Rethinking plastic entrapment: Misconceptions and implications for ecosystem services in coastal habitats.

This study addresses the pressing issue of plastic pollution in coastal and marine ecosystems, challenging the misconception that the entrapment of plastics can be considered as an ecosystem service. We differentiate between essential natural processes that sustain ecological balance and biodiversity and the detrimental accumulation of synthetic polymers. The pathways through which plastics enter these environments-from terrestrial to maritime sources-are examined, alongside their pervasive impacts on crucial ecosystem services such as habitat quality, the vitality of marine species, and nutrient cycling. Our findings highlight the paradox of resilience and vulnerability in these ecosystems: while capable of accumulating substantial amounts of plastic debris, they suffer long-lasting ecological, socio-economic, and health repercussions. We argue for a paradigm shift in management strategies aimed at reducing plastic production at the source, improving waste management practices, conducting targeted cleanup operations, and rehabilitating impacted ecosystems. Emphasizing a comprehensive understanding of plastic pollution is vital for framing effective solutions and necessitates a reevaluation of societal, industrial, and regulatory frameworks. This shift is imperative not only to address current pollution levels but also to safeguard and sustain the functionality of coastal ecosystems, ensuring their ability to continue providing essential services and supporting biodiversity.

Elaboración de una biorresina intercambiadora de cationes a partir de cáscara de plátano o guineo para eliminar metales pesados en agua contaminada / Preparation of a cation exchanger bioresin start from banana peel or guineo to remove heavy metals in polluted water

Esta investigación tuvo por objetivo obtener una bio-resina intercambiadora de cationes utilizando cáscaras de guineo o plátano, la cual reduzca la concentración de metales pesados en agua contaminada. A esta bio-resina se le realizaron pruebas fisicoquímicas: densidad seca aparente, pH y solubilidad en agua y solventes orgánicos. Se evaluó su efectividad filtrando agua contaminada con metales pesados, tales como hierro, cromo y níquel (Fe3+, Cr6+ y Ni2+), variando las condiciones de tiempo de contacto, temperatura y el tipo de cáscara. La cuantificación de la concentración de los metales en el agua filtrada se llevó a cabo por espectrofotometría visible. Se llegó a la conclusión que la bio-resina obtenida es efectiva para disminuir la concentración de metales pesados en agua, teniendo especial afinidad química por el cromo hexavalente; metal pesado que logró remover arriba del 90%. Las condiciones óptimas de operación de la bio-resina son a 30°C y 90 minutos de tiempo de contacto con la muestra. Además, las pruebas fisicoquímicas, permitieron tipificarla preliminarmente como una resina de intercambio catiónico débil con un grado de entrecruzamiento bajo.

This research aimed to obtain a cation exchange bio-resin, using plantain or banana peels, that reduces the concentration of heavy metals in contaminated water. The bio-resin underwent physico-chemical tests like apparent dry density, pH, solubility in water and organic solvents. Its effectiveness was tested by filtering contaminated water with heavy metals such as iron, chromium and nickel (Fe3+, Cr6+ y Ni2+) and by varying contact time conditions, temperature and type of peel. The measure of concentration of metals in filtered water was taken through visible spectrophotometry. We concluded that the resulting bio-resin is effective in reducing the concentration of heavy metals in water, showing special chemical affinity with hexavalent chromium, a heavy metal that was able to remove above 90%. The bio-resin optimum working conditions are 30°C and 90 minutes of contact with the sample. Also, the physico-chemical tests allowed to preliminary typify it as a weak cation exchange resin with a low degree of crosslinking.

Scavenging of nickel and chromium toxicity in Aulosira fertilissima by immobilization: effect on nitrogen assimilating enzymes

The ubiquity of heavy metals in the biosphere results in the introduction of high amounts of toxic metals into the food chain from various sources. In the present study, one of the strongest nitrogen fixing cyanobacterium of the rice fields, Aulosira fertilissima, was subjected to nickel and chromium stress and the ameliorating effect of immobilization was investigated. Cell immobilization could protect the organism's growth against the toxicity of both heavy metals at LC50 as compared to lethal concentrations. The nitrate reductase activity in free cells treated with the metals was substantially inhibited but immobilized cells treated with 0.1 ppm nickel was not affected by the metal treatment. Cell immobilization also resulted in a significant protection against sub-lethal concentration of chromium but to a lesser degree than it did with sub- lethal levels of nickel. Control immobilized cells also had higher Nitrogenase activity than control free cells. Nickel and chromium addition markedly decreased the enzyme activity in free cells but immobilized cells exposed to sublethal concentrations of both metals could overcome this decrease. Glutamine synthetase showed similar response under immobilized conditions compared to free cells with both metals. The addition of algal filtrate in 3:1 ratio further increased the nitrogenase activity compared with immobilized cells treated with sublethal doses of both metals. Immobilization facilitated higher uptake of nickel as compared to chromium. The observations of the present study clearly demonstrate the protective effect of immobilization on Aulosira fertilissima against Nickel and chromium toxicity. Rice field ecosystem thus possess a bidirectional natural metal ameliorating system where Aulosira mats act as a naturally immobilized system and the decay of Aulosira along with other cyanobacteria act as natural chelators protecting the rice plants from deleterious effects of the heavy metals. Most importantly is...

Results based on global experience of monitoring crop protection products in water

The pesticides for which the most expensive data on use are currently available are those applied in agricultural settings. Similarly, the majority of information on pesticide detections in ground water has been collected for pesticides used within predominantly agricultural areas. The available data indicate that the pesticides detected most frequently in ground water are also those used widely in agriculture, namely, the triazines and acetanilides. Some of the more heavily used insecticides and fumigants, such as aldicarb, DBCP, and EDB, have also been among the pesticides detected most often in ground water. For those detected, pesticide detections in ground waters generally become more common with greater use and greater analysis. Direct relations between pesticides detection frequencies and use become more evident when data on pesticide use are aggregated over smaller areas. When pesticide use is assessed at comparatively large spatial areas, low use is typically associated with low frequencies of pesticide detection in ground water, while high use is associated with a broad range of detection frequencies. A comprehensive review of published information on the distribution of pesticides in ground water indicates that pesticides from various chemical classes heve been detected in ground water. Many of these compounds are commonly present at low concentrations in shallow ground water immediately beneath agricultural land. Information on pesticides in ground water is not sufficient to provide either a statistically representative view of pesticide occurence in ground water across various countries or an indication of long-term trends or changes in the severity or extent of this contamination over time.This is largely due to wide variations in analytical detection limits, site selection procedures, and other design features among studies conducted in different countries at different times. Past approaches have not been well suited for distinguishing "point source" from "no-point source" pesticide contamination. Among the variety of natural and anthropogenic factors examined, those that appear to be most strongly associated with the intensity of pesticide contamination of ground water are the depth, construction, and age of the sampled wells, the amount of the recharge (precipitation or irrigation), and the depth of the tillage, proximity to surface water (gw/sw interactions) are responsible for a huge number of detections, since surface run-Off...

O controle de trihalometanos (THM) nas águas de abastecimento público / Control of trihalomethanes in public water supplies

Apresenta uma revisäo bibliográfica, onde foram reunidos grande parte dos fundamentos teóricos sobre o tema. Inclui um conjunto de informaçöes sobre as pesquisas publicadas no período de 1980 a 1988, oriundas de literatura americana. O conjunto de informaçöes apresenta alguns pontos de vista ingleses e canadenses. Destacou-se as técnicas menos difundidas, onde a análise da literatura foi mais aprofundada. Reuniu-se as experiências desenvolvidas pela SABESP nos últimos anos, com informaçöes sobre as pesquisas em andamento e as que se espera por em prática em futuro próximo. Expôs-se um estudo de caso para a Baixada Santista que consistiu em dar-se um tratamento estatístico e discussäo dos resultados de análises dos últimos três anos. A interpretaçäo e conclusöes foram baseadas na parte teórica e nas observaçöes das experiências dos últimos anos.