Avaliação do parâmetro transmissividade de LNAPLs para caracterização de áreas contaminadas no estado de São Paulo / Assessment of LNAPL transmissivity for contaminated sites characterization in São Paulo state

RESUMO Fases líquidas não aquosas leves (LNAPL), como combustíveis líquidos, estão presentes em muitas áreas contaminadas. Para o gerenciamento dessas áreas, é importante conhecer a mobilidade desse produto, a fim de subsidiar decisões sobre sistemas de remediação e avaliação de risco. Uma alternativa para quantificar a mobilidade é o parâmetro transmissividade de LNAPL, ainda pouco aplicado no Brasil. Esse trabalho avaliou a aplicabilidade desse parâmetro em diferentes áreas contaminadas por LNAPL. Foram realizados testes em três áreas com litologias, tipos de contaminantes e históricos de contaminação distintos. Em alguns testes, não foi possível determinar a transmissividade de LNAPL devido à instabilidade do nível de fluidos, por consequência da operação de sistemas de bombeamento e precipitação, além de problemas operacionais durante a realização do teste. Apesar de ser um teste simples, em alguns casos, a determinação de transmissividade de LNAPL pode ser inviável, principalmente para LNAPL de baixa mobilidade por requerer testes mais prolongados. Os principais fatores determinantes no valor de transmissividade de LNAPL foram a litologia, a posição do poço na pluma e a posição do nível d'água em relação a série histórica. Assim, a transmissividade de LNAPL pode ser um parâmetro útil no gerenciamento de áreas contaminadas, cuja interpretação deve ser feita de forma cautelosa e integrada com outros dados de investigação da área.

ABSTRACT Light non-aqueous phase liquids (LNAPL), such as liquid fuels, are present in many contaminated sites. To adequately manage these sites, it is important to know the product mobility, to support decisions on remediation systems and risk assessment. One alternative to quantify mobility is to quantify the LNAPL transmissivity, which is rarely applied in Brazil. This work aimed to evaluate the applicability of this parameter in LNAPL contaminated sites with different conditions. Tests were performed in three sites, with different lithologies, types of contaminants and contamination histories. In some tests, it was not possible to obtain representative values of LNAPL transmissivity due to fluids levels instability, caused by pumping systems and precipitation events, and operational problems during the tests. Despite being a simple test, in some cases, the determination of LNAPL transmissivity may not be feasible, especially for low mobility LNAPLs, that require long period tests. The main factors controlling LNAPL transmissivity values were lithology, position of the well in the plume, and water level elevation in relation to the historical series. Thus, LNAPL transmissivity can be a useful parameter in the management of contaminated sites, but its interpretation must be made cautiously and integrated with other site data.

Bibliometric analysis on bioremediation of organic contaminated soil and groundwater based on Web of Science database / 生物工程学报

Bioremediation is regarded as one of the most promising methods for the remediation of the soil and groundwater contaminated with organic compounds, mainly due to its cost-effectiveness and environmental friendliness. Using VOSviewer and CiteSpace, we analyzed all publications in this area in core database of Web of Science from 1990 to 2020. The number of publications in this area showed an increasing trend worldwide. The country with the largest total number of publications was USA, followed by China and India. Since 2012, the number of annual publications of China exceeded USA and ranked the first. The top three journals which published papers in this area were Chemosphere, Environmental Science & Technology, and Science of the Total Environment. The Chinese Academy of Sciences published the largest number of papers among the research institutions globally, but the University of California in USA had the highest total citations and h-index. Bibliometric analysis indicated that it is important to develop biotechnologies of bioremediation coupled with chemical/physical remediation to overcome the challenge of low efficiency and long remediation duration associated with bioremediation. In addition, the bioremediation on the mixed contaminants, such as organic contaminants and heavy metals, or mixtures of different organic contaminants, is an important direction. Finally, the rapid development of microbiome technologies will further promote the exploration of mechanisms involved in bioremediation on the genetic and molecular level.

Efectos sobre factores ocupacionales y en el medio ambiente originados por el proceso de descarne a partir del curtido / Effects on occupational factors and environment as a result from rawhide process of the tanning

La ciudad de León cuenta con 500 empresas de curtiduría y 9 dedicadas al procesamiento del sebo cuyos subproductos (descarne) son desechos que se vierten al medio ambiente en grandes cantidades, ya que no representan un interés para su procesamiento y comercialización, lo que ha causado diversos problemas de contaminación en las zonas habitacionales circundantes por el vertido de aguas residuales, residuos sólidos y emisiones atmosféricas. El impacto al medio se puede considerar como adverso, directo y temporal; reversible, pero con un alto costo económico, lo que implica la necesidad de establecer medidas preventivas de control y mitigación. En el presente estudio se describen las etapas delproceso, las buenas y malas prácticas, los procedimientos estándares de operación y los impactos al medio ambiente originados por el inadecuado manejo de los residuos de las industrias sebaderas. Los resultados muestran que el 80 por ciento de las empresas procesadoras carece de sistemas de almacenamiento adecuado y no poseen sistemas de control ambiental. De igual manera, la mayoría de los operarios no cuenta con equipos de protección personal y no existe un adecuado manejo de sustancias utilizadas en los procesos, lo que incrementa el riesgo de accidentes laborales.

The city of León has 500 tannery companies and nine work in fat processing, whose by-product waste (rawhide) is dumped to the environment in tons because there is no interest in processing and commercializing this substance. This situation has caused several contamination problems in surrounding residential areas because ofthe discharge of wastewater, solid waste, and atmospheric emissions. Impact on environment can be considered as adverse, direct and temporal, as well reversible, but excessively expensive, which involvesthe need of established preventive measures of control and mitigation.The present study describes the different stages of the process, goodand bad practices, standard operational procedures, and environmentalimpacts due to the inadequate handling of waste by these companies. Results show that 80 percent of the processing companies lack appropriate storage systems and do not have an environmental control system. Additionally, most of the operators do not have personal protective equipment and there is not a proper handling of the substances used in processes; this increases the risk of work-related accidents.

Application of Photocatalysis in Drinking Water Disinfection / 环境与健康杂志

This article presents the feasibility on application of TiO 2 photocatalysis in drinking water disinfection involving the removal of organic contaminants, inactivation of bacteria and virus. However, the efficacies of TiO 2 photocatalyst in killing of recalcitrant pathogenic protozoans such as Giardia lambia and Cyptosporidium or persistent algae need frurther investigation, and the photocatalytic approach lacks any residual disinfection capacity.