WO2019114946A1

WO2019114946A1 - Passive sampling device for the collection of pollutants from an aquatic environment

Info

Publication number: WO2019114946A1
Application number: PCT/EP2017/082616
Authority: WO
Inventors: Mark Bowkett; Breda MOORE; Patrick Roche; Kevin Harrington; Matthieu BIRET
Original assignee: T.E. Laboratories Ltd
Priority date: 2017-12-13
Filing date: 2017-12-13
Publication date: 2019-06-20

Abstract

A pre-assembled passive sampling device (100) for accumulating micro-pollutants over a predetermined period of time from an aquatic environment. The passive sampling device (100) comprising a pollutant sampling unit arranged to be releasably secured in at least an airtight manner to a retaining ring (2) and an outer casing body (1). The retaining ring (2) comprising an opening (7) arranged for at least partially exposing when in use, the pollutant collection element (6) to the aqueous environment. The retaining ring (2) comprises a removable sealing member (3) arranged, when in place, to airtightly seal the opening (7) of the retaining ring (2) so as to prevent the drying out of the pollutant collection element during shipping and storage, the sealing member (3) being removed prior to deployment.

Description

PASSIVE SAMPLING DEVICE FOR THE COLLECTION OF POLLUTANTS FROM AN

AQUATIC ENVIRONMENT

The present invention relates to a passive sampling device for accumulating pollutants from an aquatic environment over a period of time. More specifically, the present invention relates to a passive sampling device that can be shipped and stored in a pre-assembled form and can be easily deployed by non-technically skilled users.

Background to the Invention

The number of Priority Substances, Priority Hazardous Substances and the Watch List substances in SI 386 of 2015 (based on the EU DIRECTIVE 2013/39/EU) were increased in 2015. Indeed the NORMAN network now has over 1000 substances in its database of emerging contaminants, and its function is to enhance the exchange of information on emerging contaminants. Despite the Norman Network remit to enhance the exchange of information on emerging contaminants, there is still a knowledge gap in relation to the fate of many of these substances and their metabolites and the ability of WWTPs to remove them is largely unknown and unquantified. Therefore there is a need to provide targeted high-quality monitoring information on the most relevant emerging contaminants. As reported by Tiedeken et. al. in‘Research Report: Investigation of the Implications for Ireland of Emerging Standards on Pharmaceuticals in Receiving Waters’, issued by the EPA, the need for targeted high-quality monitoring information is due to the lack of information on the dynamics of emerging contaminants, how they interact with each other in the water column and what kind of transformations take place to produce various metabolites and the time taken for these transformations to take place. However, these substances are difficult to detect as they are present at very low levels in the aquatic environments, which are often below the detection limits of most analytical equipment and can be missed entirely by grab sampling methods.

Most monitoring programmes involve the periodic collection of low volume spot samples (bottle or grab) of water, which is challenging, particularly where levels fluctuate over time and when chemicals are only present at trace, yet toxicologically relevant concentrations. Passive samplers are recognised as being able to provide high-quality monitoring of emerging contaminants. The potential advantages of passive samplers over other sampling and measurement strategies include the ability to integrate pollutant levels over extended sampling periods (up to several weeks), as well as inherent speciation capabilities, allowing for critical in situ speciation of metals. Passive samplers are relatively low-cost and do not require fixed secure locations or additional infrastructure, making them ideal devices for certain monitoring tasks. The majority of known passive sampling devices use a receiving phase disk for collecting the pollutants from the aquatic environment, in combination with a diffusion-limiting membrane. During use of the passive sampling device, pollutant compounds pass through the membrane across a fixed and substantially constant diffusion gap, e.g. equal to the thickness of the membrane, to the receiving phase where they are retained. After retrieval from the environment, the pollutants are eluted from the disk and analysed in the laboratory using conventional instrumental methods. The diffusion-limiting membrane and the receiving phase disk can be adapted to monitor a wide range of pollutants.

An example of a known passive sampling device is described in US7059206. The passive sampling device described therein is provided with a PTFE body separated into two parts - a front and a rear part, which are water-tightly joinable by machined screw threads. The screw thread enables the unit to be taken apart to remove or insert a chromatographic receiving phase disk, which is positioned between the diffusion-limiting membrane to the front and a thin, rigid supporting PTFE disk to the rear. Therefore, with the passive sampling device of US7059206, the membrane and supporting disk are held in place between the two halves of the body. The front face of the body is open to allow contact between the aqueous environment and the membrane.

However, one of the main disadvantages of the current passive sampling devices is that they cannot be shipped or stored in a pre-assembled, and ready for deployment, form due to the difficulties posed in preventing the drying out of the disks. Therefore, current passive sampling devices need to be prepared and assembled on-site before deployment by a technically skilled user. In many cases, the preparation of the device can be very complicated and requires several steps to ensure that the device is ready for deployment. For example, prior to deployment the following steps may need to be carried out: a) the components of the device may need to be cleaned and chemically prepared for the particular application; b) the membrane disks may need to be manually punched to the desired shape and dimensions from a membrane sheet; c) the membrane disks may also need to be prepared by removing any traces from the manufacturing process; etc. Furthermore, to correctly remove the phase disk for extraction of the pollutants from the exposed devices, require technical knowledge. For example, once retrieved from the aquatic environment, the phase disks need to be removed from the exposed samplers in a specific manner, e.g. using solvent-rinsed tweezers, and the membrane needs to be carefully removed.

Current sampling devices not only are cumbersome to use by non-technical users but are also costly and difficult to manufacture, which ultimately limits the widespread use of the device.

Summary of the invention

It is an object of the present invention to provide a passive sampling device that overcomes the disadvantages of the prior art solutions. More specifically, the present invention aims to provide a passive sampling device that can be shipped and stored in a pre-assembled form, which can be easily deployed for the monitoring of an aquatic environment by non-skilled users. Furthermore, the present invention aims to provide a passive sampling device that is easy and less complex to manufacture. Moreover, the present invention aims to provide a passive sampling device, wherein the pollutant sampling unit can be used directly with existing laboratory equipment for the extraction and collection of the pollutants accumulated in the pollutant collection element.

The objects of the present invention are achieved by providing a passive sampling device for the accumulation of micro-pollutants over a predetermined period from an aquatic environment having the characteristics of the first claim.

More specifically, according to a first aspect of the present invention, a passive sampling device for accumulating micro-pollutants over a predetermined period of time from an aquatic environment may be provided. The passive sampling device is provided with an outer casing body comprising at least one opening for receiving a pollutant sampling unit. The outer casing body comprises an outer surface releasable fastening means for securing the passive sampling unit to a deployment device during use. The pollutant sampling unit is releasably secured in the at least one opening of the outer casing body and comprises a supporting member and a pollutant collection element. The supporting member comprises a first vertical wall extending upwardly along the periphery of a base to define a receiving space. The support member is provided with at least one securing structure that extends downwards from an outer surface of the base, which is securing structure is arranged to be releasably secured in the at least one opening of the outer casing body. The pollutant collection element is positioned in the receiving space defined by the first vertical wall, the pollutant collection element being arranged for accumulating the micro-pollutants from the aquatic environment. A retaining ring is releasably secured on the first vertical wall of the supporting member. The retaining ring comprising an opening arranged for at least partially exposing when in use, the pollutant collection element to the aqueous environment. The retaining ring comprises a removable sealing member arranged, when in place, to air-tightly seal the opening so as to prevent the drying out of the pollutant collection element during shipping and storage. The sealing member being removed prior to deployment. For example, the sealing member may be sealingly attached to the retaining ring along the rim of the opening. The sealing member may be provided with a tab portion that extends beyond the perimeter of the opening, which can be gripped by the user to remove the sealing member prior to deployment. The sealing member may be provided in the form of a foil made from a gas and liquid impermeable material.

It has been found that by providing a removable sealing member configured for airtightly sealing the opening of the retaining ring, has the advantage of preventing the pollutant collection element from coming in contact with the air. As a result, with the passive sampling device of the present invention, the pollutant collection element is prevented from drying out and remains at the desired conditioning levels for a prolonged period of time. Therefore, in contrast to the existing passive sampling devices, the present invention enables the passive sampling device to be shipped and stored in a stable pre-assembled form, which is ready for deployment. In this way, the passive sampling device of the present invention does not require conditioning prior to deployment and thus can be directly used in the target aquatic environment with minimum preparation by a non-skilled user. Furthermore, by providing a sealing member significantly minimises the risk of contamination of the pollutant-receiving phase and further prolongs the shelf-life and storage period of the passive sampling device. To achieve an airtight seal, the sealing member may be sealingly attached along the rim perimeter of the opening. The attachment of the sealing member may be achieved by induction welding, adhesion, or any other suitable method known to the skilled person. Prior to deployment, the sealing member is removed so that the pollutant collection element is exposed, during use, to the aquatic environment for the accumulation of pollutants. A tab portion may be provided that can be gripped by the user to remove the sealing member to expose the pollutant collection element, thereby eliminating the need for using sharp items, e.g. knives, scissors, and the like. As a result, the risk of damaging the passive sampling device, e.g. damaging the pollutant collection member or the supporting member, is significantly reduced.

According to embodiments of the present invention, the retaining ring is releasably secured on the first vertical wall by means of a press-fitting flexible connection so as to form an airtight releasable connection between the retaining ring and the receiving space of the supporting member. Moreover, the retaining ring may comprise on an internal surface at least one securing element arranged to apply a radially compressive force on an inner and/or outer surface of the first vertical wall so as to at least form an airtight releasable connection between the retaining ring and the receiving space of the supporting member.

It has been found that by dimensioning the retaining ring so that it tightly fits on the first vertical wall of the supporting member, an airtight releasable connection may be achieved. For example, the perimeter of the retaining ring may be adapted to be slightly larger than the perimeter of the first vertical wall, so that it tightly fits, by means of force around the first vertical wall. The first vertical wall and the retaining ring wall may be arranged to flex under stress. As a result, when the retaining ring is pushed on top of the first vertical wall, the force applied may cause the mutually engaging surfaces to flex by a predetermined degree in a predetermined direction, thereby allowing the first vertical wall to move within the space defined by the retaining ring wall. The retaining ring may comprise a stop surface, which when reached, prevents the further movement of the first vertical wall within the space defined by the retaining ring wall. Because of the tight fit, a compressive force may be applied to the mutually engaging surfaces, thereby forming an airtight flexible connection between the retaining ring and the first vertical wall. The airtight flexible connection may be reversed by pulling in opposite directions the retaining ring and the supporting member. In order to increase the strength of the airtight flexible connection, the retaining ring may be provided on an inner surface with at last one securing element. The at least one securing element may be adapted to apply, when the retaining ring is connected with the supporting member, a compression force against an inner and/or an outer surface of the first vertical wall. For example, the securing element may be in the form of at least one clamp, which is adapted to engage an inner and/or outer surface of the first vertical wall so as to increase the force applied, thereby enhancing the airtight flexible connection provided. In preferred embodiments, the connection between the retaining ring and the first vertical wall of the supporting member may also be watertight. The at least one securing element may also be used to secure the pollutant collection element on the base of the supporting member.

According to embodiments of the present invention, the retaining ring and the first vertical wall may comprise complementary securing elements provided on corresponding surfaces, which are arranged when connected to at least form an airtight releasable connection between the retaining ring and the receiving space of the supporting member. For example, the complementary securing elements may be in the form of screw threads, snap-fit connections, clamps and the like. The complementary securing elements may be used as an alternative or in combination with the press-fitting flexible connection.

The provision of complementary securing elements may offer a quick and easy way for connecting the retaining ring to the supporting member in an airtight manner. Moreover, the use of complementary securing elements may offer to the user a quick way to verify that the airtight connection has been achieved. For example, in the case where the complementary securing elements are in the form of screw threads, the user can check that the retaining ring is sufficiently tightened on the first vertical wall of the supporting member. Furthermore, in the case that the complementary elements are in the form of snap-fit connections or clamps, then an audible indication that the complementary elements have been secured may be provided, which may indicate to the user that the desired connection, airtight and/or watertight connection, has been achieved.

According to embodiments of the present invention, the securing structure is releasably secured in the at least one opening of the outer casing body by means of a press fitting flexible connection so as to at least form an airtight releasable connection between the outer casing body and the receiving space of the supporting member. For example, the securing structure may comprise on at least an outer surface at least one securing element arranged to apply a radial compressive force on at least an inner surface of the at least one opening so as to at least form an airtight releasable connection between the outer casing body and the receiving space of the supporting member. Furthermore, the securing structure and the at least one opening may be provided on the corresponding surface with complementary securing elements, which are arranged when connected to form an airtight releasable connection between the outer casing body and the receiving space of the supporting member. For example, the complementary securing elements may be in the form of screw threads, snap-fit connections, clamps and the like.

Similarly, with previous embodiments, the supporting member may be dimensioned so that it tightly fits, by means of force, in the at least one opening provided on the outer casing body. Furthermore, additional securing elements, e.g. clamps, may be provided to further enhance the connection between the securing member and the at least one opening. Moreover, complementary securing elements may be provided, e.g. screw threads, to enhance properties of the desired connection, and further provide a quick and easy way to verify that the desired connection has been achieved.

By providing, an airtight and watertight seal between the outer casing body, the retaining ring, and the receiving space of the supporting member, may further contribute to maintaining the pollutant collection element at the desired conditioning levels during storage and transportation, while preventing the contamination of the pollutant collection element. The provision of complementary securing elements may further enhance the strength and airtight/watertight properties of the connection between receiving space of the supporting member, and the retaining ring and the outer casing body. As a result, the risk of the different parts of the passive sampling device becoming disengaged during transportation or deployment may be significantly reduced.

According to embodiments of the present invention, the at least one securing structure of the supporting member may be in the form of a second vertical wall extending downwards along the periphery of the base and defining an internal space. The at least one securing structure may be in the form of an outlet port protruding from an outer surface of the supporting member base and in fluid communication with the internal space defined by the second vertical wall. Furthermore, supporting member may be provided with different types of securing structures, e.g. vertical walls, a protruding outlet port, clamps, etc., each arranged to be positioned in a corresponding opening of the outer casing body.

According to embodiments of the present invention, the supporting member is configured for being connected via the first vertical wall and the at least one securing structure to an analytical device for the extraction of the micro-pollutants from the pollutant collection element. In this way, after the passive sampling device has been exposed to the aquatic environment, the pollutant-sampling unit can be removed and directly coupled to an analytical device for the extraction and collection of the pollutants from the pollutant collection element. For example, the supporting member of the pollutant collection unit may be connected to an analytical device configured for extracting the pollutant by an elution process. For example, the first vertical wall may be water-tightly connected to a funnel containing a predetermined fluid solution, while the protruding outlet port may be water- tightly connected to a container configured for collecting the eluate. Therefore, the pollutant sampling unit of the present invention can be used directly as a filtering device, thereby significantly reducing costs and preparation time associated with the analysis of the exposed samples. In some cases, before extraction, the pollutant collection element may require further preparation, e.g. drying, removal of the membrane, etc. According to embodiments of the present invention, the opening of the protruding outlet port may be sealingly covered during storage, transportation and deployment of the passive sampling device. For example, the opening of the outlet port may be covered by a lid, a sealing member similar to the one covering the opening of retaining ring, or in any other way known to the skilled person. It has been found that by sealingly covering the opening of the outlet may prevent, during deployment of the passive sampling device, the flow of water in the receiving space of the supporting member through the outlet port. Furthermore, by sealingly covering the opening of the outlet may further enhance the airtight and/or water tight connection between the outer casing body and the receiving space of the supporting member. The cover on the outlet port may be removed by the user, before the pollutant extraction process, for collecting the eluate through the outlet port by means of a laboratory analytical device.

According to embodiments of the present invention, the inner base surface comprises a plurality of flow channels arranged for directing a fluid solution to the outlet port. The inner base surface is arranged to slope downwards at a predetermined angle from the base perimeter towards the outlet port. The provision of flow channels and a slopping base may improve the flow of the fluid solution and reduce the time required for extracting the eluate during the elution process. According to embodiments of the present invention, the outer casing body is made as a unitary element provided with at least one opening at the top that extends towards a base surface. For example, the outer casing body may be made by any known process, e.g. injection moulding, 3D-printing, and the like. Similarly, the supporting member and the retaining ring may be made similarly to the outer casing body.

According to embodiments of the present invention, the releasable fastening means comprise a clip-in connection mechanism arranged for cooperating with an opening of the deployment device to releasably secure the passive sampling device. For example, the clip- in connection mechanism may comprise first and second resilient members each comprising at one end at least one locking element arranged to cooperate, when inserted through the opening of the deployment device, with corresponding surfaces on the deployment device to releasably secure the passive sampling device. In this way, the passive sampling device can be releasably secured to the deployment device without the need for additional elements, e.g. pins. Therefore, the present invention provides a passive sampling device that can be properly secured in an easy and quick manner by a non-skilled user. The locking element may be in the form of a barb, or in another form that is arranged for engages with corresponding surfaces of the deployment device for securing the passive sampling device. Furthermore, the clip-in connection may be in the form of a snap-fit connection or any other connection type capable of releasably securing the passive sampling device to the deployment device.

According to embodiments of the present invention, the pollutant sampling unit may be disposable. Furthermore, the outer casing body and retaining ring may also be disposable. The pollutant sampling unit, the outer casing body and the retaining ring are made from a recyclable and disposable material. In this way, the device can be discarded after a single use, which eliminates the risk of contamination encountered by the existing reusable passive sampling devices.

According to a second aspect of the present invention, a deployment kit for accumulating pollutants over a predetermined period of time from an aquatic environment is provided. The deployment kit may comprise a deployment device comprising a base, and at least one supporting element comprising at least one opening; and at least one passive sampling device according to any one of claims 1 to 26, the at least one passive sampling device arranged for being releasably secured to the at least one opening of the deployment device.

According to embodiments of the present invention, the pollutant collection element comprises a receiving phase disk arranged for accumulating the pollutants, and a diffusion- limiting membrane contactable in use with the aquatic environment and adapted to allow rate-limited diffusion of the pollutants to the receiving phase disk. The diffusion limiting membrane and/or the receiving disk may be adapted to capture specific types of micro pollutants or nutrients from the aquatic environment.

Brief Description of the drawings

The following drawings are provided as examples of embodiments according to the present invention to explain further and describe various aspects of the invention.

Figure 1 shows an example of a pre-assembled passive sampling device according to embodiments.

Figure 2 shows an exploded view of the different components of the passive sampling device of figure 1 .

Figures 3 shows a cross-sectional view of the passive sampling device of figure 1 according to embodiments of the present invention.

Figure 4 shows an example of a passive sampling device according to embodiments of the present invention.

Figure 5 shows a bottom view of a supporting member according to embodiments of the present invention.

Figure 6 shows a perspective view of the pollutant-sampling unit connected to an extraction component of an analytical device according to embodiments of the present invention.

Figure 7 shows an example of a deployment kit according to embodiments of the present invention.

Figures 8 and 9 show a top and side view the deployment device according to embodiments of the present invention.

Figure 10 shows an example of the deployment kit assembled and with the cage attached according to embodiments of the present invention. Detailed Description

The present invention will be illustrated using the exemplified embodiments shown in the Figures 1 and 10, which will be described in more detail below. It should be noted that any references made to dimensions are only indicative and do not restrict the invention in any way. While this invention has been particularly shown and described with reference to certain illustrated embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.

Figure 1 shows an example of a pre-assembled passive sampling device 100 according to embodiments of the present invention. As shown, the pre-assembled passive sampling device may be provided with a pollutant collection element, which is releasably secured in at least an airtight manner to an outer casing body 1 and a retaining ring 2. The pre-assembled passive sampling device 100 further comprises a protective sealing member 3, which covers the opening 7 of the retaining ring 2 in an airtight and preferably a watertight manner. The sealing member 3 may be in the form of a foil made from a gas and/or fluid impermeable material that is attached along the rim 2a perimeter of the opening 7. The foil may be made from a range of materials, e.g. aluminium, PVC (Polyvinyl chloride), PVDC (polyvinylidene chloride), and the like. The sealing member 3 may be attached along the rim 2a perimeter of the opening 7 using a sealing layer e.g. heat seal adhesive, and the like, which can be activated using a range of techniques, e.g. induction sealing, heat sealing, and any other suitable method configured for hermetically sealing the opening 7 of the retaining ring 2. The sealing member 3 may be provided with a tab portion 3a, which extends from the sealed perimeter of the opening 7. The tab portion 3a can be griped by the user to remove the sealing member 3 from the retaining ring prior to the deployment of the passive sampling device 100, so as to allow, during use, at least a top layer of the pollutant collection element 6, e.g. a diffusion-limiting membrane, to come in contact with the aquatic environment. The passive sampling device 100 may be vacuumed packed so that air is removed from the pre-assembled device before sealing. In this way, the pre-assembled passive sampling device 100 may be stored and shipped over an extending period of time, while ensuring that the pollutant collection element 6 is prevented from drying out. The passive sampling device 100 may be provided with fastening means 4 for releasably securing the passive sampling device 100 to an opening 23 of a deployment device 200. The purpose of the fastening means 4 is to maintain the orientation of the passive sampling device 100, so that the at least part of the pollutant collection element 6 is maintained exposed to the aquatic environment during the sampling period. The fastening means 4 may be arranged to protrude from an outer surface of the outer casing body 1 , e.g. from an outer base surface. The fastening means 4 may in the form of a clip-in connection mechanism that can be clipped, using force, to an opening 23 of the deployment device 200. For example, the clip-in connection mechanism may comprise first and second resilient members 4a, each comprising at least one protruding locking element 5, e.g. a hook, stud or bead. The resilient elements 4a when pushed through the opening 23 of the deployment device maybe displaced inwards, to allow for the locking elements 5 to go through the opening 23. Once through the opening, the locking elements 5 may be arranged to engage a bottom surface of a deployment supporting member 21 , thereby securing the passive sampling device 100 to the deployment device 200. To remove the passive sampling device 100 from the deployment device 200, the protruding locking members 5 may be briefly displaced inwards causing their disengagement from the mating engagement surfaces of the deployment supporting member 21 , which allows them to pass through the opening 23. In this way, the passive sampling device 100 can be reversibly secured in an easy and quick way on the deployment device 200 without the need of additional elements, e.g. pins, or other special equipment. Clip-in connection, also referred to as snap-fit connections, are very simple to use, economical, and offer a rapid way of assembling two different components.

Figure 2 shows a detailed view of the different components contained in the passive sampling device 100 shown in Figure 1 according to embodiments of the present invention. The pollutant sampling unit may comprise a supporting member 8 provided with a base 18, which is arranged to support on an inner base surface a pollutant collection element 6. The pollutant collection element 6 may be in the form of a disk and may comprise a receiving phase disk arranged for accumulating the pollutants, and a diffusion-limiting membrane contactable in use with the aquatic environment and adapted to allow rate-limited diffusion of the pollutants to the receiving phase disk. The pollutant collection element 6 may be adapted to accumulate specific types of micro-pollutant or nutrients from the aquatic environment. For example, the receiving phase disk and the diffusion-limiting membrane may be similar to the ones discussed in US7059206. The supporting member 8 may be provided with a first vertical wall 9 extending upwards from the periphery of the base, a second vertical wall 10 extending vertically downwards from the periphery of the base, and an outlet port 16 in fluid communication with the internal space defined by the second vertical wall 10. The first and second vertical walls 9 and 10 may be arranged to respectively corporate with the retaining ring 2 and the outer casing body 1 to releasably secure the pollutant sampling unit in an airtight, and preferably, water tight manner. For example, the first vertical wall 9 may cooperate with an internal wall of the retaining ring 2 to at least form an airtight flexible connection. As previously discussed, the retaining ring 2 may be press- fitted on top the first vertical wall 9. The retaining ring 2 may further be provided with additional securing elements 14, e.g. clamps, on an inner or an outer surface to further enhance the connection between the retaining ring 2 and the first vertical wall 9. Furthermore, the securing elements 14 may also secure the position of the pollutant collection element 6 on the base 18 of the supporting member 8. Similarly, the second vertical wall 10 may cooperate with at least one opening 12 of the outer casing body to releasably secure the pollutant collection element to the outer casing body 1 in at least an airtight manner. For example, the second vertical wall 10 may be press-fitted, using force, in the opening 12. The second vertical wall 10 may be provided on an outer surface with at least one securing element 13, which engage with inner surfaces of the opening to enhance the connection provided. For example, the securing elements 13 may be arranged to maintain, and further enhance, the compressive force applied to the second vertical wall 10 as it pushed downwards in the opening. As shown the outer casing body 1 may be provided with a central opening 17, which is arranged to accommodate the protruding outlet port 16 of the supporting member 8. The protruding outlet port 16 may further cooperate with the opening 17 to releasably secure the pollutant sampling unit to the outer casing body 1 in at least an airtight manner. The second vertical wall may cooperating with the inner surfaces of the opening 12 to additionally form a water barrier, which at least during deployment, prevents water from flowing in the receiving space of the supporting member 8 through the outlet port 16. The opening of the outlet port 16 may further be covered, at least during deployment, with a sealing member e.g. a lid, or a foil, so as to further prevent the flow of water in the receiving space of the supporting member 8 though the outlet port 16.

Figure 3 shows a cross-sectional view of a passive sampling device 100 that is ready for deployment, i.e. with the sealing member 3 removed, according to embodiments of the present invention. . As shown, the second vertical wall 10 may be positioned, by means of press-fitting, in the opening 12 of outer casing body 1 . The securing elements 13 are arranged to cooperate with inner surfaces of the opening 12 to maintain a compressive force against the second vertical wall 10, so as to secure into position the pollutant sampling unit in an airtight, and preferably, a watertight manner. In some cases, the securing elements 13 may be in the form of a wedge that is arranged to secure into the opening 12 the second vertical wall 10. The dimensions of the second vertical wall 9 and type and number of securing elements provided may be adapted so that it can fit tightly into the opening such that an airtight, and preferably, a watertight releasable connection is formed, but at the same can be easily removed by the user. A central opening 17 may be further provided on the outer casing body 1 to accommodate a protruding outlet port 16 of the supporting member 8. The outlet port 16 may also act as securing member and may be adapted to be press-fitted into the opening 17 to form an airtight, and preferably, a watertight connection. As previously discussed, the opening of the outlet port 16 may be sealingly covered, so as to further prevent the flow of water, during deployment, in the receiving space of the supporting member 8. As shown in figure 3, the retaining ring 2 is positioned on top of the supporting member 8 in an airtight manner. As previously discussed, the perimeter of the retaining ting 2 may be adapted so that it is slightly bigger than the perimeter of the first vertical wall 9. As a result, to fit the retaining ring 2 on the first vertical wall, a force may need to be applied. In this way, the retaining ring 2 may be press-fitted onto the first vertical wall 9 to form an airtight connection. The retaining ring 2 may be provided with a stop surface 2b, that limit the range of movement of the retaining ring 2 on the first vertical wall 9. The retaining ring 2 may be provided with securing elements 14, e.g. clamps that fix the position of retaining ring 2 on the first vertical wall 9. The securing elements 14 may also press against the pollutant collection element 6 to secure its position on the base 18 of the supporting member. As previously discussed, the retaining ring 2 may be provided with an opening 7 comprising a rim 2a, on which rim 2a the sealing member 3 is attached prior to deployment.

Figure 4 shows a cross-sectional example of a passive sampling device 100 according to embodiments of the present invention. The main difference with the passive sampling device shown in previous figures, is that the second vertical wall 10 and the opening 12 of the outer casing body 1 are provided with complementary securing elements 33a and 33b, which in this case are in the form of screw threads. In this way, the supporting member 8 can be screwed on the outer casing body 1 . The complementary securing elements 33a and 33b may take other forms e.g. snap-fit connections, clamps, etc. The complementary securing elements may also be combined with the press-fitted connection discussed in previous embodiments. The complementary securing elements 33a and 33b may also be provided on the first vertical wall 9 and the retaining ring 2, or in any other desired location. Similarly to other embodiments, the complementary securing elements 33a and 33b may at least provide an airtight, and preferably, a watertight connection.

Figure 5 shows a bottom view of the supporting member 8 of the pollutants sampling unit. As shown, the supporting member 8 maybe provided with a protruding outlet port 16, which extends outwards from an outer surface 18b of the base 18. The outlet port 16 is in fluid communication with space defined by the second vertical wall 10. As previously discussed, the opening of the outlet port 16 may be sealingly covered, by means of a foil or a lid, to prevent during deployment water from flowing, through the outlet port 16, to the receiving space of the supporting member 8. The cover of the outlet port opening may be removed, before the extraction process, so that the eluate can be collected through the outlet port 16.

As shown in figure 6, the pollutant sampling unit may be adapted so that it can be used directly with an analytical device for the extraction and collection of the pollutants from the pollutant collection element 6. For example, the supporting member 8 may be in the form of a filtering device. As shown in figure 6, the protruding outlet port 16 may be attached to an extraction component 30 of an analytical device. The attachment can be performed by means of a press-fitting connection, and/or by providing complementary securing elements, e.g. screw threads. For example, the first vertical wall 9 may be attached to funnel containing a fluid solution for extracting the pollutant from the pollutant collection element 6, while the outlet port 16 may be attached to a container or an extraction device 30 configured for collecting the eluate. The flow of the fluid solution through the pollutant sampling unit may be enhanced by providing on an inner base surface of the supporting member 8, a plurality of channel for guiding the fluid to the outlet port 16. The inner base surface may slope downwards at a predetermined angle from the base perimeter towards the outlet port 16. For example, the sloping angle may be between 0.1 ° and 5° depending on the configuration and size of the supporting member 8. According to embodiments of the present invention, the passive sampling device 100 may be designed as a disposable unit. Furthermore, some or all of the components of the passive sampling device 100, e.g. outer casing 1 , retaining ring 2, supporting member 8, may be made from a disposable and/or recyclable material.

Figure 7 to 10 shows examples of a deployment device according to embodiments of the present invention. The deployment device 200 may be provided with a base 24 configured for supporting on a central post 22, a plurality of deployment supporting members 21. Each deployment supporting member 21 may be provided with a plurality of openings 23, each arranged for receiving a passive sampling device 100 according to the present invention. The deployment device 200 may be covered with a cage 25, which is secured on the base 24, via the central post 22. The cage 25 is provided with openings 26 to allow the aquatic environment to enter the internal space of the deployment device and come in contact with the passive sampling devices 100.

It should be noted that although the passive sampling device has been presented as a disposable unit, certain elements may be reusable, e.g. the retaining ring 2 and the outer casing body 1 . The pollutant sampling unit may be provided in the form of dispensable vacuum packed packages that can be attached, as previously described, to the outer casing body 1 and the retaining ring. In the case of the pollutant sampling unit being in the form of a dispensable packages, the openings defined by the first vertical wall 9, the second vertical wall 10, and/or the outlet port, may be sealingly covered in an airtight, and prefereably, a watertight manner.

Claims

1. A passive sampling device (100) for accumulating micro-pollutants over a predetermined period of time from an aquatic environment, the passive sampling device (100) comprising:

an outer casing body (1 ) comprising at least one opening (12, 17) for receiving a pollutant sampling unit, the outer casing body (1 ) comprising at an outer surface releasable fastening means (4) for securing the passive sampling unit to a deployment device (200) during use;

a pollutant sampling unit being releasably secured in the at least one opening (12, 17) of the outer casing body (1 ), the pollutant sampling unit comprising

a supporting member (8) comprising

a first vertical wall (9) extending upwardly along the periphery of a base (18) so as to define a receiving space, and at least one securing structure (10, 16) extending downwards from an outer surface (18b) of the base (18), the at least one securing structure (10, 16) being releasably secured in the at least one opening (12, 17) of the outer casing body (1 ), and

a pollutant collection element (6) positioned in the receiving space defined by the first vertical wall (9), the pollutant collection element (6) being arranged for accumulating the micro-pollutants from the aquatic environment; and

a retaining ring (2) releasably secured on the first vertical wall (9) of the supporting member (8), the retaining ring (2) comprising an opening (7) arranged for at least partially exposing, when in use, the pollutant collection element (6) to the aqueous environment;

wherein the retaining ring (2) comprises a removable sealing member (3) arranged, when in place, to airtightly seal the opening (7) so as to prevent the drying out of the pollutant collection element during shipping and storage, the sealing member (3) being removed prior to deployment.

2. A passive sampling device (100) according to claim 1 , wherein the sealing member (3) is sealingly attached along a rim (18) of the opening (7).

3. A passive sampling device (100) according to claim 1 or claim 2, wherein the sealing member (3) comprises a tab portion (3a) that extends beyond the perimeter of the opening (7), which can be gripped by the user to remove the sealing member (3) prior to deployment.

4. A passive sampling device (100) according to any one of the preceding claims, wherein the sealing member (3) is the form of a foil made from a gas and liquid impermeable material.

5. A passive sampling device (100) according to any one of the preceding claims, wherein the retaining ring (2) is releasably secured on the first vertical wall (10) by means of a press-fitting flexible connection so as to form an airtight releasable connection between the retaining ring (2) and the receiving space of the supporting member (8).

6. A passive sampling device (100) according to any one of the preceding claims, wherein the retaining ring (2) comprise on an internal surface (2a) at least one securing element (14) arranged to apply a radial compressive force on an inner and/or outer surface of the first vertical wall (9) so as to at least form an airtight releasable connection between the retaining ring (2) and the receiving space of the supporting member (8).

7. A passive sampling device (100) according to any one of the preceding claims, wherein the retaining ring (2) and the first vertical wall (9) comprise complementary securing elements provided on corresponding surfaces, which are arranged when connected to at least form an airtight releasable connection between the retaining ring (2) and the receiving space of the supporting member (8).

8. A passive sampling device (100) according to claim 7, wherein the complementary securing elements (33a, 33b) are in the form of screw threads, snap-fit connections, clamps and the like.

9. A passive sampling device (100) according to any one of the preceding claims, wherein the securing structure (10, 16) is releasably secured in the at least one opening (12, 17) of the outer casing body (1 ) by means of a press-fitting flexible connection so as to form an airtight releasable connection between the outer casing body (1 ) and the receiving space of the supporting member (8).

10. A passive sampling device (100) according to any one of the preceding claims, wherein the securing structure (10, 16) comprises on at least an outer surface at least one securing element (13) arranged to apply a radially compressive force on at least an inner surface of the at least one opening (12, 17) so as to at least form an airtight releasable connection between the outer casing body (1 ) and the receiving space of the supporting member (8).

1 1 . A passive sampling device (100) according to any one of the preceding claims, wherein the securing structure (10, 16) and the at least one opening (12, 17) comprise complementary securing elements (33a, 33b) provided on the corresponding surface, which securing elements (33a, 33b) are arranged when connected to form an airtight releasable connection between the outer casing body (1 ) and the receiving space of the supporting member (8).

12. A passive sampling device (100) according to claim 1 1 , wherein the complementary securing elements (33a, 33b) are in the form of screw threads, snap-fit connections, clamps and the like.

13. A passive sampling device (100) according to any one of the preceding claims, wherein the at least one securing structure of the supporting member (8) is in the form of a second vertical wall (10) extending downwards along the periphery of the base and defining an internal space.

14. A passive sampling device (100) according to claims 1 to 12, wherein the at least one securing structure is in the form of an outlet port (16) protruding from an outer surface (18b) of the supporting member base and in fluid communication with the internal space defined by the second vertical wall (10).

15. A passive sampling device (100) according to any one of the preceding claims, wherein the supporting member comprises at least two securing structures (10, 16) each arranged to be positioned in a corresponding opening (12, 17) of the outer casing body.

16. A passive sampling device (100) according to any one of the preceding claims, wherein the supporting member (8) is configured for being connected via the first vertical wall (9) and at least one securing structure (10, 16) to an analytical device (30) for the extraction of the micro-pollutants from the pollutant collection element (6).

17. A passive sampling device (100) according to any one of claims 14 to 16, wherein the inner base surface comprises a plurality of flow channels (15) arranged for directing a fluid solution towards the outlet port (16).

18. A passive sampling device (100) according to any one of claims 14 to 17, wherein the inner base surface is arranged to slope downwards at a predetermined angle from the base perimeter towards the outlet port (16).

19. A passive sampling device (100) according to any one of claims 14 to 18, wherein the outlet port (16) is located in the centre of the base.

20. A passive sampling device (100) according to any one of the preceding claims, wherein the pollutant collection element (6) comprises a receiving phase disk arranged for accumulating the pollutants, and a diffusion-limiting membrane contactable in use with the aquatic environment and adapted to allow rate-limited diffusion of the pollutants to the receiving phase disk.

21 . A passive sampling device (100) according to any one of the preceding claims, wherein the releasable fastening means (4) comprise a clip-in connection mechanism arranged for cooperating with an opening (23) of the deployment device (200) to releasably secure the passive sampling device.

22. A passive sampling device (100) according to claim 21 , wherein the clip-in connection mechanism comprises first and second resilient members (4a) each comprising at one end at least one locking element (5) arranged to cooperate, when inserted through the opening (23) of the deployment device (200), with corresponding surfaces of at least one deployment supporting member (21 ) to releasably secure the passive sampling device (100) on the deployment device (200).

23. A passive sampling device (100) according to claim 22, wherein the locking elements (4a) are in the form of a barb.

24. A passive sampling device (100) according to any one of the preceding claims, wherein the supporting member (8), the outer casing body (1 ) and the retaining ring (1 ) are made from a recyclable and disposable material having a predetermined flexibility.

25. A deployment kit for accumulating pollutants over a predetermined period of time from an aquatic environment, the deployment kit comprising:

a deployment device (200) comprising a base (24), and at least one deployment supporting member (21 ) comprising at least one opening (23), the deployment supporting member (21 ) being secured on a central post (22); and

at least one passive sampling device (100) according to any one of claims 1 to 24, arranged for being releasably secured to the at least one opening (23) of the deployment device (200).