ABSTRACT Fluorine is released into the water environment naturally or by anthropogenic activities. Fluorine promotes health benefits at low concentrations, but it promotes adverse effects ranging from fluorosis to carcinogenic problems at high concentrations. Although fluorine removal from environment can occur through processes such as adsorption, reverse osmosis, and electrodialysis, the phytoremediation emerges as an accessible and environmentally friendly treatment. This research aimed to study the phytoremediation potential of Landoltia punctata for treating water contaminated with fluorine ion (fluoride). The central composite rotatable design was used to assess the effect of three variables in the process: pH ranging from 5 to 9; phosphate concentration from 0 to 10 mg L−1; and nitrate concentration from 0 to 800 mg L−1. The plants were exposed to a fluoride initial concentration of 5 mg L-1 in 3L-vessels that also included Clark's solution for a period of 10 days. Experimentally, removal of up to 21% was observed for the supplied fluoride. Values of the order of 30% for the removed fluoride mass can be predicted by the obtained model. Landoltia punctata is a promising candidate for the phytoremediation of fluoride-contaminated waters.

RESUMO Objetivou-se neste trabalho avaliar a remediação de água contendo o inseticida clorpirifós, por meio de sistemas alagados construídos (SAC) cultivados com as espécies Polygonum punctatum, Cynodon spp. e Mentha aquatica operados sob diferentes tempos de retenção hidráulica: 24, 48, 96, 144 e 192 h. A eficiência do sistema foi baseada na redução da concentração inicial do clorpirifós e toxicidade da água contaminada. Os resultados mostraram que os sistemas alagados construídos são uma excelente alternativa na biorremediação do inseticida clorpirifós no meio aquoso. Observou-se média geral de eficiência na remoção do inseticida de 98,6%, sendo que no primeiro tempo de retenção hidráulica, 24 h, houve remoção do clorpirifós para valores inferiores ao limite detecção para todos os SAC. Tal resultado é atribuído principalmente aos processos de adsorção e degradação microbiana. Para os ensaios padronizados qualitativos de toxicidade aguda com Daphnia similis, para a maioria das amostras observou-se a redução de toxicidade acima de 80%. Constatou-se que os testes ecotoxicológicos com os efluentes dos sistemas alagados construídos estudados são uma boa opção como indicativo da eficiência dos tratamentos e uma promissora alternativa na complementação de análises físicas e químicas.

ABSTRACT The objective of this study was to evaluate the remediation of water containing the insecticide chlorpyrifos by using constructed wetlands (CW) cultivated with Polygonum punctatum, Cynodon spp. and Mentha aquatica, operated under different hydraulic retention times: 24, 48, 96, 144 and 192 h. The system efficiency was based on reduction of the initial concentration of chlorpyrifos and toxicity of the contaminated water. The results showed that constructed wetlands are an excellent alternative for remediation of the insecticide chlorpyrifos in aqueous medium. It was observed that the average overall removal efficiency of the insecticide was 98.6%, and in the first hydraulic retention time, 24 h, chlorpyrifos was removed to levels below the detection limit in all CW. This result is mainly attributed to adsorption and microbial degradation. For the qualitative standard acute toxicity tests with Daphnia similis, for most samples there was a reduction in toxicity greater than 80%. It was reported that the ecotoxicological tests with the effluents of the constructed wetland are a good option as an indicator of the effectiveness of treatments and a promising alternative to complement the physical and chemical analyses.

RESUMO Estudos relacionados ao aproveitamento de resíduos agrícolas tornaram-se imprescindíveis pela possibilidade de seu uso na produção de mudas de olerícolas e por minimizar o risco de contaminação ambiental decorrente do descarte inadequado. O objetivo do trabalho foi avaliar o crescimento de mudas de tomateiro produzidas em substratos compostos por fibra de coco, casca de ovo e com níveis crescentes de moinha em substituição ao substrato comercial Bioplant. As composições dos substratos testados foram: T0= substrato comercial; T1= 15% de moinha (MO: resíduo da secagem dos grãos de café) + 15% fibra de coco (FC) + 5% casca de ovo (CO) + 65% substrato comercial (SC); T2= 30% MO+ 15% FC + 5% CO+ 50% SC; T3= 45% MO+ 15% FC + 5% CO + 35% SC; T4= 60% MO + 15% FC + 5% CO + 20% SC. Número de folhas, altura de plântula, diâmetro de caule, massa fresca e seca da parte aérea, de raiz e da planta inteira foram avaliados. Os substratos alternativos contendo de 15 a 32% de moinha + 15% fibra de coco + 5% casca de ovo + 48% a 65% de substrato comercial proporcionam os maiores valores de todas as variáveis analisadas. Todas as proporções de moinha estudadas promovem valores das variáveis de crescimento superiores àqueles obtidos quando se usa somente o substrato comercial. O uso de 5% casca de ovo, 15% de fibra de coco, 15 a 32% de moinha e 48 a 65% de substrato comercial é uma alternativa de substrato para produção de mudas de tomate, permitindo um adequado destino a esses resíduos agrícolas.

ABSTRACT Studies concerning the use of agricultural wastes are essential considering they can be employed on seedling production, minimizing the risk of environmental contamination due to inappropriate disposal. We evaluated growth variables of tomato seedlings produced on substrates composed by coconut fiber, eggshell and increasing levels of moinha replacing the commercial substrate Bioplant. The experiment was carried out in a completely randomized design, with five treatments and ten replications, treatments being: T0= commercial substrate; T1= 15% moinha (MO: wastes from the coffee seeds drying) + 15% coconut fiber (FC) + 5% eggshell (CO) + 65% commercial substrate (SC); T2= 30% MO + 15% FC + 5% CO + 50% SC; T3= 45% MO + 15% FC + 5% CO + 35% SC; T4= 60% MO + 15% FC + 5% CO + 20% SC. Number of leaves; seedling height, stem diameter; fresh and dry matter of root, aboveground part and of the whole plant were evaluated. The alternative substrate containing 15 to 32% moinha + 15% coconut fiber + 5% eggshell + 48 to 65% commercial substrate provided the highest values for all analyzed variables. All the proportions of moinha in the substrate promoted growth variables values higher than those obtained when using only the commercial substrate. The use of 5% eggshell, 15% coconut fiber, 15 to 32% moinha and 48 to 65% commercial substrate is an alternative substrate for the production of tomato seedlings, this being a suitable destination for the agricultural wastes.