance of source separation to each of the households, once again the generated wastes were collected, weighed and separated. The difference in the composition and amount of waste generated before and after the training was compared by independent t-test. The effect of the demographic characteristics of the head of the household on reducing the amount of generated waste was determined by correlation test. The results highlighted the training as an effective intervention on the weight of produced waste from each household before and after the training (P=0.000). Education increases people's awareness about waste, recycling, harms of waste, definition of separation, benefits of separation, source separation and level of household education. The reduction in the amount of produced waste had no significant correlation with the age (P=0.89), occupation (P=0.16), income (P=0.95) and education level (P=0.36) of the heads of each household. The findings of this research showed that education, regardless of demographic characteristics, is an effective method to change specific behavior and create motivation to reduce the amount of waste at source, underlining the importance of training to improve waste recycling management.

Environmental Management Plan (EMP) is regarded as a guidance document to attain and measure compliance with the mitigation requirements and environmental protection of projects, which are normally requirements for project approvals. The study mainly aims to present an Environmental Management Plan for dams whose construction was suspended by opposing stakeholders for the harmful impacts on the environment in forested areas. As a case study, the Hyrcanian forests (Caspian forests) are located in western Asia and were inscribed on the United Nations Educational Scientific and Cultural Organization (UNESCO) World Heritage List in 2019. The construction of the hydropower Shafarood dam began in these forests in 1990. Because of budget deficits and the suspensions incurred by opposing activists in 2013, dam construction has only advanced by 23% ever since. To meet that aim, the research data was collected through analysis of documents, letters, articles, field visits to the construction site, and interviews. The semi-structured interviewing method was employed in holding interviews with governmental and environmental NGOs, local people, specialists, and academics because of their good cooperation. The results indicate that the most negative effects in the construction phase have been produced by deforestation and degradation of vegetation, source of material supply, settlement and livelihood of migrants impacted by dam impoundment, water, air and sound quality. Ultimately, an Environmental Management Plan was proposed for this dam and those under construction or suspended in forested areas to minimize the negative environmental effects of the Hydropower Shafarood dam, which technically concentrates on mitigating measures.