Development and environmental application of a genus-specific quantitative PCR approach for Pseudo-nitzschia species

Quantitative polymerase chain reaction (qPCR) for the identification and quantification of microbes has become a common tool for the study of harmful algal blooms (HABs). We developed a qPCR method for the diatom genus Pseudo-nitzschia. Several species of this genus form toxic blooms through the production of the neurotoxin domoic acid (DA). Outbreaks of toxicity attributed to DA along the US west coast have caused sickness and death of marine mammals and seabirds through food web contamination. The method developed here quantifies Pseudo-nitzschia spp. at low abundances in natural samples, thereby, providing a method to improve our understanding of the environmental conditions leading to blooms of these species. This has been accomplished previously by techniques for identification and quantification that are slow and laborious compared to qPCR. The approach was successfully tested and validated using eight species of Pseudo-nitzschia and 33 non-target organisms and employed to follow local bloom dynamics.     

Solid beef cattle manure application impacts on soil properties and 17β-estradiol fate in a clay loam soil

Livestock manure applied to agricultural land is one of the ways natural steroid estrogens enter soils. To examine the impact of long-term solid beef cattle (Bos Taurus) manure on soil properties and 17β-estradiol sorption and mineralization, this study utilized a soil that had received beef cattle manure over 35 years. The 17β-estradiol was strongly sorbed and sorption significantly increased (P < 0.05) with increasing soil organic carbon content (SOC) and with an increasing annual rate of beef cattle manure. The 17β-estradiol mineralization half-life was significantly negatively correlated, and the total amount of 17β-estradiol mineralized at 90 days (MAX) was significantly positively correlated with 17β-estradiol sorption. The long-term rate of manure application had no significant effect on MAX, but the addition of fresh beef cattle manure in the laboratory resulted in significantly (P < 0.05) smaller MAX values. None of the treatments showed MAX values exceeding one-third of the 17β-estradiol applied.     

WATERSHEDS ARE NOT EQUAL: EXPLORING THE FEASIBILITY OF WATERSHED MANAGEMENT1

ABSTRACT: We propose that some watersheds may be better candidates for watershed management than others. The extent of success of watershed management may depend, in part, on attributes intrinsic to watersheds: scientific feasibility, social feasibility, and motivational feasibility. Using illustrations from New Jersey watershed management efforts, we tie scientific feasibility to the nature of environmental problems and the scientific capability to solve them. Social feasibility encompasses civic infrastructure and engagement. Motivational feasibility includes issue salience linked to values or economic considerations. We suggest that assessments should be made about the viability of watershed management in specific watersheds and that priorities should be developed based on these assessments. Research on watershed management should explore not only how to improve watershed management but also where to conduct it.     

Estimation of vinyl chloride emissions from gasholders and validation of in situ emission reduction methods

Gasholders consist of a floating bell in a tank filled with water. Water provides a seal between the enclosed gas and ambient air. Gasholder emissions come from the contaminated water seal exposed to ambient air and the wet bell wall. The study objectives were to define parameters influencing gasholder emissions, determine the quantities of vinyl chloride (VC) emitted, generate a correlation equation between parameters of influence and mass emissions, and evaluate the efficiency of emission reduction methods. The research project was carried out on a laboratory-scale representation of a gasholder. The classic two-phase resistance model was used successfully to generate a correlation equation, which can be used to calculate the gasholder water seal emissions. A strictly empirical model was generated to estimate the wet wall emissions. Two in situ reduction methods were evaluated with the laboratory installations: floating objects and an oil layer. Both methods showed significant emission reductions, but the oil layer was the most effective. To reduce emissions even further, it is recommended that the water level of the gasholder be set to the lowest achievable level, that a windshield be placed around the water seal perimeter, and that hydrophobic paint be used on the bell wall.     

Effect of dissolved organic carbon on the environmental distribution of nonpolar organic compounds

The effect of dissolved organic carbon on the process of pollutant sorption to aquatic sediments was studied using sediments from the Boonton Reservoir/Rockaway River system in northern New Jersey. Addition of DOC to the aqueous phase reduced the sorption of DDT to sediments, but had no effect on the sorption of Lindane. The effect of the DOC is to increase the amount of DDT in the soluble phase and enable transport of the compound throughout an aquatic system. The apparent influence of DOC on the equilibrium distribution of organic compounds is illustrated by modifying an existing environmental model.     

Seasonal and annual dynamics of harmful algae and algal toxins revealed through weekly monitoring at two coastal ocean sites off southern California, USA

Reports of toxic harmful algal blooms (HABs) attributed to the diatom Pseudo-nitzschia spp. have been increasing in California during the last several decades. Whether this increase can be attributed to enhanced awareness and monitoring or to a dramatic upswing in the development of HAB events remains unresolved. Given these uncertainties, the ability to accurately and rapidly identify an emerging HAB event is of high importance. Monitoring of HAB species and other pertinent chemical/physical parameters at two piers in southern California, Newport and Redondo Beach, was used to investigate the development of a site-specific bloom definition for identifying emerging domoic acid (DA) events. Emphasis was given to abundances of the Pseudo-nitzschia seriata size category of Pseudo-nitzschia due to the prevalence of this size class in the region. P. seriata bloom thresholds were established for each location based on deviations from their respective long-term mean abundances, allowing the identification of major and minor blooms. Sixty-five percent of blooms identified at Newport Beach coincided with measurable DA concentrations, while 36 % of blooms at Redondo Beach coincided with measurable DA. Bloom definitions allowed for increased specificity in multiple regression analysis of environmental forcing factors significant to the presence of DA and P. seriata. The strongest relationship identified was between P. seriata abundances 2 weeks following upwelling events at Newport Beach.     

Pollution prevention at the 3M corporation: Case study insights into organizational incentives, resources, and strategies

3M initiated its “Pollution Prevention Pays” (3P) program in 1975 and is probably the U.S. corporation which has been most identified with using preventive strategies to reduce toxic releases. This case study draws on interviews conducted with representatives of 3M manufacturing plants and corporate staff to provide both an overview of 3M's pollution prevention efforts and explore the organizational dimensions of two types of pollution prevention projects. The analysis addresses two key questions: (1) what do 3M's accomplishments indicate about the potential for pollution prevention approaches? and (2) what are the organizational incentives, resources and strategies which underpin 3M's pollution prevention efforts?     

Solute transport modeling under cultivated sandy soils and transient water regime

Drainable lysimeters offer the possibility to integrate heterogeneous solute leaching conditions caused by row crops and transient water regime, and to conveniently measure water and solute fluxes at the drainage outlet. To compare solute leaching behavior in and around drainable lysimeters operating under a transient water regime in potato (Solanum tuberosum L.) fields, parameters of the convective lognormal transfer (CLT) function model were fitted using bromide (Br-) flux concentrations (Cf) measured in lysimeters and from Br- resident concentrations (Cr) measured in adjacent soil cores. Expected mean values Ez(I) obtained from Cr and Cf CLT parameters were equivalent and well correlated (R2 = 0.78). However, estimated median values mu of the CLT function were smaller when derived from Cr (1.05 to 1.28) compared with Cf (1.23 to 2.14). Most mu values were also smaller than previously reported values for a 30-cm reference depth, indicating that 50% of solute mass would leach more readily in these coarse sandy soils. Higher variance and dispersion of Cr compared with those of Cf could be related to a smaller sampling support (sample size/sampling area) in the case of Cr measured by soil coring, or to disruption of solute transport mechanisms in the repacked lysimeter. Retained Br- in the top soil layer after 12 to 17 cm of cumulative drainage was indicated by measured Cr. Neither CLT function simulated well residual topsoil Cr values, indicating that Br- plant cycling or preferential flow probably interfered even though tuber Br- uptake was relatively small.     

Juvenile growth of the polychaete Nereis virens feeding on a range of marine vascular and macroalgal plant sources

A laboratory experiment was conducted to examine variation of juvenile growth (% d^-1) of the polychaete Nereis virens (Sars) in relation to tidal flat plant species as food sources. We used vegetable materials (algae and vascular plants) which are carried along by tidal currents and are found abundantly at the upper tidal level. Juveniles (2-yr-old) markedly increased in wet weight with the algae Laminaria longicruris (weight-specific growth rate : 1.7% d^-1) and Enteromorpha intestinalis (: 1.6% d^-1) as food sources. A higher value of assimilation efficiency was observed for algal species (L. longicruris 55.1±7.9%; E. intestinalis 54.8±0.5%; Fucus vesiculosus 40.6%) than for marine vascular plants (Spartina alterniflora 26.8±10.9%; Zostera marina 1.4%). The digestion of marine vascular species lasts longer (19 to 38 h) than that of algal species. All these characteristics (growth, assimilation efficiency and duration of the digestive process) seem to correlate positively with lignin and cellulose concentrations in the plant structure.     

Solid beef cattle manure application impacts on soil properties and 17β-estradiol fate in a clay loam soil

Livestock manure applied to agricultural land is one of the ways natural steroid estrogens enter soils. To examine the impact of long-term solid beef cattle (Bos Taurus) manure on soil properties and 17β-estradiol sorption and mineralization, this study utilized a soil that had received beef cattle manure over 35 years. The 17β-estradiol was strongly sorbed and sorption significantly increased (P < 0.05) with increasing soil organic carbon content (SOC) and with an increasing annual rate of beef cattle manure. The 17β-estradiol mineralization half-life was significantly negatively correlated, and the total amount of 17β-estradiol mineralized at 90 days (MAX) was significantly positively correlated with 17β-estradiol sorption. The long-term rate of manure application had no significant effect on MAX, but the addition of fresh beef cattle manure in the laboratory resulted in significantly (P < 0.05) smaller MAX values. None of the treatments showed MAX values exceeding one-third of the 17β-estradiol applied.