Peter J. Stoffella

Phytoremediation of heavy metal polluted soils and water: Progresses and perspectives

Environmental pollution affects the quality of pedosphere, hydrosphere, atmosphere, lithosphere and biosphere. Great efforts have been made in the last two decades to reduce pollution sources and remedy the polluted soil and water resources. Phytoremediation, being more cost-effective and fewer side effects than physical and chemical approaches, has gained increasing popularity in both academic and practical circles. More than 400 plant species have been identified to have potential for soil and water remediation. Among them, Thlaspi, Brassica, Sedum alfredii H., and Arabidopsis species have been mostly studied. It is also expected that recent advances in biotechnology will play a promising role in the development of new hyperaccumulators by transferring metal hyperaccumulating genes from low biomass wild species to the higher biomass producing cultivated species in the times to come. This paper attempted to provide a brief review on recent progresses in research and practical applications of phytoremediation for soil and water resources.

Compost Utilization In Horticultural Cropping Systems

Compost utilization in horticultural cropping systems , Compost utilization in horticultural cropping systems , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Land Application of Biosolids in the USA: A Review

Land application of biosolids has proven a cost-effective method of waste disposal by beneficially recycling organic matter and nutrients and improving soil quality; however, it may also pose potential threat to the environment and human health. The purpose of this paper is to provide information on recent research progresses and regulation efforts regarding land application of biosolids, including forms and types and nutrient values of biosolids, environmental and health concerns, and related best management practices (BMPs) of biosolids application, with emphasis on its land application in agriculture. More research and regulations are expected to minimize potential risks of biosolids land application, especially its long-term impacts.

Nitrogen mineralization and transformation from composts and biosolids during field incubation in a sandy soil.

Field evaluation of nutrient release from composts is important to estimate nutrient contribution to crops, potential leaching of nutrients, and, ultimately, to determine optimum application rates, timing, and placement of composts. Field incubation and laboratory analyses were conducted to evaluate

Uptake and distribution of metals by water lettuce (Pistia stratiotes L.)

Background, aim and scopeWater quality impairment by heavy metal contamination is on the rise worldwide. Phytoremediation technology has been increasingly applied to remediate wastewater and stormwater polluted by heavy metals.Materials and methodsLaboratory analysis and field trials were conducted to evaluate the uptake of metals (Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn) by an aquatic plant, water lettuce (Pistia stratiotes L.), and metal distribution in the plant.ResultsThe growth of water lettuce reduced Al, Fe, and Mn concentrations in water by >20%, K and Cu by >10%, and Ca, Mg, Zn, and Na to a lesser extent. A larger proportion of Ca, Cd, Co, Fe, Mg, Mn, and Zn was adsorbed or deposited on the external root surfaces while more Al, Cr, Cu, Ni, and Pb were absorbed and accumulated within the roots.DiscussionWater lettuce has a great ability in concentrating metals from its surrounding water with a concentration factor (CF) ≥102. The bio-concentration factor (BCF), which excludes the part on the root surfaces, is a more appropriate index than the CF for the differentiation of hyperaccumulation, accumulation, or non-accumulation plants for metals.ConclusionsWater lettuce is a hyperaccumulator for Cr, Cu, Fe, Mn, Ni, Pb, and Zn and can be applied for the remediation of surface waters.Recommendations and perspectivesFurther study on the bioavailability of metals in the water lettuce is needed for the beneficial use of metal-enriched plant biomass.

Analysis of bisphenol A, nonylphenol, and natural estrogens in vegetables and fruits using gas chromatography-tandem mass spectrometry.

Bisphenol A (BPA), nonylphenol (NP), and steroidal estrogens in vegetables and fruits were analyzed using gas chromatography with tandem mass spectrometry (GC-MS/MS). Isotope dilution standards were spiked before the extraction to account for extraction inefficiency and loss of analytes during sample workup. Recoveries were >90% for all of the compounds in each matrix. The limit of detection (LOD) ranged from 0.03 to 0.3 μg kg(-1), whereas the limit of quantitation (LOQ) ranged from 0.1 to 1.0 μg kg(-1). All analytes can be monitored in a single GC-MS/MS run with a run time of 20 min. Occurrence of these endocrine-disrupting chemicals (EDCs) in vegetables and fruits from local markets was observed using the established analytical method. BPA was detected in all vegetable and fruit samples, ranging from 0.2 ± 0.1 to 9.0 ± 4.9 μg kg(-1), indicating significant exposure potential for humans. NP was detected in pumpkin, sweet potato, citrus, and apple samples. The concentration of 4-n-NP ranged from 5.3 ± 2.4 to 18.9 ± 8.0 μg kg(-1), whereas that of 4-NP ranged from 5.1 ± 2.6 to 12.2 ± 3.6 μg kg(-1). Concentrations of 17-β-estradiol in vegetables and fruits ranged from 1.3 ± 0.4 to 2.2 ± 1.0 μg kg(-1) except those in tomato and strawberry, in which no 17-β-estradiol was detected. The estimated daily intake of 17-β-estradiol was beyond the recommended acceptable daily intake (ADI) for children as recommended by the Joint FAO/WHO Expert Committee on Food Additives (JECFA).

Development of compost-based media for containerized perennials

Growth of Bolivian sunset (Gloxinia sylvatica (HBK) Wiehler), Brazilian plume (Justicia carnea Lindl.), and golden globe (Lysimachia congestiflora) transplants was evaluated in media containing 25, 50, 75, or 100% compost (derived from biosolids and yard trimmings) as compared to commercial peat-based media. Compost-based media had higher pH, EC, bulk density, particle density and total porosity as compared to peat-based media. The effects of media composition on plant growth and development varied with each species tested. Gloxinia generally were smaller with reduced flower development when grown in compost-based media as compared to peat-based media. However, regardless of media composition, plants were of high visual color and quality. Justicia were similar in size or smaller when grown in compost-based media as compared to peat-based media but flower development was unaffected. However, the visual color and quality of the plants suffered when plants were grown in compost alone. Growth indexes of Lysimachia were similar among media or slightly reduced by 12%. Although, flower development was reduced by 16% in the second trial, plants were still acceptable in terms of visual color and quality, regardless of media composition.

Leaching of Nitrate, Ammonium, and Phosphate From Compost Amended Soil Columns

Compost amendment to agricultural soils has been reported to reduce disease incidence, conserve soil moisture, control weeds, or improve soil fertility. Application rate and placement of compost largely depends on the proposed beneficial effects and the rate may vary from 25 to 250 Mg ha−1 (N content up to 4 percent). Application of high rates of compost with high N or P levels may result in excessive leaching of nitrate, ammonium, and phosphate into the groundwater. Leaching could be a serious concern on the east coast of Florida with its inherent high annual rainfall, sandy soils and shallow water table. In this study, five composts (sugarcane filtercake, biosolids, and mixtures of municipal solid wastes and biosolids) were applied on the surface of an Oldsmar sand soil (in 7.5 cm diameter leaching columns) at 100 Mg ha−1 rate and leached with deionized water (300 ml day−1, for five days; equivalent to 34 cm rainfall). The concentrations of NO3-N, NH4-N, and PO4-P in leachate reached as high as 246, 29,...

Uptake and Accumulation of Cadmium and Zinc by Sedum Alfredii Hance at Different Cd/Zn Supply Levels

Abstract Sedum alfredii Hance has been identified to be a zinc (Zn) hyperaccumulating plant species native to China. In this study, growth responses, uptake and accumulation of cadmium (Cd) and Zn by S. alfredii were examined at Cd/Zn combining supply levels. The results showed that optimal growth for both shoots and roots was found when the plant grew at the Cd/Zn level of 100/500 μmol L−1. The concentrations of Cd and Zn in leaves and Sstems of Sedum afredii H increased with increasing Cd and Zn supply levels. The distributions of the metals in different plant parts decreased in the order: stem > leaf ≫ root for Zn and leaf > stem ≫ root for Cd. The highest concentrations of Zn (23.2 mg g−1) in the stems and Cd (12.1 mg g−1) in the leaves were noticed when the plants were grown at the Zn/Cd levels of 1000/50 and 500/400 μmol L−1, respectively. The maximum Cd and Zn accumulations in the shoots were 5.1 and 11.2 mg plant−1 at the Cd/ Zn combining levels of 400/250 and 100/500 μmol L−1, respectively. Zinc supply levels <500 μmol L−1 enhanced Cd concentrations in stems and leaves at the Cd levels <100 μmol L−1 and Cd concentration in roots at the Cd levels <50 μmol L−1. Cadmium at the supply levels ≥100 μmol L−1 decreased considerably root Zn concentrations for all the Zn levels, slightly increased leaf Zn concentrations at the Zn levels ≥250 μmol L−1, but had minimal effect on leaf Zn concentrations at the Zn levels ≥500 μmol L−1. The results indicate that S. Alfredii has an extraordinary ability to co-tolerate Cd/Zn toxicities, and to absorb and hyper-accumulate Cd and Zn under a range of Cd/Zn combining levels. Zinc addition at relatively low levels could stimulate Cd uptake and translocation, whereas Cd supply enhanced Zn translocation and partition to the shoots. Sedum alfredii is a Zn/Cd hyperaccumulator, which can be a valuable material for further study on the mechanisms of metal uptake and accumulation and for phytoremediation of the soils with Zn/Cd combined contamination.

ASSESSING COPPER THRESHOLDS FOR PHYTOTOXICITY AND POTENTIAL DIETARY TOXICITY IN SELECTED VEGETABLE CROPS

Copper pollution in soils is widespread, and its accumulation in crop products could pose a risk on human health. In this paper, bioavailability of added copper (Cu) and critical Cu concentrations in a vegetable garden soil was evaluated for Chinese cabbage (Brassica chinensis L.), pakchoi (Brassica chinensis L.), and celery (Apiumg graveolens L. var. dulce DC) based on human dietary toxicity. The availability of added Cu in the soil decreased with incubation time, and had minimal change after 10–12 weeks. After incubated for 12 weeks, about 60% of added Cu was not extractable by DTPA. The same crops were also grown in sand culture to determine their responses to solution Cu. Shoot growth was significantly inhibited at Cu concentrations above 10 mg kg−1 in the solution or above 150 mg kg−1 (DTPA-Cu) in the soil. The sensitivity of the crops to Cu toxicity differed among the three vegetable crops. Copper concentration in shoots and edible parts varied with Cu supply levels and type of the vegetables. Negative correlations (r=−0.90–0.99**) were noted between Cu concentration in shoots and fresh matter yields, but Cu concentrations in the edible parts were positively correlated with available and total Cu in the soil (r=0.91–0.99**). The critical tissue Cu concentrations at 10% shoot DM reduction were 19.4, 5.5, 30.9 mg kg−1 for Chinese cabbage, pakchoi, and celery, respectively. Based on the threshold of human dietary toxicity for Cu (10 mg kg−1), the critical concentrations of total and available Cu in the soil were 430 and 269 mg kg−1 for pakchoi, 608 and 313 mg kg−1 for celery, and 835 and 339 mg kg−1 for Chinese cabbage, respectively.