Aquatic microcosm assessment of the effects of tylosin on Lemna gibba and Myriophyllum spicatum

Tylosin is a macrolide antibiotic commonly used for therapeutic treatment and prophylaxis in livestock. As part of a larger ecotoxicological study, the potential phytotoxic effects of tylosin on the rooted macrophyte Myriophyllum spicatum and the floating macrophyte Lemna gibba were assessed under semi-field conditions using 15 12 000-L microcosms. Concentrations of 0, 10, 30, 300 microg/L (n = 3), and 600, 1000, and 3000 microg/L (n = 1) were evaluated as part of separate ANOVA and regression analyses over an exposure period of 35 days. Fate of tylosin was monitored over time in the highest three treatments, where dissipation followed pseudo-first order kinetics with associated half-lives ranging from 9 to 10 days. For both M. spicatum and L. gibba, tylosin was found to cause no biologically significant changes to any endpoint assessed compared to controls at a Type I error rate of 0.1. However, subsequent power analyses revealed that there was generally insufficient power to declare that there were no significant differences at a Type II error rate of 0.2. Conclusions concerning biologically significant impacts were therefore further assessed based on other statistical criteria including comparisons of percent differences between replicated treatments and controls, minimum significant and minimum detectable differences, and coefficients of variation. Based on these criteria, at an ecological effect size of >20% change, tylosin was concluded to elicit no biologically or ecologically significant toxicity to M. spicatum or L. gibba. A hazard quotient assessment indicated that tylosin poses little risk to either species of macrophyte, with an HQ value calculated to be nearly three orders of magnitude below 1 (0.002).     

Trends in fine particle concentration and chemical composition in southern California

Airborne fine particle mass concentrations in Southern California have declined in recent years. Trends in sulfate and elemental carbon (EC) particle concentrations over the period 1982-1993 are consistent with this overall improvement in air quality and help to confirm some of the reasons for the changes that are seen. Fine particle sulfate concentrations have declined as a strict sulfur oxides (SOx) emission control program adopted in 1978 was implemented over time. Fine particle elemental (black) carbon concentrations have declined over a period when newer diesel engines and improved diesel fuels have been introduced into the vehicle fleet. Organic aerosol concentrations have not declined as rapidly as the EC particle concentrations, despite the fact that catalyst-equipped cars having lower particle emission rates were introduced into the vehicle fleet alongside the diesel engine improvements mentioned above. This situation is consistent with the growth in population and vehicle miles traveled in the air basin over time. Fine particle ammonium nitrate in the Los Angeles area atmosphere contributes more than half of the fine aerosol mass concentration on the highest concentration days of the year, emphasizing both the need for accurate aerosol nitrate measurements and the likely importance of deliberate control of aerosol nitrate as a part of any serious further fine particle control program for the Los Angeles area.     

Organochlorine pesticide in water and bottom sediment from Aiba Reservoir (Southwestern Nigeria)

Levels of organochlorine pesticides (OCPs) in water and sediment from Aiba reservoir (Southwestern Nigeria) have been assessed. The aim of the study was to investigate the pollution status of the reservoir water and the bottom sediment. Analytical measurements were carried out for 20 OCPs using standard literature methods. The results showed higher levels of OCPs in the bottom sediment than the water. Significant positive correlations at p<0.05 level were observed for OCPs compounds in water except γ-BHC and endosulfan III, whereas in sediments α-chlordane, dieldrin, endosulfan II, pp-DDT, endrin ketone and methoxychlor did not show any correlation, and aldrin was negatively correlated with pp-DDD. The mean levels of OCPs in both water and sediments were higher, in most cases, than recommended levels for drinking water. Owing to possible toxicity and bioaccumulation tendency of OCPs by the aquatic habitats, the levels of OCPs detected in water and sediment samples could be a source of future health problems. Environmental monitoring of the reservoir is highly recommended.     

Equilibrium,kinetic, and quantum chemical studies on the adsorption of Congo red using Imperata cylindrica leaf powder activated carbon

Leaf powder of spear grass, otherwise known as Imperata cylindrica (IC), was used to prepare activated carbon. The Imperata cylindrica activated carbon (ICAC) prepared was used for the removal of Congo red (CR) dye from aqueous solution. Operation parameters such as initial dye concentration, contact time, adsorbent dosage, pH, and temperature were studied in batch systems. Equilibrium was attained in 150 and 180?min at lowest and highest concentrations, respectively. Maximum adsorption was observed at pH 3. Quantum chemical studies suggested that the protonation of aniline groups and minimal molecular size at planar geometry coupled with electrostatic interaction enhances the adsorption at low pH. Adsorption data were tested using pseudo-first-order and second-order reaction kinetics; the latter was found to be more suitable with a coefficient of determination of ≥0.99. The adsorption process fits Langmuir isotherm model better than the Freundlich model, with a maximum monolayer coverage of 313?mgg^?1. This study shows that ICAC is effective in removing CR dye from aqueous solutions.     

Protective effects of honey against cadmium-induced alteration of some biochemical parameters in rats

The objective of this study is to elucidate on the effect of honey on plasma and organ biochemical parameters of albino rats exposed to acute and sub-chronic dose of cadmium chloride. Uric acid levels, activities of plasma lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities, organ (liver, lungs, and kidney) AST, ALT, superoxide dismutase (SOD), and catalase (CAT) were determined. Plasma uric acid and glucose levels, plasma LDH, AST, and ALT activities were significantly decreased; activities of organ SOD, CAT, AST, and ALT activities were increased in rats administered sub-chronically and acutely with cadmium (Cd). Treatment with honey restored their levels to normal.     

Effect of electronic waste on E. coli genomic integrity: a possible role for metal induced carcinogenesis

Electronic waste (e-waste) poses a major public health threat for developing countries’ populations. The hazards of e-waste are exacerbated by crude recycling methods. In this study, the presence of metals in e-waste samples obtained from Lagos, Nigeria, was assessed using atomic absorption spectrometry. The effect of e-waste on Escherichia coli (E. coli) PQ-37 genomic integrity was evaluated using the SOS chromotest. The means of metal concentrations in the evaluated samples were 16 (cadmium), 7.3 (nickel), 11 (chromium), 20 (lead), 3100 (iron), 90 (zinc), and 2000 (copper) μg_L^?1. Damage to E. coli deoxyribonucleic acid (DNA) increased proportionally to the metal concentrations. Significant amounts of DNA damaging agents from inadequately processed e-waste are present in the studied environment, which will have implications for adverse effects on public and ecological health. Existing policies against dumping of toxic materials in susceptible communities should be enforced.     

Human exposure to 2,4-D following controlled activities on recently sprayed turf.

Total body dose of 2,4-D was determined in 10 volunteers following exposure to sprayed turf 1 hour following application and in 10 volunteers exposed 24 hours following application. Each group of 10 volunteers was divided in half and five wore long pants, a short-sleeved shirt, socks and closed footwear. The other five wore shorts and a short-sleeved shirt and were barefoot. All volunteers were exposed to a 2 by 15 m area of turf for 1 hour during which they alternated between walking and sitting or lying on the turf surface for intervals of 5 minutes. Dislodgeable residues of 2,4-D taken during the exposure sessions showed a rapid decline from 1 hour following application (8%) to 24 hours following application (1%). No detectable residues were found in 4-day urine samples supplied by volunteers except for 3 people who were barefoot and wearing shorts and contacted the turf 1 hour following 2,4-D application. The highest dose was measured in a volunteer who removed his shirt for 30 minutes of the exposure session (426 micrograms). Exposure levels of the other two volunteers who wore the prescribed clothing were lower (153 and 103 micrograms). No detectable residues were found in urine samples supplied by volunteers exposed to sprayed turf 24 hours following application. These results indicate that at the doses measured, exposure to sprayed turf should present little risk in humans. However, people can reduce exposure to non-detectable levels by remaining off treated turf for a period of 24 hours or until after rainfall or irrigation so that dislodgeable residues and therefore potential exposure are essentially zero.     

The impact of atrazine on lake periphyton communities, including carbon uptake dynamics using track autoradiography

Chlorophyll a, freshweight biomass, ash-free dry weight, cell numbers, species richness, community carbon uptake and species-specific carbon uptake were used to monitor the impact of atrazine (2 chloro-4-ethylamino-6-isopropylamino-s-triazine) on an in situ, enclosed periphyton community. Atrazine concentrations ranging from 0.08 to 1.56 mg litre(-1) were used during the 2 years of study. In both 1982 and 1983, there was a shift from a chlorophyte- to a diatom-dominated community. In 1982 the cyanobacterium Cylindrospermum stagnale and the chlorophyte Tetraspora cylindrica developed isolated colonies in the 1.56 mg litre(-1) treatment, indicating resistance to atrazine at this concentration. After atrazine exposure, community productivity was reduced by 21% to 82% in the low to high exposures, respectively. After day 21 productivity returned to control levels. It was shown, using track autoradiography, that the productivities of the larger algae Mougeotia sp., Oedogonium sp., Tolypothrix limbata and Epithemia turgida were the most affected, with reductions of 74.3% to 93.1% that of the controls. All the biotic measures indicated reduced growth after herbicide exposure.     

An appraisal of air quality,thermal comfort,acoustic, and health risk of household kitchens in a developing country

Environmental Science and Pollution Research - Few studies have documented the air quality, noise, thermal comfort, and health risk assessment of household kitchens related to Sub-Sahara Africa. In...     

3-Indolepropionic acid prevented chlorpyrifos-induced hepatorenal toxicities in rats by improving anti-inflammatory,antioxidant, and pro-apoptotic responses and abating DNA damage

Environmental Science and Pollution Research - The application of chlorpyrifos (CPF), an organophosphorus pesticide to control insects, is associated with oxidative stress and reduced quality of...