Toxicología ambiental y analítica

The present study was undertaken to determine the pre harvest interval (PHI) for quinalphos in Eggplant, Cabbage and Yard long bean; malathion in Eggplant, Yard Long bean and Cauliflower; cypermethrin in Tomato and Yard long bean; and diazinon in Eggplant and Yard long bean depending on Maximum Residue Limit (MRL) set by FAO/ WHO. Five supervised field trials were conducted and sprayed with the field dose (2 ml/L of water) of each pesticide except cypermethrin (1 ml/L of water). Samples were collected at 0, 1, 3, 5, 7, 10, 12, 15 and 18 days after spray. The collected samples were analyzed using Gas Chromatography (GC) coupled with Flame Thermionized Detector (FTD) and Electron Capture Detector (ECD) for the determination of pesticide residues. The level of residues were above MRL up to 10 DAS for quinalphos in Cabbage, 7 DAS in Eggplant, 5 DAS in Yard long bean; for malathion 5 DAS in Yard long bean and Eggplant, 7 DAS in cauliflower; for diazinon 5 DAS in Yard long bean and Eggplant; and 3 DAS for cypermethrin in Yard long bean and Tomato. The determined PHI for quinalphos were 12 DAS in Cabbage and 10 DAS in Eggplant and 7 DAS in Yard long bean; For malathion 7 DAS in Yard long bean and Eggplant and 10 DAS in cauliflower; For diazinon 7 DAS in Yard long bean and Eggplant; For cypermethrin 5 DAS in Yard long bean and Tomato.

This study deals with the impact of chronic exposure to cadmium on male and female’s fertility in rats. In fact, some male and female rats are given distilled water for drinking (T: controls), whereas the other ones are given distilled water enriched with chloride cadmium, either 10 (C1 group) or 20 mg/l (C2 group) for 1, 5, 10, 15, 30, 45, 60 or 90 days. In male rats, Cadmium, which induced a pathological change in spermatogenesis, is observed by histological studies: arrest of cell germ maturation, Then, an alteration of the structure of the seminiferous tubes with blockage of spermatogenesis (presence of male gametes without flagella or total absence of spermatozoa and destruction of the sertoli cells, testified by the presence of spans). Then, a decrease of the motility and the number of spermatozoa at the end of the treatment indicates the local cytotoxic effect of cadmium (Cd) on spermatogenesis, inducing an apoptotic phenomenon revealed by borated toluidine blue in the testicular cells, which affects the different stages of spermatogenesis. Serum testosterone level is found to be low at the beginning of the treatment, reaches a peak, then returns to the control values and even exceeds them in spite of the continuation of the treatment. It is therefore a hormonal adaptation to this pollutant. In female rats, the practiced vaginal smears revealed the oestrus phase in all the groups. Exposed females are mated to control males, and fertility is assessed later by counting the number of pregnancies. Fertility is found to be reduced in females of C1 and C2 groups as compared to control females (T group).

In 2006, the Agency for Toxic Substances and Disease Registry received a request to determine whether a cluster of polycythemia vera patients existed in a northeast Pennsylvania community. A significant cluster of PV cases was identified at the nexus of three counties near several hazardous waste sites. The current study evaluated the potential for a select number of environmental contaminants previously detected in the cluster area to induce DNA damage using in vitro assays with hematopoietic stem-cell derived progenitor cells. CD34+ cells were isolated from normal cord blood samples and were cultured for 48-72 hours to generate erythroid progenitor cells. Eighteen compounds were chosen for the assay; arsenic trioxide, benzo(a)pyrene, benzene, methylene chloride, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), trichloroethylene, potassium chloride, ethylbenzene, benzo[k]fluoranthene, styrene, cadmium chloride, hydroquinone, 1,1,1-trichloroethane, sodium cyanide, manganese chloride, chromium oxide, lead oxide, and sodium arsenite. Genotoxicity of the compounds was determined using the comet assay, and toxicity determined via the cell viability assay. Using the comet assay, 16 compounds at 10 nM concentration, induced a significant amount of DNA damage compared to the control. When evaluating whether a dose-dependent relationship was present, seventeen of the eighteen compounds led to greater DNA damage with increasing exposure concentrations. 2,3,7,8-TCDD was particularly potent, inducing DNA damage in virtually all cells at 1 μM. In conclusion, most of the toxins evaluated using the comet assay showed potential to induce DNA damage in hematopoietic cells, and the genotoxic effects were dose-dependent.

In 1943, Los Alamos National Laboratory (LANL) was established as part of the Manhattan project to design atomic weapons. LANL now operates as a multidisciplinary research institution. As part of an ongoing assessment of siterelated ecological risk, organochlorine pesticides, their metabolites, polycyclic aromatic hydrocarbons, polychlorinated biphenyls (PCBs), and 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) were evaluated in western bluebird (Sialia mexicana) and ash-throated flycatcher (Myiarchus cinerascens) eggs relative to a developed but non-industrial reference area; PCBs and TEQs were also evaluated in nestlings. Chemicals were below detection limits in the majority of samples. Western bluebird eggs collected from the study area had significantly lower concentrations of dieldrin, oxychlordane, and trans-nonachlor when compared with eggs from the reference area. No differences were observed in concentrations of dichlorodiphenyldichloroethylene (DDE), dichlorodiphenyltrichloroethane (DDT), and heptachlor epoxide. Ash-throated flycatcher eggs contained higher total TEQ concentrations when compared with western bluebird eggs; however, no differences in concentrations of DDE, DDT, dieldrin, or total PCBs were observed. No differences were observed in total PCBs or TEQs in nestlings between the two species. Western bluebird eggs contained higher levels of total PCBs and TEQs when compared with nestlings; no differences were observed in total PCBs or TEQs between ash-throated flycatcher eggs and nestlings. Chemical concentrations detected in eggs of both species were below levels that are associated with adverse effects reported in the scientific literature, suggesting that concentrations of organic chemicals observed here appear to be at levels causing negligible risks to local bird populations.

Soil contamination by heavy metals, though restricted to surface horizons, based on soil texture are occluded, organically complexed, modified and specifically adsorbed based on anthropogenic sources, resulted in toxicity ramification on human health, has been in vogue as a serious environmental problem for last few decades. A laboratory study was planned due to reduction of Lead, Cadmium and Nickel toxicity by a low-cost soil amendment. Apricot (Prunus armeniaca L.) pit shell an abundant and low cost natural resource in Iran was used to adsorbing some heavy metals from contaminated soil of vegetable farmlands. Different adsorption parameters like adsorbent dose, particle size of adsorbent and time of growing vegetable were studied. Composite soil sample were collected from four randomized farmland locations at three agricultural fields (each one more than 10 hectares), in Yazd county in Yazd Province. Cultivated Leafy vegetables were grown under controlled similar physical conditions, including pH, light and demonized watering. Leaves, roots and soil samples were examined, analyses and studied, at various frequencies for heavy metals.

The presence of heavy metals has been reported in cosmetics and their assessment in these products is of significantly important to protect the users. The objective of this study was to assess the levels of cadmium, lead and zinc in face powders and provide information on the risk associated with human exposure to these heavy metals in the products. The samples were pretreated using dry ashing technique and analyzed by flame atomic absorption spectrophotometer. The level of lead in face powders was below the detection limit while the concentrations of cadmium and zinc ranged from 0.13 to 0.215 mg/kg and not detected to 7.05 mg/kg, respectively. The systemic exposure dosage values for these metals in the products were below their respective provisional tolerable daily intake and/or recommended daily intake values. The margin of safety values were higher than 100 which exhibited that the concentrations of metals observed in these products do not cause substantial health risk to the users.

The toxicity of zinc phosphide-based rodenticide formulated and sold in Nigeria was investigated. Preliminary toxicity study was conducted using 24 rats and based results a dosage of zinc phosphide-based rodenticides 1 g to 200 g feed was adopted for this study. A further batch of 30 albino rats was procured for the main study. The rats were observed for period of 3 and 6 hours. At the end of the time interval, the animals were euthanized under chloroform anesthesia, blood samples were collected into sterile ethylene diaminetetraacetic acid and heparin sample bottles. Kidney and liver organs were collected and stored in 40% formaldehyde. Biochemical parameters, ALT, AST, Creatinine, urea, uric acid and potassium concentrations were enhanced 3 and 6 hours after administration of the rodenticide to the albino rats. There were also elevations for total WBC and PLT values. The enhancement of most of the biochemical and hematological parameters investigated suggest the possible failures of several organs of the rats studied. Histological slides indicated breakdown of cellular matrix compared to the slide obtained for the control. Also, there was congestion of liver sinusoids. The sinusoidal congestion found after 6 hours of ZP administration in this study may be the reason for the markedly elevated ALT and AST levels.

The production and use of silver nanoparticles (Ag NPs) are increasing in the United States and across the globe. The Ag NPs may enter the terrestrial ecosystem with the application of sewage sludge as a fertilizer on agricultural farms. The present study investigated the influence of soil pH on the uptake of Ag NPs by insects. Two insects A. domesticus and T. molitor were selected for the experiment. The insects were exposed to Ag NPs under different soil pH including: 5, 6, 7, 8 (control), and 9. The Ag NPs were characterized prior to the study with transmission electron microscopy, dynamic light scattering, and powder X-ray diffraction techniques. The concentration of silver in insects was measured with inductively coupled plasma-optical emission spectroscopy. Increased levels of silver in insects was observed in normal and alkaline soil as compared to acidic soil treatment groups. Additionally, there was no significant difference due to insect species in the silver uptake.

Purpose: Phthalate esters (PAEs) are commonly detected in agricultural soils of China, which can post potential threats to human health. Understanding their sorption to soils is important in assessing their transport and bioavailability in environment. Limited research focuses on the influence of soil organic carbon (SOC) on PAEs adsorption to soils at different depths and increased dissolved organic carbon (DOC) after adsorption. Materials and Methods: Batch sorption experiments of diethyl phthalate (DEP) to four types of soils were conducted in this study, including black soil, fluvo-aquic soil, paddy soil, and red soil. Total concentration of solute DEP and the concentration of free DEP not sorbed to DOC were measured with HPLC. The UV absorbance of supernatant was measured and specific UV absorbance at 254 nm was calculated for DOC aromaticity. Sorption isotherms of DEP to soil particles were fitted to the Langmuir model and the Freundlich model. Results and Discussion: Partial SOC can dissolve to DOC in solution, and 47.4- 89.4% of total DEP can be sorbed to DOC. Increasing DEP in solution can enhance aliphatic SOC dissolving. The sorption coefficients of DEP are higher to fluvo-aquic soils (Koc for surface soils 1820 L kg-1 and subsurface soils 1388 L kg-1) than to other soils (<520 L kg-1), which indicates that SOC fractions of different soils have varied affinity to DEP. Conclusions: SOC plays an important role in DEP sorption to soil particles. Soil samples from surface layers have higher affinity than those from subsurface layers. DOC from SOC in solution is important for DEP transport in soil, and organic pollution can accelerate SOC dissolving.

In the present study, adsorption of Zn (II), Cd (II) and Hg (II) ions on rice husk ash (RHA) has been investigated in single, binary and tertiary systems. Batch experiments were also carried out for mono- and multi-component systems with varying metal ions concentrations (mg/l) to investigate the competitive adsorption characteristics. Rice husk ash (RHA) has been studied for their adsorption properties pertaining to mono component solutions of metal ions. However, to treat waste water with new materials, their performance needs to be ascertained in multi component system. The scanning electron micrographs (SEM) of rice husk ash surfaces before and after the adsorbent was equilibrated with the metal ions solution, clearly establishes the presence of the metal ions and some surface modifications can be observed on the rice husk ash particles adsorption with (i) surface chemistry of the pellets on the surface of rice husk ash and (ii) inside layers of the rice husk ash. Applicability of the isotherm models namely Freundlish and Langmuir to predict the equilibrium uptake of Zn(II), Cd(II) and Hg(II) in mono, binary and tertiary systems have also been tested.

Mesoamerican nephropathy (MeN), also known as chronic kidney disease of unknown etiology (CKDu), is an unusual form of kidney disease not associated with diabetes, hypertension, or glomerular nephritis. It has a number of known risk factors, none of which adequately explain the skyrocketing prevalence of the disease among sugarcane workers in El Salvador and Nicaragua. In this paper, we narrow the research focus from agricultural chemicals, in general, to glyphosate, in particular, an herbicide routinely used on sugarcane. We explain how glyphosate compellingly contributes to CKDu, by reviewing the evidence for glyphosate’s direct toxicity to kidneys and showing how the herbicide amplifies the damage to kidneys from other known risk factors. Using standard web search on index words and phrases, we gathered and perused a large collection of papers describing the pathology of MeN and associated metrics, on the one hand, and the mechanisms of toxicity of glyphosate in humans, animals and in in vitro studies, on the other hand. We show that glyphosate is used on sugarcane in three distinct ways, with exposure greatest when the herbicide is used as a ripener near harvest time. We identify several pathologies associated with MeN that have been found to be implicated in papers on glyphosate exposure, such as enhancing the growth of Clostridia species and fungus, promoting arsenic toxicity, suppressing the synthesis of adrenocorticotropic hormone (ACTH), disrupting fructose metabolism, and promoting dehydration and high serum urate. A companion paper explains how glyphosate’s substitution for glycine could cause additional renal damage. Together, these two papers strongly suggest that glyphosate is a causative agent in CKDu. Overall, the research literature provides compelling evidence that glyphosate exposure is a significant factor in MeN. Glyphosate usage on crops should be curtailed in order to protect the agricultural worker population from this devastating and life-threatening disease.

Mesoamerican Nephropathy (MeN), also known as Chronic Kidney Disease of unknown etiology (CKDu), is an unusual form of kidney disease affecting agricultural workers in Central America. Its prevalence is alarmingly high among young male sugarcane workers in Nicaragua and El Salvador. The absence of known etiologies for CKD, such as hypertension and diabetes, has led researchers to explore a number of potential risk factors, though none adequately explain the timing and epidemic nature of the disease. In this paper, we explore the idea that glyphosate, an herbicide routinely used on sugarcane, could play a significant causal role in MeN, mediated by its property as an analogue of the coding amino acid glycine. Glyphosate is a glycine molecule with a methyl phosphonyl group attached to its nitrogen atom. Its substitution in place of glycine could disrupt multiple proteins critical for kidney health. Here, we first present prior evidence from the research literature that glyphosate may be substituting erroneously for glycine. In particular, multiple species of both bacteria and plants have mutated to remove a highly conserved glycine residue in the enzyme in the shikimate pathway that is disrupted by glyphosate, and this mutation has caused the enzyme to be completely insensitive to glyphosate. We have identified multiple proteins with key roles related to kidney function, whose disruption by glyphosate substitution for critical glycine residues could explain most of the unique features of MeN. Specifically, glycine substitution in aquaporin, chloride channels, cytochrome C oxidase and collagen, among others, could contribute to dehydration, increased urinary acidification, renal fibrosis, rhabdomyolysis and mitochondrial dysfunction. While the hypothesis that glyphosate could be disrupting protein synthesis is not yet proven, it is remarkable how well it explains multiple features of MeN. Investigations to verify whether glyphosate is in fact disrupting protein synthesis are urgently needed.

This study was conducted to study the yield and some macro-morphological characters of Pleurotus pulmonarius fruit bodies cultivated on Hydrochloric acid (HCl) optimized oil palm bunch (OPB) substrate. Concentrated HCl was diluted in tap water at 0.1%, 0.2%, 0.3%, 0.4% and were used to induce changes on the initial pH (9.5) of OPB to 8.9, 8.2, 7.9, 6.2 and control (9.1) respectively; after soaking for 48 hrs. One way Analysis of variance (ANOVA) and Correlation test were adopted for data analysis. Mean separation was also done by Duncan Multiple Range Test (DMRT) at probability level of 5%. Results showed that 0.1%, 0.2%, 0.3% and 0.4% HCl treated OPB substrates produced P. pulmonarius primordia after 9, 9, 10, 11 and control (12 days) respectively. Results further revealed that 0.4% HCl treated OPB substrate induced the highest (900 g/kg) fruit body yield and Biological Efficiency (90%) while control (493 g/kg and B.E 49.3%) respectively, produced the lowest quantity of fruit bodies. Some macro-morphological characters of harvested fruit bodies revealed that mean cap size (C.Scm) and Weight (wt.g/kg) of fruit bodies were highest (3.83 cm and 3.5 g/kg) in 0.4% HCl treated OPB respectively. Mean Stipe Length (S.Lcm) was highest (2.77 cm) in 0.3% OPB substrate and was significant at p ≤ 0.05. S.L and C.S of fruit bodies as well as C.S and Wt. were significantly correlated while there was no correlation between S.L and Wt. of fruit bodies. HCl was found as a suitable acid buffer for the optimization of the pH of the highly alkaline OPB for cultivation of P. pulmonarius fruit bodies. Oil palm bunch should therefore be adopted in the commercial production of the Oyster mushroom if certified safe for human consumption.

Walnut shell filter materials has strong adsorption and contaminants interception ability, anti-oil immersion, high hardness, good wear resistance and stable chemical properties, its surface was easily polluted by the absorbed crude oil in oily sewage to reduce its filtering and backwashing effect. The surface modification of the walnut shell was the introduction of hydrophilic groups to enhance its hydrophilic oleophobic property; Used different ratio of sulfite to boil the walnut shell at a certain temperature to make a modification on the hydrophilicity of walnut shell surface, the modified filter materials with varying degree of surface modification was obtained. Measured the contact angle between walnut shell and water, the wetting performance was significantly improved, the contact angle was decreased from 95° to 36.75°, the surface properties were changed from lipophilicity to hydrophily. the micropores of surface become smaller, and it was conducive to the accumulation of emulsified oil beads; After filtration treatment of oily wastewater containing polymer, filter oil removal rate was over 78%, the oil removal rate of the modified filter materials was increased by 25% than that of the unmodified filter materials, and oil content in the filtered sewage was below 45 mg/L, the backwashing oil removal effect of modified filter materials increased from 17% to 87%, intercepted oil in the before process of filtration was more easier removed in the after process of backwashing to make the filtering performance regeneration of walnut shell filter materials. In the case of filtration treatment on the same amount of oily sewage its lifetime could be extended more than twice.