Although banned from production for decades, PCBs remain a significant risk to human health. A primary target of concern is the developing brain. Epidemiological studies link PCB exposures in utero or during infancy to increased risk of neuropsychiatric deficits in children. Nonclinical studies of legacy congeners found in PCB mixtures synthesized prior to the ban on PCB production suggest that non-dioxin-like (NDL) congeners are predominantly responsible for the developmental neurotoxicity associated with PCB exposures. Mechanistic studies suggest that NDL PCBs alter neurodevelopment via ryanodine receptor-dependent effects on dendritic arborization. Lightly chlorinated congeners, which were not present in the industrial mixtures synthesized prior to the ban on PCB production, have emerged as contemporary environmental contaminants, but there is a paucity of data regarding their potential developmental neurotoxicity. PCB 11, a prevalent contemporary congener, is found in the serum of children and their mothers, as well as in the serum of pregnant women at increased risk for having a child diagnosed with a neurodevelopmental disorder (NDD). Recent data demonstrates that PCB 11 modulates neuronal morphogenesis via mechanisms that are convergent with and divergent from those implicated in the developmental neurotoxicity of legacy NDL PCBs. This review summarizes these data and discusses their relevance to adverse neurodevelopmental outcomes in humans.

We developed and applied a multidisciplinary approach to the impact of an accidentally spilled acid on the underlying geomedia and subsurface environment, based on the concept of geoecosystem. We used mineralogical, geochemical, microbiological, and ecotoxicological techniques to identify and assess the multiple aspects involved. First, we constructed a conceptual model for the acid interactions with the underlying subsurface environment by introducing the concept of a geoecosystem—a multicomponent system composed of inorganic, organic, and biological components to describe the subsurface environment. Second, we designed and manufactured a two dimensional cell to visualize acid transport through geomedia. Third, we hypothesized that the acids are neutralized through dissolution of minerals and protonation of functional groups on the surfaces of minerals and organic matter. We tested this hypothesis by conducting batch-type geomedia-acid reaction and surface titration experiments. Fourth, we observed changes in soil microbial communities before and after the acid exposure and neutralization treatment. Fifth, we performed flow-through experiments using columns packed with soil samples pre-contaminated with arsenic to investigate potential longer term, secondary effects of remnant acids on geoecosystems. Finally, we conducted ecotoxicological investigations using various geomedia and observed that suitability of the geoecosystem as a habitat deteriorated to different degrees depending on the respective systems’ acid neutralizing power. We conclude that a holistic understanding of the interactions among the multiple components of geoecosystems and subsequent estimation of the influenced area requires a multidisciplinary approach such as those used in this study. Based on the findings of this study, we propose geoecosystems’ vulnerability defined as the reciprocal of their acid-neutralizing capacity against the moving acid fronts and present this concept as central to a quantitative assessment of the impact of acid spills on geoecosystems. We also inventoried the essential components, factors, and parameters necessary in developing geoecosystems’ acid vulnerability assessment system.

Plastic pollution has enormous impacts on freshwater and marine ecosystem health, and it is one of the topmost environmental concerns of the current geological period (i.e. the Anthropocene). Thus, the goal of our study was to provide baseline information and bridge the information gap on the occurrence of microplastics (MPs) in African freshwater systems, using two tributaries of the Gulf of Guinea (Ogun and Osun Rivers) in Nigeria as a case study and three freshwater insect species of different feeding guilds as bioindicators. A total of 29 individuals of the insect species were chemically digested and subsequently analysed for MP presence under a digital microscope and a micro-Fourier-transform infrared (μFTIR) spectroscope. Collector-gatherers (Chironomus sp. and Siphlonurus sp.) recorded the highest MP load per gram wet weight, while the predatory Lestes viridis recorded the lowest. The highest diversity of polymers was recorded in Chironomus sp. of Ogun River, i.e. styrene ethylene butylene styrene, acrylonitrile butadiene styrene (ABS), chlorinated polyethylene, polypropylene (PP), and polyester, while two polymers each were recorded in Siphlonurus sp. (i.e. polyester and ABS) and L. viridis (i.e. polyester and PP) of Osun River. We conclude that collector-gatherers like Chironomus sp. and Siphlonurus sp. could be best employed as MP bioindicators in freshwater systems. However, their suitability as MP bioindicators should be further investigated in different freshwater ecosystems worldwide. Graphical abstract

Currently, to reduce the use of nonrenewable energy sources in energy matrices, some industries have already incorporated biomass as a source of energy for their processes. Additionally, filters are used in an attempt to retain the particulate matter present in exhaust gases. In this work, the emission gases of a cashew nut shell (CNS) combustion reactor and the deleterious effects on the respiratory system of mice exposed to gaseous fraction present in CNS emissions (GF-CNS) are analyzed. The system for CNS combustion is composed of a cylindrical stainless steel burner, and exhaust gases generated by CNS combustion were directed through a chimney to a system containing two glass fiber filters to retain all the PM present in the CNS exhaust and, posteriorly, were directed to a mice exposure chamber. The results show changes in the variables of respiratory system mechanics (G, H, CST, IC, and PV loop area) in oxidative stress (SOD, CAT, and NO₂⁻), as well as in the histopathological analysis and lung morphometry (alveolar collapse, PMN cells, mean alveolar diameter, and BCI). Through our results, it has been demonstrated that even with the use of filters by industries for particulate material retention, special attention should still be given to the gaseous fraction that is released into the environment.

In recent years, honeybees and bee products such as pollen and honey have been used as bioindicators for monitoring environmental pollution. Unfortunately, there are few studies about polychlorinated biphenyl (PCB) concentrations in honeybees and bee products from Turkey. Honeybee and pollen samples were taken between May and September 2017, and honey samples were taken between July and September 2017 at urban and semi-urban areas in Bursa (Turkey). PCB concentrations measured by gas chromatography-microelectron capture detector (GC-μECD) were found to be 135.46 ± 6.53, 81.47 ± 23.52, and 106.35 ± 21.60 ng g⁻¹ dry weight (dw) for honeybee, pollen, and honey samples in the urban area, respectively; and 126.35 ± 26.54, 67.57 ± 27.34, and 118.88 ± 55.28 ng g⁻¹ dw for honeybee, pollen, and honey samples in the semi-urban area, respectively. Pearson correlation was made between meteorological parameters and pollutant concentrations. According to the correlation results, a significant relationship was found between the pollen and honey results and the total cloudiness and temperature in the semi-urban area. The coefficient of divergence (COD) and Pearson correlation coefficient (PCC) methods were applied to determine the similarities and differences between the pollutant concentrations and sources of the two areas and the temporal variation. According to these two methods, PCB concentrations and emission sources in honeybee and pollen samples in urban and semi-urban areas were generally different in May and June, and similar in August and September.

The measured gross alpha and gross beta activities in the edible muscle tissues of eleven selected marine species along the coast of North Vietnam varied from 10.2 ± 1.5 to 73.2 ± 8.1 Bq/kg (wwt) and from 10.6 ± 0.4 to 68.8 ± 2.8 Bq/kg (wwt), respectively. The lowest gross alpha activity was recorded for bigfin reef squid (Sepioteuthis lessoniana) as a result of its carnivorous diet, and the highest alpha activity was noted for blood cockle (Anadara granosa) as a result of its omnivorous diet. However, the gross beta activities in both carnivorous and omnivorous species were similar. The highest and lowest gross beta activities were observed for narrow-barred Spanish mackerel (Scomberomorus commerson) and for bigfin reef squid and squid (Teuthida), respectively. All three aforementioned species have carnivorous diets. The calculated annual committed effective dose resulting from the consumption of 25 kg of muscle tissue per year varied from 192 to 1375 μS with an average of 689 μS.

Many of South Africa’s freshwater impoundments are compromised by pesticide pollution, and the Roodeplaat Dam, near Pretoria, is no exception. This paper is, to the best of our knowledge, the first report of the herbicides Dacthal, metribuzin, simazine, tebuthiuron, terbuthylazine, and the fungicides azoxystrobin, carbendazim, epoxiconazole, metalaxyl (Ridomil), propiconazole, pyrimethanil and thiabendazole in a South African freshwater impoundment. This short note reports on the screening results of water and muscle tissue samples against a comprehensive library of pesticides, herbicides and fungicides in the polluted Roodeplaat Dam. Muscle samples of Oreochromis mossambicus screened positive for p,p'-DDE and p,p'-DDD and for DCPA (chlorthal-methyl). The muscle tissue of Clarias gariepinus screened positive for p,p'-DDE and p,p'-DDD, chlorpyrifos, trans-chlordane, DCPA and terbuthylazine. The presence of these pesticides, herbicides and fungicides in this impoundment is of great concern as there is substantial evidence of adverse health effects in fish exposed to these chemicals.

Water hyacinth (WH) has high tolerance in extreme environmental conditions. Here, we examined the potentials of WH (Eichhornia crassipes (Mart) solms) to remove excess nutrients from sewage wastewater. We used four prototypes of water systems: prototypes A (WH + underlay water) and C (WH + sewage water), whereas prototypes B and D were experimental control for A and C, respectively. For prototype A, the percentage removal efficiencies (%Rₑ) for nitrate and phosphate achieved were 75.12 ± 4.22% and 78.90 ± 8.72%, respectively, with a pH increase from 6.29 to 7.69; whereas for prototype C, the values were 54.7 ± 8.11% and 86.10 ± 7.34%, respectively, with a pH decrease from 8.13 to 7.15. For the 3-week retention time, the biomass weight increased in both prototype A (33.26%; [Formula: see text] rate = 15.46 g/week) and prototype C (26.43%; [Formula: see text] rate = 12.54 g/week). Further, the respective mechanical strength and nutritional values of the WH’s fiber and the organic extracts were examined. The air-dried WH stem showed an average tensile stress of 0.04 MPa on a load at maximum stress of 137.1 N. By comparison, a strand of WH has a tensile strength of 14 MPa, inferior to 15, 61, and 400 MPa shown by timber, wood, and steel, respectively. However, by knitting, four strands of WH yielded a much-improved tensile strength of 315 MPa. Finally, a gas chromatography-mass spectrometer analysis of the plant’s extract showed that it contains 35.51% oleic acid, a nutritional extract of high value. Thence, we established a profound economic significance of WH, a macrophyte with latent immense benefits.

Based on expectancy valence theory, people’s behavior is affected by their self-perception and the external environment. In rural China, policy instruments as robust external environment factors have a strong effect on waste separation behavior (WSB). The purpose of the paper is to explore the influencing mechanism of policy instruments (infrastructure and information) on perceived value (perceived benefit and perceived cost) and waste separation behaviors. The data were collected from 689 rural households of Shaanxi province in China, and analyzed by using structural equation model (SEM). According to the results, the mediation effect proves that policy instruments not only can affect WSB directly but also can affect it indirectly through the perceived value. Specifically, information and infrastructure influence the perceived benefit positively and the perceived cost negatively, and information and infrastructure have an indirect effect on WSB through the mediation effect of the perceived cost. Second, policy instruments have a stronger effect on rural people’s waste separation behavior than perceived value. Specifically, infrastructure has the most important impact on waste separation behavior, followed by information and then perceived cost. Third, the perceived cost is significantly negatively related to WSB, and perceived benefit has a positive effect but is statistically insignificant. It has a practical implication for the government. Providing sufficient infrastructure and launching effective information activities could improve the perceived benefit including biospheric, egoistic, social-altruistic, and reputation; and reduce the perceived cost of time, physical, learning, and money, which could then induce rural households to engage in WSB.