Some flip-flops, sandals, clogs, and rubber shoes recently tested in the Philippines have shown high concentrations of chemicals that are harmful to human health and the environment, an investigation by a Swedish environmental group revealed.

“We have found frightening concentrations of environmental toxins in the shoes that can spread to people and to the environment as the shoes become worn,” Swedish Society for Nature Conservation (SSNC) president Mikael Karlsson said.

The investigation on toxins in flip-flops, sandals, clogs, and rubber shoes was conducted in seven countries: the Philippines, Indonesia, India, Tanzania, Uganda, South Africa, and Sweden.

Based on the report “Chemicals Up-Close,” 17 of the 27 pairs of rubber shoes tested positive for phthalates, which are used as softening agents in polyvinyl chloride (PVC) plastic.

SSNC’s local partner, Ecological Waste Coalition (EcoWaste), said phthalates contains endocrine disruptors which are associated with developmental and reproductive disorders, including incomplete testicular growth and decreased fertility in men.

In particular, the di-ethylhexyl phthalate or DEHP is officially classified as a cause for impaired fertility and harm to the unborn child.

In the Philippines, three of the four samples were found to contain DEHP, with one sample containing DEHP and di-isodecyl phthalate or DiDP, and another sample containing DEHP and dibutyl phthalate or DBP.

EcoWaste bought a pair of Adorable Dora sandals and a pair of locally-manufactured slippers for children in one of the malls in Quezon City. They tested to contain 6.9 percent of DEHP and 4.7 percent of DiDP.

Meanwhile, Chaya slippers, a China-made flip-flop, bought from a supermarket in Quezon City tested with 8.6 percent of DEHP.

Likewise, a World Balance pair of slippers for men bought in a mall also in Quezon City registered the highest amount of DBP at 9.6 percent among the rubber shoe samples tested from the seven countries.

Calonzo said that while Beachwalk sandals bought in a mall in Quezon City tested negative for phthalates, it however tested positive for varying concentrations of heavy metals.

SSNC said the samples from the seven countries were also tested for a number of tin organic compounds and for heavy metals such as arsenic, cadmium, cobalt, chromium, copper, lead, mercury, manganese, nickel and zinc.

It said that all the samples from the Philippines and elsewhere tested positive for varying concentrations of one or more of the 10 heavy metals analyzed, many of which are harmful to the endocrine, nervous, and reproductive systems, are carcinogenic and allergenic, and highly toxic to aquatic organisms.

It noted that the highest level of copper content was found in one shoe sample from the Philippines, while another sample (also from the Philippines) tested high for nickel content.