Toxicología ambiental y analítica

Soils contaminated with hydrocarbons are a serious problem in Nigeria and 70% of such soils are distributed in the Niger Delta. This pot experiment was conducted to determine the interactions of selected soil minerals with organic contaminants from oil spill site. V. subterranean, which potential for stimulating the biodegradation processes of petroleum hydrocarbons was established was employed under the application of two fertilizer types. Iron concentrations were greater than maximum permissible levels, MPL for plants grown in contaminated soil and showed significant variation (p > 0.05) compared to control. Poor zinc concentrations in oil –stressed regimes decreases ear size, slowed growth and maturity of specie. Both iron and manganese became less available at pH > 7 in the absence of organic matter and water (dehydrated due to oil – stress). Concentration of available P was sensitive to soil pH and was more available to Poultry manure – amended soil as pH correction was evident. Plant tissue analyses revealed significantly (p ≤ 0.05) higher increases in accumulation, in comparison with those grown in unpolluted (Control) regimes. Also, soils depleted mineral nutrients were replenished (> 30%) by test plant and best practice. These results indicated that soil minerals affect the dynamics and transformations of organic materials and metabolic processes even in a stressed soil type with modifications due to clean-up.

The main of this research was to study of the efficiency of using granular actived carbon (GAC), Biofilm and biological actived carbon (BAC) columns to treat low concentration of Nickel bearing water streams and the effects of temperature and pH on the adsorption isotherms. Studies were conducted to delineate the effect of pH, temperature, initial Ni and adsorbent concentration on adsorption of Ni2+ by GAC, BAC and Biofilm. Breakthrough curves for removal of 0.5 mg/L Ni2+ by GAC, Biofilm and BAC columns at two contact times were plotted. Batch adsorption and column data are compared, pH is shown to be the decisive parameter in Ni removal for GAC but not for BAC or biofilter. Lagergren plots confirms applicability of first-order rate expression for adsorption of Ni2+ by GAC, BAC and Biofilm.The adsorption coeficient(Kad) for BAC were 2-3 times greater than those with plain GAC. Bed Volumes of water containing 0.5 mg/L Ni2+ treated at breakthrough for GAC, Biofilm and BAC columns were 45 ml, 85 ml and 180 ml of Bed Volume respectively. BAC is more efficient than GAC in the removing of Ni from water environment.

Dissolved organic matter (DOM) affects several processes in soil and water including nutrient cycling, soil and water pollution and CO2 flux between the soil and atmosphere. The aim of this review is to collate and synthesize the literature on the transport processes of DOM in soil. The DOM normally comprises of only a small fraction of soil organic matter (SOM) and originates mainly from the decomposition and solubilization of SOM, which is accumulated on soil surface or soil profile from plant residues and additions of organic amendments such as animal and poultry manures and other biosolids. The DOM is one of the most reactive and mobile SOM fractions and has a major influence on biogeochemical processes in both terrestrial and aquatic environments. Terrestrially borne DOM is subjected to microbial decomposition, photodegradation and adsorption on soil mineral surfaces. It is sorbed on mineral surfaces and high adsorption capacities of clay minerals and oxides for DOM sorption are demonstrated in laboratory studies. However, these high sorption values are not reproduced in limited field studies. Similarly, a few data available on the transport of DOM through macropores also demonstrate the limited control of sorption on DOM retention in soil profile. Thus, there is a need to further investigate the physical and chemical protection mechanisms, as well as the biodegradability of DOM shown in laboratory studies. There is an increasing need to clearly understand the formation, fate and transport of DOM at field scales. The environmental factors such as precipitation and temperature, land use change, land management, and biological factors have profound and discrete influences on DOM dynamics in soil profile. Future research efforts must focus on the assessment of the influences of these factors by conducting field studies in different climatic zones, soils, and land use and management systems.

The release of treated municipal wastewaters to the aquatic environment raises concern about the health impacts on local resident invertebrates such as mussels. The purpose of this study was to examine the immunotoxicity of two types of treated municipal effluents—physico-chemical treated and physico-chemical with additional ozonation—to freshwater mussels. Immunocompetence was followed by tracking changes in hemocyte viability, adherence, phagocytosis, vitellogenin (Vtg)-like proteins and the pro-inflammatory precursors nitric oxide (NOx) production and arachidonate cyclo-oxygenase (COX) activity. The study results revealed that following a two-week continuous-flow exposure to the effluents, a reduction in hemocyte viability, adherence, NOx and COX activities was observed. Vtg like proteins were also increased, highlighting the estrogenic nature of the effluents. A significant correlation was
found between Vtg-like proteins and the phagocytic efficiency index (r=0.34; p<0.001), which suggests that estrogenic compounds may have been involved in the immunocompetence of mussels exposed to municipal effluents. In conclusion, short-term exposures to treated municipal effluents have the potential to impede the immunocompetence of mussels occurring in the vicinity of an effluent dispersion plume.

The aim of this study was to identify the pharmaceutical substances in the waters of the river Volturno in Campania and to identify the genetic alterations that they induce in fish. These vertebrates, living in water, are particularly sensitive to polluting substances dissolved in their water that interact with DNA leading to the formation of additions or breaks, as well as to the loss or chemical modifications of the bases, because they can conserve and concentrate the substances discharged into their natural habitat. A preventive chemical analysis was carried out on the waters of the river Volturno. The results showed the presence of various drugs, among which Carbamazepine, a known antiepileptic and Diclofenac, a non-steroid anti-inflammatory agent. The genotoxicity of these two compounds was evaluated in 155 individuals of Danio rerio using the Comet Test, the Diffusion Assay and RAPD-PCR. The alkaline version of the Comet Test was used for the erythrocytes of the zebrafish to evaluate the presence of DNA breaks of a single strand. Furthermore, the Diffusion Assay was used to estimate the number of apoptotic cells. The specimens were treated with Carbamazepine and Diclofenac at the same average concentrations found in the river Volturno and were killed after three, seven and fifteen days. The results of the Comet Test showed a statistically significant loss of DNA integrity after only three days of exposure to the drugs. Also the percentage of apoptotic cells reached its maximum values after three days of exposure to Carbamazepine and after one week to Diclofenac. By RAPD-PCR the genotoxicity was evaluated at the molecular level. The amplification products from the individuals exposed to the same concentrations of the environmental pollutants showed significant changes in their electrophoretic pattern with respect to the negative controls. The results of all three tests clearly show the genotoxicity of the compounds analyzed.