Thanks to helmets, knee pads, and mouth guards, high school student-athletes are well equipped to endure the hazards of colliding with other players on the field. But what happens when the hazards come from the fields themselves?Four high school fields in separate locations in eastern Massachusetts – Concord-Carlisle, Lincoln-Sudbury, Boston, and Charlestown – recently tested positive for lead. These fields share something else in common: They are all constructed from synthetic turf.This is the same kind of substance used on the playing surface of Manning Field, but a representative of A-Turf, the Buffalo-based company that provided the turf for Lynn, had reassuring words.”To the best of my knowledge, there is no lead or lead chromate in that field,” said Webb Cook, vice president of sales of A-Turf.That’s comforting, but events within the past year should cause communities in this state and across the nation to use a little less haste in following trends like adopting artificial surfaces, which numerous Bay State cities and towns have done this decade. In several states, synthetic fields have generated concerns. Two older fields in New Jersey were closed out of fears of lead dust. Another field, in East Harlem, was found to contain amounts of lead that exceeded the EPA maximum standard for bare soil in children’s play areas. That field has been targeted for removal. And then, this week, the four Massachusetts sites tested positive, with the amounts of lead at Concord-Carlisle coming close to the maximum amount set by the EPA.Let’s be clear that there are good reasons for schools to adopt synthetic surfaces. Although I prefer the natural kind – especially after seeing the Peabody and Malden Catholic football teams play one straight out of “Leatherheads” at Coley Lee Swamp on Thanksgiving Day – there are undeniable benefits to turf.”It is very practical,” said Manning Field site director John Kasian of the Lynn Community Development Office. “Look at Lynn. There are four high schools. In the fall, there were basically games there every single day for over 90 days, Labor Day to Dec. 2.”There were four varsity football teams, eight varsity soccer, three youth football programs, and semipro football. If it was a grass field, you wouldn’t have played one-fourth of those games there.”Kasian called the maintenance costs of a grass field – seed, fertilizer, and repair – “very expensive.” He also cited safety benefits to turf.”We’ve seen a real reduction in injuries, especially in inclement weather,” he said. “Footing on the field is excellent, even in rainstorms.”Based on what Kasian and Cook said, it seems that the City of Lynn chose synthetic turf for commendable reasons and used a respectable company to produce it. But I still think the events of this past year, and this week, should serve as a cautionary tale. The four Massachusetts communities affected – Concord-Carlisle, Lincoln-Sudbury, Boston, and Charlestown – represent both rich and poor levels of income. Concord-Carlisle spent $3.8 million on its turf field, or $800,000 more than what the Boston Red Sox paid Kevin Youkilis last season, and it still tested positive for lead. Lynn proved to be both lucky and good.So I hope the city recognizes that while there may be outstanding reasons to stay up-to-date, it may want to follow the crowd at a prudent distance. And I also hope that when the time comes to replace the current surface of Manning Field, Lynn follows the example of many a Massachusetts motorist: Go for the unleaded variety.Rich Tenorio is an Item sports copy editor.