The trafficking and smuggling of people to the U.S. and to Europe have reached alarming proportions in recent years. Human smugglers have made a lucrative business out of facilitating illegal migration, offering a wide range of services such as transportation, accommodation and fraudulent documents. They put at risk the health and lives of people being trafficked or smuggled.
Human trafficking and smuggling can take place in many forms, including by boat, marine containers, air cargo, and trucks and cars at border crossings.
Human smuggling undermines a country’s security. Large-scale arrivals make it difficult to properly investigate whether those who arrive, including the smugglers themselves, pose risks to the country on the basis of either criminality or national security. People are hidden in containers arriving by ship or through border crossings, which makes it difficult to detect – when dealing with thousands of containers arriving to a seaport, lack of resources to check each container makes the screening process impossible. The containers are usually sealed and, through inside collaborators, smuggled people are released from the container and freely enter the country.
In a joint effort between University of Waterloo and Teknoscan Systems Inc. (TSI), specific organic acids emitted from humans were monitored as an effective method to discover the presence of hidden people in enclosures like containers and trucks. The method involves sampling the air from the inside of the enclosure through the air vent and enriching the collected vapor trace on a nano-carbon-coated sample card. The enriched sampled is immediately analyzed for the specific acid metabolites lactic and pyruvic acids and the results reported in a span of 1-2 minutes.
The approach was validated through laboratory tests on people’s hands exposed in a glass chamber and sampled to determine the emission rate of these acids. The identification of target skin emission compounds relies on the comparison of retention and drifts times of ion mobility peaks with the respective libraries of retention times and drift times or reduced mobility constants obtained from standard mixtures.
Sample acquisition was carried out using a battery-operated, handheld sampler loaded with the vapor enrichment card. The instrument used is a GC-IMS model TSI-3000 manufactured by Teknoscan Systems Inc. The process of sample taking and analysis is shown in Figure 1 and equipments used for the study are shown in Figure 2.
Two metabolic organic acids have been identified in the literature (Environmental Health Perspectives Vol.36, pp.77-84, 1980), which are ionized and detected in the negative ion modes. Lactic acid and pyruvic acids form specific negative ion peaks in the TSI-3000 instrument forming (M-H)– ions at respective masses of 87 and 89. In IMS, the identification of these acids is based on their specific reduced mobility constants, which are programmed in the instrument.
The front GC separation provides another dimension for characterization of these acids in the presence of complex chemical matrix usually encountered in screening air cargos and marine containers.
Both pyruvic and lactic acid are known to be breakdown products of glucose metabolism. They are universally present in humans and are good indicators to discover hidden people in containers. Experimental testing of people’s hands has shown that lactic acid concentration in the glass chamber was 20ppbv (parts per billion volumes). Typical accepted values of a male skin surface area is 1.8m2 and a female 1.6m2. Assuming 10 percent of the skin is exposed, we determined an average person’s skin emission rate for lactic is roughly 43ppb/person or, in terms of weight per volume, 159ng/L/person (nanogram per liter per person).
Since a person will be a constant source of organic acids, buildup inside the container or other types of enclosures would continue to increase as a function of residence or incubation time of the hidden people. Therefore, the non-invasive screening of the container or enclosure would register a positive hit for the presence of a hidden human.
To validate this approach, we loaded a 20-foot container with boxes of all types and placed in the middle of the container a small amount of a diluted solution of lactic acid, simulating a person’s emission inside the container. The container was closed and sampling was carried out through the door gasket using the handheld sampler and the vapor enrichment card.
The results of continuous sampling are plotted in Figure 3 and show a gradual increase of the organic acid signal as a function of time, starting from 6ppbv concentration and reaching 30ppbv after four hours of soak time.
In the context of locating humans in containers, the chemical detection of volatile markers can be considered a very promising approach. The same approach is applicable in operations to rescue buried people.
The same technology has been used to locate hidden drugs, explosives and other contrabands in marine containers since 2012.
The interactions of human-related chemical fingerprints with the container shipment environment have not been investigated in sufficient depth. Most field experience has been for identifying different types of contraband.
When the emitted organic acids, which form part of the human scent, are spread throughout the void spaces of the containers, they can interact with surrounding materials, and mix with contaminants present in the container. As mentioned earlier, additional factors can affect vapor emissions from people such as temperature and humidity inside the container and whether the container is fully or partially packed.
What is needed is to conduct joint field testing with U.S. Customs and Border Protection on real shipments to assess the programmed biomarkers that we reported in our laboratory studies. It identifies possible false alarms from various shipments or possible interferences.
We also need to conduct joint experimentation in which volunteers are kept inside a container for few hours and sniffing the headspace vapor of the container at different intervals. This will help to validate the proposed approach in a real field scenario. This could be a border crossing with Mexico or a seaport where marine containers are unloaded from a ship.
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