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{{Main|Diffusive gradients in thin films}}
Diffusive gradients in thin films (DGT) samplers passively sample [[ion]]ic trace metals, as well as [[antibiotic]]s, [[oxyanion]]s, [[bisphenol]]s, and [[nanoparticle]]s in different configurations. They are composed of plastic pistons and caps, with a window that exposes a binding gel, diffusive gel, and filter membrane to the sampling water. They can be used in both freshwater and marine environments, as well as in the water located between freshwater and marine [[sediment]] particles, called ''pore water'' or ''interstitial water''. Once the mass of accumulated contaminants on the DGT sampler is known, the DGT equation (based on [[Fick's law]]) can be used to calculate the time averaged water concentration of contaminants.<ref name="DGT">{{cite journal |last1=Zhang |first1=Chaosheng |last2=Ding |first2=Shiming |last3=Xu |first3=Di |last4=Tang |first4=Ya |last5=Wong |first5=Ming H |title=Bioavailability assessment of phosphorus and metals in soils and sediments: a review of diffusive gradients in thin films (DGT) |journal=Environmental Monitoring and Assessment |date=2014 |volume=186 |issue=11}}</ref>
=== Microporous polyethylene tubes (MPT) ===
Microporous polyethylene tubes (MPT) attempt to mitigate the flow-dependency of other kinetic passive samplers such as Chemcatcher and POCIS by introducing a thicker membrane <ref>{{Cite journal|last=Fauvelle|first=Vincent|last2=Kaserzon|first2=Sarit L.|last3=Montero|first3=Natalia|last4=Lissalde|first4=Sophie|last5=Allan|first5=Ian J.|last6=Mills|first6=Graham|last7=Mazzella|first7=Nicolas|last8=Mueller|first8=Jochen F.|last9=Booij|first9=Kees|date=2017-03-07|title=Dealing with Flow Effects on the Uptake of Polar Compounds by Passive Samplers|url=https://doi.org/10.1021/acs.est.7b00558|journal=Environmental Science & Technology|volume=51|issue=5|pages=2536–2537|doi=10.1021/acs.est.7b00558|issn=0013-936X}}</ref>. The diffusive polyethylene layer prevents the thickness of the water-boundary layer (which is affected by flow) from dominating diffusion<ref name=":0">{{Cite journal|last=Fauvelle|first=Vincent|last2=Montero|first2=Natalia|last3=Mueller|first3=Jochen F.|last4=Banks|first4=Andrew|last5=Mazzella|first5=Nicolas|last6=Kaserzon|first6=Sarit L.|date=2017|title=Glyphosate and AMPA passive sampling in freshwater using a microporous polyethylene diffusion sampler|url=https://pubmed.ncbi.nlm.nih.gov/28886558/|journal=Chemosphere|volume=188|pages=241–248|doi=10.1016/j.chemosphere.2017.08.013|issn=1879-1298|pmid=28886558}}</ref>. The tube is filled with sorbents depending on the chemicals or chemical groups being sampled and has been successfully used to sample glyphosate, AMPA<ref name=":0" />, illicit drugs and pharmaceuticals and personal care products<ref>{{Cite journal|date=2020-02-20|title=Calibration and validation of a microporous polyethylene passive sampler for quantitative estimation of illicit drug and pharmaceutical and personal care product (PPCP) concentrations in wastewater influent|url=https://www.sciencedirect.com/science/article/abs/pii/S0048969719358863|journal=Science of The Total Environment|language=en|volume=704|pages=135891|doi=10.1016/j.scitotenv.2019.135891|issn=0048-9697}}</ref>.
===Peepers===
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