‘Baseline’ contamination study to inform Netherlands trial in which shops will sell drug produced by licensed growers. Lead, pesticides and potentially harmful bacteria were among the contaminants found during an investigation into cannabis sold in semi-legal “coffee shops” in the Netherlands.
The research, which aimed to establish a “baseline” level of typical contamination , was carried out by the Netherlands Institute of Mental Health and Addiction (Trimbos Institute). It will be used to inform a trial starting in April in which shops in 10 municipalities will sell cannabis that is produced by licensed growers and subject to limits on contaminants.
The researchers tested 50 cannabis samples, both resin and weed, bought from randomly selected sellers. One in five of the samples contained “microbiological transgressions” such as Staphylococcus aureus bacteria or fungal residue, and pesticide traces were found in about one-third. One hashish sample contained almost six times the amount of lead (28.5mg/kg) that will be allowed in the cannabis sold during the trial.
“Yes, there are contaminants in the cannabis,” said Pieter Oomen, an analytical chemist and researcher on the Dutch drug market. “We found multiple pesticides, multiple instances of microbiological contamination and one sample that contains lead.”.
Although tourists flock to the Netherlands under the impression that cannabis is fully legal, since 1976 a tolerance policy has simply meant that the sale of hash and marijuana is permitted in regulated “coffee shops”. However, since growing more than five plants is illegal, shops must buy from illegal suppliers, raising concerns about encouraging criminality.
