Lawrence A. Morris

Patterns of Development and Abnormalities among Tadpoles in a Constructed Wetland Receiving Treated Wastewater

Constructed wetlands are promoted for effectiveness at treating wastewater and potential value as wildlife habitat; however, wildlife performance studies in treated wastewater wetlands are limited. We used repeated surveys of larval amphibians along three wetland systems and four reference sites to test the hypothesis that bullfrog tadpoles exposed to direct inputs of treated wastewater develop slower, show a higher frequency of abnormalities, and are smaller at metamorphosis compared to tadpoles from reference ponds. Bullfrog tadpoles from wastewater wetlands were similar in size at metamorphosis compared to tadpoles from reference sites; however, they did show a much higher frequency of abnormalities including severe edema, scoliosis, and extreme calcinosis of soft tissues. Calcinosis was novel to the literature on amphibian abnormalities, the most frequent abnormality, and restricted exclusively to treatment wetlands. Within the constructed wetlands, tadpole development was slower and the frequency of scoliosis and calcinosis was higher in those cells receiving direct inputs of treated wastewater. Our results suggest that portions of constructed wetlands that directly receive treated wastewater may be poor amphibian habitat.

Modelagem da retenção de herbicidas em zonas ripárias

This work aimed to investigate the retention of atrazine and picloram, carried by surface flow, in riparian zones. The surface flow, containing a mixture of both herbicides and kaolin, was then simulated within riparian zones established in pine plantations in north-eastern Georgia, USA. Five plots were established within riparian zones, each with a different slope (2, 5, 10, 15 and 20%). The influence of the initial moisture and of the O horizon condition in herbicide retention was analyzed. An exponential model, commonly used for the estimate of biochemical demand of oxygen (BOD) and nutrients attenuation in overland flow treatment, was used to estimate the attenuation of kaolin and herbicides in riparian zones. The model allowed an accurate estimate of the attenuation of kaolin and atrazine from the surface runoff mixture along 10 m of riparian zone. Generally, slope showed the best correlation with retention of the pollutants presented in the runoff mixture within the riparian zone. The O horizon present in the steeper slopes improved the sedimentation of kaolin and the atrazine adsorption.

Treated Industrial Wastewater Effects on Chemical Constitution Maize Biomass, Physicochemical Soil Properties, and Economic Balance

ABSTRACT Irrigation with treated wastewaters can improve nutrient levels and yield of crops planted on degraded soils. This study evaluated how irrigation with treated industrial wastewater affected biomass production and nutrition of maize plants and physio-chemical properties of a degraded soil. The experiment was conducted in a greenhouse using PVC columns. Treatments consisted of 8 treatments irrigated with clean water and increasing doses of N and P, and 8 treatments with 4 proportions of wastewater irrigation (25%, 50%, 75% and 100% v/v). In general, maize biomass did not differ between irrigation water sources. Differences were largely associated with N nutrition. We observed increases in concentrations of N, P, K, S, Mn, Na, Cu, and Zn in tissue of maize under irrigation with wastewater. The addition of treated wastewater increased the P and Na concentrations, and EC values in the soil without affecting clay dispersion in water. An associated economic analysis indicated that wastewater irrigation would not be economically feasible without including environmental benefits. In southern Brazil, the proportion of irrigation water that is wastewater should not exceed 50%.

Release of Electron Donors during Thermal Treatment of Soils

Thermal treatment of soil and groundwater may provide an in situ source of soluble organic compounds and hydrogen (H2) that could stimulate microbial reductive dechlorination (MRD) at sites impacted by chlorinated solvents. The objectives of this study were to identify and quantify the release of electron donors and fermentable precursors during soil heating and to estimate availability of these compounds following thermal treatment. Fourteen solid materials containing <0.01 to 63.81 wt % organic carbon (OC) were incubated at 30, 60, or 90 °C for up to 180 d, leading to the release of direct electron donors (i.e., H2 and acetate) and fermentable volatile fatty acids (VFAs). Total VFA release ranged from 5 ± 0 × 10-9 carbon per gram solid (mol C/gs) during 30 °C incubation of quartz sand to 820 ± 50 × 10-6 mol C/gs during 90 °C incubation of humic acid, and was positively impacted by incubation time, temperature, and solid-phase OC content. H2 gas was detected at a maximum of 180 ± 50 × 10-9 mol H2/gs, accounting for less than 0.3% of reducing equivalents associated with VFAs released under the same conditions. These findings will allow for more reliable prediction of substrate release during thermal treatment, supporting the implementation of coupled thermal and biological remediation strategies.

Impact of Treated Industrial Effluent on Physical and Chemical Properties of Three Subtropical Soils and Millet Nutrition

ABSTRACT The use of treated industrial effluents to irrigate plants is an alternative, because of nutrients that can increase yield of the agricultural crops. This study was conducted to determine irrigation with treated effluent and gypsum application, which changes the chemical and physical characteristics of soils and the growth and nutrition of millet (Pennisetum glaucum). Thus, an experiment was conducted on PVC columns with three soil classes, Typic Hapludox, Typic Hapludult, and Arenic Hapludult. Nutrient and Na+ concentrations in the millet biomass reflected concentrations of elements in the effluent and soil. In the control, low N levels were found in the biomass, while higher leaf N concentrations were observed, due to irrigation with treated effluent. In the short term, irrigation with treated industrial effluent by controlled application could be an alternative and a complementary source of nutrients for plants, reducing the volume of nutrients and organic materials discharged into water bodies.

Eucalyptus urograndis and Pinus taeda enhance removal of chlorobenzene and benzene in sand culture: A greenhouse study.

ABSTRACT Contamination of soils and groundwater by chlorobenzene and benzene is a common problem at industrial sites worldwide. Since chemical remediation techniques are rarely completely effective, remnants of these contaminants often persist at levels that can still influence ecosystem health. We evaluated the potential of Pinus taeda and Eucalyptus urograndis to accelerate the removal of these compounds from sand/water systems using a completely randomized block greenhouse experiment with a no-plant control. At 2-day intervals, we added a solution containing both chlorobenzene and benzene with the same concentration of 50 mg L−1 (25 mg pot−1), and we monitored leachate concentrations daily. The planted treatments showed greater decrease of contaminants over time. In the absence of plants, the contaminant mass decreased 50–60% during each 2-day cycle; whereas, in the planted treatments the contaminant mass decreased 91–98%. At the end of the experiment the plant roots, leaves, and the sand-substrate each contained less than 1 mg kg−1 of contaminants, which is ∼1% of the total contaminant mass added. In addition, we observed no tree mortality even at concentrations exceeding the aqueous solubility limit of both compounds. Our results suggest both trees are good candidates for remediating chlorobenzene and benzene in soils and groundwater.

Streamside management zone (SMZ) efficiency in herbicide retention from simulated surface flow

Experimento de escoamento superficial, em escala piloto, foi conduzido para se avaliar a eficiencia de zonas riparias (SMZs) na retencao de herbicidas presentes no escoamento superficial gerado em atividades silviculturais. A retencao do herbicida foi avaliada em terrenos com cinco diferentes declividades (2, 5, 10, 15 e 20%), duas condicoes de cobertura do solo (com e sem o horizonte O) e dois periodos de distintos teores de agua no solo (verao seco e inverno umido). Picloram (altamente soluvel em agua) e atrazina (moderadamente adsorvivel as particulas de solo), em concentracoes na faixa de 55 e 35 µg L 1, e caulinita (aproximadamente 5 g L-1) foram misturados com 13.000 litros de agua e aplicados sobre o solo de areas experimentais florestadas de 5 x 10 m. O escoamento superficial foi coletado a 2, 4, 6 e 10 m abaixo do ponto de aplicacao, para que se pudesse avaliar as mudancas nas concentracoes dos contaminantes na suspensao em escoamento. Resultados mostraram que, em media, faixas de 10 m de comprimento de SMZ florestada foram capazes de proporcionar remocao em torno de 25% na concentracao inicial de atrazina e foram, geralmente, ineficientes na remocao de picloram, sendo essa remocao de apenas 6% do total aplicado. As reducoes percentuais de massa, com a infiltracao da suspensao no solo, foram de 36% apara a atrazina e 20% para o picloram. Existe forte relacao entre profundidade do horizonte O e retencao de atrazina e isso sugere que maior contato solido-solucao associado com baixas velocidades de percolacao, em mais profundos horizontes, sao fatores de maior influencia na sorcao do herbicida do que o teor de agua no solo e a inclinacao do terreno.