Exponent UK

Harrogate, United Kingdom

Exponent UK

Harrogate, United Kingdom
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Bravo-Linares C.,Austral University of Chile | Ovando-Fuentealba L.,Austral University of Chile | Mudge S.M.,Exponent UK | Loyola-Sepulveda R.,University of Concepción
Fuel | Year: 2013

Spilled oil in the coastal zone may be remediated through biodegradation by naturally occurring bacteria. It is possible to enhance the removal rates through addition of nutrients and biosolvents. These rates may differ within the intertidal area due to many environmental factors including surf washing. Laboratory experimentation is complex when there are so many factors involved. In a simple three factor remediation experiment, the effect of the timing of addition of a biosolvent, the type of nutrients added and the quantity of biosolvent relative to the amount of oil spilled were examined at three levels. A response surface methodology (RSM) was used to identify the key experiments to conduct and 17 separate trials were carried out with high, mid and low tide microcosms. The petroleum hydrocarbons were quantified by GC-MS methods and the data were examined with Design of Experiments (MODDE) and Partial Least Squares (PLS) Statistical (SIMCA-P) software. Different factors were important at the different intertidal locations: at low tide, the timing of application was most important while in the mid tide location, the proportion of biosolvent was most important. Of the nutrient additions, inorganic nutrients alone were more effective than organic forms of nitrogen or mixtures of urea with inorganic nutrients. Overall, the amount of biosolvent was the least important of the three factors examined. The use of RSM significantly reduced the experimental effort needed to investigate the factors and their interactions. © 2012 Elsevier Ltd. All rights reserved.


Munoz J.,Catholic University of the Holy Conception | Mudge S.M.,Exponent UK | Loyola-Sepulveda R.,University of Concepción | Munoz G.,Envitech Ltd. | Bravo-Linares C.,Austral University of Chile
Journal of Environmental Monitoring | Year: 2012

A pipe rupture during unloading led to a spillage of 350-700 tonnes of Caño Limon, a light sweet crude oil, into San Vicente Bay in 2007. Initial clean-up methods removed the majority of the oil from the sandy beaches although some oil remained on the rocky shores. It was necessary for the responsible party to clean the spilled oil even though at this location there were already crude oil hydrocarbons from previous industrial activity. A biosolvent based on vegetable oil derivatives was used to solubilise the remaining oil and a statistical approach to source apportionment was used to determine the efficacy of the cleaning. Sediment and contaminated rock samples were taken prior to cleaning and again at the same locations two days after application of the biosolvent. The oil was extracted using a modified USEPA Method 3550B. The alkanes were quantified together with oil biomarkers on a GC-MS. The contribution that Caño Limon made to the total oil hydrocarbons was calculated from a Partial Least Squares (PLS) analysis using Caño Limon crude oil as the source. By the time the biosolvent was applied, there had already been some attenuation of the oil with all alkanes


Newton A.,Institute of Air Research | Newton A.,University of Algarve | Icely J.,University of Algarve | Cristina S.,University of Algarve | And 26 more authors.
Estuarine, Coastal and Shelf Science | Year: 2014

The paper gives an overview of some of the large, shallow, semi-enclosed coastal systems (SECS) in Europe, These SECS are important both from the ecological and the economic perspective (socio-ecological systems) and provide many valuable ecosystem goods and services.Although some of the systems are transitional waters under the Water Framework Directive, this is not the case for all of the systems. The paper adopts a Driver-Pressure-State-Impact-Response approach to analyse the ecological status, vulnerability and future perspectives of these systems in the context of global change. © 2013.


Wang Z.,Environment Canada | Yang C.,Environment Canada | Yang Z.,Environment Canada | Yang Z.,South-Central University for Nationalities | And 8 more authors.
Journal of Environmental Monitoring | Year: 2012

Total petroleum hydrocarbons (TPH) or petroleum hydrocarbons (PHC) are one of the most widespread soil contaminants in Canada, the United States and many other countries worldwide. Clean-up of PHC-contaminated soils costs the Canadian economy hundreds of millions of dollars annually. In Canada, most PHC-contaminated site evaluations are based on the methods developed by the Canadian Council of the Ministers of the Environment (CCME). However, the CCME method does not differentiate PHC from BOC (the naturally occurring biogenic organic compounds), which are co-extracted with petroleum hydrocarbons in soil samples. Consequently, this could lead to overestimation of PHC levels in soil samples. In some cases, biogenic interferences can even exceed regulatory levels (300 μg g-1 for coarse soils and 1300 μg g-1 for fine soils for Fraction 3, C16-C34 range, in the CCME Soil Quality Level). Resulting false exceedances can trigger unnecessary and costly cleanup or remediation measures. Therefore, it is critically important to develop new protocols to characterize and quantitatively differentiate PHC and BOC in contaminated soils. The ultimate objective of this PERD (Program of Energy Research and Development) project is to correct the misconception that all detectable hydrocarbons should be regulated as toxic petroleum hydrocarbons. During 2009-2010, soil and plant samples were collected from over forty oil-contaminated and paired background sites in various provinces. The silica gel column cleanup procedure was applied to effectively remove all target BOC from the oil-contaminated sample extracts. Furthermore, a reliable GC-MS method in combination with the derivatization technique, developed in this laboratory, was used for identification and characterization of various biogenic sterols and other major biogenic compounds in these oil-contaminated samples. Both PHC and BOC in these samples were quantitatively determined. This paper reports the characterization results of this set of 21 samples. In general, the presence of petroleum-characteristic alkylated PAH homologues and biomarkers can be used as unambiguous indicators of the contamination of oil and petroleum product hydrocarbons; while the absence of petroleum-characteristic alkylated PAH homologues and biomarkers and the presence of abundant BOC can be used as unambiguous indicators of the predominance of natural organic compounds in soil samples. This journal is © The Royal Society of Chemistry 2012.


Mudge S.M.,Exponent UK | Deleo P.C.,American Cleaning Institute | Dyer S.D.,Procter and Gamble
Environmental Toxicology and Chemistry | Year: 2012

Fatty alcohols are naturally produced hydrocarbons present in all living organisms. They are also used in detergent and cosmetic formulations, may be sourced from either petroleum or biological materials, and are typically disposed of down the drain. This study was conducted on the Luray catchment, Virginia, USA, where sales data indicate that approximately 2kg of fatty alcohols from detergent enter the wastewater every day. Reconstructing fatty alcohols in the influent on the basis of sales data indicated a mix of odd and even chain compounds, with C12 being dominant. This profile was influenced strongly by liquid laundry detergents (69%). Sediment and soil samples from the catchment were analyzed by gas chromatography-mass spectrometry and by stable isotope ratio mass spectrometry to determine the δ13C and δ2H signatures. The long-chain components in agricultural soils and river sediments were distinguishable clearly from the algal fatty alcohols produced within the river system. The wastewater was a mixture of fecal and detergent sources of fatty alcohols in a ratio of 75:25%. The fatty alcohols in the effluent had different stable isotopic signatures and chain-length profiles from the influent, indicating that these compounds are not the same as those that entered the treatment plant. The total quantity of fatty alcohols leaving the treatment plant through the effluent pipe was low compared with the input. Analysis of the contributions based on the stable isotopes and profiles suggests that of the fatty alcohols present in the river system downstream of the treatment plant, 84% were derived from terrestrial plant production, 15% came from in situ algal synthesis, and 1% were derived from the effluent. © 2012 SETAC.


Mudge S.M.,Exponent UK | DeLeo P.C.,American Cleaning Institute | Dyer S.D.,Procter and Gamble
Science of the Total Environment | Year: 2014

Samples of influent, effluent and sediments of the receiving waters of eight WWTPs were collected in each of three eco-regions of the USA, a total of 24 facilities. Six different treatment technologies were included to determine the fate of anthropogenic fatty alcohols. The lipids were analysed by compound-specific stable isotope ratio mass spectrometry. There were significant differences in the profiles of the influent among eco-regions, due to differences in the products used within the catchment, the diets of the inhabitants, or in-pipe processes. The sediments of all the receiving waters had similar fatty alcohol profiles, with terrestrial plant matter dominating and secondary contributions from algal and bacterial synthesis. Any contributions from the WWTP liquid effluents were small (<. 1%) and not from the original fatty alcohols suite in the influent. These compounds might have the same chain lengths, but they have different stable isotopic signatures. The type of secondary treatment did not affect the removal of fatty alcohols and the sediments of the receiving waters were dominated by terrestrial plant inputs; the eco-region may affect the profile of the influents but not the stable isotopes. The ecological risk from the use of these particular chemicals, which are disposed of down the drain, is minimal. © 2013.


Mudge S.M.,Exponent UK | Deleo P.C.,American Cleaning Institute
Environmental Sciences: Processes and Impacts | Year: 2014

Fatty alcohol-based surfactants are widely used in detergents and personal care products; they are typically disposed of down-the-drain and are degraded or removed during wastewater treatment. Analytical data had shown concentration and profile differences between regions of the United States. Market sales data were purchased relevant to the sampling dates. In combination with analysis of the fatty alcohol profiles in the top selling products, the influent profiles were reconstructed and compared to the whole U.S. sales data. The per capita usage rate for fatty alcohols through these 4000+ top selling products was 4.9 g per day, with 88% arising from liquid laundry detergents and hand dish detergents. This extrapolates to a national usage of 185000 tonnes per year. There were significant differences in the purchasing habits of the inhabitants across the four regions sampled, although this had minimal impact on the fatty alcohol profile which was dominated by the C12 moiety. The U.S. market was also dominated by petrochemically-sourced chemicals. This market forensics approach using purchased sales data was able to extend our knowledge of the fate of these chemicals without a major (expensive) sampling and analytical campaign. © 2014 The Royal Society of Chemistry.


PubMed | Exponent UK, Procter and Gamble and American Cleaning Institute
Type: | Journal: The Science of the total environment | Year: 2014

Samples of influent, effluent and sediments of the receiving waters of eight WWTPs were collected in each of three eco-regions of the USA, a total of 24 facilities. Six different treatment technologies were included to determine the fate of anthropogenic fatty alcohols. The lipids were analysed by compound-specific stable isotope ratio mass spectrometry. There were significant differences in the profiles of the influent among eco-regions, due to differences in the products used within the catchment, the diets of the inhabitants, or in-pipe processes. The sediments of all the receiving waters had similar fatty alcohol profiles, with terrestrial plant matter dominating and secondary contributions from algal and bacterial synthesis. Any contributions from the WWTP liquid effluents were small (<1%) and not from the original fatty alcohols suite in the influent. These compounds might have the same chain lengths, but they have different stable isotopic signatures. The type of secondary treatment did not affect the removal of fatty alcohols and the sediments of the receiving waters were dominated by terrestrial plant inputs; the eco-region may affect the profile of the influents but not the stable isotopes. The ecological risk from the use of these particular chemicals, which are disposed of down the drain, is minimal.


PubMed | Exponent UK
Type: Journal Article | Journal: Environmental science. Processes & impacts | Year: 2013

Fatty alcohol-based surfactants are widely used in detergents and personal care products; they are typically disposed of down-the-drain and are degraded or removed during wastewater treatment. Analytical data had shown concentration and profile differences between regions of the United States. Market sales data were purchased relevant to the sampling dates. In combination with analysis of the fatty alcohol profiles in the top selling products, the influent profiles were reconstructed and compared to the whole U.S. sales data. The per capita usage rate for fatty alcohols through these 4000+ top selling products was 4.9 g per day, with 88% arising from liquid laundry detergents and hand dish detergents. This extrapolates to a national usage of 185,000 tonnes per year. There were significant differences in the purchasing habits of the inhabitants across the four regions sampled, although this had minimal impact on the fatty alcohol profile which was dominated by the C12 moiety. The U.S. market was also dominated by petrochemically-sourced chemicals. This market forensics approach using purchased sales data was able to extend our knowledge of the fate of these chemicals without a major (expensive) sampling and analytical campaign.


PubMed | Exponent UK
Type: Journal Article | Journal: Environmental toxicology and chemistry | Year: 2012

Fatty alcohols are naturally produced hydrocarbons present in all living organisms. They are also used in detergent and cosmetic formulations, may be sourced from either petroleum or biological materials, and are typically disposed of down the drain. This study was conducted on the Luray catchment, Virginia, USA, where sales data indicate that approximately 2 kg of fatty alcohols from detergent enter the wastewater every day. Reconstructing fatty alcohols in the influent on the basis of sales data indicated a mix of odd and even chain compounds, with C(12) being dominant. This profile was influenced strongly by liquid laundry detergents (69%). Sediment and soil samples from the catchment were analyzed by gas chromatography-mass spectrometry and by stable isotope ratio mass spectrometry to determine the (13)C and (2)H signatures. The long-chain components in agricultural soils and river sediments were distinguishable clearly from the algal fatty alcohols produced within the river system. The wastewater was a mixture of fecal and detergent sources of fatty alcohols in a ratio of 75:25%. The fatty alcohols in the effluent had different stable isotopic signatures and chain-length profiles from the influent, indicating that these compounds are not the same as those that entered the treatment plant. The total quantity of fatty alcohols leaving the treatment plant through the effluent pipe was low compared with the input. Analysis of the contributions based on the stable isotopes and profiles suggests that of the fatty alcohols present in the river system downstream of the treatment plant, 84% were derived from terrestrial plant production, 15% came from in situ algal synthesis, and 1% were derived from the effluent.

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