Environmental Effects Monitoring in Sydney Harbor During Remediation of One of Canada's Most Polluted Sites: A Review and Lessons Learned

This article reviews a comprehensive marine environmental effects monitoring program (MEEMP) comprised of components capable of detecting changes in the marine environment over short or extended temporal scales during remediation of one of Canada's most polluted sites at the Sydney Tar Ponds. The monitoring components included: water and sediment quality, amphipod toxicity testing, mussel tissue, crab hepatopancreas tissue, and benthic community assessments. The MEEMP was designed to verify the impact predictions for the remediation project (i.e., no immediate damage to the marine ecosystem through remediation activities). Some components were capable of providing conclusive data (e.g., sediment and water quality), while others only yielded data that were inconclusive or difficult to attribute to remediation activities (e.g., intertidal community assessments and amphipod toxicity testing). Components that provided only inconclusive results or were difficult to attribute to remediation activities were discontinued, resulting in substantial cost savings during the project, but without compromising the overall objectives of the program, which was to monitor for potential adverse environmental effects of remediation on the marine environment in Sydney Harbor and to verify environmental effects predictions made in the Environmental Impact Statement for the project. The rationale for discontinuing certain MEEMP components and discussion of conclusive results are incorporated into “lessons learned” for environmental remediation practitioners and regulators working on similar large‐scale multiyear remediation projects. © 2014 Wiley Periodicals, Inc.     

Co-pyrolysis of swine manure with agricultural plastic waste: Laboratory-scale study

Manure-derived biochar is the solid product resulting from pyrolysis of animal manures. It has considerable potential both to improve soil quality with high levels of nutrients and to reduce contaminants in water and soil. However, the combustible gas produced from manure pyrolysis generally does not provide enough energy to sustain the pyrolysis process. Supplementing this process may be achieved with spent agricultural plastic films; these feedstocks have large amounts of available energy. Plastic films are often used in soil fumigation. They are usually disposed in landfills, which is wasteful, expensive, and environmentally unsustainable. The objective of this work was to investigate both the energetics of co-pyrolyzing swine solids with spent plastic mulch films (SPM) and the characteristics of its gas, liquid, and solid byproducts. The heating value of the product gas from co-pyrolysis was found to be much higher than that of natural gas; furthermore, the gas had no detectable toxic fumigants. Energetically, sustaining pyrolysis of the swine solids through the energy of the product gas could be achieved by co-pyrolyzing dewatered swine solids (25% m/m) with just 10% SPM. If more than 10% SPM is used, the co-pyrolysis would generate surplus energy which could be used for power generation. Biochars produced from co-pyrolyzing SPM and swine solid were similar to swine solid alone based on the surface area and the ¹H NMR spectra. The results of this study demonstrated the potential of using pyrolysis technology to manage two prominent agricultural waste streams (SPM and swine solids) while producing value-added biochar and a power source that could be used for local farm operations.     

Metal-contaminated potato crops and potential human health risk in Bolivian mining highlands

This study assessed metals in irrigation water, soil and potato crops impacted by mining discharges, as well as potential human health risk in the high desert near the historic mining center of Potosí, Bolivia. Metal concentrations were compared with international concentration limit guidelines. In addition, an ingested average daily dose and minimum risk level were used to determine the hazard quotient from potato consumption for adults and children. Irrigation water maximum concentrations of Cd, Pb and Zn in mining-impacted sites were elevated 20- to 1100-fold above international concentration limit guidelines. Agricultural soils contained total metal concentrations of As, Cd, Pb and Zn that exceeded concentration limits in agricultural soil guidelines by 22-, 9-, 3- and 12-fold, respectively. Potato tubers in mining-impacted sites had maximum concentrations of As, Cd, Pb and Zn that exceeded concentration limits in commercially sold vegetables by 9-, 10-, 16- and fourfold, respectively. Using conservative assumptions, hazard quotients (HQ) for potatoes alone were elevated for As, Cd and Pb among children (range 1.1–71.8), in nearly all of the mining-impacted areas; and for As and Cd among adults (range 1.2–34.2) in nearly all of the mining-impacted areas. Only one mining-impacted area had a Pb adult HQ for potatoes above 1 for adults. Toxic trace elements in a major regional dietary staple may be a greater concern than previously appreciated. Considering the multitude of other metal exposure routes in this region, it is likely that total HQ values for these metals may be substantially higher than our estimates.     

Assessing the ecological condition of streams in a southeastern Brazilian basin using a probabilistic monitoring design

Prompt assessment and management actions are required if we are to reduce the current rapid loss of habitat and biodiversity worldwide. Statistically valid quantification of the biota and habitat condition in water bodies are prerequisites for rigorous assessment of aquatic biodiversity and habitat. We assessed the ecological condition of streams in a southeastern Brazilian basin. We quantified the percentage of stream length in good, fair, and poor ecological condition according to benthic macroinvertebrate assemblage. We assessed the risk of finding degraded ecological condition associated with degraded aquatic riparian physical habitat condition, watershed condition, and water quality. We describe field sampling and implementation issues encountered in our survey and discuss design options to remedy them. Survey sample sites were selected using a spatially balanced, stratified random design, which enabled us to put confidence bounds on the ecological condition estimates derived from the stream survey. The benthic condition index indicated that 62 % of stream length in the basin was in poor ecological condition, and 13 % of stream length was in fair condition. The risk of finding degraded biological condition when the riparian vegetation and forests in upstream catchments were degraded was 2.5 and 4 times higher, compared to streams rated as good for the same stressors. We demonstrated that the GRTS statistical sampling method can be used routinely in Brazilian rain forests and other South American regions with similar conditions. This survey establishes an initial baseline for monitoring the condition and trends of streams in the region.     

Long-term chemical and biological improvement in an acid mine drainage-impacted watershed

Acid mine drainage (AMD) is a common result of coal and metal mining worldwide caused by weathering of metal sulfides exposed during mining. AMD typically results in low-pH, high-metal, high-conductivity water that does not support aquatic life. Chemical water quality improvement does not necessarily lead to rapid biological recovery. Little Raccoon Creek, a major tributary to Raccoon Creek in the Western Allegheny Plateau of Ohio, drains 401 km², has a legacy of AMD that stems from mining activities over more than a century. Since 1999, seven major passive treatments systems have been installed in the watershed to a total of over $6.5 million. This study analyzes the hourly water quality data collected at a United States Geological Survey gage station alongside trends in fish and macroinvertebrate communities. Both fish and macroinvertebrate communities have shown a statistically significant improvement in the lower reaches of Little Raccoon Creek since treatment began. Long-term chemical monitoring shows a significant increase in pH, but no significant change in conductivity. The conductivity data is well correlated with sulfate concentrations and discharge, while the pH is well correlated with net  alkalinity data, but not with discharge. Significant investment in passive treatment systems and land reclamation has decreased the percent occurrence of pH measurements below the target of 6.5 and has led to recovery of both fish and macroinvertebrate communities in the downstream reaches of Little Raccoon Creek. Long-term monitoring has proven to be a valuable tool to assess success of a high-cost remediation program.     

Occurrence of naproxen,ibuprofen, and diclofenac residues in wastewater and river water of KwaZulu-Natal Province in South Africa

The present paper reports a detailed study that is based on the monitoring of naproxen, ibuprofen, and diclofenac in Mbokodweni River and wastewater treatment plants (WWTPs) located around the city of Durban in KwaZulu-Natal Province of South Africa. Target compounds were extracted from water samples using a multi-template molecularly imprinted solid-phase extraction prior to separation and quantification on a high-performance liquid chromatography equipped with photo diode array detector. The analytical method yielded the detection limits of 0.15, 1.00, and 0.63 μg/L for naproxen, ibuprofen, and diclofenac, respectively. Solid-phase extraction method was evaluated for its performance using deionized water samples that were spiked with 5 and 50 μg/L of target compounds. Recoveries were greater than 80% for all target compounds with RSD values in the range of 4.1 to 10%. Target compounds were detected in most wastewater and river water samples with ibuprofen being the most frequently detected pharmaceutical. Maximum concentrations detected in river water for naproxen, ibuprofen, and diclofenac were 6.84, 19.2, and 9.69 μg/L, respectively. The concentrations of target compounds found in effluent and river water samples compared well with some studies. The analytical method employed in this work is fast, selective, sensitive, and affordable; therefore, it can be used routinely to evaluate the occurrence of acidic pharmaceuticals in South African water resources.     

The use of ultrasound-assisted anaerobic compost tea washing to remove poly-chlorinated dibenzo-p-dioxins (PCDDs), dibenzo-furans (PCDFs) from highly contaminated field soils

The remediation of dioxin-contaminated soil of a specific coastal area previously employed for the manufacture of pentachlorophenol (PCP) in southern Taiwan’s Tainan City has attracted much attention of researchers there. This work addresses the possibility of providing an effective and environmentally friendly option for removing PCDD/Fs from soil in that field. Soil screening/sieving was first conducted to assess particle distribution. Fine sand was observed to be the major component of the soil, accounting for more than 60% of the total mass. A combination of ultrasonification and mechanical double-blade agitation was used to facilitate the washing of the soil using the biosurfactant anaerobic compost tea. More than 85 and 95% of total removal efficiencies were achieved for moderately and highly contaminated soils after 6 and 10 washing cycles, respectively, under ambient temperature, a soil/liquid ratio 1:2.5, 700 rpm, and over a relatively short duration. These results were achieved through the collision and penetration effects of this combined treatment as well as PCDD/F partitioning between the particles and anaerobic compost tea. This study represents the first to report the use of anaerobic compost tea solvent to wash soil highly contaminated by dioxin. It was concluded that anaerobic compost tea, rich in non-toxic bio-surfactants (e.g., alcohols, humic acids), can be used to improve bioavailability and bioactivity of the soil making bio-attenuation and full remediation more efficient.     

Biodegradation characteristics of organic matters in swine carcasses under different initial operating conditions of simulated anaerobic lysimeter

This study was aimed to investigate the biodegradation characteristics of organic matters in swine carcasses. The lysimeters were simulated with different initial operating conditions: 30 % volumetric moisture content and no sludge addition for lysimeter A (control), 30 % volumetric moisture content and anaerobic sludge addition for lysimeter B, and 40 % volumetric moisture content and anaerobic sludge addition for lysimeter C. The degradation efficiency (18.4 %) of lysimeter B was higher than that (15.2 %) of lysimeter A due to anaerobic sludge addition. Lysimeter B showed higher CH₄ yield (15.6 L/kg VS) and CH₄ production rate (0.41 L/kg VS days) compared to lysimeter A by 31 % and 14 %, respectively. In addition, the degradation efficiency improved from 18.4 % (lysimeter B) to 26.3 % (lysimeter C) by increasing volumetric moisture content. The CH₄ yield (22.9 L/kg VS) and CH₄ production rate (0.68 L/kg VS days) of lysimeter C were higher than those of lysimeter B, respectively. Total organic carbon (TOC) removed in lysimeter C was converted to leachate (20.3 %) and gas (6.0 %), whose values were higher than those of lysimeter A and B. These results demonstrated that the proper control of initial operating conditions could accelerate the anaerobic degradation of organic matters in swine carcasses.