The Sicilian mafia was definitely involved in heroin as well, but in Europe I don't think they were as big as a source as the Chinese were in the 70's and 80's. Especially from the mid 70's to mid 80's with the Corleone-Palermo conflict, a lot of European traffickers did business with the Chinese instead. The USA is a different story.
sicilian mafia supplied the whole italian market that alone was very big and to a lesser extent other places like germany, switzerland, france and uk, so i don't think chineses were the biggest source in europe at that time, they supplied the benelux area mostly
Italy I'm sure and I'm not too sure about Germany or Switzerland - any of the big three Italian types of OC, Sicilian mafia, Ndrangheta, Camorra, have always had a major presence in Germany so it's plausible - but France or the UK is a different story.
In the south of France I'm sure the Sicilians did have quite a large share of the market down that neck of the woods. The northern French criminal milieu though was the one that had a large share of the retail market in Belgium as well and I know for a fact that their #1 source for heroin were the Chinese. Adding to that, in Paris for instance a lot of heroin was imported by Chinese as well as Vietnamese groups.
The heroin business in the UK in the 70's to early 80's was largely traced back to the Chinese as well. Due to the historical relations of the British with the Cantonese there was quite a Cantonese community living in London in particular those days. The Chinese imported a lot of heroin over there, which was distributed by local British firms. I haven't come across a source that states the Italians had a big involvement in UK's heroin trade in the 70's and 80's.
The Sicilians were the biggest source for heroin in Italy, the USA and few other pockets in Europe. Italy and the USA alone were HUGE markets.
Netherlands, northern France, Belgium, UK though? That was largely Chinese and were big smack markets as well.
