Low-density Polyethylene Strips Research Articles

Biodegradation of LDPE (low density polyethylene) using bacterial strain

The applications of polyethylene are enormous and they are popular because of their relatively low cost, lack of difficulty in manufacture, adaptability and durability. In the past decade, the increase in the utilization of plastics and the accumulation of polyethylene in the environment all around the globe has drawn the attention of environmentalists and scientists. The plastic materials are commonly derived from petrochemicals extracted from coal and natural gas. They are produced in a wide range in synthetic, semi synthetic organic polymers. The degradation of LDPE film was determined by residual dry weight loss of the LDPE films. The potent strain showed 42.5% degradation ability in 90 d. Degradation of LDPE results in the breakdown of the polymer backbone chain producing CO2 which was checked by gravimetric analysis. Enzyme kinetic studies showed the production of three ligninolytic extracellular enzymes- lignin, laccase and manganese peroxidase by bacterial strain AJ01 in LDPE degradation. Degradation of LDPE strips followed first order kinetics model with a rate constant (R2) of 0.9783 d-1. Estimation of protein from post treated LDPE using bacterial isolate showed a total concentration of 0.440mg/0.1mL and 0.703mg/0.2mL. LDPE degradation was confirmed by using analytical techniques such as SEM which showed changes in the surface topology of LDPE strips and FTIR analysis showed changes in complex chemical structure of LDPE post 90 d of degradation using microorganisms thereby reducing carbonyl index (CI) value.

Optimum conditions for the biodegradation of waste low-density polyethylene strips by bacteria isolated from parts of north central Nigeria

Optimum conditions (Temperature, pH and incubation time) were studied for selected bacterial isolates Pseudomonas aeruginosa1(PA1), Pseudomonas aeruginosa2 (PA2), Bacillus megaterium, Providencia stuarti, Alcaligenes faecalis, Enterobacter hormaechei, Klebsiella pneumonia and Proteus vulgaris to biodegrade low-density polyethylene (LDPE) waste by using Basal Salts Medium (BSM) containing 0.500g LDPE strips (1 cm by 5 cm each) using changes in mechanical properties and weight loss of the strips as indicators for ability of these microorganisms to degrade LDPE. The results revealed that four of the eight bacterial isolates, Pseudomonas aeruginosa1, Pseudomonas aeruginosa2, Bacillus megaterium, and Providencia stuarti showed high ability to degrade the LDPE strips after 8 weeks of incubation in liquid Basal Salts Medium at pH 6.5 -7.5 and 32oC. The tensile strength of the LDPE strips was reduced by 0.047±0.41 MN/M2 (47%) for P. aeruginosa1, 0.040±0.30 MN/M2 (40%) for P. aeruginosa2, Bacillus megaterium, 0.033±0.61 MN/M2 (33%), and Providencia stuarti, 0.027±0.41 MN/M2 (27%). The weight loss of the LDPE recorded for Pseudomonas aeruginosa1 was 19.80±0.04 %, for Pseudomonas aeruginosa2 19.40±0.08 %, 13.40±0.10 %, for Bacillus megaterium and 19.20±0.42 % for Providencia stuarti respectively. There was significant difference in the weight loss of the LDPE strips at pH 6.5 for Bacillus megaterium, Providencia stuarti, Alcaligenes faecalis and Enterobacter hormaechei and at 30-32 oC for Pseudomonas spp., Bacillus megaterium, Klebsiella pneumonia and Proteus vulgaris(P>0.05 %).

Biodegradation of low-density polyethylene (IDPE) by bacteria isolated from dump sites in some metropolitan cities in north central Nigeria

In this study, biodegradation of Low-Density Polyethylene (LDPE) by bacteria isolated from dump sites was evaluated in a liquid Basal Salts Medium. The bacteria, including Psuedomonas aeruginosa, Bacillus megaterium, Providencia stuarti, Alcaligenes faecalis, Enterobacter hormaechei, Klebsiella pneumonia and Proteus vulgaris were isolated from soil samples taken from municipal dump sites in some metropolitan cities in North Central Nigeria, namely, Abuja, Makurdi and Jos and screened for their ability to utilize LDPE using the clear zone method. 0.500 gram waste LPDE strips (1 cm x 5 cm) were placed into a 500 milliliter flask containing sterilized liquid medium at 30 °C and incubated in a rotary shaker for eight (8) weeks. Each bacterium was added to a separate flask. Biodegradation was measured by pH changes of the media and gravimetrically by weight loss of the waste LDPE strips two weekly during the incubation period. The results obtained showed a gradual decrease in the pH of the media originally set at 7.05 with incubation time for all isolated bacteria. Psuedomonas aeruginosa and Providencia stuarti recorded the highest weight loss of the LDPE strips after eight (8) weeks at 19.80±0.04 %, with a final pH of 3.75±0.01 and 19.20±0.42 %, and final pH 4.85±0.01 respectively followed by Bacillus megaterium at 13.40±0.10% and final pH of 3.95±0.01. Klebsiella pnuemonia and Proteus vulgaris recorded the least gravimetric weight loss at 1.40±0.02 %, with a final pH of 4.75±0.01 and 0.80±0.01 %, pH 4.85±0.01 respectively. This work reveals that bacteria play a vital role in the degradation of low-density polyethylene waste in the natural environment. This can be applied to the development of commercial bioreactors in the future for the degradation of polyethylene wastes.

Biodeterioration of low-density polyethylene by mangrove-associated endolichenic fungi and their enzymatic regimes.

Fungal involvement in the biodeterioration of low-density polyethylene (LDPE) has received great attention in recent years. Among diverse groups of fungi, endolichenic fungi (ELF) are adapted to thrive in resource-limited conditions. The present study was designed to investigate the potential of mangrove-associated ELF, in the biodeterioration of LDPE and to quantify key-depolymerizing enzymes. A total of 31 ELF species, isolated from 22 lichens of mangrove ecosystems in Negombo lagoon, Sri Lanka were identified using DNA barcoding techniques. ELF were inoculated into a mineral salt medium, containing LDPE strips and incubated at 28 ± 2°C, for 21 days, under laboratory conditions. After incubation, biodeterioration was monitored based on percent reductions in weights and tensile properties, increments in the degree of water absorption, changes in peaks of infrared spectra and surface erosions using scanning electron microscopy. Out of 31 species, Chaetomium globosum, Daldinia eschscholtzii, Neofusicoccum occulatum, Phanerochaete chrysosporium, Schizophyllum commune and Xylaria feejeensis showed significant changes. Production of depolymerizing enzymes by these species was assayed qualitatively using plate-based methods and quantitatively by mass-level enzyme production. Among them, Phanerochaete chrysosporium showed the highest enzyme activities as (9·69 ± 0·04) × 10-3 , (1·96 ± 0·01) × 10-3 , (5·73 ± 0·03) × 10-3 , (0·88 ± 0·01), (0·64 ± 0·06), (1·43 ± 0·01) U ml-1 for laccase, lignin peroxidase, manganese peroxidase, amylase, lipase and esterase, respectively.

BEHAVIOUR OF SILTY SAND REINFORCED WITH LOW DENSITY POLYETHYLENE (LDPE) STRIPS

In this study, silty sand is reinforced with plastic strips to improve the engineering properties of soil. Sand and silty sand soils have been used as base materials and low-density polyethylene (LDPE) strips as reinforcement materials. The LDPE strips are used in various dimensions (e.g., width ranging from 6 to 15mm and length ranging from 15 to 30mm). The randomly distributed LDPE strips are added to sand and silty sand specimens at varying percentages (e.g., 0.1% to 0.3%) by weight of dry soil specimen. Direct shear tests are performed on sand and silty sand specimens in both unreinforced and reinforced conditions. Stress strain, volumetric strain (e.g., compression/dilation behaviour) and strength envelopes are plotted to investigate the improvement in the shear strength parameter (e.g., internal friction angle). The results show that in sand specimens, the maximum improvement in shearing behaviour has been achieved with strips of 6x30mm in dimensions and at 0.3%. For silty sand specimens, the maximum improvement in shearing behaviour has been achieved with strips of 6x25mm in dimensions and at 0.3%. In addition, it has been observed that reinforced soil specimens increased the values of internal frictional angle compared to unreinforced soil specimens. In sand specimens, maximum increase of 19.72% in internal friction angle (Φ) has been observed with 6x30mm strips at similar percentage. In case of silty sand specimens, the maximum increase in internal friction angle (Φ) has been observed as 19.28% with the addition of strips of 6x25mm and at 0.3%.

Isolation, characterization and optimization of bacterial isolate SARR1 for biodegradation of pretreated low density polyethylene

Accumulation of low-density polyethylene (LDPE) has caused a threat to the environment because of its stable and inert nature as it cannot be degraded easily by microorganisms. Its lightweight, low cost, strength, durability, and its various other applications, have led to the wide usage of the polymer, which is exerting a negative effect on both marine and land biota. The development of an eco-friendly or a promising strategy is needed to reduce LDPE waste from both land and water. In the present study, observations have been made to isolate highly efficient LDPE degrading bacteria. The response surface methodology (RSM) was used to predict the best optimization of media for the degradation of LDPE by isolate SARR1. The isolate SARR1 was selected through primary screening by weight loss method and secondary screening using CO2 evolution test, TTC and MATH Test. The isolate SARR1 showed 6.30 ± 0.25 g/L CO2 evolution. The microbial adhesion hydrophobicity (MATH) was observed during log phase (100 to 56.89 ± 0.97 %) and stationary phase (100 to 82.92 ± 1.24 %). An isolate SARR1 converted the TTC into red coloured insoluble triphenyl formazan (TPF) after incubation of 7 days. The isolated bacteria SARR1 showed 38.3 ± 1.27 % biodegradation efficiency in the pretreated LDPE strips at 37 °C and pH 7.0 under optimized conditions within 30 days of incubation. This bioremediation and biodegradation approach is eco-friendly and safe for the environment. The results of treatment with isolate SARR1 had a potential hope to degrade LDPE at higher rate than natural degradation.

MICROBIAL DEGRADATION OF LOW-DENSITY POLYETHYLENE (LDPE) BY FUNGUS ISOLATED FROM LANDFILL SOIL

A low density polyethylene (LDPE) is one of the hazardous polymers accelerates land and water pollution. Standardizing the protocol for degradation of plastics in an aesthetic approach is a big task. Low density polyethylene polymer can be degraded by microbial enzymes by means of cutting down the molecular chains. Two fungal strains Aspergillus fumigus and Xylaria sp. were showing high degradable activity through the determination of pH variation and carbon di oxide estimation. Aspergillus fumigus and Xylaria sp shows pH variation in the culture media containing LDPE strips after 30 days and was recorded as 6.5 to 8.4 and 6.5 to 7.7 respectively. The efficacy of polyethylene degradation was confirmed further by CO2 estimation of culture filtrate and was recorded as 1.460 g/l in Aspergillus fumigus and 1.350 g/l in Xylaria sp. Surface erosion and the formation of pits and cavities on the surface of the LDPE strips were also observed using Scanning Electron Microscope and significant disappearance in carbonyl peak with respect to the control band absorbance (2361.61 cm-1) and increase or decrease in peak intensity with respect to control indicates structural changes in chemical bond due to degradation process.

Effects of Low-Density Polyethylene (LDPE) Strips on Some Engineering Properties of Cement-Stabilized Lateritic Soils

The study investigated the compaction and strength characteristics of lateritic soils stabilized with 3% cement and waste sachet water-proof (low-density polyethylene, LDPE) strips. Three (3) lateritic samples collected from Ugwuoba, Nawfia, and Okpuno in Enugu and Anambra states of Nigeria were used in the study. Index properties tests on the samples show that they fall within class A-2-6(1) and A-2-4(0) based on the American Association of State Highway and Transportation Officials (AASHTO) and SM/SC based on Unified Soil Classification System (USCS). LDPE strips were varied at 0, 0.25, 0.5, 0.75, 1, 1.5, and 2% based on the dry unit weight of the soil. Results of unconfined compressive strength (UCS) tests show significant improvement in the strength of the soils at 2 % LDPE strips. Statistical analysis also shows that a significant relationship exists between the percentage of LDPE strips, compactive effort, and maximum dry unit weight (MDUW)/optimum moisture content (OMC), UCS of the soils. The tensile and flexural strength of lateritic soil stabilized with 3% cement can be improved optimally by the addition of 2% of low-cost LDPE strips of aspect ratio (AR) of 10 mm  10 mm.

Using diffuse reflectance spectroscopy (DRS) technique for studying biofilm formation on LDPE and PET surfaces: laboratory and field experiments.

Biofilm formation on plastic debris needs to be further investigated, because microorganisms attached to plastics are transferred in all three dimensions to new regions by ocean currents. The current study aims to investigate biofilm formation on plastic strips in aquatic ecosystems using a simple physicochemical method commonly used to characterize solid surfaces, namely, the diffuse reflectance UV-Vis spectroscopy (DRS) method. Using virgin polymers that have not being exposed to the environment as a reference, DRS peaks can be attributed to the microorganisms attached to the polymer surface with time. The polymers tested were low-density polyethylene (LDPE) and polyethylene terephthalate (PET). For LDPE strips for all sampling times in the field, the development of the peaks among 10 similar samples was rather uniform in terms of peak wavelength with time. For PET strips during the early sampling time, the development of the peaks among 10 similar samples was rather uniform in terms of peak wavelength but varied in terms of intensity. This last observation phased out with longer exposure times that the peaks had similar distribution in terms of peak wavelength and intensity. Similar experiments were run for longer exposure times both in an oligotrophic laboratory bioreactor and in the marine environment. In both cases, the biofilm on PET samples seems to reach a steady state faster than LDPE with similar peaks found on both samples DRS proved to be a robust and useful tool to study the formation of biofilm on plastic samples without any pretreatment and without sample destruction. Graphical abstract.

Isolation and identification of low-density polyethylene (LDPE) biodegrading bacteria from waste landfill in Yazd

ABSTRACTMicroorganisms used as a biodegradation technique can provide economic benefits and can be compatible with the environment. The aim of this study was to isolate low-density polyethylene (LDPE) degrading bacteria. The waste samples were collected from Yazd landfills. Biochemical and molecular tests based on 16S rDNA sequencing were done to identify the superior isolates. Biodegradation rate was measured using weight loss measurement, spectroscopic analysis with Fourier-transform infrared (FTIR) spectroscopy and an investigation of surface morphology changes using scanning electron microscopy (SEM). Two biodegrading isolates were identified as Pseudomonas aeruginosa strain SKN1 and strain SKN2. The weight loss of LDPE strips was measured at 10.32%. SEM micrographs showed the surface degradation and colony formation on LDPE strips. The FTIR spectrum revealed the structural changes on LDPE strip surfaces. Bio-decomposition was observed to have taken place and the bacterial strains had a special ability to biodegrade LDPE wastes.

Plastic waste management, a matter for the 'community'.

Plastic waste management, a matter for the 'community'.

Fungal-mediated deterioration and biodegradation study of low-density polyethylene (LDPE) isolated from municipal dump yard in Chennai, India

Low-density polyethylene (LDPE) is a conventionally used polymer and possesses diverse applications in various industries due to its low cost, excellent strength, and numerous mechano-thermal properties. Unfortunately, the deliberate and unconscious release of excess polythene in the environment causes serious ecological threat. To deal with this issue, biodegradation of LDPE was considered using different fungal strains, namely Aspergillus flavus, Aspergillus versicolor, and Fusarium solani isolated from local municipal dump yard in Chennai, India. For degradation study, the polymers were subjected to microbial cultures for 60 days under laboratory conditions. The extent of the degradation was quantified in terms of the weight loss of the LDPE films, pH changes of the culture medium, mineralization, and analysed by field emission scanning electron microscopy (FESEM) and Fourier transform infrared (FTIR) spectroscopy. FESEM micrographs revealed the fungal colonization on the polythene matrix due to their metabolic activities, whereas FTIR spectra showed the changes in chemical nature of the polymer films and confirmed the biodegradation of LDPE. By comparing the reduction in dry weight of LDPE strips and Sturm test results, A. versicolor strain was found to be a potential LDPE-degrading candidate than A. flavus and F. solani and, hopefully, can address the global issue of polymer pollution.

PORE WATER CONTRIBUTION TO IN-SITU SAMPLING OF POLYCYCLIC AROMATIC HYDROCARBONS IN SEDIMENT USING LOW DENSITY POLYETHYLENE

Passive sampling with low-density polyethylene (LDPE) was assessed to study the way it accumulates contaminants in sediment. Strips of LDPE were deployed in river sediment for a period of two months to evaluate their polycyclic aromatic hydrocarbon (PAH) accumulation following two modes: LDPE buried in sediment and exposed to pore water flow and contaminants desorbed from particles were compared to LDPE strips in the same sediment but in a confined space. The results present an obvious difference of accumulation between the two modes of exposure. LDPE exposed to pore water accumulated PAH depending on their hydrophobicity whereas LDPE only exposed to contaminant desorption from confined particles did not accumulate nor desorb PAH significantly. This observation shows that LDPE only takes up PAH present in pore water and not the PAH bound to sediment particles. Accumulation in LDPE is not the result of forced desorption from particles. The present study also found that LDPE sampling cannot estimate adsorbed molecules in confined sediment nor in turbid water. LDPE is an efficient tool for investigating pore water, the fate of micropollutants in sediment, the effect of bioturbation and bioirrigation on micropollutants and the effect of micropollutants on bioturbation activity.

Novel bacterial consortia isolated from plastic garbage processing areas demonstrated enhanced degradation for low density polyethylene.

This study aimed to formulate novel microbial consortia isolated from plastic garbage processing areas and thereby devise an eco-friendly approach for enhanced degradation of low-density polyethylene (LDPE). The LDPE degrading bacteria were screened and microbiologically characterized. The best isolates were formulated as bacterial consortia, and degradation efficiency was compared with the consortia formulated using known isolates obtained from the Microbial Culture Collection Centre (MTCC). The degradation products were analyzed by FTIR, GC-FID, tensile strength, and SEM. The bacterial consortia were characterized by 16S ribosomal DNA (rDNA) sequencing. The formulated bacterial consortia demonstrated 81±4 and 38±3% of weight reduction for LDPE strips and LDPE pellets, respectively, over a period of 120days. However, the consortia formulated by MTCC strains demonstrated 49±4 and 20±2% of weight reduction for LDPE strips and pellets, respectively, for the same period. Furthermore, the three isolates in its individual application exhibited 70±4, 68±4, and 64±4% weight reduction for LDPE strips and 21±2, 28±2, 24±2% weight reduction for LDPE pellets over a period of 120days (p<0.05). The end product analysis showed structural changes and formation of bacterial film on degraded LDPE strips. The 16S rDNA characterization of bacterial consortia revealed that these organisms were novel strains and designated as Enterobacter sp. bengaluru-btdsce01, Enterobacter sp. bengaluru-btdsce02, and Pantoea sp. bengaluru-btdsce03. The current study thus suggests that industrial scale-up of these microbial consortia probably provides better insights for waste management of LDPE and similar types of plastic garbage.

Low density polyethylene (LDPE) passive samplers for the investigation of polychlorinated biphenyl (PCB) point sources in rivers

This study aims to provide a passive sampling approach which can be routinely used to investigate polychlorinated biphenyl (PCB) sources in rivers. The approach consists of deploying low density polyethylene (LDPE) strips downstream and upstream of potential PCB sources as well as in their water discharges. Concentrations of indicator PCBs (iPCBs) absorbed in samplers (Cs) from upstream and downstream sites are compared with each other to reveal increases of PCB levels. Cs measured in water discharges are used to determine if released amounts of PCBs are compatible with increases revealed in the river. As water velocity can greatly vary along a river stretch and influences the uptake at each site in a different way, differences in velocity have to be taken into account to correctly interpret Cs. LDPE strips were exposed to velocities between 1.6 and 37cms−1 using a channel system built in the field. Relationships between velocity and Cs were established for each iPCB to determine the expected change in Cs due to velocity variations. For PCBs 28 and 52, this change does not exceed a factor 2 for velocity variations in the range from 1.6 to 100cms−1 (extrapolated data above 37cms−1). For PCBs 101, 138, 153 and 180, this change only exceeds a factor 2 in the case of large velocity variations. The approach was applied in the Swiss river Venoge to first conduct a primary investigation of potential PCB sources and then conduct thorough investigations of two suspected sources.

ISTA 14—in‐situ accumulation of PAHs in low‐density polyethylene membranes in sediment

The use of passive samplers for the assessment of organic contaminants has been extended to solid matrixes for the past decade. Passive sampling is usually applied to sediment in laboratory experiments involving significant upheaval, whereas in-situ experiments remain rare. In this study, low-density polyethylene (LDPE) strips were deployed within the sediments of a small river contaminated with polycyclic aromatic hydrocarbons (PAHs). LDPE strips were deployed in the 3-cm depth sediment layer. Over a period of 36 days, LDPE strips were regularly retrieved and accumulated PAHs in LDPE were extracted and analyzed. Accumulations of hydrophobic contaminants in LDPE directly exposed in the sediment were observed. Accumulations in LDPE were observed for moderately hydrophobic PAHs with the highest concentrations in the sediment. Low accumulations were observed for more hydrophobic compounds, despite their presence in high concentrations in the sediment. This was explained by very low exchange rates and competitive interactions with particles in the sediment.

Measurement of Freely Dissolved PAH Concentrations in Sediment Beds Using Passive Sampling with Low-Density Polyethylene Strips

To assess hydrophobic organic chemical (HOC) contamination in sediments, a method was developed using polyethylene (PE) passive samplers inserted directly in the intact sediment beds to measure freely dissolved HOC concentrations. Performance reference compounds (PRCs: d10-phenanthrene, d10-pyrene, and d12-chrysene), impregnated into the PE before use, allowed porewater concentrations to be deduced after exposure times much shorter than would be required for sampler equilibration (days instead of months). Three diverse sediments were used in the laboratory, and PE-deduced porewater concentrations of six native PAHs (phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene, and chrysene) matched results from air-bridge testing and from direct porewater extractions after correcting for colloid effects. PE strips, deployed from a boat in Boston Harbor, yielded concentrations that were like those measured in porewaters from a sediment core collected nearby. Notably, equilibrium partitioning (EqP) estimates were always much higher (up to 100x) than those measured using the other methods, suggesting the large inaccuracy of that approach. Hence, PE passive sampling appears to greatly improve the accuracy of assessing the hazards posed by compounds like PAHs in sediment beds.

Dissolved PCBs, PAHs, and HCB in pore waters and overlying waters of contaminated harbor sediments.

Aqueous concentrations of polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), pentachlorobenzene, and hexachlorobenzene (HCB) were determined by exposing low-density polyethylene (LDPE) strips to the pore waters and the overlying water in two contaminated harbors. LDPE strips were also exposed in the laboratory to sediment slurries and to stagnant sediments collected at the same locations. Surprisingly short equilibration time scales (1-60 days for log K(ow) < 7) were observed for the exposures to sediment slurries. This was a result of a profound decrease in transport resistance, due to the presence of particles in the aqueous boundary layer. Concentrations in the pore water were calculated from the initial uptake rates and the dissipation rates of performance reference compounds. Good correspondence existed with concentrations estimated from the equilibrium amounts in the strips and LDPE-water partition coefficients. Sediment-water partition coefficients for PAHs were higher than for PCBs and chlorobenzenes by approximately 1 order of magnitude. A one-dimensional diffusion model was used to describe contaminant uptake by LDPE strips from stagnant sediments. The results indicated that 95% of the PAHs and 50% of the PCBs were immobile on a time scale of two months. A comparison of concentrations in pore waters and water columns indicated that a fair degree of equilibrium existed for PCBs and that one sediment was a potential source of PAHs. Concentrations of HCB near a former discharge site were higher by a factor of 6 compared to reference locations.

Temperature-dependent uptake rates of nonpolar organic compounds by semipermeable membrane devices and low-density polyethylene membranes.

The effect of temperature on sampling rates and sampler-water partition coefficients of semipermeable membrane devices (SPMDs) and low-density polyethylene (LDPE) strips was studied in an experimental setup under controlled flow conditions. Aqueous concentrations of chlorobenzenes, polychlorinated biphenyls (PCBs), and polyaromatic hydrocarbons (PAHs) were maintained by continuous circulation of the water over a generator column. Sampling rates for standard design SPMDs (460 cm2) were in the range of 20-200 L d(-1). No significant differences were observed between sampling rates of SPMDs and LDPE strips, but the latter samplers reached equilibrium faster because of their smaller sorption capacity. Sampling rates at 30 degrees C were higher than at 2 degrees C by a factor of about 3. Sampling rate modeling indicated boundary layer-controlled uptake for compounds with log octanol-water partition coefficients smaller than 4.4 and aqueous boundary-layer controlled uptake for more hydrophobic compounds. SPMD-water partition coefficients did not significantly change with temperature, but LDPE-water partition coefficients were larger at 2 degrees C than at 30 degrees C by a factor of 2. For field application of SPMDs, the results imply that temperature is not a key factor that controls uptake rates unless large geographical and temporal scales are involved. The results confirm that water flow velocity has a profound effect on sampling rates.