Environmental Contamination and Toxicology

The Adsorption Behavior of Atrazine in Common Soils in Northeast China Abstract The objective of this study was to evaluate the adsorption capacity of atrazine and the effects of different environmental conditions such as temperature, pH, Ca2+ and biochar on the adsorption characteristics of atrazine in different types of soil using the intermittent adsorption method. The kinetic experiment showed that the adsorption of atrazine in albic, black and saline–alkaline soils reached equilibrium within 24 h. In the thermodynamics experiment, the Freundlich model effectively described the adsorption characteristics of atrazine in all three types of soil, indicating that the adsorption process forms multi-molecular layers. Lower soil pH conditions were more favorable for the absorption of atrazine. The addition of appropriate concentrations of Ca2+ or biochar could promote the adsorption of atrazine by the soil. Biochar could promote the fixation of atrazine in soils.

Parasites and Metals in Walleye ( Sander vitreus ) and Northern Pike ( Esox lucius ) from Boreal Montreal Lake (Saskatchewan, Canada): Assessment of Human Health Risks Abstract Industrial activities conducted in Northern Canada have raised concerns among Indigenous communities regarding wildlife contamination and potential consequences for human health. Therefore, an investigation on the chemical (metals/metalloids) and biological (parasite) burden of adult walleye (Sandervitreus) and northern pike (Esoxlucius) from Montreal Lake, Saskatchewan, was conducted to assess health risks related to fish consumption. Dissection revealed that both fishes displayed typical parasite communities, with Eubothrium sp. (Cestoda) and Raphidascarisacus (Nematoda) occurring the most frequently. None of the identified parasite species were infectious to humans. Concentrations of most inorganic contaminants in fish muscle were low and both walleye and pike can be considered healthy components of a balanced diet. However, due to slightly elevated mercury concentrations, excessive daily consumption of these fishes is not recommended, as mercury exposure over time may lead to adverse health effects.

Development and Validation of an Analytical Method for the Detection and Quantification of Bromazepam, Clonazepam and Diazepam by UPLC-MS/MS in Surface Water Abstract The development of analytical methods capable of determining micropollutants is essential for quality control of drinking water. Benzodiazepines, a class of pharmaceuticals with anxiolytic properties, have received increasing attention as micropollutants. The purpose of this study was to develop an analytical method for determination of three benzodiazepine drugs (bromazepam, clonazepam and diazepam) in surface water. For the extraction of the matrix analytes, SPE cartridges (C18, 500 mg/3 mL) were used. The method was validated according to the quality criteria of the USEPA 8000D Validation Guide. The developed and validated method showed recovery values between 57 and 100%, RSD < 20% and R2 > 0.9949. LD ranged between 2.70 and 5.00 ng L−1 for bromazepam and clonazepam respectively whereas LQ was 0.01 μg L−1 for all analytes. The matrix affected the signal intensity of clonazepam thus evidencing the matrix effect by analysis statistic (F test).

Intraspecific Genetic Variation for Lead-Induced Changes in Reproductive Strategies Abstract We aimed to identify genetic variation in the response of reproductive behaviors to lead (Pb2+) exposure. We reared a subset of the Drosophila Genetic Reference Panel (DGRP) inbred lines on control or Pb-treated (500 μM PbAc) medium and tested for differences in copulation latency, copulation duration, and fecundity. Pb exposure decreased fecundity (p < 0.05) and increased copulation duration (p < 0.05) across DGRP lines. We found intraspecific genetic variation in latency, duration, and fecundity in both control and Pb-treated flies, with heritability ranging from 0.45 to 0.80. We found a significant genotype-by-environment interaction for copulation duration (p < 0.05). Genetic correlation matrices revealed significant genetic variation in common between control and Pb-treated flies for each trait (p < 0.05). Our results indicate that intraspecific genetic variation plays a role in Pb susceptibility and emphasize the importance of considering the impacts of variation in susceptibility to Pb pollution.

Multi-pollutant Monitoring in a Rehabilitated Estuary: Elements and Radionuclides Abstract The Golden Horn Estuary, Istanbul, Turkey, had been exposed to untreated industrial discharges and municipal wastewater for over fifty years; however, during the last fifteen years pollution has been reduced due to an extensive rehabilitation campaign. Since sediment is the main accumulation matrix of marine ecosystems, surface sediment samples were collected from the estuary and analyzed for concentrations of some elements and radioactivity. The elements of predominant anthropogenic origin such as As, Cu, Pb, Sb, Sn and Zn and 137Cs were observed in the mid-estuary. Also, elevated geoaccumulation indices for Ag, Cd, Cu and Sb showed that pollution was still occurring in the estuary despite the rehabilitation. There is a huge residential area near the estuary; therefore, people living in this area are affected due to the pollution of the estuary. Thus, the obtained data of the elements and radionuclides are very important for the ecosystem of the Golden Horn.

Spatial Distribution and Potential Sources of Five Heavy Metals and One Metalloid in the Soils of Xiamen City, China Abstract In our study, we collected 146 surface soil samples in Xiamen City and measured the concentrations of five heavy metals (Cr, Cu, Pb, Ni, and Zn) and one metalloid (As). Multivariate statistics, geostatistics and Random Forest methods were applied to identify the potential sources and spatial variation of the six elements. The results revealed that As, Cr, and Ni originated mainly from industrial activities, and higher concentrations were found in developed areas. The amounts of Cu, Pb, and Zn in soils were mainly predetermined by soil parent material and agricultural activities. Besides, the atmospheric deposition rather than industrial activities substantially influenced the accumulation of Pb in the soils near the boundary between Tong’an and Quanzhou City, because there were few industries but many forests in this area. Because of the connections of the six elements with factor values of factor analysis, appropriate and accessible covariates could be used in co-kriging to increase the accuracies of interpolation of heavy metal and metalloid concentrations relative to that in ordinary kriging.

Immobilization Mechanism of Nano-Hydroxyapatite on Lead in the Ryegrass Rhizosphere Soil Under Root Confinement Abstract The immobilization effect and mechanism of nano-hydroxyapatite(NHAP) on Pb in the ryegrass rhizosphere soil were studied by root-bag experiment. The speciation analysis results revealed that the residual Pb concentrations in the rhizosphere soil significantly increased after NHAP application. The acid-soluble and reducible Pb concentrations significantly decreased, indicating that NHAP had obviously immobilized Pb. Meanwhile, NHAP significantly promoted the secretion of tartaric acid from ryegrass roots, resulting the rhizosphere soil pH had been below that of the control group. This helped to relieve the stress of Pb on ryegrass, also promoted the dissolution of NHAP, resulting the formation of stable precipitation with more Pb ions. NHAP increased the rhizosphere soil pH by 0.03 to 0.17, which promoted the conversion of Pb to non-utilizable bioavailability. The total Pb mass balance indicated only a very small proportion Pb transferred to the shoots through ryegrass roots. The formation of pyromorphite by Pband NHAP in soil was accordingly to interpret the dominant mechanism for Pb immobilization.

Species-Specific ( Hyalella azteca and Lymnea stagnalis ) Dietary Accumulation of Gold Nano-particles Associated with Periphyton Abstract Ecological effects of gold nano-particles (AuNP) are examined due to growing use in consumer and industrial materials. This study investigated uptake and movement of AuNPs through an aquatic food chain. Simple (single-species) and diverse (multi-species) periphyton communities were exposed to AuNP (0, 100, 500 µg L−1 treatments). AuNP quickly aggregated and precipitated from the water column, suggesting it is an insignificant route of AuNP exposure even at elevated concentrations. Gold was measured in 100 and 500 µg L−1 periphyton treatments. Gold accumulation was similar between periphyton treatments, suggesting physical processes were important for AuNP basal accumulation. Hyalella azteca and Lymnea stagnalis whole body tissue analysis indicated gold accumulation may be attributed to different feeding mechanisms, general versus selective grazing, respectively. Results suggest trophic transfer of AuNP is organism specific and aggregation properties of AuNP are important when considering fate of nano-particles in the environment and movement through aquatic food webs.

Determination of the Leaching Potential and Residues Activity of Imidazolinone Herbicide in Clearfield Rice Soil Using High-Performance Liquid Chromatography Abstract The residual activity of herbicides may be detrimental to the environment, requiring analysis of the persistent residues in the soil and water. A field study was conducted to measure the residues of Imidazolinone (IMI) in three Clearfield® rice field soils at three different locations in Malaysia. The analyses of IMI in the soil samples were carried out using a high-performance liquid chromatography (HPLC). These herbicides are widely used; however, few studies have been conducted on both residues, especially in the context of Malaysian soil. Residues of imazapic and imazapyr were found to fall within 0.03–0.58 µg/mL and 0.03–1.96 µg/mL, respectively, in three locations. IMI herbicides are persistent in the soil, and their residues remain for up to 85 days after application. A pre-harvest study was suggested for these herbicides on water, which will provide a clearer indicator on the use of IMI in Clearfield® rice fields.

Phytoremediation of Three Herbaceous Plants to Remove Metals from Urban Runoff Abstract Phytoremediation experiments were carried out to assess the ability of different herbaceous buffer strips to absorb metals. Results revealed the Medicago sativa buffer strip had the best removal capacity for copper, lead, and cadmium in the runoff and seepage flow. Copper and lead content in M. sativa were significantly higher than in Lolium perenne and Poa pratensis (p < 0.05). Cadmium content in P. pratensis was significantly higher than in L. perenne and M. sativa(p < 0.05). Total accumulation of copper and lead in M. sativa buffer strips was 13.45 mg kg−1 and 1.01 mg kg−1, respectively. Total cadmium accumulation was approximately 0.50 mg kg−1 in both M. sativa and P. pratensis. Overall, results indicated that using M. sativa in the buffer strips was optimal for the remediation of copper, lead, and cadmium in sewage water.